Asynchronous bilateral ovarian torsion

BACKGROUND

Pediatric ovarian torsion (OT) is a serious condition, especially in cases of asynchronous bilateral ovarian torsion (ABOT). The authors sought to evaluate the predisposing factors for ABOT and to evaluate the most appropriate treatment for ovarian torsion.

METHODS

The authors retrospectively reviewed the charts of patients with ovarian torsion between 1980 and 2002. Data collected included age at presentation, type and duration of symptoms, ultrasound scan findings, interval to surgery, procedures, pathology report, and follow-up.

RESULTS

Seventy-six patients had adnexal torsion confirmed at surgery, 4 of whom had ABOT. The mean age was 10 years. The mean duration of complaints before hospitalisation and interval to surgery were 56 and 33 hours, respectively. Thirty-five patients had simple tubo-ovarian torsion (46%), including all the patients with ABOT (11.4%), and 41 had an ovarian pathology (54%). All patients with ABOT underwent salpingo-oophorectomy at the first episode. They presented earlier for the second episode and had a shorter interval to surgery where detorsion with oophoropexy was performed. Follow-up ultrasound scan showed perfusion and follicles in the remaining ovary.

CONCLUSIONS

The diagnosis of ovarian torsion often is delayed, especially when a solid tumor is suspected. Conservative management should be strongly considered when there is no underlying ovarian pathology. Furthermore, oophoropexy of the ipsilateral and contralateral ovary should be considered to prevent a potentially devastating recurrence.

Abdominal injuries associated with thoraco-lumbar fractures after motor vehicle collision

PURPOSE

The goal of the current study was to evaluate the risk of intraabdominal injury in children who sustained spinal fractures in a motor vehicle collision (MVC).

METHODS

Between 1980 and 1999, 48 patients, 24 girls and 24 boys, with a mean age of 12.8 years (range, 4 to 17) were reviewed. Twenty-nine were rear seat passengers, 12 front seat, and 7 unknown. Fifty-eight percent wore a seat belt. Thirty fractures involved the lumbar spine, 12 the thoracic, and 6 combined. Computed tomography (CT) scan, abdominal ultrasound, and peritoneal lavage were used to screen for abdominal injuries.

RESULTS

Twenty-two of 48 patients had an intraabdominal injury. Eighteen (38%) required an early (<24 hours; n = 12) or delayed (n = 6) therapeutic laparotomy. Fourteen patients were rear seat passengers, 15 wore a seat belt, and 13 had an abdominal wall ecchymoses (AWE). They were 17 lumbar fractures (13 Chance) and one thoracic. The most common findings at laparotomy were hollow viscus injury (n = 12), mesenteric tear (n = 9), and solid organ injury (n = 8). Seventy-two percent of patients presenting with a lumbar fracture and AWE needed a therapeutic laparotomy. The overall survival rate was 98% with only 1 death. The mean hospital stay was 22.4 days. In this study, 38% of patients presenting with a spinal fracture required laparotomy, 68% of whom had simultaneous lumbar fracture and AWE.

CONCLUSION

In light of these results, the authors propose that laparoscopy or laparotomy should be strongly considered in patients sustaining lumbar fracture and AWE after MVC. J Pediatr Surg 36:760-762.

Autophagy is associated with chemoresistance in neuroblastoma

Background

Neuroblastoma (NB) is a frequent pediatric tumor characterized by a poor prognosis where a majority of tumors progress despite intensive multimodality treatments. Autophagy, a self-degradative process in cells, could be induced by chemotherapy and be associated with chemoresistance. The aim of this study was to determine whether: 1) autophagy is present in NB, 2) chemotherapy modified its levels, and 3) its inhibition decreased chemoresistance.

Methods

Immunohistochemical stainings were performed on samples from 184 NB patients in order to verify the expression of LC3B, a specific marker for autophagy, and Beclin 1, a positive regulator of autophagy. In addition, we performed an in vitro study with six NB cell lines and six drugs (vincristine, doxorubicin, cisplatin temozolomide, LY294002 and syrolimus). Inhibition of autophagy was performed using ATG5 knockdown cells or hydroxychloroquine (HCQ). Cell survival was measured using the MTT cell proliferation assay. Autophagy was detected by monodansylcadaverine, confocal microscopy and Western blot. In vivo study with tumor xenografts in NSG mice was performed.

Results

Our results have indicated that autophagy was present at low levels in NB and was not a prognostic factor, while Beclin 1 was highly expressed in children with poor NB prognosis. However, autophagy levels increased after chemotherapy in vitro and in vivo. Tumor progression was significantly decreased in mice treated with a combination of HCQ and vincristine.

Conclusions

Taken together, autophagy is present in NB, induced by chemotherapy and associated with chemoresistance, which is significantly reduced by its inhibition. Therefore, targeting autophagy represents a very attractive approach to develop new therapeutic strategies in NB.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2906-9) contains supplementary material, which is available to authorized users.

Expression of Disialoganglioside (GD2) in Neuroblastic Tumors: A Prognostic Value for Patients Treated With Anti-GD2 Immunotherapy

Neuroblastoma, a malignant neoplasm of the sympathetic nervous system, is one of the most aggressive pediatric cancers. Patients with stage IV high-risk neuroblastoma receive an intensive multimodal therapy ending with an immunotherapy based on a chimeric monoclonal antibody ch14.18. Although the use of ch14.18 monoclonal antibody has significantly increased the survival rate of high-risk neuroblastoma patients, about 33% of these patients still relapse and die from their disease. Ch14.18 targets the disialoganglioside, GD2, expressed on neuroblastic tumor (NT) cells. To better understand the causes of tumor relapse following ch14.18 immunotherapy, we have analyzed the expression of GD2 in 152 tumor samples from patients with NTs using immunohistochemical stainings. We observed GD2 expression in 146 of 152 samples (96%); however, the proportion of GD2-positive cells varied among samples. Interestingly, low percentage of GD2-positive cells before immunotherapy was associated with relapse in patients receiving ch14.18 immunotherapy. In addition, we demonstrated in vitro that the sensitivity of neuroblastoma cell lines to natural killer-mediated lysis was dependent on the proportion of GD2-positive cells, in the presence of ch14.18 antibody. In conclusion, our results indicate that the proportion of tumor cells expressing GD2 in NTs should be taken in consideration, as a prognostic marker, for high-risk neuroblastoma patients receiving anti-GD2 immunotherapy.

Spontaneous pneumomediastinum: are we overinvestigating?

BACKGROUND

Spontaneous pneumomediastinum (SPM) is uncommon in pediatrics. Because of the growing concern about the risks of radiation in children, the authors analyzed whether an extensive radiologic workup influences management and outcome.

METHODS

In a retrospective study from 1991 to 2003, 53 patients were diagnosed with SPM. Charts were reviewed for demographics, predisposing factors, presentation, investigation, and evolution. Pneumomediastinum occurring in the neonatal period or related to either pneumothorax, barotrauma, or trauma were excluded.

RESULTS

Of 53 cases, 26 (49%) were bronchospasm related, 11 (21%) had respiratory tract infections, and 8 (15%) were idiopathic. Four (7.5%) were caused by inhaled foreign bodies while other causes accounted for the remaining 7.5%. No esophageal perforations were identified. Presentations included dyspnea (64%), subcutaneous emphysema (60%), cough (45%), cervical or chest pain (42%), and Hamman's sign (19%). Postero-anterior chest x-rays (CXR) were diagnostic in all cases except one. Mean number of CXR per hospitalization was 3. Only 3 patients subsequently had pneumothorax, and none required pleural drainage. Of the 8 patients with idiopathic SPM, 5 underwent a barium swallow, and 2 had a chest CT scan; results of all were normal.

CONCLUSIONS

More than 70% of SPMs were related to bronchospasm or respiratory tract infections. Idiopathic SPMs deserve more attention because of the concern about esophageal perforation, although most investigations will be negative. SPM usually is a self-limited condition, and prognosis is related to the underlying disorder. Consequently, with clinical improvement, aggressive investigation and follow-up x-ray rarely is warranted.

Outcomes of transplantation in children with primary hepatic malignancy

HBL and HCC are the most common hepatic malignancies in children. The role of OLT in children with HCC is still a matter of debate. The aim of this study was to review our experience of OLT for HCC. Medical records of patients (<18 yr) who underwent OLT for HCC were reviewed and compared to children who underwent OLT for HBL and for indications other than malignancy. There were 25 patients: HCC (10 cases) and HBL (15 cases). The actuarial patient survival for HCC at one and five yr was 100% and 83.3%, for the HBL group the survival was 86.7% at both one and five yr, and for indications (n=377) other than malignancy the patient survival for pediatric OLT at our center was 87.7% and 84.7% at one and five yr, respectively. The actuarial recurrence free survival at five yr was 83.3% for HCC and 66.8% for HBL. In conclusion, OLT is a good therapeutic modality for children with HCC and HBL.

Melanoma in children and the use of sentinel lymph node biopsy

BACKGROUND

The rarity of pediatric melanoma prompted our review of sentinel lymph node biopsy (SLNB) and associated prognosis.

METHODS

A chart review from 1989 to 2004 revealed 12 cases of cutaneous melanoma. Variables analyzed included demographics, site, histology, tumor characteristics, nodal status, and distant metastasis (TMN status), SLNB and/or therapeutic lymph node dissection (TLND), adjuvant treatment, disease-free survival, and overall survival.

RESULTS

Mean age at diagnosis was 8.5 years with 7 of 12 patients younger than 10 years (range, 0.3-17.9 years). Site distribution was the extremity (7), trunk (4), and head and neck (1). All patients had wide local excision and primary closure or skin graft. Breslow's thickness averaged 3.5 mm (range, 0.8-6 mm). Only patients diagnosed after 2000 with melanomas thicker than 1 mm were offered SLNB (extremity = 2, trunk = 1, head and neck = 1). Two patients had positive sentinel lymph node: one received TLND and interferon and one is followed closely (unclear pathology). Disease-free survival and overall survival by stage were stage I (n = 2, 3.9 years, 100%), stage II (n = 6, 7.7 years, 83%), stage III (n = 4, 2.6 years, 75%), and stage IV (n = 0). A stage II patient with negative SLNB, adjuvant chemotherapy, and interferon died 26 months after diagnosis, and a stage III patient with clinically and pathologically positive nodes after TLND died 15 months after diagnosis.

CONCLUSION

Although a negative SLNB does not guarantee a favorable prognosis, its increasing use will further define its role in pediatric melanoma.

Optimizing outcomes for neonatal ARPKD

A retrospective analysis was conducted on 10 consecutive cases of neonatal ARPKD, 9 of whom received kidney transplants (KT). All were diagnosed antenatally (n = 6) or at birth. In the first month of life 70% required ventilatory support. Pre-emptive bilateral nephrectomy and peritoneal dialysis (PD) catheter placement were performed in 9 at a mean age of 7.8 +/- 11.9 months. The indications for nephrectomy were massive kidneys, resulting in suboptimal nutrition and respiratory compromise. All patients received assisted enteral nutrition, with significant increase in mean tolerated feeds following nephrectomy (p < 0.05), with increase in mean normalized weight and height (0.92 and 1.2 delta SDS respectively), by one year post-transplantation. KT was performed at a mean age and weight of 2.5 +/- 1.4 years and 13.3 +/- 6.1 kg. The mean creatinine clearance at one year post-KT was 91.3 +/- 38.1 mls/min/1.73 m(2), with a projected graft life expectancy of 18.4 years. Patient survival was 89% and death censored graft survival was 100%, at a mean follow-up of 6.1 +/- 4.5 years post-transplant. Six patients demonstrated evidence of hepatic fibrosis, one of which required liver transplantation. In patients with massive kidneys from ARPKD, pre-emptive bilateral nephrectomy, supportive PD and early aggressive nutrition, can minimize early infant mortality, so that subsequent KT can be performed with excellent patient and graft survival.

Population pharmacokinetics and Bayesian estimation of tacrolimus exposure in paediatric liver transplant recipients

AIMS

The objectives of this study were to develop a population pharmacokinetic (PopPK) model for tacrolimus in paediatric liver transplant patients and determine optimal sampling strategies to estimate tacrolimus exposure accurately.

METHODS

Twelve hour intensive pharmacokinetic profiles from 30 patients (age 0.4-18.4 years) receiving tacrolimus orally were analysed. The PopPK model explored the following covariates: weight, age, sex, type of transplant, age of liver donor, liver function tests, albumin, haematocrit, drug interactions, drug formulation and time post-transplantation. Optimal sampling strategies were developed and validated with jackknife.

RESULTS

A two-compartment model with first-order absorption and elimination and lag time described the data. Weight was included on all pharmacokinetic parameters. Typical apparent clearance and central volume of distribution were 12.1 l h(-1) and 31.3 l, respectively. The PopPK approach led to the development of optimal sampling strategies, which allowed estimation of tacrolimus pharmacokinetics and area under the concentration–time curve (AUC) on the basis of practical sampling schedules (three or four sampling times within 4 h) with clinically acceptable prediction error limit. The mean bias and precision of the Bayesian vs. reference (trapezoidal) AUCs ranged from -2.8 to -1.9% and from 7.4 to 12.5%, respectively.

CONCLUSIONS

The PopPK of tacrolimus and empirical Bayesian estimates represent an accurate and convenient method to predict tacrolimus AUC(0-12) in paediatric liver transplant recipients, despite high between-subject variability in pharmacokinetics and patient demographics. The developed optimal sampling strategies will allow the undertaking of prospective trials to define the tacrolimus AUC-based therapeutic window and dosing guidelines in this population.

Unilobar congenital pulmonary lymphangiectasis mimicking congenital lobar emphysema: an underestimated presentation?

BACKGROUND

Congenital lobar emphysema (CLE) is characterized by unilobar alveolar distension secondary to bronchomalacia or absent cartilage. In contrast, congenital pulmonary lymphangiectasis (CPL) is defined as distended lymphatics in the bronchovascular bundle, in the interlobular septa, and in the subpleural space. Little information is available regarding the radiologic presentation of CLE as it correlates with histological diagnosis.

METHODS

In a retrospective chart review from 1995 to 2002, 8 patients (5 boys and 3 girls) with clinical and radiologic diagnosis of CLE were reviewed.

RESULTS

The mean age at diagnosis was 26 months (range, 11 days to 10 years). All but one had classic respiratory symptoms of CLE. Six of 7 chest computed tomography (CT), scans were suggestive of CLE. Of 8 patients, 3 were treated without pulmonary resection with resolution of symptoms. Five patients underwent lobectomies, and histology results showed CPL in 3. CT failed to identify CPL in all cases.

CONCLUSIONS

Diagnosis of CLE is not as straightforward as the literature suggests. Even retrospectively, radiologic distinction between CLE and CPL could not be achieved by an experienced pediatric radiologist. CPL, thus, mimics CLE clinically and radiologically and, therefore, should be considered in the differential radiologic diagnosis of CLE.

Activation of the phosphatidylinositol 3'-kinase/AKT pathway in neuroblastoma and its regulation by thioredoxin 1

Neuroblastoma is a malignant pediatric tumor with poor survival. The phosphatidylinositol 3'-kinase/AKT pathway is a crucial regulator of cellular processes including apoptosis. Thioredoxin 1, an inhibitor of tumor-suppressor phosphatase and tensin homolog, is overexpressed in many tumors. The objective of this study was to explore phosphatidylinositol 3'-kinase/AKT pathway activation and regulation by thioredoxin 1 to identify potential therapeutic targets. Immunohistochemical analysis was done on tissue microarrays from tumor samples of 101 patients, using antibodies against phosphatidylinositol 3'-kinase, AKT, activated AKT, phosphatase and tensin homolog, phosphorylated phosphatase and tensin homolog, thioredoxin 1, epidermal growth factor receptor, vascular endothelial growth factor and receptors (vascular endothelial growth factor 1 and vascular endothelial growth receptor 2), platelet-derived growth factor receptors, insulin-like growth factor 1 receptor, neurotrophic tyrosine kinase receptor type 2, phosphorylated 70-kd S6 protein kinase, 4E-binding protein 1, and phosphorylated mammalian target of rapamycin. Using 3 neuroblastoma cell lines, we investigated cell viability with AKT-specific inhibitors (LY294002, RAD001) and thioredoxin 1 alone or in combination. We found activated AKT and AKT expressed in 97% and 98%, respectively, of neuroblastomas, despite a high expression of phosphatase and tensin homolog correlated with thioredoxin 1. AKT expression was greater in metastatic than primary tumors. Insulin-like growth factor 1 receptor, tyrosine kinase receptor type 2, vascular endothelial growth receptor 1, and downstream phosphorylated 70-kd S6 protein kinase were correlated with activated AKT. LY294002 and RAD001 significantly reduced AKT activity and cell viability and induced a G(1) cell cycle arrest. Thioredoxin 1 decreased cytotoxicity of AKT inhibitors and doxorubicin, up-regulated AKT activation, and induced cell growth. Thus, vascular endothelial growth receptor 1, tyrosine kinase receptor type 2, insulin-like growth factor 1 receptor, and thioredoxin 1 emerged as preferentially committed to phosphatidylinositol 3'-kinase/AKT pathway activation as observed in neuroblastoma. Thioredoxin 1 is a potential target for therapeutic intervention.

Topical mitomycin-C for the treatment of anal stricture

BACKGROUND

Anal stricture is a well-known and feared consequence of anorectal surgery. Daily dilatations are often prescribed in the immediate postoperative period to avoid stricture of the anus. Nonetheless, stricture may still occur and, particularly in older children, may require multiple dilatations under anesthesia. Topical mitomycin-C has been found to be effective in the treatment of strictures at various anatomical locations. In this article, we review our experience with topical mitomycin-C as an adjunct to anal dilatation for children with anal stricture.

MATERIALS AND METHODS

Cases of children with anal stricture who were treated with a single application of topical mitomycin-C as an adjunct to anal dilatation between 2000 and 2008 were analyzed retrospectively. Anal diameter was measured with Hegar dilators. Cottonoid swabs soaked in mitomycin-C were placed on the anal mucosa for 5 minutes after dilatation. Treatment success was defined by sustained improvement in anal size, decrease in symptoms, parental satisfaction, and need for additional intervention.

RESULTS

Ten children with anal stricture who underwent anal dilatation with application of topical mitomycin-C were identified. All children presented with severe constipation. Average increase in anal size after dilatation under sedation was 5.7 mm (+/-3.2 mm). Average improvement in anal diameter on first clinic visit after mitomycin-C application was 3.7 mm. On follow-up, only 1 child required repeated intervention for stricture after treatment with mitomycin-C. No complications were associated with the use of mitomycin-C.

CONCLUSIONS

All children treated with mitomycin-C showed early improvement in their anal size after dilatation under sedation. A single application of topical mitomycin-C allowed them to retain an increased anal diameter over time and avoid additional dilatations. Furthermore, the application of mitomycin-C in our population was straightforward and safe. Therefore, we advocate its use as an adjunct to anal dilatation under sedation in the treatment of severe anal stricture.

GX15-070 (Obatoclax), a Bcl-2 family proteins inhibitor engenders apoptosis and pro-survival autophagy and increases Chemosensitivity in neuroblastoma

Background

Neuroblastoma (NB) is a frequent pediatric tumor associated with poor prognosis. The disregulation of Bcl-2, an anti-apoptotic protein, is crucial for the tumoral development and chemoresistance. Autophagy is also implicated in tumor cell survival and chemoresistance. The aim of our study was to demonstrate therapeutic efficiency of GX 15–070, a pan-Bcl-2 family inhibitor, used alone and in combination with conventional drugs or with hydroxychloroquine (HCQ), an autophagy inhibitor.

Methods

Five neuroblastoma cell lines were tested for the cytotoxic activity of GX 15–070 alone or in combination with cisplatin, doxorubicin, HCQ or Z-VAD-FMK a broad-spectrum caspase inhibitor. Apoptosis and autophagy levels were studied by western-blot and FACS. Orthotopic injections were performed on NOD/LtSz-scid/IL-2Rgamma null mice that were treated with either GX 15–070 alone or in combination with HCQ.

Results

Synergistic cytotoxicity was observed for the drug combination in all of the 5 neuroblastoma cell lines tested, including MYCN amplified lines and in cancer stem cells. GX 15–070 significantly increased apoptosis and autophagy in neuroblastoma cells as evidenced by increased levels of the autophagy marker, LC3-II. Inhibition of autophagy by HCQ, further increased the cytotoxicity of this combinatorial treatment, suggesting that autophagy induced by these agent plays a cytoprotective role. In vivo, GX 15–070 combined with HCQ significantly decreased the growth of the tumor and the number of distant metastases.

Conclusions

Based on the synergistic effect of HCQ and GX 15–070 observed in this study, the combination of these two drugs may be utilized as a new therapeutic approach for neuroblastoma.

Genotype analysis of tumor-initiating cells expressing CD133 in neuroblastoma

Neuroblastoma (NB) is the most common and lethal extracranial solid tumor of childhood. Despite aggressive therapy, more than half of the children with advanced NB will die of uncontrolled metastatic disease. After chemotherapy, tumor-initiating cells (TICs) could persist, cause relapses and metastasis. The aim of this study is to demonstrate the tumor-initiating properties of CD133high NB cells and to identify new specific genetic abnormalities. Isolation of the CD133high cell population from NB cell lines was followed by neurosphere formation, soft agar assays, and orthotopic injections in NOD/SCID/IL2Rγc-null mice. A differential genotyping analysis was performed with Affymetrix SNP 6.0 arrays on CD133low and CD133high populations and the frequency of the abnormalities of 36 NB tumors was determined. Our results show that CD133high NB cells possess tumor-initiating properties, as CD133high cells formed significantly more neurospheres and produced significantly more colonies in soft agar than CD133low. Injection of 500 CD133high cells was sufficient to generate primary tumors and frequent metastases in mice. Differential genotyping analysis demonstrated two common regions with gains (16p13.3 and 19p13.3) including the gene EFNA2 in the CD133high population, and two with loss of heterozygosity (16q12.1 and 21q21.3) in the CD133low population. The gain of EFNA2 correlated with increased expression of the corresponding protein. These abnormalities were found in NB samples and some were significantly correlated with CD133 expression. Our results show that CD133high NB cells have TICs properties and present different genotyping characteristics compared to CD133low cells. Our findings reveal insights into new therapeutic targets in NB TICs.

Open transumbilical pyloromyotomy: is it more painful than the laparoscopic approach?

BACKGROUND

Open transumbilical pyloromyotomy (UMBP) and laparoscopic pyloromyotomy (LAP) have been compared on different outcomes, but postoperative pain as a primary end point had never been assessed. The aim of this study was to compare the use of analgesia in UMBP and LAP patients.

METHODS

Infants with hypertrophic pyloric stenosis treated by UMBP in 2008-2009 were matched with LAP-treated infants. Demographics, type and use of analgesia, and length of stay were recorded. Statistical analysis was performed using the Fisher exact test.

RESULTS

Each group contained 19 patients (N = 38) with comparable demographics and no comorbid condition. Bupivacaine was injected intraoperatively in all UMBP and 89% of LAP infants. There was a trend toward increased acetaminophen use in LAP infants (79% vs 58%, P = .61) in the recovery room. There was no difference in opiates use (3 UMBP vs 1 LAP, P = .60). In the ward, more UMBP patients received acetaminophen (78% vs 53%, P = .03). This difference was significant. Mean postoperative length of stay was similar in both groups.

CONCLUSION

Our study suggests that UMBP infants might experience more postoperative pain in the ward, without any impact on various outcomes. A prospective study with a larger sample size should be undertaken to verify these findings.

A child with unresectable biliary rhabdomyosarcoma: 48-month disease-free survival after liver transplantation

We describe here a two-yr-old boy with biliary RMS successfully treated by chemotherapy and LT. The child presented with obstructive jaundice at 20 months of age. A mildly vascularized, non-calcified, partially cystic lesion was visualized in the left hepatic lobe. Solid infiltration of the common bile duct and of both left and right hepatic ducts was suspected. Liver biopsy suggested a botryoid-type embryonal RMS originating from the biliary tract. After extrahepatic spread of the tumor was excluded, a biliary drain was applied and neoadjuvant chemotherapy was started. After the treatment, although reduced in volume, the mass was still unresectable without aggressive surgery and gross residual disease. LT with a reduced segment II/III graft was performed four months after diagnosis. The patient received six cycles of adjuvant chemotherapy, and he is alive and recurrence-free 48 months post-transplantation. A posteriori, the transplant might have possibly been avoided with an aggressive resection with biliary reconstruction. Nevertheless, although the risk of the transplant has to be balanced against the chemoresponsiveness of the tumor, the four-yr disease-free survival of this patient suggests that, when coupled with effective chemotherapy, transplantation might be considered a potential treatment for unresectable biliary RMS.

Management and recurrence of spontaneous pneumothorax in children

Objective

No guideline clearly prescribes an approach to management of spontaneous pneumothorax in children. The objectives of this study were to evaluate practice variation in the management of spontaneous pneumothorax in children and its probability of recurrence.

Methods

This study was a retrospective chart review followed by a phone follow-up that included all children who had visited a tertiary care paediatric hospital for a first episode of spontaneous pneumothorax between 2008 and 2017. The primary outcomes were the management of pneumothorax (observation, oxygen, needle aspiration, intercostal chest tube, surgery) and the probability of recurrence. All charts were evaluated by a rater using a standardized report form and 10% of the charts were evaluated in duplicate. All children/families were contacted by phone to assess recurrence. The primary analyses were the proportions of each treatment modalities and recurrence, respectively.

Results

During the study period, 76 children were deemed eligible for the study. Among them, 59 had a primary spontaneous pneumothorax while 17 were secondary. The most common first therapeutic approaches were chest tube insertion (31), oxygen alone (27), and observation (14). A total of 54 patients were available for follow-up among whom a recurrence was observed in 28 (37% of the total cohort or 52% of available children).

Conclusion

Chest tube insertion was the first line of treatment in about 40% of children with a first spontaneous pneumothorax. In this population, the recurrence probability is established between 37 and 52% and the majority occurs in the following months.

Abstract 4344: Membrane-type 1 matrix metalloproteinase-mediated pro-invasive properties of neuroblastoma initiating cells

Introduction. Neuroblastoma is the most common and deadly extracranial solid tumour of childhood. Unlike localized neuroblastomas which have generally good prognosis, metastatic stages are associated with poor outcome. In this context, increasing evidences suggest that neuroblastoma may contain tumor-initiating cells (TICs) that cause relapse and metastasis. Our recent work indicates that CD133, a putative marker of TICs in various cancers, is associated with chemoresistance and poor outcome in neuroblastoma. In addition, we and others have demonstrated that membrane-type 1 matrix metalloproteinase (MT1-MMP) is associated with neuroblastoma progression and metastasis.

Purpose. The purpose of this study was to characterize the tumor-initiating properties of CD133high neuroblastoma cells and determinate the role of MT1-MMP in pro-invasive properties of these cells.

Methods/Results. Following CD133high cells selection from neuroblastoma cell lines (SK-N-DZ, SK-N-FI, SK-N-SH and SJ-NB10) with FACSAria cell sorter, we have examined their tumor-initiating features with neurosphere-forming assay in serum-free medium, colony-forming assay in soft agar and orthotopic transplantation into the adrenal gland (major site of primary neuroblastoma) of severe immunocompromised NOD/SCID/IL2Rγ- mice (NSG). Contrary to their counterpart CD133low, CD133high cells formed more colonies in soft agar and develop more neurospheres. Interestingly, orthotopic transplantation of as few as 500 CD133high cells into NSG mice resulted in tumor formation into the adrenal gland and dissemination to liver, lungs, brain and bone marrow, while matched control CD133low presented no tumor, suggesting that CD133high cells are TICs in neuroblastoma. Further western blot analyses of neuroblastoma cell lines revealed that CD133 expression correlated with that of MT1-MMP. In addition, CD133high cells growth within three-dimensional type I collagen matrices was markedly higher than CD133low cells and was significantly reduced by anti-MT1-MMP neutralizing antibodies. In the same vein, we performed cell migration assay in Boyden chamber and observed that CD133high cells exhibit more migratory abilities that CD133low cells, this migration being inhibited by anti-MT1-MMP neutralizing antibodies.

Conclusions. Altogether, these findings strongly suggest that CD133-expressing TICs of neuroblastoma exhibit high pro-invasive capacities, requiring the involvement of MT1-MMP. Targeting pro-invasive capacities of neuroblastoma TICs with MMPs-activaed pro-drugs in combination with conventional therapy, represents an attractive therapeutic strategy aimed at eliminating both neuroblastoma TICs and the bulk of the tumour.

Acknowledgment. Fondation Centre de cancérologie Charles-Bruneau.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4344. doi:10.1158/1538-7445.AM2011-4344

Implementing a standardized gastroschisis protocol significantly increases the rate of primary sutureless closure without compromising closure success or early clinical outcomes

PURPOSE

Standardized protocols have been shown to improve outcomes in several pediatric surgical conditions. We implemented a multi-disciplinary gastroschisis practice bundle at our institution in 2013. We sought to evaluate its impact on closure type and early clinical outcomes.

METHODS

We performed a retrospective review of uncomplicated gastroschisis patients treated at our institution between 2008-2019. Patients were divided into two groups: pre- and post-protocol implementation. Multivariate logistic regression was used to compare closure location, method, and success.

RESULTS

Neonates (pre-implementation n = 53, post-implementation n = 43) were similar across baseline variables. Successful immediate closure rates were comparable (75.5% vs. 72.1%, p = 0.71). The proportion of bedside closures increased significantly after protocol implementation (35.3% vs. 95.4%, p < 0.01), as did the proportion of sutureless closures (32.5% vs. 71.0%, p < 0.01). Median postoperative mechanical ventilation decreased significantly (4 days IQR [3, 5] vs. 2 days IQR [1, 3], p < 0.01). Postoperative complications and duration of parenteral nutrition were equivalent. After controlling for potential confounding, infants in the post-implementation group had a 44.0 times higher odds of undergoing bedside closure (95% CI: 9.0, 215.2, p < 0.01) and a 7.7 times higher odds of undergoing sutureless closure (95% CI: 2.3, 25.1, p < 0.01).

CONCLUSIONS

Implementing a standardized gastroschisis protocol significantly increased the proportion of immediate bedside sutureless closures and decreased the duration of mechanical ventilation, without increasing postoperative complications. Level of Evidence III Type of Study Retrospective comparative study.

Differentiating congenital ovarian cysts from other abdominal cystic lesions in female infants: A study by the Canadian Consortium for Research in Pediatric Surgery (CanCORPS)

PURPOSE

The origin of congenital abdominal cysts in the female fetus often dictates management. While most arise from the ovary and are often managed non-operatively, some are non-ovarian and are frequently removed. We analyzed a national sample of female infants with congenital abdominal cysts to elucidate prenatal and postnatal factors associated with the diagnosis of a non-ovarian cyst.

METHODS

A retrospective cohort study of female infants who were prenatally diagnosed with abdominal cysts between 2013 and 2017 at 10 Canadian pediatric surgical centres was performed. Clinical characteristics, pre- and postnatal sonographic findings, and cyst trajectories were compared between patients with proven ovarian etiology and those with cysts arising from other organs.

RESULTS

Of 185 infants with prenatally diagnosed abdominal cysts, 22 (12%) were non-ovarian, five of which had clear non-ovarian organ of origin on prenatal ultrasound. Comparison of the other 17 cysts with 163 congenital ovarian cysts showed the following factors to be associated with a non-ovarian origin: earlier gestational age at diagnosis (23.5 vs 33.5 weeks, p <0.001), smaller diameter on first prenatal ultrasound (15.8 vs. 39.7 mm, p <0.001), change in sonographic character from simple to complex (87% vs 22%, p <0.001), and postnatal sonographic characteristics of complex cyst (87% vs. 48%, p = 0.004).

CONCLUSION

Clear organ of origin, diagnosis earlier in gestation, smaller initial prenatal cyst diameter, and sonographic cyst character change differentiate congenital non-ovarian cysts from their ovarian counterparts. These characteristics may be used to guide diagnosis and management.

Glomerular filtration rate in liver transplant for unresectable hepatoblastoma

Most children with hepatoblastoma manifest, at the time of LT, a decrease in renal function due to chemotherapy that could be further deteriorated by the use of calcineurin inhibitors. The purpose of this work was to examine the long-term follow-up of renal function in a cohort of children transplanted for unresectable hepatoblastoma. We present a retrospective observational study of 10 pediatric patients who received a LT for unresectable hepatoblastoma between 1996 and 2016. All patients included in this study were followed up on a regular basis and were assessed for GFR before transplantation and at least once a year during follow-up. All patients received standardized chemotherapy treatment for hepatoblastoma and immunosuppression according to hospital protocols. There was a marked decrease in GFR at the time of the LT in five patients presenting renal complications during the pretransplant cycles of chemotherapy. Three patients, one of them with prior kidney involvement, presented complications after LT, namely acute kidney failure and decrease in GFR. Those patients who presented with the lowest GFR at the time of LT eventually recovered renal function at levels similar to the rest of the group on follow-up. Chemotherapy-induced nephrotoxicity is a concern in patients treated for hepatoblastoma. Some individuals will develop low GFR after chemotherapy; therefore, strict follow-up is recommended, as low GFR may affect the doses of subsequent chemotherapy and immunosuppression. Stabilization of GFR levels and occasional improvement can be observed in the post-transplant period.

Preclinical study of a PARP inhibitor in neuroblastoma

9570

Background: Neuroblastoma (NB) is the most common extracranial solid tumor of childhood. In spite of many therapeutic improvements, only 60% survive long term despite aggressive combinations of multi-agent chemotherapy. In previous studies, we have demonstrated that tumor initiating cells (TIC) expressing CD133 (CD133high) in NB are more resistant to chemotherapy. Moreover, these cells express higher levels of PARP-1, a central protein involved in DNA repair. PARP-1 expression is significantly lower in NB usually showing spontaneous regression than in standard NB, suggesting an implication of PARP-1 in NB progression. The objective of this study is to determine the efficacy in vitro of AG-014699 (AG), a PARP- inhibitor, used in monotherapy or in combination to cisplatine (CP) and doxorubicine (DR), classical chemotherapeutic agents used in NB treatment, on NB cell survival. Methods: Six NB cell lines (parental or CD133high purified by flow cytometry (FACS)) were treated with AG alone or in association to CP or DR. PARP-1 ELISA protein assay was used to determine the optimal drug concentration needed to inhibit the protein. Cell survival was measured by MTT test. Western Blots were done to evaluate any apoptotic or autophagic pathway modulations. Quantification of DNA damage in treated cell was done by immunofluorescence of H2A-X protein. Results: We showed that a 4µM concentration of AG is sufficient for PARP-1 inhibition. One third of celllines presented a sensitivity to AG when used in monotherapy with an IC50 lower than 5µM. However, AG demonstrated synergistic effects when associated to DR, decreasing the IC50 by half, although none is observed when combined to CP. Sentitivity of the TIC did not appear to be more important than the bulk cells. With increasing concentration of AG, our WB showed no increase in cleaved Caspase-3 suggesting no modulation of the apoptotic pathway. However, autophagy seemed to be upregulated confirmed by an increase in cleaved LC3 II protein. Double strand breaks increased 2.5 folds when 4µM AG is added to the IC50 of DR. Conclusions: AG used in combination at potentially therapeutic doses shows promising results in NB. These results will allow for the improvement of NB treatments by introducing a new therapeutic strategy.