Multiple surgical interventions due to recurrent intussusception in a patient with henoch-schönlein purpura: a case report

Gastrointestinal (GI) symptoms in Henoch-Schönlein purpura (HSP) are common and occur in about two-thirds of patients. Surgical complications, while uncommon, are potentially severe. The preoperative diagnosis is based mainly on a high index of suspicion leading to imaging studies that may include abdominal sonography. We describe here the first case of a patient who developed recurrent intussusception attributed to HSP that led to repeated surgical interventions.

Salivary gland choristoma of the anterior chest wall

Salivary gland choristoma (heterotopic salivary gland tissue) is a rare condition that occurs at various locations within the head and neck. Diagnostic criteria and embryogenesis of this entity remain unclear. Presented herein is the first reported case of salivary gland choristoma on the anterior chest wall. Surgical treatment is recommended.

Diminished epidermal growth factor levels in infants with necrotizing enterocolitis

BACKGROUND/PURPOSE

Because epidermal growth factor (EGF) is trophic to the intestinal mucosa, and neonatal necrotizing enterocolitis (NEC) is associated with a disrupted intestinal mucosal barrier, the authors sought to determine whether diminished levels of EGF were present in infants with NEC.

METHODS

Saliva, serum, and urine specimens were obtained from infants with NEC during a 3-year period (February 1995 to May 1998). Control patients without NEC were chosen based on similar postnatal age and birthweight. EGF levels were determined by enzyme-linked immunosorbent assay (ELISA). Differences between groups were compared using Mann-Whitney Rank sum test with P less than .05 considered significant. Results are presented as mean values +/-SEM.

RESULTS

Twenty-five infants with NEC were compared with 19 control patients. Birth weight (1,616+/-238 g control v. 1,271+/-124 g NEC) and postnatal age (23+/-6 days control v. 22+/-3 days NEC) were similar. Infants with NEC had significantly lower levels of EGF in both saliva (590+/-80 pg/mL control v. 239+/-41 pg/mL NEC; P<.001) and serum (35+/-8 pg/mL control v. 5.6+/-1.9 pg/mL NEC; P<.001). Urinary EGF was also lower in the NEC group, but was not statistically significant.

CONCLUSIONS

Premature infants with NEC have significantly diminished levels of salivary and serum EGF. Reduced levels of this growth factor may distinguish infants at risk for NEC and play a pivotal role in the pathogenesis of the perturbed intestinal mucosal barrier that is central to this condition.

Differential expression of ileal Na(+)/H(+) exchanger isoforms after enterectomy

BACKGROUND

Na(+)/H(+) exchangers (NHE) are transporters involved in the absorption of NaCl along the gastrointestinal tract. The aim of this study was to determine the expression pattern of the intestinal brush border NHE isoforms 2 and 3 following massive small bowel resection (SBR). Additionally, the effect of epidermal growth factor (EGF) and salivarectomy (removal of the primary source of EGF) on the expression pattern was studied.

MATERIALS AND METHODS

ICR mice underwent a proximal SBR or sham surgery and then received either orogastric saline or EGF (50 microg/kg/day). In separate experiments mice underwent salivarectomy followed by SBR or sham. Postoperatively the remaining ileum was isolated and levels of NHE-2 and NHE-3 mRNA and protein were resolved.

RESULTS

Following SBR, the expression of both mRNA and protein for NHE-3 increased by approximately 2.5-fold. Treatment with EGF enhanced NHE-3 mRNA in sham animals with further elevation following SBR. The expression of NHE-2 mRNA demonstrated minimal change while protein marginally increased (40%) following SBR. EGF did not affect the expression of NHE-2 mRNA. Salivarectomy did not influence NHE-2 protein expression and inhibited the increased NHE-3 protein expression following SBR.

CONCLUSIONS

Following SBR, the expression pattern for brush border NHE isoforms is distinctive. Increased expression of NHE-3 secondary to SBR and/or EGF treatment with loss of this increase following salivarectomy implies a common mechanism to enhance enterocyte proliferation and luminal absorption of NaCl and water. These results suggest that NHE-3 is an important ileal exchanger following SBR.

Intestinal overexpression of EGF in transgenic mice enhances adaptation after small bowel resection

The effect of direct intestinal overexpression of epidermal growth factor (EGF) on postresection adaptation has been investigated by the production of transgenic mouse lines. A murine pro-EGF cDNA construct was produced, and expression of the EGF construct was targeted to the small intestine with the use of the rat intestinal fatty acid-binding protein promoter. An approximately twofold increase in intestinal EGF mRNA and protein was detected in heterozygous mice. No changes in serum EGF levels were noted. Except for a slightly shortened small intestine, no other abnormal phenotype was observed. Intestinal adaptation (increases in body weight, DNA, protein content, villus height, and crypt depth) was markedly enhanced after a 50% proximal small bowel resection in transgenic mice compared with nontransgenic littermates. This transgenic mouse model permits the study of intestinal adaptation and other effects of EGF in the small intestine in a more physiological and directed manner than has been previously possible. These results endorse a direct autocrine/paracrine mechanism for EGF on enterocytes as a means to enhance adaptation.

Intestinal adaptation and enterocyte apoptosis following small bowel resection is p53 independent

Adaptation following small bowel resection (SBR) signals enterocyte proliferation and apoptosis. Because p53-induced p21(waf1/cip1) may be important for apoptosis in many cells, we hypothesized that these genes are required for increased enterocyte apoptosis during adaptation. Male C57BL/6 (wild-type) or p53-null mice underwent 50% proximal SBR or sham operation (bowel transection-reanastomosis). Adaptation (DNA-protein content, villus height-crypt depth, enterocyte proliferation), appearance of apoptotic bodies, and p53 and p21(waf1/cip1) protein expression were measured in the ileum after 5 days. Adaptation was equivalent after SBR in both wild-type and p53-null mice as monitored by significantly increased ileal DNA-protein content, villus height, and enterocyte proliferation. The number of crypt apoptotic bodies increased significantly after SBR evenly in both wild-type and p53-null mice. In the p53-null mice, SBR substantially induced the expression of p21(waf1/cip1) protein in villus enterocytes. The p53-independent induction of p21(waf1/cip1) may account for the similar intestinal response to SBR between wild-type and p53-null mice. Intestinal adaptation and increased enterocyte apoptosis following intestinal resection occur via a p53-independent mechanism.

Apoptosis and the pattern of DNase I expression following massive small bowel resection

INTRODUCTION

Following massive small bowel resection (SBR), histologic evidence of increased enterocyte apoptosis has been demonstrated in several animal models. Deoxyribonuclease I (DNase I) is requisite for intranuclear cleavage of DNA during apoptosis; we therefore hypothesized that the expression of this gene would be increased following SBR.

METHODS

Male ICR mice underwent either 50% proximal SBR or sham surgery (bowel transection/reanastomosis). After 12 h and 1, 3, and 7 days, rates of enterocyte proliferation and apoptosis were recorded as well as DNase I mRNA expression and activity.

RESULTS

Adaptation after SBR was confirmed at each time point by increased proliferation. Enterocyte proliferation was increased by 12 h and apoptosis was increased by 24 h and remained elevated through Day 7. When compared with sham-operated mice, SBR resulted in a twofold increase in both DNase I expression and activity at 24 h postoperatively, which returned to baseline by Postoperative Day 3.

CONCLUSIONS

DNase I expression and activity are increased early following massive SBR but return to baseline despite persistent increased rates of enterocyte apoptosis and proliferation. This enzyme may be important in the early induction of apoptosis following massive SBR, but not once a new set point has been established in the balance between the rate of enterocyte production and enterocyte loss.

The adaptive intestinal response to massive enterectomy is preserved in c-SRC-deficient mice

BACKGROUND/PURPOSE

The Src family of protein tyrosine kinases has been implicated in the downstream mitogenic signaling of several ligands including epidermal growth factor (EGF). Because EGF likely plays a role in adaptation after massive small bowel resection (SBR), we tested the hypothesis that c-src is required for this important response.

METHODS

A 50% proximal SBR or sham operation (bowel transection or reanastomosis alone) was performed on c-src-deficient (n = 14) or wild-type (C57bl/6) mice (n = 20). The ileum was harvested on postoperative day 3 and adaptive parameters determined as changes in ileal wet weight, protein and DNA content, proliferation index, villus height, and crypt depth. Comparisons were done using analysis of variance (ANOVA), and a Pvalue less than .05 was considered significant. Values are presented as mean +/- SEM.

RESULTS

The activity of c-src was increased in the ileum of wild-type mice after SBR but remained unchanged in c-src-deficient mice. Despite this lack of increase, adaptation occurred after SBR in the c-src-deficient mice as demonstrated by increased ileal wet weight, protein and DNA content, proliferation index, villus height, and crypt depth similar to wild-type mice.

CONCLUSIONS

The adaptive response of the intestine to massive SBR is preserved despite reduced activity of the c-src protein. The mitogenic signaling that characterizes intestinal adaptation and is associated with receptor activation by EGF or other growth factors probably occurs by mechanisms independent of c-src protein tyrosine kinase.

The expression and activation of EGF and c-NEU receptors are increased in enterocytes during intestinal adaptation

BACKGROUND/PURPOSE

After massive small bowel resection (SBR), epidermal growth factor (EGF) and its intestinal receptor (EGF-R) play major roles during adaptation. The expression of a homologous enterocyte receptor termed c-neu (c-neu-R) is capable of forming heterodimers with EGF-R to facilitate cellular signaling. The purpose of this study was to determine the expression and activation of EGF-R and c-neu-R during the adaptive intestinal response to SBR.

METHODS

Male ICR mice underwent either SBR or sham surgery. After 1, 3, and 7 days, enterocytes were isolated and protein immunoprecipitated with antibody to either EGF-R or c-neu-R. Receptor protein expression and activation status were determined.

RESULTS

When compared with sham operation, the expression and activation status of both EGF-R (six- and twofold, respectively) and c-neu-R (nine- and twofold, respectively) were increased substantially in enterocytes from the adapting ileum after SBR by postoperative day 3. Minimal changes were appreciated for either EGF-R or c-neu-R expression or activation in the remnant bowel after enterocyte removal, liver, or kidney.

CONCLUSIONS

Both the expression and activation status of EGF-R and c-neu-R are increased substantially in enterocytes from the adapting ileum by postoperative day 3 after massive SBR. These changes provide a unique mechanism for the enterocyte to enhance cellular signaling in response to EGF during intestinal adaptation.

The effect of epidermal growth factor on differentiation of isolated enterocytes after small bowel resection

BACKGROUND/PURPOSE

In previous studies using mucosal scrapings or whole-bowel homogenates, epidermal growth factor (EGF) augments adaptation after massive small bowel resection (SBR). The purpose of this study was to determine directly the effect of adaptation and EGF on enterocyte differentiation using an explicit enterocyte cell population.

METHODS

Male ICR mice underwent 50% proximal SBR or sham (bowel transection-reanastomosis) and were selected randomly to either orogastric saline or EGF (50 microg/kg/d). After 3 days, enterocytes were isolated from the remnant ileum by mechanical vibration and assayed for DNA and protein content as well as sucrase and alkaline phosphatase (AlkP) activity.

RESULTS

Ileal wet weight, enterocyte protein, and DNA content were increased significantly after SBR and boosted even further with EGF. When normalized for protein, SBR caused an increase in AlkP and sucrase activity, and EGF treatment caused AlkP and sucrase activity to return to baseline.

CONCLUSIONS

EGF enhances adaptation; however, when normalized for protein, the activity of two enterocyte-specific enzymes was not significantly altered by EGF. This analysis of an explicit enterocyte population supports the notion that the beneficial effects of EGF are more likely caused by increased numbers of enterocytes rather than an increase in the functional activity of each individual cell.

The distribution of endogenous epidermal growth factor after small bowel resection suggests increased intestinal utilization during adaptation

BACKGROUND/PURPOSE

Although exogenous epidermal growth factor (EGF) amplifies adaptation after massive small bowel resection (SBR), the role for endogenous EGF is unclear. The authors sought to determine whether SBR was associated with changes in the levels of EGF in the serum, saliva, or urine and EGF receptor (EGF-R) signaling in the ileum.

METHODS

Male ICR mice underwent 50% proximal SBR or sham surgery bowel transection/reanastomosis). After 3 days, levels of EGF were measured by enzyme-linked immunosorbent assay (ELISA) in the serum, saliva, and urine. EGF-R activation was measured in isolated ileal enterocytes by probing an EGF-R immunoprecipitate with an antibody to phosphotyrosine.

RESULTS

When compared with sham, SBR resulted in no change in serum, increased salivary (2209+/-266 nmol SBR v 1183+/-119 nmol sham, P<.05) and decreased urinary (417+/-58 nmol SBR v 940+/-143 nmol sham; P<.05) EGF levels. EGF-R activation increased 2.5-fold after SBR.

CONCLUSIONS

Increased salivary and reduced urinary EGF linked with enhanced EGF-R activation suggests increased ileal utilization of EGF during adaptation. This observation, along with the known beneficial effects of exogenous EGF, infers a crucial role for endogenous EGF in the pathogenesis of intestinal adaptation after SBR.

Adaptation after small bowel resection is attenuated by sialoadenectomy: the role for endogenous epidermal growth factor

BACKGROUND

Epidermal growth factor (EGF) is likely involved during adaptation after small bowel resection (SBR) because some studies have shown enhanced adaptation by EGF administration. Because the major source of endogenous EGF in mice is the submandibular glands, we sought to determine the effect of submandibular gland excision (SAL) and luminal or systemic EGF replacement on adaptation after SBR.

METHODS

A 50% proximal SBR or Sham-SBR (bowel transection and reanastomosis) was performed on male C57BL/6 mice after either SAL or gland mobilization only. Additional mice underwent both SBR and SAL and then received daily EGF or saline solution by intraperitoneal or orogastric administration. At 1 week, adaptation was characterized in the ileum as changes in villus height, DNA, and protein content.

RESULTS

SAL significantly attenuated the increase in ileal villus height, total protein, and DNA content after SBR. Both systemic and oral EGF reversed these findings equally and significantly augmented all parameters of intestinal adaptation after SAL.

CONCLUSIONS

Submandibular EGF is important for the adaptive response to massive SBR. As both luminal and systemic EGF equally reversed the findings following SAL and SBR, the specific site of action for endogenous EGF during adaptation is either the luminal or basolateral surface of the enterocyte.

Intestinal adaptation is enhanced by epidermal growth factor independent of increased ileal epidermal growth factor receptor expression

BACKGROUND/PURPOSE

Intestinal adaptation after massive small bowel resection (SBR) is augmented by epidermal growth factor (EGF) via an unknown mechanism. We recently have observed that EGF increases the expression of EGF receptor mRNA and protein content in the remnant ileum after SBR. The purpose of this study was to determine whether the magnitude of EGF-induced receptor expression correlates with intestinal adaptation.

METHODS

A 50% proximal SBR or sham operation (bowel transection with reanastomosis) was performed on male ICR mice. Animals from each group were then selected randomly to receive either human recombinant EGF (150 microg/kg/d) or saline by twice daily intraperitoneal injections. The remnant ileum was harvested at 1 week, and parameters of adaptation measured as changes in protein content. Ileal EGF receptor mRNA was quantitated using a ribonuclease protection assay. Changes in the expression ileal EGF receptor protein were determined by Western blot after immunoprecipitation. Comparisons of mean values between groups was performed using analysis of variance (ANOVA) and a P value of less than .05 was considered significant. Values are presented as mean +/- SEM.

RESULTS

EGF was mitogenic to the ileum after sham operation as monitored by increases in ileal protein content (2.21 +/- 0.002 mg/cm Sham v 2.97 +/- 0.25 mg/cm Sham +/- EGF; P < .05). After SBR, adaptation resulted in increased ileal protein content (4.45 +/- 0.27 mg/cm), which was substantially boosted by EGF (5.98 +/- 0.39 mg/cm; P < .05). No differences were detected in ileal EGF receptor mRNA or protein expression between Sham or SBR groups that did not receive EGF. However, EGF significantly enhanced the expression of ileal EGF receptor mRNA to an equal extent after both sham and SBR (approximately threefold). The magnitude of this increase in EGF receptor protein (four- to sixfold) was similar in both EGF groups as shown by Western blotting.

CONCLUSIONS

Changes in ileal EGF receptor expression are not mandatory for adaptation to occur. EGF upregulates the expression of mRNA and protein for its own intestinal receptor in vivo. Because EGF-induced receptor expression was comparable after both SBR and Sham operation, the beneficial effect of EGF during adaptation is likely caused by other factors in addition to increased receptor expression.

The EGF\EGF-receptor axis modulates enterocyte apoptosis during intestinal adaptation

BACKGROUND

Adaptation after small bowel resection (SBR) is characterized by a new set point in the balance of enterocyte proliferation and apoptosis. Since epidermal growth factor (EGF) augments both proliferation and adaptation, we sought to determine the effect of EGF receptor manipulation on apoptosis following SBR.

MATERIALS AND METHODS

Male ICR mice underwent 50% SBR or sham operation (bowel transection with reanastomosis) and then were given EGF (50 microg/kg/day) or saline by orogastric gavage. At 1 week, a proliferation index (PI) was measured in the ileum by BrdU uptake and an apoptosis index in crypts (cAI) and villi (vAI) scored by counting apoptotic bodies in enterocytes. In other experiments, AI was scored after SBR in mice with defective receptors (waved-2). Results are expressed as means +/- SE and evaluated statistically using ANOVA. # denotes P < 0.001.

RESULTS

Following SBR, EGF increased PI (40 +/- 2% vs 50 +/- 1% BrdU + cells; #), villus height (252 +/- 4 micro(m) vs 401 +/- 15 micro(m); #), and crypt depth (77.3 +/- 1.5 micro(m) vs 120.8 +/- 5 micro(m); #). When compared with sham, SBR resulted in increased cAI (0.3 +/- 0.02 vs 2.0 +/- 0.1; #) and vAI (0.4 +/- 0.05 vs 1.1 +/- 0.1; #). EGF attenuated both cAI (0.5 +/- 0. 04) and vAI (0.5 +/- 0.03) following SBR. In the waved-2 mice, the highest levels of cAI (3.1 +/- 0.2) and vAI (3.6 +/- 0.3) were noted after SBR.

CONCLUSIONS

Enterocyte apoptosis during adaptation is attenuated by EGF and exaggerated when the EGF receptor is defective. In addition to enhancing proliferation, suppression of apoptosis may provide a previously unrecognized mechanism for the beneficial effect of EGF during intestinal adaptation.

Epidermal growth factor augments adaptation following small bowel resection: optimal dosage, route, and timing of administration

BACKGROUND

In assorted animal models of small bowel resection (SBR), exogenous epidermal growth factor (EGF) has been shown to augment intestinal adaptation. This study was designed to elucidate the optimal dose, route, and timing of exogenous EGF to boost adaptation in our murine model of SBR.

METHODS

Male ICR mice underwent either 50% proximal SBR or sham surgery (bowel transection with reanastomosis) and then randomized to receive either saline or human recombinant EGF (5, 50, 150, or 300 microg/kg/day) by twice daily intraperitoneal (i.p.) injection or orogastric gavage (o.g.). At 7 days, protein and DNA content, crypt depth, and villus height were determined in the ileum. The premium dose and route was then given for 1 week either during (1 week after SBR) or after the adaptive phase (1 month after SBR). Differences between group means were analyzed using ANOVA. A P < 0.05 was considered significant.

RESULTS

EGF enhanced DNA and protein content, crypt depth, and villus height to the greatest extent at a dosage of 50 microg/kg/day by the o.g. route. EGF had no significant effect on enhancing adaptation when given after the adaptive response had already occurred.

CONCLUSIONS

Intestinal adaptation is optimally enhanced by a specific dose and route of EGF. Exogenous EGF enhances adaptation only during the adaptive response to SBR and not after it has already taken place. Determination of the best circumstances for EGF administration will permit a systematic approach toward understanding a mechanism for the beneficial effect of EGF during intestinal adaptation.

Epidermal growth factor upregulates the expression of its own intestinal receptor after small bowel resection

BACKGROUND/PURPOSE

Epidermal growth factor (EGF) binds to its enterocyte receptor and enhances intestinal adaptation after massive small bowel resection (SBR). To ascertain the mechanism for enhanced adaptation by EGF, we sought to determine the effect of EGF administration on in vivo expression of the intestinal EGF receptor after SBR.

METHODS

Male ICR mice underwent a 50% proximal SBR and then were assigned randomly to EGF (150 microg/kg/d) or saline by twice daily intraperitoneal injection. After 3 days, the ileum was harvested and total protein and DNA content were measured. Northern hybridization and a ribonuclease protection assay were used to detect qualitative and quantitative expression of EGF receptor mRNA. The remaining ileum was pooled for each group and Western blotting used to determine expression of EGF receptor protein.

RESULTS

EGF augmented adaptation after SBR as monitored by significant increases in ileal protein (2.7+/-0.08 saline versus 3.9+/-0.17 mg/cm EGF; P<.001) and DNA (55.8+/-1.6 saline versus 104+/-8.4 microg/cm EGF; P<.001) content. Northern blotting results showed a marked (>fivefold) increase in ileal EGF receptor mRNA, which was confirmed with the ribonuclease protection assay. Administration of EGF after SBR induced a similar expression of EGF receptor protein.

CONCLUSIONS

EGF enhanced intestinal adaptation after SBR. This augmented response is associated with increased ileal expression of EGF receptor mRNA and protein. Increased EGF receptor expression and subsequent enhanced ligand/ receptor activity may be one important mechanism for the beneficial effect of EGF administration during intestinal adaptation.

Ovarian cysts in the pediatric population

With the widespread availability and use of pelvic sonography, the rate at which ovarian cysts are detected in the pediatric population has increased, and such cysts are an important problem encountered in pediatric surgical practice. Rational management should take into account key factors such as symptoms, patient age, menarchal status, cysts size, and character, as well as associated medical conditions. The purpose of this review is to discuss the incidence and pathophysiology of ovarian cysts in children. A management strategy is presented based on the above-mentioned key factors.

Enterocyte apoptosis is increased following small bowel resection

The intestinal mucosa is in a steady state of turnover as the rate of cellular proliferation is balanced by the rate of cell death. Although it is accepted that adaptation after small bowel resection (SBR) results in increased proliferation, its effect on apoptosis is not known. The purpose of this study was to determine the effect of adaptation following SBR on rates of enterocyte apoptosis. Male ICR mice underwent either 50% proximal SBR or sham operation (bowel transection/reanastomosis). After 12 and 24 hours, and 3 and 7 days, rates of proliferation were measured in the ileum as the percentage of crypt cells incorporating bromodeoxyuridine. Apoptosis was quantiated by end labeling of DNA strand breaks and propidium iodide staining of the number of apoptotic bodies per crypt and villus. Significant increases in enterocyte proliferation (30% to 40%) as well as apoptosis (57% to 87%) occurred at all time points following SBR when compared with sham-operated mice. Adaptation following SBR increases both the rate of enterocytc proliferation and the rate of apoptosis. Understanding the pathophysiology of intestinal adaptation and therapeutic interventions designed to augment this important response will require complete characterization of their effects on both proliferation and apoptosis.

Epidermal growth factor receptor expression following small bowel resection

BACKGROUND

Adaptation following massive small bowel resection (SBR) is an important compensatory response. While epidermal growth factor (EGF) has been shown to augment this response, the mechanism and role of EGF and its intestinal receptor (EGF-R) during adaptation are not known. The purpose of this study was to determine the effect of massive SBR and adaptation on intestinal expression of EGF-R.

MATERIALS AND METHODS

Male Sprague-Dawley rats underwent either a 75% mid-SBR with primary reanastomosis or sham operation (bowel transection with reanastomosis). Ileal mucosa was harvested from animals of each group at 6 and 12 hr, 1, 3, and 5 days, and 1, 2, and 4 weeks after operation. Expression of EGF-R protein was studied by Western blotting. Expression of EGF-R mRNA was determined by quantitative reverse-transcriptase polymerase chain reactions normalized to beta-actin.

RESULTS

When compared with sham, SBR resulted in a modest (32%) increase in the expression of EGF-R mRNA at 1 week (P < 0.003). A twofold greater expression of EGF-R protein corresponded to this time point. While not statistically significant, expression of EGF-R mRNA was slightly greater after SBR at every other time point measured.

CONCLUSION

Following massive SBR, expression of both EGF-R mRNA and protein is slightly increased in the ileum with a more pronounced increase in protein. These findings, which have not previously been reported, suggest that changes in EGF-R signaling may not play a major role during the initiation and or progression of intestinal adaptation following massive SBR.