Critical review of controversial issues in the management of advanced pediatric liver tumors

Hepatocellular carcinoma (HCC) and hepatoblastoma (HB) are the most common primary tumors of liver in children. The management of patients with locally advanced, unresectable disease or those with extra‐hepatic distant metastases provides substantial challenges to pediatric oncologists, hepatologists, and surgeons. Herein, we critically debate the two sides of three specific controversies: (1) the role of chemotherapy in the treatment of advanced pediatric HCC; (2) the indications for liver transplantation in children with HCC, specifically, the appropriateness of using adult Milan criteria; and (3) the role of liver trasplantation in children with unresectable HB that present with metastatic disease. Pediatr Blood Cancer 2011;56:1013–1018. © 2010 Wiley‐Liss, Inc.     

Neurologically intact children with an isolated skull fracture may be safely discharged after brief observation

Purpose

The management of children presenting with an isolated skull fracture (ISF) posttrauma is highly variable. We sought to estimate the risk of neurologic deterioration in children with a Glasgow coma score (GCS) 15 and ISF to reduce unnecessary hospital admissions.

Methods

A retrospective review at a level I pediatric trauma referral center was conducted for patients with ISF on head computed tomography from 2003 to 2008. Patients were excluded for injury greater than 24 hours prior, GCS less than 15, intracranial pathology, significant fracture depression, or complex fractures involving facial bones or skull base.

Results

A total of 235 patients were identified with an ISF. The median age was 11 months, with falls accounting for 87% of the injuries. One hundred seventy-seven patients were admitted, and 58 patients were discharged from the emergency department after a period of observation (median, 3.3 hours). Median length of stay for those admitted to the hospital was 18.2 hours. One patient developed vomiting following overnight observation and a repeat computed tomography scan demonstrated a small extra-axial hematoma that required no intervention. The mean total costs for patients discharged from the emergency department were $291 vs $1447 for those admitted for observation (P < .001).

Conclusion

Patients with a presenting GCS of 15 and an ISF can be safely discharged from the emergency department after a short period of observation if they are asymptomatic and have a reliable social environment. This could result in significant savings by eliminating inpatient costs.     

Contribution of Autolysin and Sortase A during Enterococcus faecalis DNA-Dependent Biofilm Development

Biofilm production is a major attribute of Enterococcus faecalis clinical isolates. Although some factors, such as sortases, autolysin, and extracellular DNA (eDNA), have been associated with E. faecalis biofilm production, the mechanisms underlying the contributions of these factors to this process have not been completely elucidated yet. In this study we define important roles for the major E. faecalis autolysin (Atn), eDNA, and sortase A (SrtA) during the developmental stages of biofilm formation under static and hydrodynamic conditions. Deletion of srtA affects the attachment stage and results in a deficiency in biofilm production. Atn-deficient mutants are delayed in biofilm development due to defects in primary adherence and DNA release, which we show to be particularly important during the accumulative phase for maturation and architectural stability of biofilms. Confocal laser scanning and freeze-dry electron microscopy of biofilms grown under hydrodynamic conditions revealed that E. faecalis produces a DNase I-sensitive fibrous network, which is important for biofilm stability and is absent in atn-deficient mutant biofilms. This study establishes the stage-specific requirements for SrtA and Atn and demonstrates a role for Atn in the pathway leading to DNA release during biofilm development in E. faecalis.Biofilms are bacterial communities encased within an extracellular matrix composed of carbohydrates, proteins, and nucleic acids (10). They are an ideal environment for exchange of genetic materials, such as genes encoding virulence factors and antibiotic resistance determinants, among bacteria within a community (61, 76), while allowing the flow of water and nutrients, as well as ions and various small molecules, to bacteria within the community (8) and providing a protective shield against antibiotics, antimicrobial substances, and phagocytosis (33, 80). Development of a biofilm is a complex multistage process. It is initiated by primary adhesion of the bacteria to a substratum, which is followed by the formation of microcolonies and production of an exopolysaccharide matrix, and it finally culminates with the formation of a three-dimensional (3D) multicellular mature structure (48). Bacterial biofilms are important medically because they have been associated with the pathogenesis of chronic and device-related persistent infections, such as cystic fibrosis, urinary tract infections, and endocarditis (11).Enterococcus faecalis is a gram-positive bacterium that is a commensal of the gastrointestinal tract of healthy individuals. However, it is also an important opportunistic pathogen that is responsible for a wide variety of nosocomial infections, including endocarditis, urinary tract infections, and bacteremia (14, 17, 23, 44). E. faecalis accounts for approximately 65 to 80% of all enterococcal nosocomial infections (16). The ability of E. faecalis to adhere to and develop biofilms on medical devices, such as intravascular and urinary catheters (25, 26, 36, 37, 72), is thought to contribute to its pathogenesis. The increasing resistance of enterococci to most antibiotics, including vancomycin and linezolid (62, 63), especially in biofilms (41, 59, 78), makes treatment of enterococcal infections very difficult.Several putative virulence factors and cellular processes have been implicated in the development of biofilms in E. faecalis (36); however, very little is known about their regulation and molecular contribution to this process. One of these factors, the quorum-sensing two-component transduction signaling system encoded by the fsr locus, an important virulence factor in the pathogenesis of E. faecalis, was shown to control biofilm formation via positive regulation of the extracellular zinc metalloprotease GelE (gelatinase) and the serine protease SprE (19, 38, 54-56). These proteases were recently shown to contribute to enterococcal biofilm formation via regulation of cellular autolysis and fratricidal DNA release (70, 71). In these studies, Thomas et al. also provided the first evidence for a critical role of extracellular DNA (eDNA) in E. faecalis biofilms. eDNA is an important component of the extracellular matrix of bacterial biofilms, providing structural stability to the biofilm and protection against antimicrobials (1, 2, 42, 43, 47, 51, 52, 58, 60, 65, 77). However, the function of this macromolecule throughout the establishment and growth of E. faecalis biofilms is not well characterized.Bacterial murein hydrolases, also referred to as autolysins, have been implicated in biofilm production (58, 60). They are important contributors to cell wall growth and regulation, as well as several lytic processes (75). Two autolysins of Staphylococcus epidermidis, AtlE and Aae, are adhesins that contribute to bacterial attachment to polymeric surfaces and biofilm formation via release of eDNA (20, 21, 58). E. faecalis produces several autolysins, which were recently identified and characterized (12, 24, 35). The major E. faecalis autolysin, Atn (also known as AtlA), is an N-acetylglucosaminidase important for daughter cell separation during cellular division (12). Disruption of atn in E. faecalis resulted in increased chaining, a defect in primary attachment, and decreased biofilm production (3, 24, 31, 37, 57, 70). Recently, Thomas et al. (70) provided evidence that inactivation of this autolysin results in a decrease in DNA release similar to that of gelatinase-deficient mutants. Furthermore, they showed that GelE and SprE can differentially cleave Atn in vitro, and this processing may underlie the mechanism of cell death and DNA release in E. faecalis during biofilm formation.Due to their role in cell wall regulation, autolysins may affect the localization of cell wall-anchored proteins, which can be important for adhesion during biofilm development. In most gram-positive bacteria, membrane-anchored transpeptidase enzymes known as sortases are responsible for covalently anchoring cell surface proteins bearing an LPXTG motif to the cell wall (34). Thus far, only class A and class C sortases have been implicated in biofilm formation by and the virulence of E. faecalis (28). Deletion of srtC, also known as bps, which encodes sortase C (SrtC), resulted in a significant reduction in biofilm production and attenuation of virulence in a mouse model of urinary tract infection, unlike deletion of srtA, which had minor effects under similar conditions (28). However, given the ubiquitous nature of sortases and the limited knowledge of the activity and substrates of the sole SrtA characterized in E. faecalis, it is plausible that this enzyme may play an important role in E. faecalis physiology and/or pathogenesis under different conditions. For instance, SrtA was shown to anchor the plasmid-encoded protein Asc10, which is involved in the pheromone-induced aggregation of E. faecalis (30).In this study, we determined the contributions of E. faecalis SrtA, Atn, and eDNA to the major developmental stages leading to bacterial attachment and the establishment of mature biofilms under static and hydrodynamic conditions. E. faecalis biofilm development occurs in two key steps, which involve primary attachment followed by an accumulative stage. We demonstrate that both SrtA and Atn are required for efficient primary adherence to the substratum, while Atn and eDNA promote high levels of biofilm buildup and architectural stability during the accumulative stage. In the presence of hydrodynamic shear forces, the eDNA in E. faecalis biofilms is associated with a thick and long DNase-sensitive fibrous network that is associated with lysed cells present in the biofilm in some instances, as visualized by freeze-dry microscopy, transmission electron microscopy, and confocal laser scanning microscopy (CLSM). In contrast, atn-deficient mutants are unable to produce visible DNase-sensitive extracellular fibers under these conditions, although the biofilm remains partially sensitive to DNase treatment. These findings argue for a role for Atn in the temporal regulation of DNA release. Collectively, our data underscore the importance of SrtA, the major E. faecalis autolysin, and Atn-mediated DNA release at different stages during the establishment of E. faecalis biofilms. As a critical component of the extracellular matrix of E. faecalis biofilms, eDNA may serve as a novel target for the dissolution of these structures.     

Routine use of a SILASTIC spring-loaded silo for infants with gastroschisis: a multicenter randomized controlled trial

Background

Retrospective studies have suggested that routine use of a preformed silo for infants with gastroschisis may be associated with improved outcomes. We performed a prospective multicenter randomized controlled trial to test this hypothesis.

Methods

Eligible infants were randomized to (1) routine bedside placement of a preformed Silastic spring-loaded silo, with gradual reduction and elective abdominal wall closure, or (2) primary closure.

Results

There were 27 infants in each group. There was no significant difference between groups with respect to age, weight, sex, Apgar scores, prenatal diagnosis, or mode of delivery. The total number of days on the ventilator was lower in the spring-loaded silo group, although it did not reach statistical significance (3.2 vs 5.3, P = .07). There was no significant difference between groups with respect to length of time on total parenteral nutrition, length of stay, or incidence of sepsis and necrotizing enterocolitis.

Conclusion

Routine use of a preformed silo was associated with similar outcomes to primary closure for infants with gastroschisis but with a strong trend toward fewer days on the ventilator. Use of a preformed silo has the advantage of permitting definitive abdominal wall closure in a more elective setting.     

Rapid migration of thymic emigrants to the colonic mucosa in ulcerative colitis patients

Inflammatory bowel disease (IBD) is associated with imbalances of the local intestinal immune responses, with dysregulated CD4⁺ T cells contributing to the chronic inflammation. Having demonstrated altered T cell maturation in the thymus in two different mouse models of colitis, we set out to investigate whether abnormalities in T cell maturation is present in patients with ulcerative colitis (UC) or Crohn's disease (CD). Specimens were obtained from peripheral blood (CD; n = 14, UC; n = 22), colon and small intestinal specimens (CD; n = 6, UC; n = 13). As controls, peripheral blood specimens were obtained from healthy volunteers, patients with adenocarcinomas (n = 18) and colonic specimens from patients with adenocarcinomas (n = 14). Recent thymic emigrants were estimated by analysis of the normalized ratio of T cell receptor excision circles (TRECs) by real‐time polymerase chain reaction (PCR). The frequency of naive‐ and proliferating T lymphocytes and markers of extrathymic T cell maturation in the mucosa was analyzed by flow cytometry and real time‐PCR. TREC levels in peripheral blood T lymphocytes were similar between IBD patients and controls. In contrast, UC patients demonstrated significantly increased levels of TRECs both in intraepithelial and lamina propria lymphocytes from the colonic mucosa compared to patients with adenocarcinomas and CD. However, markers for extrathymic T cell maturation in the mucosa were not different between controls and IBD patients. The increased TREC levels in mucosal but not peripheral blood lymphocytes in UC patients in the absence of increased extrathymic maturation in situ in the mucosa together demonstrate that recent thymic emigrants are recruited rapidly to the inflamed mucosa of these patients.     

Evidence for a relation between the viral load and genotype and hepatitis C virus-specific T cell responses

BACKGROUND/AIMS: The reason why patients with hepatitis C virus (HCV) genotype non-1 infection respond better to antiviral therapy than patients with genotype 1 infection is not known. The aim of this study is to explore the relation between the viral genotype, viral load, and the endogenous T cell response. METHODS: The viral genotype, the viral load, and the endogenous proliferative T cell response to the non-structural 3 protein (NS3) was analysed using serum and peripheral blood mononuclear cells from 103 patients with chronic HCV infection. RESULTS: Among 71 nontreated patients a T cell response was more common among those infected by genotype 3, as compared to those infected with genotype 1 (P<0.05). Among 32 patients undergoing antiviral therapy, presence of a T cell response was more common in genotype non-1 infected patients than in those infected by genotype 1 (P<0.01). Presence of a T cell response was related to a more rapid viral clearance (P<0,05), a negative HCV RNA test at week 12 (P<0.05), and a shorter viral half-life (P<0.05). CONCLUSIONS: The presence of an NS3-specific T cell response is related to the viral genotype and to a more rapid clearance of HCV RNA during antiviral therapy.     

Diagnostic accuracy of continuous wave Doppler echocardiography in severe aortic stenosis in the elderly

Forty-four male patients (mean age 63.6 years) with aortic stenosis (AS) were evaluated by conventional hemodynamic methods and continuous wave (CW) Doppler echocardiography. The relationship between Doppler mean gradients and direct mean pressure gradients in all patients was significant, with an r value of 0.88. Sixteen of 17 patients with a mean Doppler gradient greater than or equal to 40 mmHg had severe AS (AVA less than or equal to 1.0 cm2). Twenty-seven patients had a Doppler gradient less than 40 mmHg, and 8 of these patients had severe AS (AVA less than or equal to 1.0 cm2). The sensitivity and specificity of a Doppler gradient greater than or equal to 40 mmHg in detecting severe AS were, therefore, 67% and 95%, respectively. Thirty-three percent (8/24) of patients with severe AS and low Doppler gradients (less than 40 mmHg) had evidence of poor left ventricular function, evidenced by a lower cardiac output, a higher heart rate and an abnormal PEP/LVET ratio compared to the other patients. Thus, the presence of a low stroke volume less than or equal to 60 ml/beat and PEP/LVET x HR greater than 26 is of value in identifying patients where the Doppler is likely to significantly underestimate the degree of aortic stenosis.     

Effects of coronary artery bypass grafting on resting and exercise hemodynamics in patients with stable angina pectoris: a prospective, randomized study.

In this prospective randomized study, resting and exercise hemodynamics were determined in the nonmedicated state before ("entry") and 1 year after coronary bypass surgery in 38 patients, and at entry and 1 year in 40 patients treated medically. The surgical group showed a significant decrease in mean pulmonary arterial wedge pressure during exercise (entry 23.5 +/- 6.1 [standard error of the mean] mm Hg, 1 year 18.9 +/- 1.0, P less than 0.02); an increase in cardiac index during exercise (entry 4.3 +/- 0.1 liter/min per m2, 1 year 4.6 +/- 0.1, P less than 0.05); an increase in resting mean arterial pressure (entry 94.5 +/- 2.2 mm Hg, 1 year 100.2 +/- 2.2, P less than 0.02); and an increase in resting heart rate (entry 68.5 +/- 1.9 beats/min, 1 year: 76.0 +/- 2.0, P less than 0.01). Maximal treadmill exercise performance also improved significantly in the surgical group of patients (entry 285 +/- 24 seconds, 1 year 382 +/- 24, P less than 0.002). There were no significant changes in these variables in the medically treated "control" group. The improvement in pulmonary arterial wedge pressure during exercise and in maximal treadmill exercise time in the surgical group as a whole was due to striking improvement in these variables in a subgroup of 16 surgical patients who had a more than 10 mm Hg increase in pulmonary arterial wedge pressure during exercise in their entry study. In this subgoup, considered to contain those patients with marked "ischemicdysfunction," pulmonary arterial wedge pressure during exercise fell from 31.4 +/- 1.5 mm Hg (entry) to 19.l +/- 1.8 (1 year) (P less than 0.0001) and treadmill time increased from 217 +/- 24 seconds (entry) to 357 +/- 37 (1 year) (P less than 0.001). Thus, hemodynamic evidence of ischemic left ventricular dysfunction during stress may identify those patients who will show objective improvement in ventricular performance after bypass graft surgery.     

Anomalous origin of the left coronary artery from the pulmonary artery. Surgical treatment by ostial occlusion through pulmonary arteriotomy

Two cases of anomalous origin of the left coronary artery from the pulmonary artery are reported in asymptomatic patients 15 and 27 years of age, bringing to 30 the total number of cases of this anomaly reported in the postinfantile age group. ECG exercise tests demonstrated marked ischemic changes in both patients, but angina or abnormal shortness of breath did not develop in either patient during or after exercise. The anomalous vessel was interrupted by closure of its ostium through a pulmonary arteriotomy during cardiopulmonary bypass, a procedure felt to offer a distinct technical advantage in the surgical treatment of this condition. Following ligation of the anomalous vessel, ECG exercise tests no longer showed definitive evidence of myocardial ischemia. This is interpreted as evidence that ligation should reduce the incidence of exercise-induced sudden deaths in this anomaly.