Gail E. Besner

Focused abdominal sonography for trauma (FAST) in children with blunt abdominal trauma

BACKGROUND Focused abdominal sonography for trauma (FAST) has been well reported in adults, but its applicability in children is less well established. We decided to test the hypothesis that FAST and computed tomography (CT) are equivalent imaging studies in the setting of pediatric blunt abdominal trauma. METHODS One hundred seven hemodynamically stable children undergoing CT for blunt abdominal trauma were prospectively investigated using FAST. The ability of FAST to predict injury by detecting free intraperitoneal fluid was compared with CT as the imaging standard. RESULTS Thirty-two patients had CT documented injuries. There were no late injuries missed by CT. FAST detected free fluid in 12 patients. Ten patients had solid organ injury but no free fluid and, thus, were not detected by FAST. The sensitivity of FAST relative to CT was only 0.55 and the negative predictive value was only 0.50. CONCLUSION FAST has insufficient sensitivity and negative predictive value to be used as a screening imaging test in hemodynamically stable children with blunt abdominal trauma.

Pathophysiology of congenital diaphragmatic hernia III: Exogenous surfactant therapy for the high-risk neonate with CDH

Exogenous surfactant therapy (EST) in surfactant-deficient premature infants has been shown to improve lung compliance, decrease morbidity, and improve survival. Reports have demonstrated that newborns with congenital diaphragmatic hernia (CDH) have lung compliance, pressure-volume curves, and hyaline membrane formation resembling those changes seen in surfactant deficient premature newborns. We hypothesize that EST may also benefit infants with CDH. All high risk cases of prenatally diagnosed CDH at Childrens Hospital of Buffalo from November 1988 to February 1991 were prospectively evaluated for EST. In those families who chose to participate, the surfactant preparation, Infasurf (100 mg/kg), was instilled into the newborns lungs prior to the first breath. The remainder of the perinatal, neonatal, and surgical care was performed in a routine manner. Three high-risk prenatally diagnosed newborns with left CDH were treated with EST. All showed signs of decreased pulmonary compliance, but could still be adequately oxygenated and ventilated. Surgical correction was performed after stabilization and all required patch closures. Two of the three infants suffered no life-threatening episodes of pulmonary hypertension and all survived. These infants had many known indicators for poor outcome in CDH with an expected survival of less than 20%. We believe that EST in these neonates with CDH contributed to their survival with minimum morbidity. These results suggest that surfactant replacement for the high-risk neonate with CDH warrants further consideration and a randomized clinical trial is being planned.

HB-EGF promotes angiogenesis in endothelial cells via PI3-kinase and MAPK signaling pathways.

Objective: Heparin-binding EGF-like growth factor (HB-EGF) belongs to the epidermal growth factor (EGF) superfamily of ligands. It has been implicated as a regulator of angiogenesis. However, the mechanisms by which HB-EGF promotes angiogenesis are unknown. The goal of the present study was to define the pathways by which HB-EGF stimulates angiogenesis in endothelial cells. Methods: To characterize the angiogenic activity of HB-EGF, we treated human umbilical vein endothelial cells (HUVEC) with HB-EGF and analyzed the effects on cell proliferation, migration and tube formation. Side-by-side assays with EGF were used for comparison. Results: Both HB-EGF and EGF stimulated HUVEC migration in scratch assays and promoted vascular tube formation in 2D-angiogenesis assays, without inducing cell proliferation. HB-EGF- and EGF-induced HUVEC migration and capillary tube formation were dependent upon activation of PI3K, MAPK and eNOS. Importantly, HB-EGF-and EGF-induced tube formation was comparable to, but were independent of tube formation induced by VEGF. Conclusions: We have demonstrated that HB-EGF and EGF induce angiogenesis via activation of PI3K, MAPK and eNOS in a VEGF-independent fashion. Thus, the role played by HB-EGF in stimulating physiologic processes such as wound healing in vivo may be dependent, in part, on its ability to promote angiogenesis.

Necrotizing enterocolitis in term neonates: data from a multihospital health-care system

Objective:In the past 5½ years, 30 term or near-term neonates in the Intermountain Healthcare system developed necrotizing enterocolitis (NEC) Bells stage ⩾II. We sought to identify possible explanations for why these patients developed NEC, by comparing them with 5847 others that did not develop NEC, from the same hospitals and of the same gestational ages, cared for during the same 5½-year period.Study design:Data were collected from neonates admitted to any of the Intermountain Healthcare NICUs with a birth date from 1 January 2001 to 30 June 2006, and a gestational age >36 weeks. A variety of patient features and feeding practices were compared between those that did vs did not develop NEC.Result:Forty-one neonates >36 weeks gestation were listed in the discharge records as having NEC of Bells stage II or higher. However, on review of these 41 medical records, 11 were seen to have had NEC of Bells stage I, whereas the remaining 30 had radiographs and clinical courses indicative of Bells stage ⩾II. Those 30 formed the basis of this study. Twenty-eight of the 30 developed NEC after having been admitted to an NICU for some other reason; the other two developed NEC at home, within 2 days of being discharged from an NICU. The 30 that developed NEC were more likely than the 5847 that did not develop NEC, to have congenital heart disease (P=0.000), polycythemia (P=0.002), early-onset bacterial sepsis (P=0.004) or hypotension (P=0.017). All 30 received enteral feedings before NEC developed; 29 were fed either artificial formula or a mixture of formula and breast milk. The one that was exclusively fed human milk was fed human milk with added fortifier (24 cal/oz). The 30 that developed NEC were more likely to be fed formula exclusively (P=0.000). Seven of the 30 had a laparotomy for NEC; two of the seven had total bowel necrosis and support was withdrawn. The other five had perforations and bowel resections. The mortality rate was 13% (4/30).Conclusion:In our series, NEC among term or near-term neonates was exclusively a complication developing among patients already admitted to a NICU for some other reason. We speculate that the combination of reduced mesenteric perfusion and feeding with artificial formula were factors predisposing them to develop NEC.

Small Bowel Injury in Children after Blunt Abdominal Trauma: Is Diagnostic Delay Important?

OBJECTIVE To assess the incidence and consequences of small bowel injury (SBI) in children suffering blunt abdominal trauma managed with the intent to treat nonoperatively. DESIGN Retrospective chart review. MATERIALS AND METHODS A total of 168 consecutive hemodynamically stable children admitted to a Level I pediatric trauma center during a 24-month period. RESULTS Nine of 168 children (5%) sustained SBI: three underwent early (< 4 hours) operation for recognized SBI (identified on computed tomographic scan); and six had delayed (36 +/- 16 hours) operation for missed SBI (not identified on computed tomographic scan). Increased temperature and heart rate, or decreased urine output at 24 hours suggested occult SBI. The hospital course was unaltered by delayed diagnosis. Fifty-seven percent of the children (95) suffered intra-abdominal injury; 10% required laparotomy for SBI (9) or solid organ injury (7); 90% (152) were discharged without laparotomy. CONCLUSIONS SBI is uncommon in children suffering blunt abdominal trauma. The diagnosis can be made using clinical and radiographic findings. Limited diagnostic delay does not seem to affect outcome. We conclude that clinical diagnosis of SBI is safe, permits the nonoperative treatment of most blunt abdominal injuries, and reduces the risk of unnecessary laparotomy associated with alternate approaches.

Structure and function of heparin-binding EGF-like growth factor (HB-EGF).

Heparin-binding EGF-like growth factor (HB-EGF) is a 22 kDa, O-glycosylated protein that is mitogenic for fibroblasts, smooth muscle cells (SMC) and epithelial cells. This review describes the primary structure of HB-EGF, as well as its processing. The structure of the mouse and human HB-EGF genes is also discussed. Finally, this review summarizes HB-EGF expression patterns, receptor-mediated signaling, and role in several important biological systems.

Endogenous production of heparin-binding EGF-like growth factor during murine partial-thickness burn wound healing.

Heparin-binding EGF-like growth factor (HB-EGF), a potent epithelial cell mitogen, has been identified in human burn blister fluid and excised human burn wounds. Topical application of HB-EGF to murine partial-thickness scald burns accelerated reepithelialization, increased keratinocyte proliferation, and enhanced production of endogenous transforming growth factor-alpha in the healing wounds. The goal of the present study was to examine the production of endogenous HB-EGF and transforming growth factor-alpha (TGF-alpha) in a murine partial-thickness scald burn model. Keratinocyte proliferation was assessed by 5-bromo-deoxyuridine incorporation, and tissue sections were examined by in situ hybridization for HB-EGF mRNA expression and by immunohistochemistry for HB-EGF and TGF-alpha production. HB-EGF mRNA expression and production of HB-EGF and TGF-alpha proteins by both marginal surface keratinocytes and hair follicle epithelial cells reached a maximum by postburn day five and decreased thereafter. This corresponded to the peak period of keratinocyte proliferation. We conclude that HB-EGF and TGF-alpha act in conjunction to stimulate wound healing following thermal injury.

Interaction of Heparin-Binding EGF-Like Growth Factor (HB-EGF) with the Epidermal Growth Factor Receptor: Modulation by Heparin, Heparinase, or Synthetic Heparin-Binding HB-EGF Fragments

The binding of heparin-binding EGF-like growth factor (HB-EGF) to the epidermal growth factor (EGF) receptor of human endometrial carcinoma cells was compared to that of EGF using an 125I-EGF radioreceptor assay. The inhibitory effect of HB-EGF on 125I-EGF binding was reversed either in the presence of heparin (but not by chondroitin sulfate) or by pre-treating the cells with heparinase. These treatments did not affect the binding of EGF to its receptor. To map potential regions in the HB-EGF molecule that mediate its heparin-dependent interaction with the EGF receptor, HB-EGF peptides were synthesized that were non-homologous to EGF. Accordingly residues 20-25 and 36-41, but not residues 8-19, of HB-EGF were found to be (i) heparin-binding and (ii) modulators of HB-EGF (but not of EGF) binding to the EGF receptor.

Preliminary experience with focused abdominal sonography for trauma (FAST) in children: is it useful?

BACKGROUND/PURPOSE Most pediatric surgeons and pediatric radiologists consider computed tomography (CT) the best radiological test for the evaluation of children with suspected intraabdominal injury. The majority of injured children evaluated with CT will be found to have a normal scan. Focused abdominal sonography for trauma (FAST) has been shown to be a useful screening test in the evaluation of adult patients with suspected intraabdominal injury. Limited data exist regarding the use of FAST in children. Our aim was to evaluate the usefulness of FAST as a screening test in the evaluation of children with suspected intraabdominal injury in an attempt to minimize the number of normal CT scans performed. METHODS Hemodynamically stable children evaluated for suspected intraabdominal injury were prospectively screened with FAST. FAST, real-time sonography at four sites, was performed by staff pediatric radiologists. The average duration of the examination was 2 minutes. Positive and negative FAST scan findings were defined prospectively. The result of each FAST was recorded (positive or negative) and then all patients underwent CT as a control. All management decisions were based on CT results. RESULTS Forty-six patients were included in the study. FAST identified four children with positive findings (free intraperitoneal fluid), whereas CT showed 13 children with injuries (nine with associated free intraperitoneal fluid and four with only solid organ injury and no associated intraperitoneal fluid). There were nine false-negative and no false-positive FAST scans. The sensitivity of FAST was 0.3 and the specificity was 1.0. Injuries missed by FAST included liver laceration, adrenal hematoma, renal laceration, small bowel injury and splenic laceration. CONCLUSION Preliminary results suggest that FAST alone is not a useful screening test in the evaluation of children with suspected intraabdominal injury.

Heparin-binding EGF-like Growth Factor Protects Intestinal Stem Cells from Injury in a Rat Model of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is an often catastrophic disease that typically affects premature newborns. Although the exact etiology of NEC is uncertain, the disease is associated with formula feeding, bacterial colonization of the gut, hypoxia and hypoperfusion. In light of the pathogenesis of NEC, the integrity and function of the intestinal mucosa has a major defensive role against the initiation of NEC. Various forms of intestinal injury, including NEC, injure the intestinal epithelial cell (IEC) lineages, including the intestinal stem cells (ISCs), thereby disrupting the normal homeostasis needed to maintain gut barrier function. In the current study, we examined the effects of heparin-binding EGF-like growth factor (HB-EGF) administration on enterocytes, goblet cells, neuroendocrine cells and ISCs in a newborn rat model of experimental NEC. We also examined the cytoprotective effects of HB-EGF on ISCs in in vitro cell cultures and in ex vivo crypt-villous organoid cultures. We found that HB-EGF protects all IEC lineages, including ISCs, from injury. We further found that HB-EGF protects isolated ISCs from hypoxic injury in vitro, and promotes ISC activation and survival, and the expansion of crypt transit-amplifying cells, in ex vivo crypt-villous organoid cultures. The protective effects of HB-EGF were dependent on EGF receptor activation, and were mediated via the MEK1/2 and PI3K signaling pathways. These results show that the intestinal cytoprotective effects of HB-EGF are mediated, at least in part, through its ability to protect ISCs from injury.