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Neurotensin (NT), a 13 amino-acid peptide, is predominantly released from enteroendocrine cells of the small bowel in response to fat ingestion. Free fatty acid receptors (FFARs) FFAR1 and FFAR4 regulate secretion of gut hormones and insulin. Here, we show that docosahexaenoic acid, a long-chain fatty acid, has the most dramatic effect on NT release. FFAR1 agonists slightly stimulate and FFAR4 agonists dramatically stimulate and amplify NT secretion. Double knockdown of FFAR1 and FFAR4 decreases NT release, whereas overexpression of FFAR4, but not FFAR1, increases NT release. Administration of cpdA, an FFAR4 agonist, but not TAK-875, a selective FFAR1 agonist, increases plasma NT levels and further increases olive oil-stimulated plasma NT levels. Inhibition of MAPK kinase (MEK)/ERK1/2 decreased fatty acid-stimulated NT release but increased AMP-activated protein kinase (AMPK) phosphorylation. In contrast, inhibition of AMPK further increased NT secretion and ERK1/2 phosphorylation mediated by FFAR1 or FFAR4. Our results indicate that FFAR4 plays a more critical role than FFAR1 in mediation of fat-regulated NT release and in inhibitory crosstalk between MEK/ERK1/2 and AMPK in the control of NT release downstream of FFAR1 and FFAR4.

We recently developed and validated a prognostic model that accurately predicts the 2-year risk of emergent gallstone-related hospitalization in older patients presenting with symptomatic gallstones.We used 100% Texas Medicare data (2000 to 2011) to identify patients aged 66 years and older with an initial episode of symptomatic gallstones not requiring emergency hospitalization. At presentation, we calculated each patient's risk of 2-year gallstone-related emergent hospitalization using the previously validated model. Patients were placed into the following risk groups based on model estimates:30%, 30% to60%, and ≥ 60%. Within each risk group, we calculated the percent of elective cholecystectomies (≤ 2.5 months from initial episode) performed.In all, 161,568 patients had an episode of symptomatic gallstones. Mean age was 76.5 ± 7.3 years and 59.9% were female. The 2-year risk of gallstone-related hospitalizations increased from 15.9% to 41.5% to 65.2% across risk groups. For the overall cohort, 22.3% in the low-risk group, 20.9% in the moderate-risk group, and 23.2% in the high-risk group underwent elective cholecystectomy in the 2.5 months after the initial symptomatic episode. In patients with no comorbidities, elective cholecystectomy rates decreased from 34.2% in the low-risk group to 26.7% in the high-risk group. Of patients who did not undergo cholecystectomy, only 9.5% were seen by a surgeon in the 2.5 months after the initial episode.The risk of recurrent acute biliary symptoms requiring hospitalization has no influence, or even a paradoxical negative influence, on the decision to perform elective cholecystectomy after an initial symptomatic episode. Translation of the risk prediction model into clinical practice can better align treatment with risk and improve outcomes in older patients with symptomatic gallstones.

Objectives Patients with advanced pancreatic neuroendocrine tumors have limited therapeutic options. Everolimus (RAD001), an inhibitor of the mammalian target of rapamycin (mTOR) pathway, has been shown to increase progression-free survival, but not overall survival, indicating a need to identify additional therapeutic targets. Inhibition of mTOR complex 1 by RAD001 may induce upstream AKT upregulation. We hypothesized that dual inhibition of AKT along with mTOR will overcome the limited activity of RAD001 alone. Methods The BON cell line has been used as a model to study pancreatic neuroendocrine tumor cell biology. Western blots and cell growth assays were performed with mTOR inhibitor RAD001 (50 nM), mitogen-activated protein kinase inhibitor PD0325901 (50 nM), PI3K (phosphatidylinositol 3-kinase) inhibitor LY294002 (25 μM), or vehicle control. Nude mice were treated daily for 6 weeks with RAD001 (oral gavage) and with LY29400 (subcutaneous) 1 week after intrasplenic injection of BON cells. Results Cellular proliferation was most attenuated with the combination therapy of LY29400 and RAD001. Similarly, the volume of liver metastasis was lowest in the group treated with both LY29400 (100 mg/kg per week, subcutaneous) and RAD001 (2.5 mg/kg per day) compared with that in the vehicle group (P = 0.04). Conclusion The combination therapy of LY29400 and RAD001 decreased the cell growth in vitro and progression of liver metastasis in vivo compared with vehicle or with single-drug therapy.

Current guidelines recommend minimally invasive breast biopsy (MIBB) as the gold standard for the diagnosis of breast lesions. The purpose of this study was to describe geographic patterns and time trends in the use of MIBB in Texas.We used 100% Texas Medicare claims data (2000-2008) to identify women older than 66 years of age who underwent breast biopsy. Biopsies were classified as open or MIBB. Time trends, racial/ethnic variation, and geographic variation in the use of biopsy techniques were examined.A total of 87,165 breast biopsies were performed on 75,518 breast masses in 67,582 women; 65.8% of the initial biopsies were MIBB. Radiologists performed 70.3% and surgeons performed 26.2% of MIBB. Surgeons performed 94.2% of open biopsies. Hispanic women were less likely to undergo MIBB (55.9%) compared with white (66.6%) and black (68.9%) women (p0.0001). Women undergoing MIBB were also more likely to live in metropolitan areas and have higher income and educational levels (p0.0001). The rate of MIBB increased from 44.4% in 2001 to 79.1% in 2008 (p0.0001). There are clear geographic patterns in MIBB use, with highest use near major cities. Although rates are increasing overall, rates of improvement in the use of MIBB vary considerably across geographic regions and remain persistently low in more rural areas.Despite an increase in the use of MIBB over time, MIBB use was consistently lower than recommended. We must identify specific barriers in rural areas to effectively change practice and achieve the statewide goal of 90% MIBB.

Importance Mentorship is considered a key element for career satisfaction and retention in academic surgery. Stakeholders of an effective mentorship program should include the mentor, the mentee, the department, and the institution. Objective The objective of this study was to characterize the status of mentorship programs in departments of surgery in the United States, including the roles of all 4 key stakeholders, because to our knowledge, this has never been done. Design, Setting, and Participants A survey was sent to 155 chairs of departments of surgery in the United States in July 2014 regarding the presence and structure of the mentorship program in their department. The analysis of the data was performed in November 2014 and December 2014. Main Outcomes and Measures Presence and structure of a mentorship program and involvement of the 4 key stakeholders. Results Seventy-six of 155 chairs responded to the survey, resulting in a 49% response rate. Forty-one of 76 of department chairs (54%) self-reported having an established mentorship program. Twenty-five of 76 departments (33%) described no formal or informal pairing of mentors with mentees. In 62 (82%) and 59 (78%) departments, no formal training existed for mentors or mentees, respectively. In 42 departments (55%), there was no formal requirement for the frequency of scheduled meetings between the mentor and mentee. In most departments, mentors and mentees were not required to fill out evaluation forms, but when they did, 28 of 31 were reviewed by the chair (90%). In 70 departments (92%), no exit strategy existed for failed mentor-mentee relationships. In more than two-thirds of departments, faculty mentoring efforts were not recognized formally by either the department or the institution, and only 2 departments (3%) received economic support for the mentoring program from the institution. Conclusions and Relevance These data show that only half of departments of surgery in the United States have established mentorship programs, and most are informal, unstructured, and do not involve all of the key stakeholders. Given the importance of mentorship to career satisfaction and retention, development of formal mentorship programs should be considered for all academic departments of surgery.

The recommended therapy for mild gallstone pancreatitis is cholecystectomy on initial hospitalization.Using a 5% national Medicare sample (1996-2005), we evaluated adherence to current recommendations for gallstone pancreatitis (cholecystectomy rates on initial hospitalization and the use of endoscopic retrograde cholangiopancreatography [ERCP]/sphincterotomy). We evaluated predictors of cholecystectomy, gallstone-related readmissions, and 2-year mortality.Adherence to current guidelines was low. Only 57% of 8,452 Medicare beneficiaries presenting to an acute care hospital with a first episode of mild gallstone pancreatitis underwent cholecystectomy on initial hospitalization. Of the patients who did not undergo cholecystectomy, 55% were never evaluated by a surgeon. Likewise, only 28% of patients who did not undergo cholecystectomy had a sphincterotomy. The 2-year readmission rates were higher among patients who did not undergo cholecystectomy (44% vs 4%; P.0001), and 33% of these patients required cholecystectomy after discharge. In the no cholecystectomy group, ERCP prevented readmissions (hazard ratio, 0.53; 95% confidence interval, 0.47-0.61) and when readmissions occurred they were less likely to be for gallstone pancreatitis in patients who had an ERCP (27.8% vs 53.2%; P.0001). On multivariate analysis, patients who were older, black, admitted to a nonsurgical service, lived in certain US regions, and had specific comorbidities were less likely to undergo cholecystectomy.Adherence to current recommendations for the management of mild gallstone pancreatitis is low in older patients. Our data suggest that40% of patients who did not undergo cholecystectomy would have benefited from early definitive therapy. Implementation of policies to increase adherence to guidelines would prevent gallstone-related morbidity and mortality in older patients.

Evidence-based guidelines recommend cholecystectomy during initial hospitalization for complicated gallstone disease. Previous studies and quality initiative data from our institution demonstrated that only 40% to 75% of patients underwent cholecystectomy on index admission.In January 2009, we implemented a critical pathway to improve cholecystectomy rates for all patients emergently admitted for acute cholecystitis, mild gallstone pancreatitis, or common bile duct stones. We compared cholecystectomy rates during initial hospitalization, time to cholecystectomy, length of initial stay, and readmission rates in prepathway (January 2005 to February 2008) and postpathway patients (January 2009 to May 2010).Demographic and clinical characteristics were similar between prepathway (n = 455) and postpathway patients (n = 112). Cholecystectomy rates during initial hospitalization increased from 48% to 78% after pathway implementation (p0.0001). There were no differences in operative mortality or operative complications between the 2 groups. For patients undergoing cholecystectomy on initial hospitalization, the mean length of stay decreased after pathway implementation (7.1 days to 4.5 days; p0.0001), primarily due to a decrease in the time from admission to cholecystectomy (4.1 days to 2.1 days; p0.0001). Thirty-three percent of prepathway and 10% of postpathway patients required readmission for gallstone-related problems or operative complications (p0.0001), and each readmission generated an average of $19,000 in additional charges.Implementation of a multidisciplinary critical pathway improved cholecystectomy rates on initial hospitalization and lowered costs by shortening length of stay and markedly decreasing readmission rates for gallstone-related problems. Broader implementation of similar pathways offers the potential to translate evidence-based guidelines into clinical practice and minimize the cost of medical care.

OBJECTIVES: To evaluate time trends in surgical resection rates and operative mortality in older adults diagnosed with locoregional pancreatic cancer and to determine the effect of age on surgical resection rates and 2-year survival after surgical resection. DESIGN: Retrospective cohort study using data from the Surveillance, Epidemiology, and End Results (SEER) and linked Medicare claims database (1992�2005). SETTING: Secondary data analysis of population-based tumor registry and linked claims data. PARTICIPANTS: Medicare beneficiaries aged 66 and older diagnosed with locoregional pancreatic cancer (N=9,553), followed from date of diagnosis to time of death or censorship. MEASUREMENTS: Percentage of participants undergoing surgical resection, 30-day operative mortality after resection, and 2-year survival according to age group. RESULTS: Surgical resection rates increased significantly, from 20% in 1992 to 29% in 2005, whereas 30-day operative mortality rates decreased from 9% to 5%. After controlling for multiple factors, participants were less likely to be resected with older age. Resection was associated with lower hazard of death, regardless of age, with hazard ratios of 0.46, 0.51, 0.47, 0.43, and 0.35 for resected participants younger than 70, 70 to 74, 75 to 79, 80 to 84, and 85 and older respectively compared with unresected participants younger than 70 (P

Carcinoid tumors are slow growing and highly vascular neuroendocrine neoplasms that are increasing in incidence. Previously, we showed that carcinoid tumors express vascular endothelial growth factor receptor 2 (VEGFR-2) in the epithelial compartment of carcinoid tumor sections; yet, its role is not completely understood. The purpose of our study was to: (i) assess the expression of VEGFR-2 in the novel human carcinoid cell line BON, (ii) to determine the role of PI3K/Akt signaling on VEGFR-2 expression and (iii) to assess the effect of VEGFR-2 on BON cell invasion, migration and proliferation. We found that, although VEGFR-2 is expressed in BON cells, reduction in VEGFR-2 expression actually enhanced proliferation, invasion, and migration of the BON cell line. Also, expression of VEGFR-2 was inversely related to PI3K signaling. Carcinoid liver metastases in mice demonstrated decreased VEGFR-2 expression. Furthermore, the expression of a truncated, soluble form of VEGFR-2 (sVEGFR-2), a protein demonstrated to inhibit cell growth, was detected in BON cells. The presence of VEGFR-2 in the epithelial component of carcinoid tumors and in the BON cell line suggests an alternate role for VEGFR-2, in addition to its well-defined role in angiogenesis. The expression of sVEGFR-2 may explain the inverse relationship between VEGFR-2 expression and PI3K/Akt signaling and the inhibitory effect VEGFR-2 has on BON cell proliferation, migration and invasion.

Cholecystectomy during initial hospitalization is the current recommended therapy for acute cholecystitis. The rate of cholecystectomy and subsequent health care trajectory in elderly patients with acute cholecystitis has not been evaluated.We used 5% national Medicare sample claims data from 1996 to 2005 to identify a cohort of patients aged 66 years and older, requiring urgent or emergent admission for acute cholecystitis. We evaluated cholecystectomy rates on initial hospitalization, factors independently predicting receipt of cholecystectomy, factors predicting further gallstone-related complications, and 2-year survival in the cholecystectomy and no cholecystectomy groups in univariate and multivariate models.There were 29,818 Medicare beneficiaries who were urgently or emergently admitted for acute cholecystitis from 1996 to 2005. Mean age was 77.7 +/- 7.3 years, 89% of patients were white, and 58% were female. Twenty-five percent of patients did not undergo cholecystectomy during the index admission. Lack of definitive therapy was associated with a 27% subsequent cholecystectomy rate and a 38% gallstone-related readmission rate in the 2 years after discharge; the readmission rate was only 4% in patients undergoing cholecystectomy (p0.0001). No cholecystectomy on initial hospitalization was associated with worse 2-year survival (hazard ratio 1.56, 95% CI 1.47 to 1.65) even after controlling for patient demographics and comorbidities. Readmissions led to an additional $7,000 in Medicare payments per readmission.Our study demonstrated that 25% of cholecystectomies on Medicare beneficiaries were not performed on initial hospitalization, leading to readmissions in 38% of surviving patients. For patients requiring readmission, the percentage of open procedures was increased, and the additional Medicare payment was $7,000 per re-admission. Cholecystectomy for acute cholecystitis in elderly patients should be performed during initial hospitalization to prevent recurrent episodes of cholecystitis, multiple readmissions, higher readmission rates, and increased costs.

Purpose: Carcinoid syndrome, characterized by flushing, diarrhea, and valvular heart disease, can occur following carcinoid tumor metastasis to the liver and systemic release of bioactive hormones into the systemic circulation. Treatment of this devastating disease is hampered by the lack of an in vivo model that recapitulates the clinical syndrome. Experimental Design: Here, we have injected BON cells, a novel human carcinoid cell line established in our laboratory, into the spleens of athymic nude mice to establish liver metastases. Results: The majority of mice injected intrasplenically with BON cells developed significant increases in plasma serotonin and urine 5-hydroxyindoleacetic acid, and several mice exhibited mesenteric fibrosis, diarrhea, and fibrotic cardiac valvular disease reminiscent of carcinoid syndrome by both echocardiographic and histopathologic evaluation. Mice pretreated with octreotide, a long-acting somatostatin analogue, or bevacizumab, a vascular endothelial growth factor inhibitor, developed fewer liver metastases and manifestations of carcinoid syndrome, including valvular heart disease. Conclusion: We have provided an important in vivo model to further delineate novel treatment modalities for carcinoid syndrome that will also be useful to elucidate the factors contributing to the sequelae of carcinoid disease (e.g., mesenteric fibrosis and valvular heart disease).

Background A strong volume-outcome relationship has been demonstrated for pancreatic resection, and regionalization of care to high-volume centers (>11 resections/year) has been recommended. However, it is unclear if volume alone should be the sole criteria for regionalization. The objective of this study is to evaluate variability in outcomes among high-volume hospitals (>11 resections/year). Methods We used the Texas Hospital Inpatient Discharge Database from 1999 through 2005 to evaluate variability in outcomes after pancreatic resection among high-volume hospitals in Texas. The outcome variables of interest were mortality, length of stay, discharge to a skilled nursing facility, operation within 24 hours of hospital admission, and total hospital charges. Unadjusted and adjusted models were performed. Results A total of 12 high-volume hospitals were in Texas. The number of resections at each hospital ranged from 78–608 cases for the 7-year time period studied. In unadjusted models, there was significant variability in mortality (range, 0.7%–7.7%, P < .0001), duration of stay (range of medians, 9–21 days, P < .0001), the need for ongoing nursing care at discharge (range, 0.7%–41.4%, P < .0001), operation within 24 hours of admission (range, 41%–96%, P < .0001), and total hospital charges (median range, $38,318–$110,860, P < .0001). There were significant differences in the demographics, risks of mortality, and illness severity among the 12 high-volume hospitals. Therefore, multivariate models were used to control for age group, sex, race/ethnicity, risk of mortality, illness severity, admission status, diagnosis, procedure, and insurance status. In the multivariate models, the particular hospital at which the pancreatic surgery was performed was a significant independent predictor of every outcome variable except mortality. Conclusions For pancreatic resection, there is significant variability in outcomes even among high-volume providers. Individual hospitals likely account for much of the variability not explained by hospital volume. Although the structure measure of hospital volume is easy to measure, these data suggest that it is not a reliable single measure of quality or outcomes after pancreatic surgery.

Overexpression of cyclooxygenase-2 (COX-2), an inducible enzyme regulating prostaglandin release, is mechanistically linked to the development, growth, and spread of gastrointestinal (GI) cancers. GI peptide bombesin (BBS) was reported to stimulate COX-2 gene expression. Here we show that TGF-beta1 dramatically enhances the BBS-induced expression of COX-2 mRNA and protein, and the release of PGE2 in the model rat intestinal epithelial cell (RIE-1) line. The synergistic increase in COX-2 levels results from a combination of enhanced COX-2 transcription and reduced mRNA degradation. BBS, but not TGF-beta1, stimulated COX-2 promoter activity, and TGF-beta1 enhanced COX-2 mRNA stability through a p38(MAPK)-dependent pathway. The synergistic regulation of COX-2 expression by TGF-beta1 and BBS may contribute to the upregulation of COX-2 in GI cancers.

The current recommendation is that pancreatic resections be performed at hospitals doing10 pancreatic resections annually.To evaluate the extent of regionalization of pancreatic resection and the factors predicting resection at high-volume centers (10 cases/year) in Texas.Using the Texas Hospital Inpatient Discharge Public Use Data File, we evaluated trends in the percentage of patients undergoing pancreatic resection at high-volume centers (10 cases/year) from 1999 to 2004 and determined the factors that independently predicted resection at high-volume centers.A total of 3,189 pancreatic resections were performed in the state of Texas. The unadjusted in-hospital mortality was higher at low-volume centers (7.4%) compared to high-volume centers (3.0%). Patients resected at high-volume centers increased from 54.5% in 1999 to 63.3% in 2004 (P = 0.0004). This was the result of a decrease in resections performed at centers doing less than five resections/year (35.5% to 26.0%). In a multivariate analysis, patients who were75 (OR = 0.51), female (OR = 0.86), Hispanic (OR = 0.58), having emergent surgery (OR = 0.39), diagnosed with periampullary cancer (OR = 0.68), and living75 mi from a high-volume center (OR = 0.93 per 10-mi increase in distance, P0.05 for all OR) were less likely to be resected at high-volume centers. The odds of being resected at a high-volume center increased 6% per year.Whereas regionalization of pancreatic resection at high-volume centers in the state of Texas has improved slightly over time, 37% of patients continue to undergo pancreatic resection at low-volume centers, with more than 25% occurring at centers doing less than five per year. There are obvious demographic disparities in the regionalization of care, but additional unmeasured barriers need to be identified.

AMP-activated protein kinase (AMPK), a critical fuel-sensing enzyme, regulates the metabolic effects of various hormones. Neurotensin (NT) is a 13-amino acid peptide predominantly localized in enteroendocrine cells of the small bowel and released by fat ingestion. Increased fasting plasma levels of pro-NT (a stable NT precursor fragment produced in equimolar amounts relative to NT) are associated with an increased risk of diabetes, cardiovascular disease, and mortality; however, the mechanisms regulating NT release are not fully defined. We previously reported that inhibition of the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) increases NT secretion and gene expression through activation of the MEK/ERK pathway. Here, we show that activation of AMPK increases NT secretion from endocrine cell lines (BON and QGP-1) and isolated mouse crypt cells enriched for NT-positive cells. In addition, plasma levels of NT increase in mice treated with 5-aminoimidazole-4-carboxamide riboside, a pharmacologic AMPK activator. Small interfering RNA-mediated knockdown of AMPKα decrease, whereas overexpression of the subunit significantly enhances, NT secretion from BON cells treated with AMPK activators or oleic acid. Similarly, small interfering RNA knockdown of the upstream AMPK kinases, liver kinase B1 and Ca2+ calmodulin-dependent protein kinase kinase 2, also attenuate NT release and AMPK phosphorylation. Moreover, AMPK activation increases NT secretion through inhibition of mTORC1 signaling. Together, our findings show that AMPK activation enhances NT release through inhibition of mTORC1 signaling, thus demonstrating an important cross talk regulation for NT secretion.

It is unknown whether the improved survival seen at high-volume centers has been translated to all patients with pancreatic cancer.To use the Surveillance, Epidemiology, and End Results (SEER) database to evaluate population-based trends in surgical resection and survival.All patients diagnosed with pancreatic cancer from 1988-1999 were identified. The survival and proportion of patients undergoing surgical resection were compared for each of three equal time periods.There were 24,016 patients with pancreatic cancer. 19,533 had stage data available. 9% had localized, 29% had regional, and 62% had distant disease. Resection rates increased for patients with localized and regional disease over the three time periods. Survival increased for patients with regional and distant disease. For regional pancreatic cancer patients, 2-year survival increased from 9.5% to 13.5% (p0.0001) and from 21.5% to 28.9% following surgical resection (p = 0.002). For resected local/regional pancreatic cancer, the year of diagnosis was and independent predictor of improved survival (p = 0.0001).SEER patients with regional and distant pancreatic cancer have improved survival over the past decade in both unadjusted and adjusted models. The improvement is most striking for patients with regional disease and reflects increased resection rates and improved resection techniques over time.

To determine whether sodium butyrate (NaB), a major short-chain fatty acid produced in the human gut by bacterial fermentation of dietary fiber, enhances transforming growth factor (TGF)-beta signaling and potentiates its tumor suppressor activity in the gut.The molecular mechanisms by which dietary fiber decreases the risk of colon cancers are poorly characterized. TGF-beta is an important tumor suppressor in the gut and has many similar biologic activities as NaB. Therefore, we hypothesized that the chemo-preventive effects of NaB are mediated in part by enhancing TGF-beta signaling and its tumor suppressor function in the gut.The effects of NaB on Smad3 expression in rat intestinal epithelial (RIE-1) cells and 6 human colon cancer cell lines were examined. The effects of NaB on TGF-beta-induced Smad3 phosphorylation and plasminogen activator inhibitor-1 (PAI-1) and cyclooxygenase-2 (COX-2) gene expression were also examined in RIE-1 cells. Finally, the effects of NaB and TGF-beta on anchorage-independent growth were examined in Akt-transformed RIE-1 cells.NaB induced Smad3 in RIE-1 cells and in 4 human colon cancer cell lines. NaB enhanced TGF-beta-induced Smad3 phosphorylation and potentiated TGF-beta-induced PAI-1 expression. NaB and TGF-beta synergistically inhibited anchorage-independent growth of Akt-transformed RIE-1 cells.These results demonstrate that NaB induces Smad3 and potentiates TGF-beta signaling and its tumor suppressor activity in gut epithelial cells. Our data reveal a novel molecular mechanism that may explain in part the beneficial effects of dietary fiber in decreasing the risk of colon cancers.

Background In this study, the prevalence and identity of the cells expressing functional receptors for the gastrointestinal (GI) peptide hormones: gastrin, bombesin, and neurotensin in dissociated cells from 20 freshly resected human primary colorectal carcinomas were determined. Materials and methods GI peptide hormone-induced increases in the concentration of free intracellular Ca2+ ([Ca2+]i) were used as an assay for the detection of functional receptors. Reverse-transcription polymerase chain reaction (RT-PCR) was performed in a subset of tumor samples. Agonist-responsive cells were identified as either of epithelial or stromal origin by immunocytochemistry with cytokeratin and vimentin antibodies, respectively. Results Overall, expression of GI peptide hormone receptors was more frequent in stromal cells when compared to epithelial cells. Of the three receptors, expression of bombesin receptor (95%) was most prevalent in vimentin-positive (stromal) cells; whereas, gastrin receptor expression by cytokeratin-positive (epithelial) cells was more common (39%). A single gastrin receptor splice variant differentially regulates [Ca2+]i in a cell-type specific manner. The gastrin receptor-expression profile in the 11 colon cancer-derived cell lines did not reflect the prevalence of expression in primary human cancers. Conclusions The Ca2+ assay is a sensitive method for detecting functional GI peptide hormone receptor expression by colon cancer cells. Because this approach utilizes living cells, it is amenable to further functional analyses of signal transduction mechanisms at the single cell level. Importantly, our data provide a rationale for examining of the role of these GI peptide hormones and their cognate receptors in mesenchymal cell biology.

Objective: To evaluate the role of celecoxib on 15-lipoxygenase-1 (15-LOX-1) expression, protein levels, and rates of apoptosis in colorectal cancer cell lines. Also, to evaluate the expression of 15-LOX-1 in human normal mucosa, adenoma, and carcinoma with correlation to overall survival. Background Data: The function of 15-LOX-1 is to maintain normal rates of apoptosis (programmed cell death). Decreased apoptosis is one mechanism of cancer growth and dissemination. It is our hypothesis that expression of 15-LOX-1 is reduced in human colorectal cancer (CRC) and the administration of celecoxib can reverse this process and induce apoptosis. Methods: Effect of celecoxib in cell culture: The effect of 40 μmol/L celecoxib was compared with untreated controls in tissue culture utilizing HT-29 and DLD-1 CRC cell lines. Expression of 15-LOX-1 protein was measured by immunoblot. Induction of apoptosis was evaluated by annexin V staining. All data are presented as mean ± SEM, with significance defined as P < 0.05. 15-LOX-1 in human CRC: From February 1998 to January 2002, 126 patients underwent surgical resection of either colorectal adenomas (n = 24) or carcinomas (n = 102), or both (n = 25). Tissue was macrodissected, snap frozen, and stored at -80°C. After tissue processing, RNA was extracted and gene expression of 15-LOX-1 was quantified utilizing ABI prism real-time quantitative RT-PCR. Significance evaluated by the Wilcoxon signed rank test. Results: Effect of celecoxib in cell culture: After 72 hours of treatment with celecoxib, immunoblot demonstrated a 1.5- to 2-fold increase inl5-LOX-1 protein expression in HT-29 and DLD-1 cells, respectively. Celecoxib produced greater than a 2-fold increase in the rate of apoptosis compared with control cells in both cell lines (P < 0.05). 15-LOX-1 in human CRC: The mean age of the patients was 62 ± 1 years; 78% were white and 48% were female. The mean size of the polyps and cancers were 3.0 ± 0.4 and 5.0 ± 0.1 cm, respectively. Expression of 15-LOX-1 relative to S9 was 30 in normal mucosa and significantly down-regulated to 11 in adenomas and 16 in carcinomas (P < 0.05). Conclusions: 15-LOX-1 gene expression is significantly reduced in both human colorectal adenomas and carcinomas and associated with decreased survival. Administration of celecoxib restores 15-LOX-1 protein expression and induces apoptosis. Down-regulation of 15-LOX-1 is an early event in the adenoma to carcinoma sequence, and reversal with celecoxib may represent one mechanism for chemoprevention of polyps or treatment of carcinomas.

Gastrointestinal carcinoid tumors are rare neuroendocrine tumors arising from the embryologic primitive gut. Depending on the location in the gastrointestinal tract, these tumors may secrete a variety of hormonally active substances. However, many of these tumors are found incidentally, or the diagnosis is made postoperatively. Also, there is a significant incidence of multicentric carcinoid tumors and synchronous noncarcinoid malignancies in these patients. Treatment is usually based on the size of the tumor. Surgical resection remains the cornerstone of therapy. For advanced metastatic disease, somatostatin analog therapy and surgical debulking provide the best symptomatic relief and may improve survival. Recent studies have demonstrated a benefit from radiolabeled somatostatin analogs for carcinoid tumor localization. In contrast, radiolabeled somatostatin analogs have shown little therapeutic benefit. Future directions include somatostatin receptor profiling of carcinoid tumors, with somatostatin analog therapy targeting the specific receptors.

Gastrointestinal (GI) hormones are chemical messengers that regulate the physiological functions of the intestine and pancreas, including secretion, motility, absorption, and digestion. In addition to these well-defined physiological effects, GI hormones can stimulate proliferation of the nonneoplastic intestinal mucosa and pancreas. Furthermore, in an analogous fashion to breast and prostate cancer, certain GI cancers possess receptors for GI hormones; growth can be altered by administration of these hormones or by blocking their respective receptors. The GI hormones that affect proliferation, either stimulatory or inhibitory, include gastrin, cholecystokinin, gastrin-releasing peptide, neurotensin, peptide YY, glucagon-like peptide-2, and somatostatin. The effects of these peptides on normal and neoplastic GI tissues will be described. Also, future perspectives and potential therapeutic implications will be discussed.

Background and aims: Determination of intracellular signalling pathways that mediate intestinal epithelial proliferation is fundamental to the understanding of the integrity and function of the intestinal tract under normal and diseased conditions. The phosphoinositide 3-kinase (PI3K)/Akt pathway transduces signals initiated by growth factors and is involved in cell proliferation and differentiation. In this study, we assessed the role of PI3K/Akt in transduction of proliferative signals in intestinal epithelial cells. Methods: A rat intestinal epithelial (RIE) cell line and human colorectal cancer HCA-7 and LS-174 cell lines served as in vitro models. The Balb/cJ mouse was the in vivo model. Results: PI3K activation was critical for G1 cell cycle progression of intestinal epithelial cells. Ectopic expression of either active p110α or Akt-1 increased RIE cell proliferation. In vivo experiments demonstrated that PI3K activation was closely associated with the proliferative activity of intestinal mucosa. Treatment of mice with PI3K inhibitors blocked induction of PI3K activity and attenuated intestinal mucosal proliferation associated with oral intake. Epidermal growth factor and transforming growth factor α stimulated PI3K activation which was required for growth factor induced expression of cyclin D1. Conclusions: The PI3K/Akt pathway transduces mitogenic signals from growth factor receptors to the cell cycle machinery and plays a critical role in regulation of intestinal epithelial proliferation.

Carcinoid tumors are a group of neuroendocrine neoplasms distributed widely throughout the body but most commonly occurring in the gut. These tumors retain many characteristics of their neural crest origin, including secretion of neuroactive peptides and responsiveness to neurotrophic substances. Nerve growth factor (NGF), a neurotrophic protein involved in maintenance and differentiation of peripheral sympathetic and sensory neurons, regulates growth of several neural tumor cells by inducing a differentiated phenotype and subsequent inhibition of cell growth rate. We examined the actions of NGF in a functioning human pancreatic carcinoid cell line (termed BON). NGF has no effect on the cytoarchitecture or constitutive secretion of bioamines in this carcinoid cell line. NGF, however, stimulates the in vitro cellular proliferation of BON cells. BON cells possess mRNA for the NGF receptors (p75LNGFR and p140trkA) and membrane-associated tyrosine kinase activity is increased in response to NGF. Both the mitogenic activity of NGF, as well as the receptor-linked tyrosine kinase activity, can be abrogated in BON cells by the trkA inhibitor K-252a and specific anti-NGF antibody. Our studies demonstrate that NGF is a mitogen for this carcinoid cell line without effect on cellular phenotype or cytoarchitecture. NGF may play a role in the development and progression of human carcinoid tumors.

Neurotensin (NT) plays an important role in gastrointestinal secretion, motility, and growth. The mechanisms regulating NT secretion are not entirely known. Our purpose was to define the role of the PKC signaling pathway in secretion of NT from BON cells, a human pancreatic carcinoid cell line that produces and secretes NT peptide. We demonstrated expression of all 11 PKC isoforms at varying levels in untreated BON cells. Expression of PKC-alpha, -beta2, -delta, and -mu isoforms was most pronounced. Immunofluorescent staining showed PKC-alpha and -mu expression throughout the cytoplasm and in the membrane. Also, significant fluorescence of PKC-delta was noted in the nucleus and cytoplasm. Treatment with PMA induced translocation of PKC-alpha, -delta, and -mu from cytosol to membrane. Activation of PKC-alpha, -delta, and -mu was further confirmed by kinase assays. Addition of PKC-alpha inhibitor Gö-6976 at a nanomolar concentration, other PKC inhibitors Gö-6983 and GF-109203X, or PKC-delta-specific inhibitor rottlerin significantly inhibited PMA-mediated NT release. Overexpression of either PKC-alpha or -delta increased PMA-mediated NT secretion compared with control cells. We demonstrated that PMA-mediated NT secretion in BON cells is associated with translocation and activation of PKC-alpha, -delta, and -mu. Furthermore, inhibition of PKC-alpha and -delta blocked PMA-stimulated NT secretion, suggesting a critical role for these isoforms in NT release.

Although ectopic expression of the cholecystokinin B/gastrin receptor (CCK-BR) is widely reported in human colorectal cancers, its role in mediating the proliferative effects of gastrin1-17 (G-17) on these cancers is unknown. Here we report the isolation of a novel splice variant of CCK-BR that exhibits constitutive (ligand-independent) activation of pathways regulating intracellular free Ca(2+) ([Ca(2+)](i)) and cell growth. The splice variant (designated CCK-BRi4sv for intron 4-containing splice variant) is expressed in colorectal cancers but not in normal colonic mucosa adjacent to the cancer. Balb3T3 cells expressing CCK-BRi4sv exhibited spontaneous, ligand-independent, oscillatory increases in [Ca(2+)](i), whereas cells expressing wild-type CCK-BR did not. Primary cultures of cells isolated from resected colorectal cancers also exhibited a similar pattern of spontaneous [Ca(2+)](i) oscillations. For both Balb3T3 and primary tumor cells, application of G-17 (10 and 200 nm, respectively) caused an increase in [Ca(2+)](i). Selective CCK-BR antagonists blocked the G-17-stimulated Ca(2+) responses but not the spontaneous [Ca(2+)](i) oscillations. Cells expressing CCK-BRi4sv exhibited an increased growth rate ( approximately 2.5-fold), in the absence of G-17, compared with cells expressing wild-type CCK-BR. The selective pattern of expression, constitutive activity, and trophic action associated with CCK-BRi4sv suggest that this variant may regulate colorectal cancer cell proliferation though a gastrin-independent mechanism.

Objective To determine the prevalence of gastrointestinal (GI) peptide receptor expression in pancreatic cancers, and to further assess signaling mechanisms regulating neurotensin (NT)-mediated pancreatic cancer growth. Summary background data Pancreatic cancer remains one of the leading causes of GI cancer death; novel strategies for the early detection and treatment of these cancers is required. Previously, the authors have shown that NT, an important GI hormone, stimulates the proliferation of an NT receptor (NTR)-positive pancreatic cancer. Methods A total of 26 human pancreatic adenocarcinomas, obtained after resection, and 5 pancreatic cancer xenografts were analyzed for expression of NTR, vasoactive intestinal peptide receptor (VIPR), substance P receptor (SPR), and gastrin-releasing peptide receptor (GRPR). In addition, NTR expression, [Ca2+]i mobilization, and growth in response to NT was determined in L3.6, a metastatic pancreatic cancer cell line. Results Neurotensin receptor was expressed in 88% of the surgical specimens examined and all five of the pancreatic cancer xenografts. In contrast, VIPR, SPR, and GRPR expression was detected in 31%, 27%, and 8% of pancreatic cancers examined, respectively. Expression of NTR, functionally coupled to the Ca2+ signaling pathway, was identified in L3.6 cells; treatment with NT (10 micromol/L) stimulated proliferation of these cells. Conclusions The authors demonstrated NTR expression in most of the pancreatic adenocarcinomas examined. In contrast, VIPR, SPR, and GRPR expression was detected in fewer of the pancreatic cancers. The expression of NTR and other peptide receptors suggests the potential role of endocrine manipulation in the treatment of these cancers. Further, the presence of GI receptors may provide for targeted chemotherapy or radiation therapy or in vivo scintigraphy for early detection.

Combination therapy with enterotrophic agents may be useful in patients with the short bowel syndrome. The gut hormones neurotensin (NT) and glucagon-like peptide 2 (GLP-2) are potent enterotrophic factors when administered alone; however, their combined effects are not known. Using a GLP-2-producing tumor (STC-1), we determined whether administration of NT enhances the effect of GLP-2 on intestinal growth. Athymic mice were injected with STC-1 cells (6 x 10(6)) subcutaneously. Twenty-three days after STC-1 implantation, mice received either NT (300 microg/kg or 600 microg/kg) or saline solution (control) subcutaneously three times a day for 6 days. Two groups of tumor-free mice received either saline or NT for 6 days. At sacrifice, jejunum and ileum were collected, weighed, and analyzed for DNA and protein content. In the jejunum, NT combined with GLP-2 (from STC-1) increased weight, protein content (markers of mucosal hypertrophy), and DNA content (a marker of mucosal hyperplasia), compared to either NT or GLP-2 alone. In the ileum, the combination of NT and GLP-2 significantly increased weight and/or protein content compared to NT or GLP-2 alone. Administration of NT enhances the enterotrophic effects of GLP-2, augmenting hypertrophy of the entire small bowel and hyperplasia of the jejunum. The combination of NT and GLP-2 may be useful to enhance intestinal growth in patients with the short bowel syndrome.

Gastrin-releasing peptide (GRP) and its amphibian homolog, bombesin, are potent secretogogues in mammals. We determined the roles of intracellular free Ca(2+) ([Ca(2+)](i)), protein kinase C (PKC), and mitogen-activated protein kinases (MAPK) in GRP receptor (GRP-R)-regulated secretion. Bombesin induced either [Ca(2+)](i) oscillations or a biphasic elevation in [Ca(2+)](i). The biphasic response was associated with peptide secretion. Receptor-activated secretion was blocked by removal of extracellular Ca(2+), by chelation of [Ca(2+)](i), and by treatment with inhibitors of phospholipase C, conventional PKC isozymes, and MAPK kinase (MEK). Agonist-induced increases in [Ca(2+)](i) were also inhibited by dominant negative MEK-1 and the MEK inhibitor, PD89059, but not by an inhibitor of PKC. Direct activation of PKC by a phorbol ester activated MAPK and stimulated peptide secretion without a concomitant increase in [Ca(2+)](i). Inhibition of MEK blocked both bombesin- and phorbol 12-myristate 13-acetate-induced secretion. GRP-R-regulated secretion is initiated by an increase in [Ca(2+)](i); however, elevated [Ca(2+)](i) is insufficient to stimulate secretion in the absence of activation of PKC and the downstream MEK/MAPK pathways. We demonstrated that the activity of MEK is important for maintaining elevated [Ca(2+)](i) levels induced by GRP-R activation, suggesting that MEK may affect receptor-regulated secretion by modulating the activity of Ca(2+)-sensitive PKC.

Effective clinical therapy to augment intestinal absorption of water and electrolytes does not exist; the gut hormone, peptide YY (PYY), is a potent proabsorptive agent in animal models. The purpose of our study was to evaluate the effects of two novel PYY analogs, BIM-43073D and BIM-43004C, on intestinal absorption. Dogs with ileal Thiry-Vella fistulae (TVF) were treated with either PYY, BIM-43073D, or BIM-43004C. Administration of BIM-43073D significantly increased water and sodium absorption over baseline and maintained this level of increased absorption for a longer duration than an equimolar dose of PYY. Administration of BIM-43004C significantly increased sodium and water absorption over baseline at a level equal to that of PYY. The novel PYY analogs, BIM-43073D and BIM-43004C, are effective proabsorptive agents with BIM-43073D producing more sustained effects than PYY. These compounds may be clinically useful in the treatment of gut malabsorption in conditions such as cholera, Crohn's disease, and the short-bowel syndrome.

Background. Glutamine is the most abundant amino acid in the blood, and its deprivation leads to gut mucosal atrophy. The small intestinal mucosa is maintained by a balance between cell proliferation and cell death by apoptosis. We reported that glutamine is required for mitogen-stimulated proliferation in intestinal epithelial cells. We do not know whether glutamine regulates apoptosis in the gut. The purpose of this study is to determine whether glutamine deprivation induces apoptosis in rat intestinal epithelial (RIE-1) cells and to compare the effect of glutamine starvation with that of methionine and cysteine (Met/Cys) starvation. Methods. RIE-1 cells were deprived of either glutamine or Met/Cys for 24 hours. Cell numbers were determined by cell counting and tetrazolium enzymatic assay. Apoptosis was quantified by Annexin V assay and confirmed by DNA gel electrophoresis and Hoechst nuclear staining. Results. Deprivation of glutamine or Met/Cys resulted in decreased cell numbers. However, only the glutamine-deprived group showed significant induction of apoptosis with increased Annexin V staining, DNA laddering, and nuclear condensation. Conclusions. This study provides biochemical and morphologic evidence that glutamine deprivation induces apoptosis in rat intestinal epithelial cells. In contrast, Met/Cys starvation suppresses cell number without induction of apoptosis. These results suggest that glutamine serves as a specific survival factor in enterocytes. (Surgery 1998;124:152-60.)

Gastrin-secreting tumors have been identified inectopic locations including the ovary; the mechanismsregulating gastrin gene expression, its distribution,and signaling pathways in these ectopic tissues are not known. The purpose of our present studywas to determine: (1) whether the gastrin gene andpeptide could be detected in ovarian cancer cell lines,(2) if functional gastrin releasing peptide receptors (GRP-R) are present, and (3) whether gastringene expression is altered by GRP. Five ovarian cancercell lines (SW626, OVCA 420, OVCA 429, OVCA 432, andOVCA 433) were analyzed. We identified gastrin gene and peptide expression in the SW626 cell linebut not in the OVCA lines. SW626 cells express afunctional GRP-R that is correctly coupled to theCa2+ signaling pathway. Treatment of SW626cells with bombesin, the amphibian equivalent of GRP, inhibitedexpression of the gastrin gene in a time- anddose-dependent fashion. The SW626 ovarian cancer cellline will provide a useful model to further defineregulation and expression of both the gastrin gene andpeptide in ectopic (nongastrointestinal)tissues.

BACKGROUND Recently, a nonpeptide neurotensin (NT) receptor antagonist, SR48692, was developed that selectively antagonizes the high affinity, biologically active NT binding site. The effect of SR48692 on NT-mediated growth of a human pancreatic carcinoma, MIA PaCa-2, was determined both in vitro and in vivo. METHODS 125I-NT binding and Northern blot analyses were performed for evaluation of the NT receptor in MIA PaCa-2 cells. Intracellular calcium ([Ca2+]i) mobilization and inositol phosphate (IP3) levels were measured. Cell growth studies were performed by counting cell numbers. Athymic nude mice were inoculated with MIA PaCa-2 cells and randomized into four groups to receive either vehicle (NT or SR48692) or NT + SR48692. RESULTS MIA PaCa-2 cells possess both a high affinity, SR48692-sensitive and a levocabastine-insensitive NT binding site; Northern blot analysis demonstrated expression of the NT receptor. SR48692 inhibited [Ca2+]i mobilization, IP3 turnover, and MIA PaCa-2 cell growth induced by NT in a dose-dependent fashion. In in vivo experiments, NT significantly increased the size, weight, and DNA and protein content of xenografted MIA PaCa-2 tumors; SR48692 inhibited the effect of NT. CONCLUSIONS The novel NT receptor antagonist SR48692 will be a valuable agent to delineate further the cellular mechanisms responsible for peptide-mediated growth of normal and neoplastic gut tissues. Cancer 1997; 79:1787-93. © 1997 American Cancer Society.

The growth of the human gastrinoma model (PT) in athymic nude mice is stimulated by bombesin (BBS), an amphibian peptide homologous to both human gastrin-releasing peptide (GRP) and neuromedin B (NMB). The mechanism is not known, and a potent and specific GRP-R antagonist BIM26226, which has low affinity for NMB-R, was used in vivo in athymic nude mice bearing gastrinoma subcutaneously. Both the BBS and BIM26226 stimulated the growth of PT, and the growth stimulation was even greater when given together. RT-PCR study of gastrinoma revealed the presence of both GRP-R and NMB-R mRNA, but much more abundant NMB-R mRNA. We conclude that BBS-stimulated growth of gastrinoma involves both GRP-R and NMB-R, and our findings suggest that GRP-R mediates negative and NMB-R produces positive growth effects on gastrinoma.

Objective The authors identified various colon cancers that express the gene for the gut peptide neurotensin (NT/N). In addition, the authors sought to delineate the temporal pattern of NT/N gene expression in the human fetal colon. Summary Background Data Expression of NT/N is localized to the mucosa of the adult small bowel but also has been identified in the fetal colon, which resembles the small bowel until the end of the second trimester. Ectopic NT/N expression has been shown in certain types of colon cancer, suggesting a reversion to a fetal phenotype. Methods Sensitive ribonuclease protection assays were used to determine NT/N expression in colon cancers and adjacent normal mucosa as well as colon cancers established as tumor xenografts and fetal colon samples. Results NT/N gene expression was shown in 4 of 12 (25%) human colon cancer xenografts and in 11 of 40 (28%) freshly resected colon adenocarcinomas; NT/N gene expression was not expressed in any of the samples of normal colonic mucosa adjacent to the tumors. The NT/N gene was expressed maximally in the fetal colon between 16 and 18 weeks' gestation; NT/N expression was decreased between 19 and 22 weeks and was not apparent in either the 24-week fetal colon or the adult samples. Conclusions The NT/N gene expression is expressed transiently in the fetal colon during a development stage that is characterized by morphologic similarity to the small bowel. In addition, NT/N is re-expressed in approximately one fourth of the human colon cancers, indicating that neoplastic transformation leads to reversion to a fetal phenotype in certain types of colon cancer. The NT/N gene will provide a useful model to further define the complex differentiation pathways in the normal gut as well as the process of fetal “dedifferentiation” in certain types of colon cancer.

Peptide YY (PYY) is a gut hormone localized primarily in the distal bowel. Because circulating PYY inhibits gastric acid secretion, we investigated the effects of gastric acid secretion and gastrin on gene expression and secretion of PYY. In conscious dogs, PYY release in response to oral food was inhibited (P0.05) by pharmacologic inhibition of gastric acid secretion (omeprazole, famotidine). In rats, omeprazole treatment resulted in a significant elevation in serum gastrin concentrations and a simultaneous decrease in PYY messenger RNA (mRNA) and peptide levels in the colon; administration of a gastrin receptor antagonist (L365, 260) prevented the inhibitory actions of omeprazole on colonic PYY mRNA levels. In athymic-nude mice, implantation of a human gastrinoma resulted in an elevation of serum gastrin concentrations and a concomitant depression of colonic PYY mRNA levels. We conclude that endogenous gastric acid secretion up-regulates PYY release and PYY mRNA expression. Circulating gastrin acts to down-regulate PYY release and PYY mRNA expression. This study provides evidence that foregut functions (i.e., gastric acid secretion and gastrin release) exert control over an antiacid signal (e.g. PYY release) emanating from the hindgut.

Retinoids are a class of molecules structurally related to vitamin A that have potent antiproliferative and differentiating effects on a variety of normal and neoplastic tissues. All-trans-retinoic acid (ATRA) has become a first-line chemotherapeutic agent in the treatment of certain leukemias; however, the effect of ATRA on pancreatic tumors is unknown. The purpose of this study was to determine the effect of ATRA on the growth characteristics of both exocrine and endocrine human pancreatic cancer cell lines. The in vitro growth of four cell lines was examined after treatment with a wide dose range of ATRA. The growth of all tumor cell lines was inhibited by ATRA in a dose-dependent fashion beginning at 0.1 microgram M. The in vivo growth of functioning human pancreatic carcinoid (BON) xenografts in Balb/c athymic mice was determined by treatment with several doses of ATRA over 1 month. The growth of BON tumors was inhibited in a dose-dependent fashion. These results suggest that ATRA exerts direct antiproliferative effects on both exocrine and endocrine human pancreatic cancers and may be useful in the chemotherapy of these tumors.

The purpose of the study was to produce human monoclonal antibodies (hMcAb) against human colon cancer for use in radioimmunoimaging. Human-mouse heterohybridomas were developed by fusing SHM-D33 mouse-human hybrid heteromyeloma cells with human lymphocytes from colon cancer tumor-draining lymph nodes. The hybridomas capable of secreting human monoclonal antibodies were screened by using human colon cancer cell lines and pathological biopsies with ELISA and immunohistochemical methods. hMcAb clone H11 was selected for a large-scale antibody production, which was purified from mouse ascites. Biodistribution study demonstrated that specific uptake of 125I-hMcAb H11 by human colon cancer xenografts was significantly higher than by normal tissues. Radioimmunoimaging of human colon cancer xenografts exhibited distinct tumor visualization during the period of 72-96 hr after intraperitoneal injection of 125I-hMcAb H11. The development of human monoclonal antibodies such as hMcAb H11 may be useful for radioimmunodetection and therapy of colon cancer.

Acute TPA treatment (1h, 100nM) of a human pancreatic carcinoid cell line (BON) depletes cell contents of chromogranin A (CGA) and pancreastatin (PST), a peptide derived posttranslationally from CGA. Despite removal of TPA, BON cells continue to release CGA in an unregulated fashion whereas PST secretion is reduced substantially. TPA treatment also reduced prohormone convertase-1 (PC-1) protein and increased PC-1 mRNA levels. Together, these findings indicate that the TPA-induced switch from a regulated to unregulated pattern of CGA secretion is accompanied by a decrease in the processing of CGA to PST and a decrease in the active form of a processing enzyme potentially involved in processing CGA to a smaller peptide, PST.

Hepatocyte growth is regulated by various growth factors, including epidermal growth factor (EGF) and insulin. Recently, several additional peptide hormones have been shown to stimulate growth of hepatocyte only in the presence of EGF or insulin and are thus termed secondary mitogens. Gastrin regulates growth of normal and neoplastic gastrointestinal tissues, but the effect on growth of hepatocyte is unknown. We examined the effect of gastrin on growth of a normal mouse hepatocyte (NMH) line established in our laboratory. Effect of gastrin-17 (G-17) (10−8 to 10−6 M) on growth of NMH cells was examined in either the presence or absence of EGF in the culture medium. Growth of NMH cells was evaluated by incorporation of either bromodeoxyuridine (BrdU) or 3H-thymidine and by counting cells. Presence of a cell-surface receptor for G-17 was determined by Scatchard analysis using 125I-G-17. In the presence of EGF, gastrin stimulated growth of NMH cells; in the absence of EGF, gastrin did not affect growth. The stimulatory effect of gastrin on NMH cells was blocked by JMV 320, a CCK-B type receptor antagonist. NMH cells possess a single, high affinity binding site for gastrin (Kd = 1.2 nM); EGF increased the gastrin binding capacity compared to non-treated cells (3.5 ± 0.4 vs. 2.2 ± 0.6 fmol/106 cells). G-17 stimulated growth of NMH cells through a single high affinity receptor for G-17 which pharmcologically appears to be the CCK-B type only in the presence of EGF and thus can be considered a secondary mitogen. © 1995 Wiley-Liss, Inc.

The purposes of this study were to determine the regulation of insulin-like growth factor binding protein-2 (IGFBP-2) in IEC-6 cells by transforming growth factor-beta 1 (TGF-beta 1) and insulin and to determine whether IGFBP-2 mediated the growth-inhibitory action on the cells. Utilizing Western ligand blot analysis, we found that TGF-beta 1 at concentrations of 0.5, 1.0, and 2 ng/ml significantly increased levels of 32-kDa IGFBP in the conditioned medium (CM) of IEC-6 cells in a dose-dependent fashion and that low doses of insulin (1.0 and 5.0 microgram/ml) also increased IGFBP levels in the CM of IEC-6 cells, but a high dose of insulin (10 micrograms/ml) depressed IGFBP release in the CM. Immunoblotting has shown that the IGFBP of 32 kDa was IGFBP-2 and further confirmed the above results. IGFBP-2 mRNA levels were stimulated by TGF-beta 1 (2.0 ng/ml) and suppressed by insulin (5.0 micrograms/ml). In addition, des (1–3) IGF-I (50 ng/ml) and insulin stimulated the proliferation of IEC-6 cells. Anti-IGFBP-2 antibodies partially blocked the inhibitory role in IEC-6 cell growth evoked by des (1–3) IGF-I. These findings suggest that the upregulation of IGFBP-2 by TGF-beta 1 occurs, at least in part, at the level of mRNA, whereas the regulation by insulin appears to be at a posttranslational level, and that the TGF-beta 1-stimulated production of IGFBP may contribute to the growth-inhibitory action in intestinal epithelial cells.x

We have examined age-related changes in the stimulatory effects of distal small bowel resection on the growth of the pancreas and on polyamine biosynthesis. Two groups of male Fischer 344 rats (young; 4-month-old, aged; 25-month-old) underwent either 70% distal small bowel resection or transection of distal small bowel (control). Rats from each treatment group of each age were sacrificed on the 10th or 20th postoperative day (POD), and pancreas was weighed and assayed for DNA, RNA, and protein contents as well as polyamines. We found that young rats with distal small bowel resection exhibited significant increases in pancreatic weight, RNA, protein, putrescine, and spermine contents on the 10th POD, but aged rats that had undergone resection, showed only increased spermine content. On the 20th POD distal small bowel resection increased pancreatic weight, DNA, RNA, and protein as well as spermidine and spermine contents in young rats; aged rats had increased pancreatic weight only. These findings suggest that the trophic responses of the pancreas to distal small bowel resection are altered in aged rats, and that the polyamine biosynthetic pathway appears to be involved in this impaired response.

OBJECTIVE: The authors determined whether ileojejunal transposition (IJT) stimulates the growth of the pancreas or the nontransposed segment of small intestine, and ascertained whether this trophic effect is altered by the location of transposed gut segment. SUMMARY BACKGROUND DATA: Transposition of the ileum to the proximal small intestine stimulates a marked mucosal growth of the transposed ileal segment; the cellular mechanisms responsible for this adaptive hyperplasia are not known. METHODS: The distal quarter of the small intestine (distal ileum) was transposed into the proximal (Type I), middle (Type II), or distal (Type III) portions of the remaining small intestine. On postoperative day 28, the pancreas and scraped mucosa from the segments of transposed ileum, proximal ileum, and duodenum were obtained, weighed, and examined for DNA and protein content. RESULTS: All types of IJT increased mucosal weight and DNA content of the transposed ileum. Types I and II IJT produced a significant proliferation of the pancreas and mucosa of the duodenum and proximal ileum. The magnitude of proliferative increases was greatest in Type I IJT. CONCLUSIONS: Ileojejunal transposition appears to be an excellent model to examine the mechanisms by which intestinal epithelial cells proliferate in response to luminal nutrients or humoral factors.

Over the last 2 decades, the indications for ambulatory surgery have expanded, with an increasing number of surgical procedures performed in the ambulatory setting. Currently 60% to 70% of the surgical procedures performed in the United States each year are performed in the ambulatory setting.1,2 Ambulatory surgical procedures are generally less than 1 to 2 hours in duration, have low expected blood loss and complication rates, minimal expected postoperative care, and are usually performed in patients with no medical problems or with stable chronic medical conditions. As surgical and anesthetic techniques have evolved, evidence-based guidelines regarding preoperative testing have lagged. In the United States, current recommendations for preoperative testing are based on the 2002 Practice Advisory from the American Society of Anesthesiologists (ASA) Task Force on Preanesthesia Evaluation.3 These recommendations represent a synthesis of expert opinion and are not based on a sufficient number of adequately powered and controlled trials. Moreover, there are inconsistencies between authorities, and the language of current recommendations is imprecise. For example, “advanced age” is often used as an indication for testing without a clear minimum age. Table 1 summarizes the recommendations of the ASA,3 the Canadian Anesthesiologists’ Society (CAS),4 and the Ontario Preoperative Testing Group (OPTG).5,6 In addition, recommendations for preoperative testing vary widely on the basis of single-institution studies and systematic reviews.7–10 TABLE 1 Summary of Current ASA, CAS, and OPTG Recommendations for Testing in Patients Undergoing Ambulatory Surgery While the cost of individual tests may be low, the aggregate costs can be substantial.11,12 In the United States, the current estimated cost of preoperative testing is $3 billion to 18 billion annually.7,13,14 On the basis of single-institution studies and literature reviews, many advocate against routine preoperative laboratory testing in asymptomatic and clinically normal patients who are undergoing elective, low-risk surgery.5,7–12,14–17 It also has been shown that abnormal results in testing done before elective low-risk surgery change management in less than 3% of cases.5,11,15 Although these groups advocate against “routine” testing, they fail to outline clear and consistent guidelines or indications for specific tests. Several studies, including 2 randomized controlled trials, have evaluated the elimination of preoperative testing in patients undergoing low-risk surgery and have demonstrated no difference in adverse events.1,17,18 Despite these data, several single-institution studies document overuse of preoperative testing in the low-risk, ambulatory setting.5,11,19 However, the use of preoperative testing has not been studied at the population level. Our study uses the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database to examine current patterns of preoperative laboratory testing in patients undergoing elective hernia repair, a representative low-risk ambulatory operation. Specifically, we examine preoperative testing in all patients and a subgroup with no NSQIP-measured comorbidities and, therefore, no clear indication for pre-operative testing. Finally, this study identifies factors associated with preoperative laboratory testing and examines 30-day outcomes in tested and untested patients and patients with normal and abnormal test results.

The role of intraoperative cholangiography (IOC) in prevention of common bile duct (CBD) injuries and the management of CBD stones is controversial, and current variation in use of IOC has not been well described.Multilevel hierarchical models using data from the Texas Hospital Inpatient Discharge Public Use data files (2001 to 2008) were used to evaluate the percentage of variance in the use of IOC that was attributable to patient, surgeon, and hospital factors.A total of 176,981 cholecystectomies were performed in 212 hospitals in Texas. There was wide variation in IOC use, ranging from 2.4% to 98.4% of cases among surgeons and 3.7% to 94.8% of cases among hospitals, even after adjusting for case mix differences. The percentage of variance in IOC use attributable to the surgeon was 20.7% and an additional 25.7% was attributable to the hospital. IOC use was associated with increased age, gallstone pancreatitis or CBD stones, Hispanic race, decreased illness severity, insurance, and later year of cholecystectomy. ERCP (24.0% vs 14.9%, p0.0001) and CBD exploration (1.63% vs 0.42%, p0.0001) were more commonly performed in patients undergoing IOC.Uncertainty regarding the benefit of IOC leads to wide variation in use across surgeons and hospitals. The surgeon and hospital are more important determinants of IOC use than measured patient characteristics. Our study highlights the need for further evaluation of comparative effectiveness of IOC in the prevention of CBD injuries and retained stones, taking into account patient risk factors, surgeon skill, cost, and availability of local expertise.

Lovastatin, an inhibitor of the rate-limiting enzyme of cholesterol synthesis, inhibits growth of pancreatic cancer cells. A possible mechanism of this inhibition is that lovastatin inhibits the activity of RAS protein by depleting farnesyl (an intermediate of cholesterol synthesis). The K-ras gene is frequently mutated in pancreatic cancers and RAS protein requires farnesyl to be bound to the cell membrane and thereby activated. To investigate whether lovastatin inhibition of cell growth depends upon the presence of ras mutation, codons 12/13 and 61 of ras genes were examined by the dideoxynucleotide chain-terminating method in five pancreatic cell lines (human CAPAN2, CAV, MIA Paca2, PANCi, and hamster H2T) on which lovastatin exerted a growth-inhibitory effect. These codons play a major role in tumorigenic mutation of ras genes. Lovastatin inhibited cell growth by 99% (MIA), 97% (H2T), 78% (CAV), 41% (CAPAN2), and 23% (PANC1), respectively, when cells were treated with 2.5 micrograms/ml lovastatin for 6 days. Activating point mutations were found in codon 12 of the K-ras gene (wild type:GGT) in MIA (GTT), H2T (GAT), CAPAN2 (TGT), and PANC1 (GAT) but not in CAV. In addition, the CAV cell line did not have a mutation in either H- or N-ras genes. Lovastatin inhibited the growth of CAV cells even though this cell line did not have ras mutation, suggesting that lovastatin inhibition of pancreatic cancer cell growth is not directly dependent on the presence of ras mutation.

Cultured LLC-WRC256 (Walker rat carcinoma) cells were exposed to different doses of high energy shock waves (HESW). The immediate viabilities were 98% in the control cells, and 74%, 53% and 18% following 400, 800, and 1500 HESW treatment, respectively. Surviving cells in the 400 and 800-treated HESW demonstrated delayed upward growth rate curves, and the 1500 HESW-treated a downward curve. Agar clonogenic etficiencies for surviving cells were 36% (control), 20% (400 HESW), 15% (800 HESW) and 3% (1500 HESW). LLC-WRC256 tumours in Wistar rats were treated once every other day with 1500 HESW on a total of three occasions. Tumours treated with HESW grew more slowly (4.9 cm3) than those in the control (13.5 cm3). HESW fragmented cells and destroyed cell membranes and intracellular organelles. A histological examination of tumours treated with HESW demonstrated local haemorrhage with necrosis in the HESW focus area. Damage to the surrounding skin and soft tissue was slight and transient. These findings suggest that the growth of tumour cells can be suppressed in vitro and in vivo by treatment with HESW.