Biomedical subjects

G E Besner

Publications and source records attributed to G E Besner.

At least 19 recordsLinked to original sources

PubMed2002

Heparin-binding EGF-like growth factor is present in human amniotic fluid and breast milk.

BACKGROUND/PURPOSE: Heparin-binding EGF-like growth factor (HB-EGF) is a member of the epidermal growth factor (EGF) family that has been implicated in the healing of various organ injuries. Endogenous HB-EGF production is upregulated in response to injury to the kidney, liver, brain, skin, and intestine. Exogenous administration of HB-EGF protects against intestinal epithelial cell apoptosis and necrosis and intestinal ischemia/reperfusion (I/R) injury. This study examines the presence of endogenous HB-EGF in human amniotic fluid and breast milk, fluids that are in intimate contact with the developing and neonatal gastrointestinal tract. METHODS: Breast milk samples were collected from lactating women and amniotic fluid was gathered from full-term uteri (cesarian sections) or preterm uteri (amniocentesis). Crude and partially purified breast milk and amniotic fluid samples were analyzed for HB-EGF levels using an HB-EGF-specific enzyme-linked immunosorbent assay (ELISA). RESULTS: Analysis results showed detectable HB-EGF levels in human amniotic fluid and breast milk, ranging from 0.2 to 230 pg/mL. Breast milk and amniotic fluid subjected to heparin affinity or HB-EGF-affinity column chromatography showed bioactivity eluting at positions consistent with those known for native HB-EGF. CONCLUSIONS: This study represents the first report of detectable HB-EGF in human amniotic fluid and breast milk. The presence of HB-EGF in these fluids may serve a role in the development of the gastrointestinal tract in utero, and in protection against gut mucosal injury after birth.

Amniotic Fluid↗

PubMed2001

Heparin-binding EGF-like growth factor decreases apoptosis in intestinal epithelial cells in vitro.

BACKGROUND/PURPOSE: The production of heparin-binding EGF-like growth factor (HB-EGF) is upregulated during organ injury and has a cytoprotective effect during hypoxic stress in intestinal epithelial cells in vitro and intestinal ischemia-reperfusion injuries in vivo. The purpose of this study was to determine if HB-EGF-related cytoprotection is manifested through alterations in apoptosis. METHODS: Human intestinal epithelial cell monolayers (DLD-1 and Caco-2) were stimulated with interleukin (IL)-1 (20 ng/mL), tumor necrosis factor (TNF)-alpha (40 ng/mL), and interferon (IFN)-gamma (10 ng/mL) with or without HB-EGF (1, 10 or 100 ng/mL) and analyzed for rates of apoptosis utilizing a Cell Death Detection ELISA and flow cytometry. RESULTS: ELISA results showed a 3-fold increase in the level of apoptosis during stimulation with cytokines compared with nonstimulated cells (P <.05). Relative levels of cytokine induced apoptosis were reduced after 12 hours of HB-EGF exposure (P <.05) in a dose-dependent fashion. Results of flow cytometric analysis also showed a reduction in apoptosis at 6 hours when cell monolayers were stimulated with cytokines in conjunction with HB-EGF compared with cytokines alone (P <.05). CONCLUSIONS: HB-EGF downregulated apoptosis in intestinal epithelial cells exposed to proinflammatory cytokines in vitro. The results of this study suggest that alterations in apoptosis may represent a possible mechanism by which this growth factor exerts its cytoprotective effect at the mucosal level during the proinflammatory state.

Analysis of Variance↗

PubMed2001

Heparin-binding EGF-like growth factor decreases inducible nitric oxide synthase and nitric oxide production after intestinal ischemia/reperfusion injury.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been shown to protect intestine from ischemia/reperfusion (I/R) injury in vivo and to down-regulate inducible nitric oxide synthase (iNOS) and nitric oxide (NO) production in intestinal epithelial cells in vitro. The present study was undertaken to investigate whether HB-EGF could modulate the iNOS/NO axis after total midgut I/R injury in rats. I/R injury induced a significant increase in iNOS gene expression (quantified by real-time RT-PCR) and protein production (detected by western blots), as well as elevation of serum NO levels (measured by chemiluminescence assay). Nitrotyrosine (NT) and iNOS production colocalized immunohistochemically, with positive staining found mainly in villous and crypt epithelial cells, as well as ganglion cells. Intraluminal administration of HB-EGF 45 min after the start of a 90-min ischemic interval significantly decreased I/R-induced iNOS gene expression and protein production, as well as serum NO levels. Immunohistochemically, HB-EGF administration led to elimination of iNOS and NT staining in crypt epithelial cells and ganglion cells, with only weak staining that remained in villous epithelial cells. Thus, HB-EGF protects the intestine from I/R injury, at least partially, through down-regulation of the iNOS/NO/NT pathway, a mechanism that is central to I/R injury in multiple organ systems.

Animals↗

PubMed2001

Site-directed mutagenesis of heparin-binding EGF-like growth factor (HB-EGF): analysis of O-glycosylation sites and properties.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a 22 kDa, O-glycosylated protein. HeLa cells infected with a recombinant vaccinia virus expressing human HB-EGF produced a secreted, bioactive protein, with Mr 22,000 that was decreased to 14,000 by treatment with O-glycanase. Site-directed mutagenesis of HB-EGF cDNA using oligonucleotide- and PCR-directed techniques was performed to change the potential glycosylation sites, Thr75 and Thr85, to alanine residues to prevent O-glycosylation. Purification and characterization of the mutant proteins demonstrated that: (i) both O-glycosylation sites of HB-EGF are utilized, (ii) HB-EGF secretion does not require O-glycosylation, (iii) removal of O-glycans does not affect proteolytic cleavage of the HB-EGF precursor, nor does it influence HB-EGF intracellular trafficking or subcellular localization, and (iv) HB-EGF produced by HeLa cells is heavily sialylated. Comparisons between glycosylation mutants and wild-type HB-EGF revealed no significant apparent differences in receptor binding activity.

Alanine↗

PubMed2000

Collision tumors in children: a review of the literature and presentation of a rare case of mesoblastic nephroma and neuroblastoma in an infant.

A mass made up of 2 distinct synchronous primary malignant tumors is a rare event in adults, and exceedingly so in children. Such lesions have been called collision tumors. Reported here is an infant who was found to have a collision tumor comprised of a neuroblastoma and a congenital mesoblastic nephroma, in contiguity, in the right kidney. This is the first report of a collision tumor in an infant. This also is the first report of a synchronous occurrence of a neuroblastoma and a congenital mesoblastic nephroma. The authors present this case and discuss the available literature.

Female↗

PubMed2000

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.

Abdominal Injuries↗

PubMed2000

Fall injuries in the pediatric population: safer and most cost-effective management.

BACKGROUND: At our children's hospital, 30% of all trauma admissions are from falls. The aim of this study was to outline inefficiencies and unnecessary costs incurred in the care of these patients. METHODS: The charts of 127 children admitted for falls (height > or = 9 feet) from 1993 to 1996 were reviewed. Patient demographics, injuries, and treatment costs were recorded and analyzed. RESULTS: Fifty-seven children (45%) were evaluated at an outside facility before transfer. Of these, 73% had injuries requiring treatment at the pediatric center. Local hospital work-up resulted in an average treatment delay of 4.5 hours. Additionally, significant cost was incurred by duplication of radiographic studies, the majority of which were normal. CONCLUSION: Improved and more cost-effective care in pediatric falls can be ensured by immediate transfer of patients with significant injuries, omission of radiographs before transfer, and avoidance of multiple routine x-ray films, the majority of which are normal.

Accidental Falls↗

PubMed1999

Heparin-binding epidermal growth factor-like growth factor protects rat intestine from ischemia/reperfusion injury.

BACKGROUND: We have shown previously that heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) is cytoprotective for intestinal epithelial cells exposed to hypoxia in vitro. We now examine the effects of HB-EGF on the recovery of small intestine from ischemic injury in vivo. METHODS: Segmental intestinal ischemia of 60-min duration was produced in adult rats by occlusion of a first-order branch of the superior mesenteric artery. Recombinant HB-EGF (100 microg) was injected intraluminally into the proximal small bowel after 45 min of ischemia in experimental animals, and buffered saline was injected in control animals. Animals were sacrificed after 48 h, and the affected bowel was resected, processed, and examined microscopically, with histologic grading of the ischemic injury. Additional animals were allowed to recover for up to 1 month to evaluate mortality differences. RESULTS: Intraluminal administration of HB-EGF resulted in significantly decreased extent and severity of ischemia/reperfusion injury, with significantly decreased grade of injury in the HB-EGF-treated compared with nontreated animals (average injury grade 0.66 compared with 2.44, respectively). Moreover, the mortality rate was significantly lower in the HB-EGF-treated animals compared with nontreated animals (0% vs 25%, respectively). HB-EGF-treated animals had increased weight gain in the postischemia recovery period. CONCLUSIONS: We conclude that HB-EGF, given intraluminally, reduces both the amount and the severity of ischemia/reperfusion injury in the small bowel, reduces the mortality associated with intestinal ischemia, and may enhance intestinal recovery. The in vitro and in vivo cytoprotective effects of this growth factor suggest that it may, in the future, be clinically useful in treating patients with intestinal ischemia.

Acute Disease↗

PubMed1999

Bronchopexy for congenital bronchomalacia in the newborn.

Congenital bronchomalacia is a very unusual cause of respiratory distress in the newborn. The surgical management of this anomaly is challenging. The authors report on a newborn with congenital bronchomalacia successfully treated with bronchopexy.

Airway Obstruction↗

PubMed1999

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.

Abdominal Injuries↗

PubMed1999

Induction of anchorage independent growth by heparin-binding EGF-like growth factor (HB-EGF).

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is initially synthesized as a membrane bound protein that is subsequently processed to yield an approximately 74 amino acid secreted product. To investigate the biological activities of HB-EGF and its role(s) in tumor formation, the full-length HB-EGF cDNA was cloned under the regulation of the mouse metallothionein promoter and stably expressed in HB-EGF deficient mouse L cells. HB-EGF immunoreactive proteins of 21 and 24 kDa were observed from transfected MLC lysates, and these lysates exhibited the ability to bind to the EGF receptor, stimulate 3H-thymidine uptake in BALB/c-3T3 cells, and induce anchorage independent growth (AIG) of normal rat kidney (NRK) cells. Furthermore, NRK cells treated with either E. coli-derived or vaccinia virus-derived HB-EGF, as well as NRK cells directly transfected with the HB-EGF construct, demonstrated AIG. We conclude that HB-EGF is a potent growth factor capable of stimulating altered cell growth and anchorage independence.

3T3 Cells↗

PubMed1998

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.

Amino Acid Sequence↗

PubMed1998

A standardized model of partial thickness scald burns in mice.

BACKGROUND: Large mammal partial thickness wound models were developed primarily for their anatomical similarity to human wounds, yet lack the economy, ease of handling, and statistical power afforded with rodent models. Previous small mammal models of partial thickness burn injury have failed to demonstrate complete reepithelialization in less than 3 weeks. We present a murine partial thickness scald model with a reepithelialization rate comparable to that of porcine wound models. METHODS: Thirty-eight adult male mice were secured in a burn template allowing exposure of a 2 x 3-cm area of the shaved dorsum to 60 degreesC water for 45 s, followed by 4 degreesC water for 45 s. Four wounds were harvested daily on Postburn Days 1-7, 10, and 14 for histologic evaluation. RESULTS: Histologic evidence of partial thickness dermal injury with sparing of dermal appendage epithelial cells was seen in all wounds. Of 134 wound sections evaluated 26 contained some areas of full thickness dermal injury, with only 8 of these 26 sections showing full thickness injury in 50% or more of the cross-sectional area of the wounds. Complete wound reepithelialization was seen between Postburn Days 10 and 14. The viable dermal thickness in all burn cross sections was at least 40-80 micrometers, and up to 1400 micrometers in reepithelialized wounds. CONCLUSIONS: This murine model of partial thickness scald injury provides a standardized thermal wound with consistent depth of injury, low mortality, and a reepithelialization rate between 10 and 14 days. A simple protocol allows easy production of 30-50 wounds daily with one technician.

Animals↗

PubMed1998

Cystic degeneration of heterotopic pancreas.

The case of a large cyst arising from heterotopically-situated pancreatic tissue in an 11-month-old girl is reported. This is the first published report of childhood pancreatic cyst that developed in heterotopic pancreatic tissue. There is strong evidence to suggest that the cyst became symptomatic as a result of secondary infection, an additional unreported phenomenon. This case serves to underscore the fact that pancreatic cysts should be considered in the differential diagnosis of intestinal duplication cysts of childhood.

Choristoma↗

PubMed1998

Heparin-binding EGF-like growth factor is cytoprotective for intestinal epithelial cells exposed to hypoxia.

BACKGROUND: During recovery from intestinal ischemic injury, there is rapid growth of intestinal epithelia with regeneration of damaged villi. This study examines the effects of heparin-binding EGF-like growth factor (HB-EGF) on the recovery of intestinal epithelial cells exposed to hypoxia. METHODS: The cytoprotective effects of HB-EGF were analyzed by placing IEC-18 cells in an anaerobic chamber with various timed HB-EGF treatments (prehypoxia, posthypoxia, pre- and posthypoxia, and no treatment). After 10 hours of hypoxia, lactate dehydrogenase (LDH) release, actin-filament (structural) integrity, adenosine triphosphate (ATP) levels, and posthypoxia proliferative activity were evaluated. RESULTS: LDH analysis showed that HB-EGF exerted a cytoprotective effect during hypoxia. Pretreated cells had a significantly lower death rate during recovery (7.48%) compared with cells with no HB-EGF treatment (22.19%, P < .009). Confocal microscopic structural analysis of posthypoxia cells showed that F-actin structure was maintained in treated cells, whereas nontreated cells showed increased structural deterioration. ATP levels were significantly higher in the HB-EGF-treated cells compared with nontreated cells at 48 hours (P < .05). Finally, HB-EGF-treated cells had a significantly improved proliferative ability compared with nontreated cells during recovery from hypoxia (P < .05). CONCLUSIONS: HB-EGF is a mitogenic growth factor for intestinal epithelial cells. Moreover, HB-EGF appears to protect intestinal epithelial cells from hypoxia, in part via maintenance of cytoskeletal structure and ATP stores. Finally, HB-EGF-treated cells also appear to have better proliferative abilities during recovery from hypoxia.

Actins↗

PubMed1998

Nonteratomatous germ cell tumors in children.

BACKGROUND/PURPOSE: Totipotential germ cells may give rise to a broad range of tumors. The teratomatous variety of germ cell tumors has been the subject of several large studies. The goal of the current study was to describe the clinical features of nonteratomatous germ cell tumors (NTGCT) by reviewing a large series of patients. METHODS: Between 1945 and 1997, there were 78 cases of nonteratomatous germ cell tumors (NTGCT's) in children at The Children's Hospital, Columbus. Their records were reviewed retrospectively. There were 35 boys and 43 girls (M:F ratio 0.8). Mean follow-up was 87 months. RESULTS: Histological subtypes included germinoma (33 cases, 42%), endodermal sinus tumor (24 cases, 31%), embryonal carcinoma (12 cases, 15%), gonadoblastoma (4 cases, 5%), mixed histology (4 cases, 5%), and choriocarcinoma (1 case, 2%). Forty-two tumors were in gonadal sites, but a significant percentage were extragonadal (36 cases, 46%). Forty-six patients (59%) had localized disease, 18 (23%) had regional disease, and 14 (18%) had metastases. Treatment consisted of surgery and selective chemotherapy and radiation. Complete tumor resection was more likely for gonadal (29 of 42, 69%) than extragonadal primaries (15 of 36, 41%; P < or = .05). Forty-nine (63%) of all patients survived, whereas 29 (37%) died of their disease. Survival in patients with gonadal primaries (32 of 42, 76%) exceeded that in patients with extragonadal primaries (17 of 36, 47%; P < or = .01). Survival in patients with localized disease (34 of 46, 74%) exceeded that in patients with regional extension or metastases (15 of 32, 47%; P < .05). CONCLUSIONS: This study highlights the fact that tumor location, gonadal versus extragonadal, was important in determining prognosis, whereas tumor histology was not. This may be the result of a higher rate of complete tumor resection for gonadal primaries and underscores the important role of surgery in the optimal treatment of these unusual tumors.

Adolescent↗

PubMed1998

Pediatric testicular problems.

Testicular problems in children may be both congenital and acquired. These problems are often difficult to diagnose and carry significant sequelae if untreated. Early surgical consultation is often needed for correction of the problem. This article reviews the pathophysiology of the most common pediatric testicular abnormalities with emphasis on the diagnostic modalities employed and current treatment alternatives.

Cryptorchidism↗

PubMed1997

Pediatric electrical burns: management strategies.

The purpose of the present study was to analyse the course of patients hospitalised with electrical burn wounds in the past 25 years at a major children's hospital in the United States in order to devise safe and cost effective management strategies for these patients. The study was a retrospective chart review of patients with electrical injuries admitted to the hospital between 1971 and 1995. We identified 127 children who were included in the study. Injuries resulted from biting an electrical cord (oral injury) (n = 48), placing an object into an electrical socket (outlet injury) (n = 33), contacting a low voltage wire or appliance indoors (low voltage household injury) (n = 25), contacting a high voltage wire outdoors (high voltage wire injury) (n = 18), or being struck by lightning (n = 3). A retrospective review revealed that the great majority of patients with low voltage electrical injuries did not need admission to the hospital and could have been cared for on an outpatient basis. Almost every patient with high voltage injury had a justified admission due to the severity of the injury. On the basis of these results we conclude that we can safely reduce the number of admissions to the hospital for children with low voltage minor electrical injuries.

Adolescent↗