Christopher B. Weldon

Mortality of necrotizing enterocolitis expressed by birth weight categories

PURPOSE Low birth weight is the most important risk factor for developing necrotizing enterocolitis (NEC). We aimed to establish birth weight-based benchmarks for in-hospital mortality in neonates with NEC. METHODS Five hundred eleven centers belonging to the Vermont Oxford Network prospectively evaluated 71,808 neonates with birth weight of 501 to 1500 g between January 2005 and December 2006. The primary outcome variable was in-hospital mortality. RESULTS Birth weight was divided into 4 categories by 250-g increments. The NEC risk (P < .001) and mortality (P < .001) decreased with higher birth weight category. Necrotizing enterocolitis was associated with a significant odds ratio for death for each category (P < .001). Across groups, the odds ratio for NEC mortality increased with higher birth weight category (category 1 = 1.6 vs category 4 = 9.9; P < .001). CONCLUSION The in-hospital mortality rate of neonates with NEC remains high and is significantly related to birth weight category. Although the risk and absolute mortality of NEC decrease with higher birth weight, the odds ratios indicate that NEC has a relatively greater impact upon mortality at higher birth weight. These data afford birth weight-based mortality benchmarks that may be useful in assessing single center NEC outcomes and facilitating comparisons between centers.

Apoptosis, Chemoresistance, and Breast Cancer: Insights From the MCF-7 Cell Model System

The MCF-7 cell line was derived from a patient with metastatic breast cancer in 1970. Since then it has become a prominent model system for the study of estrogen receptor-positive breast cancer. With this model as a focus, this review summarizes important studies addressing tumor necrosis factor-α as a prototypical apoptosis-inducing cytokine in MCF-7 cells. Both survival and death receptor signaling pathways are discussed in terms of their role in chemotherapy-induced apoptosis as well as in chemoresistance. Novel therapeutic approaches to the treatment of breast cancer are proposed utilizing knowledge of these signaling pathways as targets. Specifically, ceramide metabolism is proposed as a novel target for chemosensitivity, perhaps combined with selective inhibitors of Bcl-2 or PI3K/Akt/nuclear factor-κB. Suggested areas of future research include translational studies manipulating candidate survival and death signaling pathways.

ALK Rearrangement in Sickle Cell Trait-Associated Renal Medullary Carcinoma

Renal Medullary Carcinoma (RMC) is an aggressive malignancy that affects young black individuals with sickle cell trait. No effective treatment is available, resulting in an ominous clinical course, with overall survival averaging less than four months. We report rearrangement of the ALK receptor tyrosine kinase in a pediatric case of RMC harboring a t(2;10)(p23;q22) translocation. Mass spectrometry‐based proteomic evaluation identified a novel ALK oncoprotein in which the cytoskeletal protein vinculin (VCL) was fused to the ALK kinase domain. The resulting VCL‐ALK fusion does not contain known self‐association domains, but includes the talin binding domains of vinculin. We demonstrate coprecipitation of strongly tyrosine phosphorylated talins with the VCL‐ALK oncoprotein, suggesting that ALK oncogenic crossphosphorylation is mediated by interactions between neighboring VCL‐ALK proteins on a talin scaffold. This report widens the spectrum of ALK‐related tumors and ALK fusion partners, and provides a rationale for treating RMC with targeted ALK inhibitors.

Proteomic analysis of tumor necrosis factor-α resistant human breast cancer cells reveals a MEK5/Erk5-mediated epithelial-mesenchymal transition phenotype

IntroductionDespite intensive study of the mechanisms of chemotherapeutic drug resistance in human breast cancer, few reports have systematically investigated the mechanisms that underlie resistance to the chemotherapy-sensitizing agent tumor necrosis factor (TNF)-α. Additionally, the relationship between TNF-α resistance mediated by MEK5/Erk5 signaling and epithelial-mesenchymal transition (EMT), a process associated with promotion of invasion, metastasis, and recurrence in breast cancer, has not previously been investigated.MethodsTo compare differences in the proteome of the TNF-α resistant MCF-7 breast cancer cell line MCF-7-MEK5 (in which TNF-α resistance is mediated by MEK5/Erk5 signaling) and its parental TNF-a sensitive MCF-7 cell line MCF-7-VEC, two-dimensional gel electrophoresis and high performance capillary liquid chromatography coupled with tandem mass spectrometry approaches were used. Differential protein expression was verified at the transcriptional level using RT-PCR assays. An EMT phenotype was confirmed using immunofluorescence staining and gene expression analyses. A short hairpin RNA strategy targeting Erk5 was utilized to investigate the requirement for the MEK/Erk5 pathway in EMT.ResultsProteomic analyses and PCR assays were used to identify and confirm differential expression of proteins. In MCF-7-MEK5 versus MCF-7-VEC cells, vimentin (VIM), glutathione-S-transferase P (GSTP1), and creatine kinase B-type (CKB) were upregulated, and keratin 8 (KRT8), keratin 19 (KRT19) and glutathione-S-transferase Mu 3 (GSTM3) were downregulated. Morphology and immunofluorescence staining for E-cadherin and vimentin revealed an EMT phenotype in the MCF-7-MEK5 cells. Furthermore, EMT regulatory genes SNAI2 (slug), ZEB1 (δ-EF1), and N-cadherin (CDH2) were upregulated, whereas E-cadherin (CDH1) was downregulated in MCF-7-MEK5 cells versus MCF-7-VEC cells. RNA interference targeting of Erk5 reversed MEK5-mediated EMT gene expression.ConclusionsThis study demonstrates that MEK5 over-expression promotes a TNF-α resistance phenotype associated with distinct proteomic changes (upregulation of VIM/vim, GSTP1/gstp1, and CKB/ckb; and downregulation of KRT8/krt8, KRT19/krt19, and GSTM3/gstm3). We further demonstrate that MEK5-mediated progression to an EMT phenotype is dependent upon intact Erk5 and associated with upregulation of SNAI2 and ZEB1 expression.

Molecular Subtypes of KIT/PDGFRA Wild-Type Gastrointestinal Stromal Tumors: A Report From the National Institutes of Health Gastrointestinal Stromal Tumor Clinic.

IMPORTANCE Wild-type (WT) gastrointestinal stromal tumors (GISTs), which lack KIT and PDGFRA gene mutations, are the primary form of GIST in children and occasionally occur in adults. They respond poorly to standard targeted therapy. Better molecular and clinical characterization could improve management. OBJECTIVE To evaluate the clinical and tumor genomic features of WT GIST. DESIGN, SETTING, AND PARTICIPANTS Patients enrolled in an observational study at the National Institutes of Health starting in 2008 and were evaluated in a GIST clinic held once or twice yearly. Patients provided access to existing medical records and tumor specimens. Self-referred or physician-referred patients younger than 19 years with GIST or 19 years or older with known WT GIST (no mutations in KIT or PDGFRA) were recruited; 116 patients with WT GIST were enrolled, and 95 had adequate tumor specimen available. Tumors were characterized by immunohistochemical analysis (IHC) for succinate dehydrogenase (SDH) subunit B, sequencing of SDH genes, and determination of SDHC promoter methylation. Testing of germline SDH genes was offered to consenting patients and families. MAIN OUTCOMES AND MEASURES For classification, tumors were characterized by SDHA, B, C, or D (SDHX) mutations and other genetic and epigenetic alterations, including presence of mutations in germline. Clinical characteristics were categorized. RESULTS Wild-type GIST specimens from 95 patients (median age, 23 [range, 7-78] years; 70% female) were classified into 3 molecular subtypes: SDH-competent (n = 11), defined by detection of SDHB by IHC; and 2 types of SDH-deficient GIST (n = 84). Of SDH-deficient tumors, 63 (67%) had SDH mutations, and in 31 of 38 (82%), the SDHX mutation was also present in germline. Twenty-one (22%) SDH-deficient tumors had methylation of the SDHC promoter leading to silencing of expression. Mutations in known cancer-associated pathways were identified in 9 of 11 SDH-competent tumors. Among patients with SDH-mutant tumors, 62% were female (39 of 63), median (range) age was 23 (7-58) years, and approximately 30% presented with metastases (liver [12 of 58], peritoneal [6 of 58], lymph node [15 of 23]). SDHC-epimutant tumors mostly affected young females (20 of 21; median [range] age, 15 [8-50] years), and approximately 40% presented with metastases (liver [7 of 19], peritoneal [1 of 19], lymph node [3 of 8]). SDH-deficient tumors occurred only in the stomach and had an indolent course. CONCLUSIONS AND RELEVANCE An observational study of WT GIST permitted the evaluation of a large number of patients with this rare disease. Three molecular subtypes with implications for prognosis and clinical management were identified.

Electrospun Drug-Eluting Sutures for Local Anesthesia

We have developed a local anesthetic-eluting suture system which would combine the function and ubiquity of the suture for surgical repair with the controlled release properties of a biodegradable polymeric matrix. Drug-free and drug-loaded poly(lactic-co-glycolic acid) (PLGA) sutures were fabricated by electrospinning, with or without the local anesthetic bupivacaine. The tensile strength of the electrospun sutures decreased as drug content increased, but strains remained relatively similar across all groups. Sutures released their entire drug payload over the course of 12 days and maintained approximately 12% of their initial tensile strength after 14 days of incubation in vitro. In a rat skin wound model, local analgesia was achieved 1 day after surgery and lasted approximately 1 week in 90% of treated animals (n=10, p<0.05), and all wounds were able to heal normally without the need for further reinforcement. The sutures caused tissue reaction in vivo that was comparable to that seen with a commercially available suture composed of PLGA. Such sutures may enhance perioperative analgesia and mitigate the need for standard postoperative opioid analgesics.

Mechanical and Antibacterial Bowel Preparation in Colon and Rectal Surgery

Colorectal surgery performed prior to 1970 was fraught with postoperative infectious complications which occurred in more than 30–50% of all operations. Diversion of the fecal stream appeared mandatory when operating on an urgent or emergent basis, thereby requiring the performance of multiple, staged operations instead of a single surgery encompassing resection and primary anastomosis as is performed commonly today. Multiple studies conducted in the early 1970s determined that anaerobic colonic microflora were causative agents in postoperative infections in colon and rectal surgery, and these studies initiated the development of effective oral preoperative antibiotic prophylaxis in combination with preoperative mechanical bowel preparation. This dual-tier regimen significantly reduced the incidence of postoperative infectious complications, thus allowing most uncomplicated colon and rectal surgeries to be performed in a single stage without the need for the diversion of the fecal stream and multiple operations. Therefore, a preoperative mechanical and antibacterial bowel regimen serves as the cornerstone of modern elective colorectal surgery, and these regimens now comprise three therapeutic directives. The first step is preoperative mechanical cleansing of the bowel, which is then followed by preoperative oral antibiotic prophylaxis. Finally, perioperative parenteral antibiotics directed against aerobic and anaerobic colonic microflora are utilized.

Primary lung tumors in children and adolescents: a 90-year experience

PURPOSE Primary lung tumors in children are rare. A wide range of histopathologic tumor types occurs. The incidence of these lesions and their outcomes are still largely unknown. This study aims to determine the incidence of different primary lung tumors in children and to contribute data leading to the development of evidence-based treatment models. METHODS A single institution retrospective review was performed with institutional review board approval. Patients were included if they had primary, nonhematologic lung tumors. Simple squamous papillomas subjected to endoscopic biopsy and not resected, and vascular lesions associated with multisystem lesions, such as hereditary hemorrhagic telangiectasia, were excluded. Medical records and pathologic material for patients from 1918 to 2008 were reviewed. RESULTS Forty patients were identified (23 boys, 17 girls) with a mean age of 9.6 years (range, 3 months to 19 years). Fourteen distinct histopathologic tumor types were identified. The most common tumor types were carcinoid (8), inflammatory myofibroblastic tumor (7), and pleuropulmonary blastoma (6). Rare pediatric lung tumors including small cell carcinoma, adenocarcinoma, and pulmonary capillary hemangiomatosis were also seen. The mortality rate was 17.5% (7) in our series. Chemotherapy was used in 23% (9) and radiation in 20% (8) of the patients. Of the 33 survivors, 28 had follow-up with a median duration of 29.5 months (mean, 63.2 months; range, 1-471 months). CONCLUSIONS Primary lung tumors in children are rare and histopathologically diverse. The tumor spectrum involves many types not seen in adults, and unlike adults, patients rarely have a history of exposure to external predisposing factors. Although complete resection remains the standard for treatment of most tumors, addition of adjuvant therapy is dependent on both tumor stage and histopathologic type.

Oestrogen-mediated suppression of tumour necrosis factor alpha-induced apoptosis in MCF-7 cells: subversion of Bcl-2 by anti-oestrogens

In oestrogen receptor (ER)-positive breast carcinoma cells, 17beta-oestradiol suppresses a dose-dependent induction of cell death by tumour necrosis factor alpha (TNF). The ability of oestrogens to promote cell survival in ER-positive breast carcinoma cells is linked to a coordinate increase in Bcl-2 expression, an effect that is blocked with the pure anti-oestrogen ICI 182,780. The role of Bcl-2 in MCF-7 cell survival was confirmed by stable overexpression of Bcl-2 which resulted in suppression of apoptosis induced by doxorubicin (DOX), paclitaxel (TAX) and TNF as compared to vector-control cells. The pure anti-oestrogen ICI 182,780 in combination with TNF, DOX or TAX potentiated apoptosis in vector-transfected cells. Interestingly, pre-treatment with ICI 182,780 markedly enhanced chemotherapeutic drug- or TNF-induced apoptosis in Bcl-2 expressing cells, an effect that was correlated with ICI 182,780 induced activation of c-Jun N-terminal kinase. Our results suggest that the effects of oestrogens/anti-oestrogens on the regulation of apoptosis may involve coordinate activation of signalling events and Bcl-2 expression.

Outcomes after the Ladd procedure in patients with heterotaxy syndrome, congenital heart disease, and intestinal malrotation

PURPOSE Heterotaxy syndrome (HS) patients often present with congenital heart disease and intestinal malrotation. Controversy exists regarding the management of these patients. Risk of midgut volvulus, morbidity from elective operations, and overall prognosis must be weighed when considering a Ladd procedure on asymptomatic HS/intestinal malrotation patients. METHODS This is a retrospective review comparing HS and non-heterotaxy syndrome (NHS) patients undergoing a Ladd procedure at Childrens Hospital Boston (Mass) from January 1997 to September 2007. RESULTS Thirty-one HS and 51 NHS patients were identified. After a Ladd procedure, HS patients remained in the hospital 12.9 days, had a 9.7% risk of small bowel obstruction, and a 9.7% in-hospital mortality. If allowed to develop abdominal symptoms, 27% of HS patients with intestinal malrotation had a midgut volvulus at surgery. Intra-HS group comparison demonstrated longer hospital stays in symptomatic patients (P = .01). Mortality was greater in the HS than NHS patients, but deaths were related to cardiac disease and not to the Ladd procedure. CONCLUSIONS Elective Ladd procedures are well tolerated by HS patients. Given the risk of midgut volvulus and in light of improved survival beyond infanthood, once identified, HS patients with asymptomatic malrotation should be offered a prophylactic Ladd procedure.