Harold N Lovvorn

Vanderbilt University, Nashville, Michigan, United States

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Publications (50)92.51 Total impact

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    ABSTRACT: Wilms tumor (WT) blastema retains gene expression profiles characteristic of the multipotent nephron progenitor pool, or cap mesenchyme (CM), in the developing kidney. As a result, WT blastema and the CM are believed to represent contextual analogues of one another. Sine oculis homeobox 2 (SIX2) is a transcription factor expressed specifically in the CM, provides a critical mechanism for CM self-renewal, and remains persistently active in WT blastema, although its purpose in this childhood malignancy remains unclear. We hypothesized that SIX2, analogous to its function in development, confers a survival pathway to blastema, the putative WT stem cell. To test its functional significance in WT biology, wild-type SIX2 was overexpressed in the human WT cell line, WiT49. After validating this model, SIX2 effects on anchorage-independent growth, proliferation, invasiveness, canonical WNT pathway signaling, and gene expression of specific WNT pathway participants were evaluated. Relative to controls, WiT49 cells overexpressing SIX2 showed significantly enhanced anchorage-independent growth and early-passage proliferation representing surrogates of cell survival. Interestingly, overexpression of SIX2 generally repressed TCF/LEF-dependent canonical WNT signaling, which activates and coordinates both differentiation and stem pathways, but significantly heightened canonical WNT signaling through the survivin promoter, a mechanism that exclusively maintains the stem state. In summary, when overexpressed in a human WT cell line, SIX2 enhances cell survival and appears to shift the balance in WNT/β-catenin signaling away from a differentiation path and toward a stem cell survival path. Copyright © 2014 Neoplasia Press, Inc. Published by Elsevier Inc. All rights reserved.
    Translational oncology. 12/2014; 7(6):800-11.
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    ABSTRACT: Background Survival from Wilms tumor (WT) in sub-Saharan Africa remains dismal as a result of on-therapy mortality and treatment abandonment. Review of patients diagnosed from 2008 to 2011 in our Kenyan Wilms Tumor Registry showed a loss to follow up (LTFU) rate approaching 50%. The purpose of this study was to trace those LTFU, estimate the survival rate, and identify risk factors for treatment abandonment.ProcedureWe administered a comprehensive survey to parents of patients with WT at the two largest referral hospitals in Kenya to identify barriers to care. We also telephoned families who had abandoned care to determine vital status and identify risk factors for treatment abandonment.ResultsOf 136 registered patients, 77 were confirmed dead (56.7%), 38 remained alive (27.9%), and the vital status of 21 patients remains unknown (15.4%). After contacting 33 of the patients who either abandoned curative treatment (n = 34) or did not attend off-therapy visits (n = 20), the best estimate of 2-year overall survival of patients with WT in Kenya approaches 36%. Sixty-three percent of parents misunderstood treatment plans and 55% encountered financial barriers. When asked how to increase comfort with the child's treatment, 27% of parents volunteered improving inefficient services and 26% volunteered reducing drug-unavailability.Conclusions Treatment abandonment remains a significant problem contributing to increased mortality from WT in developing countries. This multi-center survey identified the barriers to treatment completion from the parental perspective to be lack of education about WT and treatment, financial constraints, need for quality improvement, and drug-unavailability. Pediatr Blood Cancer © 2014 Wiley Periodicals, Inc.
    Pediatric Blood & Cancer 11/2014; · 2.35 Impact Factor
  • Harold Bo N Lovvorn
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    ABSTRACT: This is a summary of the 65th Annual Meeting of the American Academy of Pediatrics Section on Surgery held in Orlando, Florida, from October 25-27, 2013.
    Journal of pediatric surgery. 06/2014; 49(6):1041-1042.
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    ABSTRACT: Wilms tumor (WT) is the most common childhood kidney cancer worldwide and arises in children of black African ancestry with greater frequency and severity than other race groups. A biologic basis for this pediatric cancer disparity has not been previously determined. We hypothesized that unique molecular fingerprints might underlie the variable incidence and distinct disease characteristics of WT observed between race groups. To evaluate molecular disparities between WTs of different race groups, the Children's Oncology Group provided 80 favorable histology specimens divided evenly between black and white patients and matched for disease characteristics. As a surrogate of black sub-Saharan African patients, we also analyzed 18 Kenyan WT specimens. Tissues were probed for peptide profiles using matrix-assisted laser desorption ionization time of flight imaging mass spectrometry. To control for histologic variability within and between specimens, cellular regions were analyzed separately as triphasic (containing blastema, epithelia, and stroma), blastema only, and stroma only. Data were queried using ClinProTools and statistically analyzed. Peptide profiles, detected in triphasic WT regions, recognized race with good accuracy, which increased for blastema- or stroma-only regions. Peptide profiles from North American WTs differed between black and white race groups but were far more similar in composition than Kenyan specimens. Individual peptides were identified that also associated with WT patient and disease characteristics (eg, treatment failure and stage). Statistically significant peptide fragments were used to sequence proteins, revealing specific cellular signaling pathways and candidate drug targets. Wilms tumor specimens arising among different race groups show unique molecular fingerprints that could explain disparate incidences and biologic behavior and that could reveal novel therapeutic targets.
    Journal of the American College of Surgeons 04/2014; 218(4):707-20. · 4.50 Impact Factor
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    ABSTRACT: Fecal sampling is widely utilized to define small intestinal tissue-level microbial communities in healthy and diseased newborns. However, this approach may lead to inaccurate assessments of disease or therapeutics in newborns because of the assumption that the taxa in the fecal microbiota are representative of the taxa present throughout the gastrointestinal tract. To assess the stratification of microbes in the newborn gut and to evaluate the probable shortcoming of fecal sampling in place of tissue sampling, we simultaneously compared intestinal mucosa and fecal microbial communities in 15 neonates undergoing intestinal resections. We report three key results. First, when the site of stool and mucosal samples are further apart, their microbial communities are more distinct, as indicated by low mean Sørensen similarity indices for each patient's fecal and tissue microbiota. Second, two distinct niches (intestinal mucosa and fecal microbiota) are evident by principal component analyses, demonstrating the critical role of sample source in defining microbial composition. Finally, in contrast to adult studies, intestinal bacterial diversity was higher in tissue than in fecal samples. This study represents an unprecedented map of the infant microbiota from intestinal mucosa and establishes discernable biogeography throughout the neonatal gastrointestinal tract. Our results question the reliance on fecal microbiota as a proxy for the developing intestinal microbiota. Additionally, the robust intestinal tissue-level bacterial diversity we detected at these early ages may contribute to the maturation of mucosal immunity.
    Gut Microbes 03/2014; 5(2).
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    ABSTRACT: Wilms tumor (WT) is the most common childhood kidney cancer and retains gene expression profiles reminiscent of the embryonic kidney. We have shown previously that CITED1, a transcriptional regulator that labels the self-renewing, multipotent nephron progenitor population of the developing kidney, is robustly expressed across all major WT disease and patient characteristics. In this malignant context, CITED1 becomes enriched in the nucleus, which deviates from its cytosolic predominance in embryonic nephron progenitors. We designed the current studies to test the functional and mechanistic effects of differential CITED1 subcellular localization on WT behavior. To mimic its subcellular distribution observed in clinical WT specimens, CITED1 was misexpressed ectopically in the human WT cell line, WiT49, as either a wild-type (predominantly cytosolic) or a mutant, but transcriptionally active, protein (two point mutations in its nuclear export signal, CITED1ΔNES; nuclear-enriched). In vitro analyses showed that CITED1ΔNES enhanced WiT49 proliferation and colony formation in soft agar relative to wild-type CITED1 and empty vector controls. The nuclear-enriched CITED1ΔNES cell line showed the greatest tumor volumes after xenotransplantation into immunodeficient mice (n=15 animals per cell line). To elucidate CITED1 gene targets in this model, microarray profiling showed that wild-type CITED1 foremost upregulated LGR5 (stem cell marker), repressed CDH6 (early marker of epithelial commitment of nephron progenitors), and altered expression of specific WNT pathway participants. In summary, forced nuclear enrichment of CITED1 in a human WT cell line appears to enhance tumorigenicity, whereas ectopic cytosolic expression confers stem-like properties and an embryonic phenotype, analogous to the developmental context.
    Oncotarget 12/2013; · 6.64 Impact Factor
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    ABSTRACT: The Yes-associated-protein-1 (YAP1) is a novel, direct regulator of stem cell genes both in development and cancer. FAT4 is an upstream regulator that induces YAP1 cytosolic sequestering by phosphorylation (p-Ser 127) and therefore inhibits YAP1-dependent cellular proliferation. We hypothesized that loss of FAT4 signaling would result in expansion of the nephron progenitor population in kidney development and that YAP1 subcellular localization would be dysregulated in Wilms tumor (WT), an embryonal malignancy that retains gene expression profiles and histologic features reminiscent of the embryonic kidney. Fetal kidneys from Fat4(-/-) mice were harvested at e18.5 and markers of nephron progenitors were investigated using immunohistochemical analysis. To examine YAP1 subcellular localization in WT, a primary WT cell line (VUWT30) was analyzed by immunofluorescence. Forty WT specimens evenly distributed between favorable and unfavorable histology (n = 20 each), and treatment failure or success (n = 20 each) was analyzed for total and phosphorylated YAP1 using immunohistochemistry and Western blot. Fat4(-/-) mouse fetal kidneys exhibit nuclear YAP1 with increased proliferation and expansion of nephron progenitor cells. In contrast to kidney development, subcellular localization of YAP1 is dysregulated in WT, with a preponderance of nuclear p-YAP1. By Western blot, median p-YAP1 quantity was 5.2-fold greater in unfavorable histology WT (P = 0.05). Fetal kidneys in Fat4(-/-) mice exhibit a phenotype reminiscent of nephrogenic rests, a WT precursor lesion. In WT, YAP1 subcellular localization is dysregulated and p-YAP1 accumulation is a novel biomarker of unfavorable histology. Pediatr Blood Cancer © 2013 Wiley Periodicals, Inc.
    Pediatric Blood & Cancer 09/2013; · 2.35 Impact Factor
  • Amy Zhai, Harold N Lovvorn
    Journal of Pediatric Surgery 09/2013; 48(9):1991. · 1.38 Impact Factor
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    ABSTRACT: Survival from Wilms Tumor (WT) exceeds 90% at 5years in developed nations, whereas at last report, 2-year event-free survival (EFS) in Kenya reached only 35%. To clarify factors linked to these poor outcomes in Kenya, we established a comprehensive web-based WT registry, comprised of patients from the four primary hospitals treating childhood cancers. WT patients diagnosed between January 2008 and January 2012 were identified. Files were abstracted for demographic characteristics, treatment regimens, and enrollment in the Kenyan National Hospital Insurance Fund (NHIF). Children under 15years of age having both a primary kidney tumor on imaging and concordant histology consistent with WT were included. Two-year event-free survival (EFS) was 52.7% for all patients (n=133), although loss to follow up (LTFU) was 50%. For the 33 patients who completed all scheduled standard therapy, 2-year EFS was 94%. Patients enrolled in NHIF tended to complete more standard therapy and had a lower hazard of death (Cox 0.192, p < 0.001). Survival of Kenyan WT patients has increased slightly since last report. Notably, WT patients completing all phases of standard therapy experienced 2-year survival approaching the benchmarks of developed nations. Efforts in Kenya should be made to enhance compliance with WT treatment through NHIF enrollment.
    Journal of Pediatric Surgery 06/2013; 48(6):1254-1262. · 1.38 Impact Factor
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    ABSTRACT: Hepatoblastomas often require neoadjuvant chemotherapy to facilitate partial hepatectomy, which necessitates freedom of tumor borders from the confluence of hepatic veins (COHV), portal vein bifurcation (PVB), and retrohepatic inferior vena cava (IVC). This study aimed to clarify the effect of incremental neoadjuvant cycles on the AHEP0731 protocol criteria of hepatoblastoma resectability. Hepatoblastoma responses to neoadjuvant chemotherapy were analyzed among patients (n=23) treated at two children's hospitals between 1996 and 2010. Using digital imaging data, ellipsoid and point-based models were created to measure tumor volume regression and respective distances from tumor borders nearest to the COHV, PVB, and IVC. Hepatoblastoma volumes regressed with incremental neoadjuvant chemotherapy cycles (p<0.001). Although tumor borders regressed away from the COHV (p=0.008), on average only 1.1mm was gained. No change from tumor borders to the PVB was detected (p=0.102). Distances from tumor borders to the IVC remained stable at one hospital (p=0.612), but increased only 0.15mm every 10days of therapy at the other (p=0.002). Neoadjuvant chemotherapy induced slightly more tumors to meet the threshold vascular margin of 1cm (baseline to completion): COHV, 11 (47.8%) to 17 (73.9%; p=0.058); PVB, 11 (47.8%) to 15 (65.2%; p=0.157); and IVC, 4 (17.4%) to 10 (43.5%; p=0.034). No differences were detected in demographic or disease-specific characteristics between patients who did or did not achieve this 1-cm margin after conclusion of chemotherapy. Hepatoblastoma volumes regress significantly with increasing neoadjuvant chemotherapy cycles. However, tumors often remain anchored to the major hepatic vasculature, showing marginal improvement in resectability criteria.
    Journal of Pediatric Surgery 06/2013; 48(6):1239-1248. · 1.38 Impact Factor
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    ABSTRACT: BACKGROUND: The current research environment for academic surgeons demands that extramural funding be obtained. Financial support from the National Institutes of Health (NIH) is historically the gold standard for funding in the biomedical research community, with the R01 funding mechanism viewed as indicator of research independence. The NIH also supports a mentor-based career development mechanism (K-series awards) in order to support early-stage investigators. The goal of this study was to investigate the grants successfully awarded to pediatric surgeon-scientists and then determine the success of the K-series award recipients at achieving research independence. METHODS: In July 2012, all current members of the American Pediatric Surgery Association (APSA) were queried in the NIH database from 1988-2012 through the NIH Research Portfolio Online Reporting Tools. The following factors were analyzed: type of grant, institution, amount of funding, and funding institute or center. RESULTS: Among current APSA members, there have been 83 independent investigators receiving grants, representing 13% of the current APSA membership, with 171 independent grants funded through various mechanisms. Six percent currently have active NIH funding, with $7.2 million distributed in 2012. There have been 28 K-series grants awarded. Of the recipients of expired K08 awards, 39% recipients were subsequently awarded an R01 grant. A total of 63% of these K-awarded investigators transitioned to an independent NIH award mechanism. CONCLUSIONS: Pediatric surgeon-scientists successfully compete for NIH funding. Our data suggest that although the K-series funding mechanism is not the only path to research independence, over half of the pediatric surgeons who receive a K-award are successful in the transition to independent investigator.
    Journal of Surgical Research 04/2013; · 2.02 Impact Factor
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    ABSTRACT: Hepatoblastoma, the most common pediatric liver cancer, consists of epithelial mixed embryonal/fetal (EMEF) and pure fetal histologic subtypes, with the latter exhibiting a more favorable prognosis. Few embryonal histology markers that yield insight into the biologic basis for this prognostic discrepancy exist. CBP/P-300 interacting transactivator 1 (CITED1), a transcriptional co-activator, is expressed in the self-renewing nephron progenitor population of the developing kidney and broadly in its malignant analog, Wilms tumor (WT). In this current study, CITED1 expression is detected in mouse embryonic liver initially on post-coitum day 10.5 (e10.5), begins to taper by e14.5, and is undetectable in e18.5 and adult livers. CITED1 expression is detected in regenerating murine hepatocytes following liver injury by partial hepatectomy and 3,5-diethoxycarbonyl-1,4-dihydrocollidine. Importantly, while CITED1 is undetectable in normal human adult livers, 36 of 41 (87.8%) hepatoblastoma specimens express CITED1, where it is enriched in EMEF specimens compared to specimens of pure fetal histology. CITED1 overexpression in Hep293TT human hepatoblastoma cells induces cellular proliferation and upregulates the Wnt inhibitors Kringle containing transmembrane protein 1 (KREMEN1) and CXXC finger protein 4 (CXXC4). CITED1 mRNA expression correlates with expression of CXXC4 and KREMEN1 in clinical hepatoblastoma specimens. These data show that CITED1 is expressed during a defined time course of liver development and is no longer expressed in the adult liver but is upregulated in regenerating hepatocytes following liver injury. Moreover, as in WT, this embryonic marker is reexpressed in hepatoblastoma and correlates with embryonal histology. These findings identify CITED1 as a novel marker of hepatic progenitor cells that is re-expressed following liver injury and in embryonic liver tumors.
    Neoplasia (New York, N.Y.) 12/2012; 14(12):1153-63. · 5.48 Impact Factor
  • Andrew J Murphy, Thomas P Rauth, Harold N Lovvorn
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    ABSTRACT: We report the complex case of a 12-month-old girl with stage IV hepatoblastoma accompanied by thrombosis and cavernous transformation of the portal vein. After neoadjuvant chemotherapy, she underwent right hepatectomy, which was complicated by iatrogenic injury of her left hepatic duct, and subsequently developed a postoperative biloma and chronic biliocutaneous fistula. Concomitant with multiple percutaneous interventions to manage the biloma nonoperatively while the child completed her adjuvant chemotherapy, she progressed to develop chronic malnutrition, jaundice, and failure to thrive. Once therapy was completed and the child was deemed free of disease, she underwent exploratory laparotomy with Roux-en-Y biliary cystenterostomy for definitive management, resulting in resolution of her biliary fistula, jaundice, and marked improvement in her nutritional status. Roux-en-Y biliary cystenterostomy is a unique and efficacious management option in the highly selected patient population with chronic biliary leak refractory to minimally invasive management.
    Journal of Pediatric Surgery 11/2012; 47(11):e5-9. · 1.38 Impact Factor
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    ABSTRACT: The aim of this study was to identify race and socioeconomic factors associated with worse outcomes among Tennessee children who sustain firearm injuries. We queried our institutional pediatric trauma registry and the Davidson County Regional Medical Examiner database for children ages 15 years and younger who sustained firearm injuries between July 1998 and July 2010. Descriptive statistics and logistic regression modeling were used to analyze demographic data, circumstance of injury (unintentional or intentional), odds of death, and characteristics of zip codes (total population, race distribution, and median income) where injuries occurred. One hundred eighty-eight children (median age, 13.2 years; range, 1.1-15.8 years) sustained a firearm injury and were either admitted to our institution or were referred directly to the medical examiner. More whites (n = 109, or 58%) sustained a firearm injury than blacks (n = 79, or 42%), but blacks were overrepresented 2.5-fold more compared with the general Tennessee population. Fifty-four children (29%) died, of whom 35 (65%) were black and 19 (35%) were white (P < .001). Ninety-three children sustained unintentional firearm injuries, and 84 were intentional (n = 67, assault; n = 17, suicide). When data were stratified by intent, 67% of blacks and 12% of whites were assaulted (P < .001). After controlling for age and intent, black children were 4 times more likely to die of firearm injuries than whites (P = .008; 95% confidence interval, 1.4-11.3). In a sample of firearm-injured Tennessee children, blacks were notably overrepresented and far more likely to die than whites. Using zip code data will help to establish firearm injury prevention programs specific to disparate populations and to reduce both violent and accidental childhood firearm injuries.
    Journal of Pediatric Surgery 06/2012; 47(6):1196-203. · 1.38 Impact Factor
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    ABSTRACT: SIX2 and CITED1 are transcriptional regulators that specify self-renewing nephronic progenitor cells of the embryonic kidney. We hypothesized that SIX2, which promotes and maintains this stem cell population, and CITED1 remain active in Wilms' tumor (WT). To evaluate expression domains and the pathogenic significance of SIX2 and CITED1 across WT, the Children's Oncology Group provided 40 WT specimens of stages I to IV (n = 10 per stage), which were enriched for unfavorable histology (n = 20) and treatment failure (relapse or death, n = 20). SIX2 and CITED1 protein expression was evaluated qualitatively (immunohistochemistry) and quantitatively (Western blot, or WB). Gene transcription was estimated using quantitative real-time polymerase chain reaction (qRT-PCR). SIX2 was visualized by immunohistochemistry in 36 (94.7%) of 38 specimens. Protein and messenger RNA expression of SIX2 were quantitatively similar across all stages of disease (P = .48 WB; P = 0.38 qPCR), in favorable or unfavorable histology (P = 0.51 WB; P = 0.58 qPCR), and in treatment failure or success (P = 0.86 WB; P = 0.49 qPCR). Although CITED1 expression paralleled SIX2 qualitatively, no quantitative correlation between SIX2 and CITED1 expression was observed (Spearman correlation coefficient, 0.28; P = 0.08). As in the fetal kidney, overlapping, but also distinct, WT cellular expression domains were observed between SIX2 and CITED1. SIX2 and CITED1 remain active across all disease characteristics of WT. Activity of these genes in WT potentially identifies a population of self-renewing cancer cells that exhibit an embryonic, stemlike phenotype. Taken together, these transcriptional regulators may be fundamental to WT cellular self-renewal and may represent targets for novel therapies that promote terminal differentiation.
    Journal of Pediatric Surgery 06/2012; 47(6):1239-49. · 1.38 Impact Factor
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    ABSTRACT: We aimed to assess the late effects of ovarian salvage or oophorectomy on gonadal function and fertility as measured by menstrual regularity. We performed a 10-year retrospective review of females aged 20 years or younger who required surgery to treat an ovarian disorder. A mail survey was distributed to these patients to evaluate the effects of ovarian surgery on menarche, menstrual regularity, and pregnancy. A total of 180 females had surgery to treat an ovarian disorder. Eighty-six of these underwent unilateral oophorectomy (48%), whereas 94 (52%) had an ovary sparing procedure. Eighty-one patients (45%) returned completed surveys. Of the respondents, 44 had oophorectomy, and 37 had ovarian salvage. Ages of menarche were similar between surgical groups. Symptoms of menstrual irregularity differed most significantly according to painful menses (oophorectomy, 27.3%; salvage, 59.5%; P < .04). Interestingly, continuation of regular menses after surgery was higher in the oophorectomy group (oophorectomy, 70%; salvage, 15%; P = .013). Unilateral oophorectomy does not appear to impair late gonadal function when compared with ovarian salvage. Surprisingly, oophorectomy appears to maintain more normal ovarian activity as estimated by menstrual regularity. Oophorectomy may be performed without apparent adverse effect on gonadal activity.
    Journal of Pediatric Surgery 06/2012; 47(6):1272-9. · 1.38 Impact Factor
  • Andrew J Murphy, Jason R Axt, Harold N Lovvorn
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    ABSTRACT: In our institutional experience treating pediatric choledochal cysts over the past 12 y, we noted that seven of 32 patients (21.9%) had comorbid congenital cardiac anomalies. This association has not been previously described other than in isolated case reports. We aimed to quantify this association on a national level. We queried the 2009 Healthcare Cost and Utilization Project Kids' Inpatient Database. We identified patients with a diagnosis of choledochal cyst (ICD-9-CM 75169, 75162, and 75160) or biliary atresia (75161). We defined cardiac anomalies using the Clinical Classification Software code (CCS 213). Comorbid choledochal cysts or biliary atresia and congenital cardiac anomalies were quantified in both infant (<12 mo) and child (1-18 y) subpopulations. Of 1646 estimated discharges for patients with choledochal cysts, 506 (30.7%) were for patients who also had congenital cardiac anomalies, compared with 2.6% in the general hospitalized population (χ(2); P < 0.001). The frequency of congenital cardiac anomalies was lower in 1973 hospitalizations for biliary atresia (13.8%) than in those for patients with choledochal cysts (χ(2); P < 0.001). We detected cardiac anomalies in 44.9% of choledochal cyst hospitalizations for infants <12 mo (versus 3.44% general hospitalized population; χ(2); P < 0.001), but in 6.9% of children ages 1-18 y (versus 1.3% general hospitalized population; χ(2); P < 0.001). We observed a strong association between pediatric choledochal cysts and congenital cardiac anomalies that commonly manifests in infancy. When choledochal cysts are diagnosed either prenatally or in infancy, we suggest echocardiographic screening for cardiac anomalies, which may affect the timing of surgery and anesthetic planning.
    Journal of Surgical Research 05/2012; 177(2):e59-63. · 2.02 Impact Factor
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    ABSTRACT: Adults undergoing oncologic resections at low-volume centers experience increased perioperative morbidity and mortality. The volume-outcome effect has not been extensively studied in pediatric oncologic resections. To clarify volume-outcome effects in pediatric oncologic resections, we analyzed resection of renal malignancies in children less than 15 y of age. We conducted a cross-sectional analysis of hospital discharges included in the health care utilization project kids' inpatient database from 1997 to 2009, examining in-hospital operative complications, length of stay (LOS), and inflation-adjusted hospital charges. Hospital volume was expressed as low (n = 1-2), medium (n = 3-4), and high (n > 4) annual volume of resections. One thousand five hundred thirty-eight patients underwent renal malignancy resection. Of these, 527 patients had resection in low-, 422 in medium-, and 589 in high-volume hospitals. Relative to low-volume hospitals, those resected in medium-volume hospitals had an odds ratio of 0.62 (95% confidence interval 0.39-0.99, P = 0.046) for operative complication and those in high-volume hospitals had an odds ratio of 1.02 (95% confidence interval 0.63-1.65, P = 0.95). There was no detectable association with LOS (P = 0.113) or inflation-adjusted charges (P = 0.331). The number of complications, total charges, and LOS attributable to resection of a childhood renal malignancy did not differ among high-, medium-, or low-operative volume hospitals, although oncologic outcomes could not be determined because of the limited nature of this administrative database.
    Journal of Surgical Research 04/2012; 177(1):e27-33. · 2.02 Impact Factor
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    ABSTRACT: Given evolving imaging technologies, we noted significant variation in the diagnostic evaluation of pediatric choledochal cysts (CDC). To streamline the diagnostic approach to CDC, and minimize associated expenses, we compared typing accuracy and costs of ultrasound (US), intraoperative cholangiography (IOC), and magnetic resonance cholangiopancreatography (MRCP). Records of 30 consecutive pediatric CDC patients were reviewed. Blinded to all clinical data, two pediatric radiologists reviewed all US, MRCPs, and IOCs to type CDCs according to the Todani classification. When compared with pathologic findings, the concordance between and accuracy of each diagnostic test were determined. Inflation-adjusted procedure charges and collections for imaging modalities were analyzed. Mean typing accuracy overlapped for US, IOC, and MRCP. Inter-rater reliability was 87 % for US (κ = 0.77), 80 % for IOC (κ = 0.62), and 60 % for MRCP (κ = 0.37). MRCP procedure charges ($1204.69) and collections ($420.85) exceeded IOC and US combined ($264.80 charges, p = 0.0002; $93.40 collections, p = 0.0021). Our data support the use of US alone in the diagnosis of pediatric CDC when no intrahepatic biliary ductal dilatation is visualized. However, when dilated intrahepatic ducts are encountered on US, MRCP should be utilized to distinguish a type I from a type IV CDC, which may alter the operative approach.
    Pediatric Surgery International 04/2012; 28(6):615-21. · 1.22 Impact Factor
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    ABSTRACT: Sub-Saharan African children have an increased incidence of Wilms' tumor (WT) and experience alarmingly poor outcomes. Although these outcomes are largely due to inadequate therapy, we hypothesized that WT from this region exhibits features of biological aggressiveness that may warrant broader implementation of high-risk therapeutic protocols. We evaluated 15 Kenyan WT (KWT) for features of aggressive disease (blastemal predominance and Ki67/cellular proliferation) and treatment resistance (anaplasia and p53 immunopositivity). To explore the additional biological features of KWT, we determined the mutational status of the CTNNB1/β-catenin and WT1 genes and performed immunostaining for markers of Wnt pathway activation (β-catenin) and nephronic progenitor cell self-renewal (WT1, CITED1 and SIX2). We characterized the proteome of KWT using imaging mass spectrometry (IMS). The results were compared to histology- and age-matched North American WT (NAWT) controls. For patients with KWT, blastemal predominance was noted in 53.3% and anaplasia in 13%. We detected increased loss to follow-up (p = 0.028), disease relapse (p = 0.044), mortality (p = 0.001) and nuclear unrest (p = 0.001) in patients with KWT compared to controls. KWT and NAWT showed similar Ki67/cellular proliferation. We detected an increased proportion of epithelial nuclear β-catenin in KWT (p = 0.013). All 15 KWT specimens were found to harbor wild-type CTNNB1/β-catenin, and one contained a WT1 nonsense mutation. WT1 was detected by immunostaining in 100% of KWT, CITED1 in 80% and SIX2 in 80%. IMS revealed a molecular signature unique to KWT that was distinct from NAWT. The African WT specimens appear to express markers of adverse clinical behavior and treatment resistance and may require alternative therapies or implementation of high-risk treatment protocols.
    International Journal of Cancer 03/2012; 131(6):E983-94. · 6.20 Impact Factor

Publication Stats

347 Citations
92.51 Total Impact Points

Institutions

  • 2005–2013
    • Vanderbilt University
      • • Division of Pediatric Surgery
      • • Department of Surgery
      Nashville, Michigan, United States
  • 2012
    • National Cancer Institute (USA)
      Maryland, United States
  • 2008
    • University of Washington Seattle
      • Department of Surgery
      Seattle, WA, United States
  • 2006
    • The University of Tennessee Health Science Center
      • Division of Pediatric Surgery
      Memphis, TN, United States
  • 1998–2000
    • The Children's Hospital of Philadelphia
      • • Division of Neonatology
      • • Children's Institute for Surgical Science
      Philadelphia, PA, United States