A kinetic model of aqueous-phase alkali hydrolysis of 2,4,6-trinitrotoluene

Alkali hydrolysis of 2,4,6-trinitrotoluene (TNT) was studied using batch experiments with starting pH values 11 and 12 in glass conical flasks covered with aluminum foil. Isothermal (25 and 40 degrees C) as well as non-isothermal experiments were conducted. Experiments starting at pH 12 resulted in >95% reduction in the concentration of TNT; those starting at pH 11 had a maximum reduction of 20-25% in TNT concentration. In all the experiments, one major stable intermediate was produced but it could not be identified. The experimental data were used to determine the overall stoichiometry of TNT and hydroxyl ions. Approximately 100 M (standard deviation 11.4) of hydroxyl ions were consistently consumed per mole of TNT. However, control experiments showed that all but 13 M (standard deviation 2) of hydroxyl ions were consumed in reactions not related to TNT. A simple kinetic model involving formation of the intermediate was proposed to account for changes in concentrations of TNT and hydroxyl ions. The rate constants and activation energies of the reactions were identified using isothermal data and the kinetic model was then used to predict the experimental data in the non-isothermal experiments reasonably well.

Characterization and predictors of prostate specific antigen progression rates after radical retropubic prostatectomy

PURPOSE

Detectable serum prostate specific antigen (PSA) after radical prostatectomy indicates recurrent disease and treatment failure. We characterized PSA recurrence after prostatectomy and identified predictors of rapid PSA progression.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 165 patients with detectable PSA after radical prostatectomy to characterize the rate of PSA increase and correlate this rate with the possible predictors of rapid PSA progression known at prostatectomy.

RESULTS

For a median of 48 months postoperatively we followed 142 patients with PSA recurrence after radical prostatectomy who received no immediate adjuvant therapy. PSA doubling time was less than 6, greater than 6, 12, 18 and 24 months in 46%, 54%, 18%, 11% and 9% of cases, while time to PSA 50 ng./ml. was greater than 5, 10, 15 and 20 years in 69%, 34%, 22% and 9%, respectively. Univariate and multivariate analyses revealed that rapid PSA doubling time was associated with Gleason secondary grade, Gleason score and time to initial detectable PSA (p = 0.019, 0.031 and 0.0001, and p = 0.043, 0.045 and 0.0001, respectively).

CONCLUSIONS

PSA recurrence progresses at a greatly variable rate and many recurrences progress slowly with a long doubling time. Gleason secondary grade and score appear to be predictive of rapid PSA progression. No other pathological features were predictive of rapid PSA progression.

Management of duodenal perforation after endoscopic retrograde cholangiopancreatography and sphincterotomy

OBJECTIVE

To evaluate the authors' experience with periduodenal perforations to define a systematic management approach.

SUMMARY BACKGROUND DATA

Traditionally, traumatic and atraumatic duodenal perforations have been managed surgically; however, in the last decade, management has shifted toward a more selective approach. Some authors advocate routine nonsurgical management, but the reported death rate of medical treatment failures is almost 50%. Others advocate mandatory surgical exploration. Those who favor a selective approach have not elaborated distinct management guidelines.

METHODS

A retrospective chart review at the authors' medical center from June 1993 to June 1998 identified 14 instances of periduodenal perforation related to endoscopic retrograde cholangiopancreatography (ERCP), a rate of 1.0%. Charts were reviewed for the following parameters: ERCP findings, clinical presentation of perforation, diagnostic methods, time to diagnosis, radiographic extent and location of duodenal leak, methods of management, surgical procedures, complications, length of stay, and outcome.

RESULTS

Fourteen patients had a periduodenal perforation. Eight patients were initially managed conservatively. Five of the eight patients recovered without incident. Three patients failed nonsurgical management and required extensive procedures with long hospital stays and one death. Six patients were managed initially by surgery, with one death. Each injury was evaluated for location and radiographic extent of leak and classified into types I through IV.

CONCLUSIONS

Clinical and radiographic features of ERCP-related periduodenal perforations can be used to stratify patients into surgical or nonsurgical cohorts. A selective management scheme is proposed based on the features of each type.

Renal cell carcinoma metastatic to the pancreas: a single-institution series and review of the literature

OBJECTIVES

To present a series of 5 patients with solitary metastatic renal cell carcinoma (RCC) to the pancreas after radical nephrectomy at our institution and review the published reports of this rare event.

METHODS

A retrospective review of the records of 5 patients with histologically confirmed RCC metastatic to the pancreas after radical nephrectomy was performed. A total of 5 patients (4 men, 1 woman) with a median age of 56 years (range 54 to 68) underwent radical nephrectomy for primary RCC. The pathologic stage was Robson I (n = 3) or Robson III (n = 2), with a left-sided tumor occurring in 3 patients and a right-sided tumor in 2 patients. The median interval from nephrectomy to the diagnosis of the pancreatic metastasis was 12 years (range 4 to 15). All patients were symptomatic at presentation, including weight loss (n = 3), abdominal pain (n = 3), early satiety (n = 1), steatorrhea (n = 1), and/or hemosuccus pancreaticus (n = 1).

RESULTS

All pancreatic metastases were hypervascular on imaging studies, and surgical removal was accomplished by pancreaticoduodenectomy (n = 3), partial pancreatectomy (n = 1), or subtotal pancreatectomy (n = 1). One patient died of disseminated disease 12 months after pancreatic resection. Two other patients had recurrences in the lung (n = 1) at 5 months or the pancreas/liver (n = 1) at 48 months. Both of these patients underwent a second resection and were disease free at 2 and 12 months afterward. The two remaining patients were disease free at 7 and 24 months after pancreatic resection.

CONCLUSIONS

RCC is an unpredictable tumor that may demonstrate very late metastases even from early-stage lesions. Aggressive surgical management of isolated pancreatic lesions offers a chance of long-term survival.

Does an infected peripancreatic fluid collection or abscess mandate operation?

OBJECTIVE

To assess the treatment of peripancreatic fluid collections or abscess with percutaneous catheter drainage (PCD).

SUMMARY BACKGROUND DATA

Surgical intervention has been the mainstay of treatment for infected peripancreatic fluid collections and abscesses. Increasingly, PCD has been used, with mixed results reported in the literature.

METHODS

A retrospective chart review of 1993 to 1997 was performed on 82 patients at a tertiary care public teaching hospital who had computed tomography-guided aspiration for suspected infected pancreatic fluid collection or abscess. Culture results, need for subsequent surgical intervention, length of stay, and death rate were assessed.

RESULTS

One hundred thirty-five aspirations were performed in 82 patients (57 male patients, 25 female patients) with a mean age of 40 years (range 17-68). The etiologies were alcohol (41), gallstones (32), and other (9). The mean number of Ranson's criteria was four (range 0-9). All patients received antibiotics. Forty-eight patients had evidence of pancreatic necrosis on computed tomography scan. Cultures were negative in 40 patients and positive in 42. Twenty-five of the 42 culture-positive patients had PCD as primary therapy, and 6 required subsequent surgery. Eleven patients had primary surgical therapy, and five required subsequent surgery. Six patients were treated with only antibiotics. The death rates were 12% for culture-positive patients and 8% for the entire 82 patients.

CONCLUSIONS

Historically, patients with positive peripancreatic aspirate culture have required operation. This series reports an evolving strategy of reliance on catheter drainage. PCD should be considered as the initial therapy for culture-positive patients, with surgical intervention reserved for patients in whom treatment fails.

Mammalian TOR controls one of two kinase pathways acting upon nPKCdelta and nPKCepsilon

There are three conserved phosphorylation sites in protein kinase C (PKC) isotypes that have been termed priming sites and play an important role in PKC function. The requirements and pathways involved in novel (nPKC) phosphorylation have been investigated here. The evidence presented for nPKCdelta shows that there are two independent kinase pathways that act upon the activation loop (Thr-505) and a C-terminal hydrophobic site (Ser-662) and that the phosphorylation of the Ser-662 site is protected from dephosphorylation by the Thr-505 phosphorylation. Both phosphorylations require C1 domain-dependent allosteric activation of PKC. The third site (Ser-643) appears to be an autophosphorylation site. The serum-dependent phosphorylation of the Thr-505 and Ser-662 sites increases nPKCdelta activity up to 80-fold. Phosphorylation at the Ser-662 site is independently controlled by a pathway involving mammalian TOR (mTOR) because the rapamycin-induced block of its phosphorylation is overcome by co-expression of a rapamycin-resistant mutant of mTOR. Consistent with this role of mTOR, amino acid deprivation selectively inhibits the serum-induced phosphorylation of the Ser-662 site in nPKCdelta. It is established that nPKCepsilon behaves in a manner similar to nPKCdelta with respect to phosphorylation at its C-terminal hydrophobic site, Ser-729. The results define the regulatory inputs to nPKCdelta and nPKCepsilon and establish these PKC isotypes downstream of mTOR and on an amino acid sensing pathway. The multiple signals integrated in PKC are discussed.

Surgical management of biliary gallstone disease during pregnancy

BACKGROUND

Biliopancreatic gallstone disorders (BPD) manifesting during pregnancy are relatively rare. The management of these conditions remains controversial. Although perioperative problems and fetal loss have been reported, recent publications have advocated an early surgical approach.

PATIENTS AND METHODS

Thirty-two pregnant women underwent operation for BPD between January 1993 and December 1997. The mean age was 29 years and ranged from 18 to 41 years.

RESULTS

Twelve patients underwent a laparoscopic cholecystectomy (LC), and 20 open cholecystectomies (OC), including two conversions from laparoscopic. Seven of the OC patients required additional open CBD exploration and intraoperative choledochoscopy for CBD stones. No maternal mortality was observed. A single fetal demise (3%) occurred for a patient with gallstone pancreatitis who underwent open cholecystectomy during her 14th week of gestation.

CONCLUSIONS

Early involvement of the obstetric team, with preoperative and postoperative fetal monitoring, and adequate management of anesthetic and tocolytic agents make cholecystectomy a safe procedure at any stage of pregnancy.

Gene therapy for primary and metastatic pancreatic cancer with intraperitoneal retroviral vector bearing the wild-type p53 gene

BACKGROUND

Metastatic pancreatic cancer is uniformly fatal because no effective chemotherapy is available. Mutations in the p53 tumor suppressor gene are found in up to 70% of pancreatic adenocarcinomas. We examined the efficacy of a retroviral vector containing the wild-type p53 gene on metastatic pancreatic cancer in a nude mouse model.

METHODS

Bxpc3 human pancreatic cancer cells were transduced with either a retroviral p53 vector or an LXSN empty vector. Cells were examined for incorporation of tritiated thymidine to determine the effect of p53 retroviral transduction on DNA synthesis, and a TACS2 assay for apoptosis was performed. The functional activity of p53 in transduced cells was assessed by Western blot analysis with an antibody to WAF1/p21. In vivo effects of intraperitoneal injections of the p53 vector were examined in a nude mouse model of peritoneal carcinomatosis.

RESULTS

Cells treated with the p53 vector exhibited a 59% to 85.5% reduction in cell number compared with the control cells (P < .05). p53-treated cells demonstrated decreased incorporation of tritiated thymidine (12.7% +/- 0.7% vs 17.5% +/- 1.4%; P = .002), increased staining for apoptosis, and increased expression of the WAF1/p21 protein. Treatment of nude mice with the retroviral p53 vector resulted in a significant inhibition of growth of the primary pancreatic tumor, as well as the peritoneal tumor deposits, compared with the LXSN control vector.

CONCLUSIONS

Intraperitoneal delivery of a retroviral p53 vector may provide a novel treatment approach for peritoneal carcinomatosis from pancreatic cancer.

Intercellular communication mediates the bystander effect during herpes simplex thymidine kinase/ganciclovir-based gene therapy of human gastrointestinal tumor cells

A bystander effect is described when nontransduced or genetically unmodified cells are killed during death of genetically modified tumor cells transduced with a suicide gene. The "bystander effect" greatly enhances the efficacy of the herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) gene therapy approach for cancer. The mechanism of the bystander effect is controversial. In this study, we examined the role of intercellular gap junction communication (GJIC) for the bystander effect in human gastrointestinal tumor cells. Our results show that the extent of the bystander effect varied amongst the tumor cell lines; pancreatic cancer cells BXPC-3 exhibited excellent bystander effects in vitro and in vivo studies whereas other gastrointestinal tumor cell lines such as pancreatic cancer cells MIAPACA-2, and colon cancer cells HT-29 showed poor bystander effects. Bystander effects were only found in the presence of cell-to-cell contact. The extent of the bystander effect was independent of the level of HSV-TK activity in the transduced tumor cells and was correlated with GJIC as demonstrated by an in vitro dye-transfer assay. Expression of the mRNA levels of gap junction protein connexin 43 was 8- to 26-fold or greater and connexin 26 gene expression was 2- to 229-fold greater in BXPC-3 cells compared to HT-29, MIAPACA-2, and PANC3 cells. Our results suggest that intercellular communication is essential for the bystander effect. The correlation between GJIC and the extent of the bystander effect suggest a role for GJIC in mediating the bystander effect. Analysis of tumors for GJIC or expression of gap junction proteins may identify the subset of patients suitable for gene therapy with the HSV-TK/GCV approach.

Mechanisms for ganciclovir resistance in gastrointestinal tumor cells transduced with a retroviral vector containing the herpes simplex virus thymidine kinase gene

Transfer of the herpes simplex thymidine kinase (HSV-TK) gene into tumor cells confers sensitivity to the cells to the viral drug ganciclovir (GCV). Although the efficacy of the HSV-TK/GCV approach is well studied, the mechanisms for the resistance of HSV-TK-transduced tumor cells to GCV are poorly understood. Here, we examined the mechanisms for GCV resistance in HSV-TK-transduced gastrointestinal (GI) cell lines. Our results show that GCV sensitivities vary in vitro and in vivo among the different HSV-TK-transduced GI tumor cell lines. GCV-resistant colonies were isolated from several different HSV-TK-transduced GI tumor cell lines after 14 days of GCV treatment. Characterization of GCV-resistant colonies demonstrated that the HSV-TK gene was either partially or completely deleted from the resistant HSV-TK-transduced cells. In the HT-29 RM and MIAPACA-2 RM cells, a 220-bp deletion of the gene was found, whereas in the HT-29 R1-R5-resistant cells, the whole TK gene was found to be absent. Immunocytochemical studies using a polyclonal antibody to the TK protein demonstrated that the HSV-TK protein was absent in the GCV-resistant, HSV-TK-transduced cells. Transfection of the resistant cells with an adenoviral vector containing a HSV-TK gene restored sensitivity to GCV. The presence of GCV-resistant cells was only demonstrable in GI tumor cell lines that also demonstrated a poor bystander effect. Our results suggest that GCV resistance found in tumor cells transduced with a retroviral HSV-TK gene is due to the lack of a functional TK protein in the tumor cells rather than any intrinsic resistance of the cells to GCV. In tumor cells with a good bystander effect, the small percentage of TK-transduced cells that do not express the TK protein are probably killed by the bystander effect because GCV-resistant tumor cells were not found in these cell lines. GCV-resistant tumor cells were found only in tumor cell lines with a poor bystander effect, by which, presumably, the transduced tumor cells lacking a functional TK gene were not killed by the bystander killing effect.

Development of systemic immunologic responses against hepatic metastases during gene therapy for peritoneal carcinomatosis with retroviral HS-tk and ganciclovir

Gene therapy with retroviral mediated gene transfer of the herpes simplex thymidine kinase (HS-tk) gene into a tumor mass confers sensitivity of the tumor cells to ganciclovir (GCV). Tumor-specific immunologic responses may develop following treatment of the primary tumor with retroviral HS-tk and GCV. In the present study we assessed whether GCV treatment of HS-tk transduced colon cancer (TK+) implanted in the peritoneal cavity induced a systemic antitumor response that would inhibit growth of a second wild-type (TK-) tumor implanted in the liver. DHDK12 rat colon cancer cells were transduced in vitro with the retroviral HS-tk vector and established as a permanent cell line (TK+ cells). TK+ or TK- DHDK12 cells (6x10(6) cells) were injected intraperitoneally on day 0 into BD-IX rats. On day 10, TK- cells (3x10(6) cells) were injected into the liver in all the groups. The animals were then treated with GCV (150 mg/kg) for 13 days. TK+ peritoneal tumors underwent significant regression during therapy with GCV (0.05+/-0.004 g; n=7) compared to wild-type (TK-) tumors (2.2+/-0.7g; n=6) (P<0.05). The volume of TK- tumors in the liver was significantly lower in GCV-treated rats with TK+ peritoneal tumors (12.5+/-8.3 mm3) compared to rats with TK- peritoneal tumors (96.7+/-18.1 mm3) (P<0.05). Histology of the liver tumors in the TK+ groups showed a dense monocytic infiltrate with fibrosis and only occasional viable tumor cells. Gene therapy with retroviral HS-tk vectors may provide a novel approach to treatment of gastrointestinal cancer by both direct cytotoxicity and an indirect mechanism that may include enhanced immuno logic responses against disseminated disease.

Color flow sonography in evaluating the resectability of periampullary and pancreatic tumors

Over the past several years, we have developed a technique to assess the resectability of periampullary and pancreatic tumors using color flow sonography. This is a feasibility study to determine if sonography with color flow imaging can play a role in evaluating patients with periampullary and pancreatic tumors. This study comprises a retrospective analysis of 51 patients referred for color flow sonographic evaluation of resectability of periampullary and pancreatic neoplasm. Scanning was performed with state-of-the-art color flow sonographic systems. Vessels that were touched or occluded by tumor were categorized according to a Pancreatic Color Doppler Score. Other factors affecting resectability (metastasis, enlarged nodes) were recorded. Sonographic findings were correlated with surgical resectability and pathologic findings regarding tumor margins. The color flow study was complete technically (all index vessels visualized) in 49 of 51 patients (96%). In all, 643 of 647 vessels (99.4%) were imaged. Forty-five patients had sufficient surgical, pathologic, or clinical proof to be included in the resectability analysis. All 18 patients with circumferential tumor or vascular occlusion (Pancreatic Color Doppler Score 4 and 5) were found to have unresectable disease. All 10 patients in whom tumor did not touch (Pancreatic Color Doppler Score 0) had negative margins. All 30 patients considered to have unresectable tumors sonographically could not be resected. Patients in this category had one or more of the following: positive pathologic margins, positive nodes, liver metastasis, or not clinically resectable. Six of 15 considered resectable sonographically (40%) were unresectable for cure. Surgeons believed that color flow sonography influenced management in 10 of 45 patients (22% overall). Color flow sonography, a painless, noninvasive, and relatively inexpensive examination, may be an effective screening tool to evaluate periampullary and pancreatic neoplasms for resectability. Our data show that color flow sonography can correctly predict unresectability of periampullary and pancreatic neoplasms. Any future evaluation of imaging and management of periampullary and pancreatic tumors should include color flow sonography.

Gene therapy of metastatic pancreas cancer with intraperitoneal injections of concentrated retroviral herpes simplex thymidine kinase vector supernatant and ganciclovir

OBJECTIVE

The objective of this study was to determine the efficacy of intraperitoneal (IP) injections of a new concentrated herpes simplex thymidine kinase (HS-tk) retroviral vector and ganciclovir (GCV) for peritoneal metastases from pancreas cancer.

SUMMARY BACKGROUND DATA

Metastatic pancreas cancer is fatal. Gene therapy may provide a novel approach for this disease. Gene therapy with adeno- or retroviral-mediated transfer of the HS-tk gene into tumor cells renders the cells susceptible to GCV. Intratumoral or intracavity injections of retroviral vectors have been ineffective in previous studies.

METHODS

Pancreatic cancer B x PC3 cells (3 x 10(7)) were injected into the tail of pancreas in nude mice. Mice received IP injections of a concentrated HS-tk vector (5 x 10(7)) cfu/mliters) or a control vector (G1Na) without the tk gene for 10 days and GCV (100 mg/kg) for 14 days. To determine whether the vector would survive in the milieu of the peritoneal cavity, the authors examined the effects of ascitic fluid on the vector. Pancreas cancer cells were transduced in vitro with HS-tk vector in presence of media or ascitic fluid and treated with GCV.

RESULTS

Highly significant reductions in the mass of metastatic peritoneal tumor deposits were found in HS-tk-treated group (124 +/- 27 mg; n = 11) compared with G1Na vector controls (910 +/- 168 mg; n = 8; p < 0.0001). Results of polymerase chain reaction analysis demonstrated integration of the vector in the tumors, and on immunohistochemistry, expression of the TK protein was seen in the number of surviving colonies (representing nontransduced cells) were similar in both groups, suggesting that the vector effectively transduced tumor cells bathed in the ascitic fluid.

CONCLUSIONS

Results demonstrate that IP administration of concentrated retroviral HS-tk vectors is effective treatment for pancreas cancer metastatic to the peritoneal cavity; furthermore, the vector is active in the presence of ascitic fluid. Intraperitoneal retroviral HS-tk may provide a novel approach to treatment of metastatic pancreas cancer.

Assessment of resectability of pancreatic head and periampullary tumors by color flow Doppler sonography

OBJECTIVE

To examine the sensitivity of color flow Doppler ultrasonography in assessing resectability of pancreatic head and periampullary tumors.

DESIGN

Validation cohort study.

SETTING

Tertiary care public hospital.

PATIENTS

Thirty-seven patients with pancreatic head or periampullary cancer were studied by color flow Doppler examination of the relevant blood vessels.

MAIN OUTCOME MEASURE

A pancreatic Doppler score (PDS) was defined as the closest circumferential contact of the tumor to the superior mesenteric vein, superior mesenteric artery, or portal vein. A PDS of 1 indicated no contact (n = 9); PDS 2, less than 50% contact (n = 10); PDS 3, 50% to 99% contact (n = 7); and PDS 4, encasement (n = 11). The PDS was compared with operative and histologic resection margins.

RESULTS

The lack of vascular invasion was confirmed operatively in 7 of 7 patients with a PDS of 1, and 6 patients who underwent resection had clear histologic margins. Nine (90%) of 10 patients with a PDS of 2 were confirmed to have no vascular invasion, and 3 (43%) of 7 patients who underwent resection had clear margins. Five (83%) of 6 patients with a PDS of 3 had correct operative findings, and both patients who underwent resection had positive margins. Operative confirmation of encasement was found in all 7 patients with a PDS of 4 who had operative exploration, and none underwent resection.

CONCLUSIONS

Color flow Doppler sonography and PDS predicted resectability and the histologic margin status (positive predictive value, 97%). Patients with a PDS of 1 are predicted to have clear histologic margins after resection. Patients with a PDS of 4 have unresectable tumors, and nonoperative palliation should be considered. Patients with a PDS of 2 or 3 have a high likelihood of positive histologic margins after resection and may be candidates for neoadjuvant chemotherapy.

Surgical treatment of recurrent pyogenic cholangitis

OBJECTIVE

To examine the evolving operative strategies in the treatment of recurrent pyogenic cholangitis (RPC).

DESIGN

Case series of patients with RPC treated surgically at the Los Angeles County-University of Southern California Medical Center between 1980 and 1994.

SETTING

Public teaching hospital.

PATIENTS

Twenty patients with RPC were studied. The clinical diagnosis of RPC was made in patients with a syndrome of chronic intermittent attacks of biliary sepsis associated with intrahepatic biliary strictures and intrahepatic stones.

MAIN OUTCOME MEASURE

The need for repeated biliary intervention after surgical treatment of RPC.

RESULTS

Four patients had a hepatic lobectomy without biliary enteric bypass. One patient had an uneventful course. Three patients had postoperative biliary sepsis, and one of these patients died. A hepaticojejunostomy without a cutaneous stoma was performed in eight patients. Five (63%) of these eight required repeated operation for biliary sepsis 1 to 4 years after surgery. In eight patients, a Roux-en-Y hepaticojejunostomy was performed after attempted clearance of intrahepatic stones with construction of a temporary cutaneous stoma. Postoperatively, these eight patients had 16 transstomal endoscopic cholangiograms (mean follow-up, 10 months). Stones proximal to intrahepatic strictures were identified in seven endoscopic sessions in five of these patients (63%). The stones were removed, and the strictures were endoscopically dilated. None required repeated biliary operation.

CONCLUSION

RPC is a progressive, lifelong disease. Construction of a hepaticojejunostomy with a cutaneous stoma allows future therapeutic intervention without the need for repeated surgery.

Laparoscopic cholecystectomy: laboratory predictors of choledocholithiasis

Liver function tests (LFTs) are most often employed to select patients for preoperative endoscopic retrograde cholangiography (ERC) and therapeutic sphincterotomy. Although ERC accurately detects CBD stones, the associated financial costs and potential morbidity argue against its indiscriminate use. We analyzed the value of LFTs to predict CBD stones in patients treated by laparoscopic cholecystectomy (LC). CBD stones were identified in 41 of 660 patients (6.2%) treated by LC during the study period (January 1991 to May 1993). CBD stones were identified by preoperative ERC in 19 of 33 patients (57.6%); by operative cholangiography in 18 of 289 patients (6.2%), and by postoperative ERC in 4 patients. In patients with CBD stones, there was a significant difference in alkaline phosphatase, total bilirubin, SGPT, and SGOT (P < 0.001). The positive predictive value (PPV) of a value > normal at admission was 5%-19%; and immediately before operation was 9%-36%. The PPV of a value > 2X normal was 30%-47%. Alkaline phosphatase and total bilirubin were independent predictors of CBD stones. If both were greater than twice normal, there was a 55 per cent incidence of CBD stones. Our analysis suggests that patients with greater than twice normal liver function tests have a sufficient incidence of CBD stones to warrant ERC. Patients without both these criteria should be managed by laparoscopic CBDE, with postoperative endoscopic stone retrieval for the failures of laparoscopic CBDE.

Effect of aging on neurotensin-stimulated growth of rat small intestine

The proliferative activity of gut mucosa is altered with aging; the potential for the aged gut to respond to trophic stimuli is not known. The purpose of this study was to determine whether there are age-related differences in the effects of the trophic gut peptide neurotensin (NT) on the structure and function of small bowel mucosa. NT (300 micrograms/kg) or saline (control) was injected subcutaneously at 8-h intervals for 5 days in rats of two age groups, young (2 mo) and aged (24 mo). On day 6, rats were killed, and the gut mucosa (proximal and distal small bowel) was scraped, weighed, and analyzed for DNA, RNA, and protein content and for disaccharidase (sucrase and maltase) activity. In a second experiment, the groups of rats and the protocol for NT administration were identical; however, when the rats were killed, the distal gut was removed for histological evaluation of crypt and villus length (mm) and density (no./cm gut segment) and bromodeoxyuridine immunohistochemistry. NT produced significant increases in mucosal growth (wt, DNA, RNA, and protein) in both age groups when compared with age-matched controls; the increase of growth measurements was the greatest in the small bowel mucosa of the aged rats. In addition, NT increased crypt density in both groups; only the aged group treated with NT demonstrated increases in crypt depth and villus height. Specific activities of sucrase and maltase did not change with NT treatment in either of the age groups. We conclude that the proliferative potential of small bowel mucosa is maintained with aging in response to administration of NT.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a human pancreatic carcinoid in vitro: morphology, amine and peptide storage, and secretion

The study of functioning human endocrine tumors has been hampered by a lack of suitable in vitro models. We have established the first permanent cell line of a human pancreatic carcinoid tumor (BON) in culture. BON cells grow in monolayer culture and form colonies in soft agar. Injection of BON cells into nude mice produces transplantable tumors in a dose-dependent fashion. The histology of tumors in athymic mice from injection of dispersed, cultured BON cells is similar to the original histology of the resected tumor. Significant amounts of neurotensin, pancreastatin, and serotonin (5-HT) are demonstrated in the cells by radioimmunoassay (RIA) and the presence of chromogranin A, bombesin, and 5-HT is confirmed by immunocytochemistry. Numerous round and pleomorphic dense-core neurosecretory granules are present on electron microscopy. Functional receptors for acetylcholine, 5-HT, isoproterenol, and somatostatin are present on cultured cells. BON cells possess a specific transport system for uptake of 5-HT from the medium; this uptake system may be a route for regulation of autocrine effects of 5-HT on carcinoid cells. This unique human carcinoid tumor cell line should provide the opportunity for new insight into the biology of carcinoid tumors and of specific intracellular mechanisms for secretagogue action in the release of amines and peptides.

The effect of endogenous cholecystokinin released by bombesin and trypsin inhibitor on the regeneration of the pancreas

OBJECTIVE

This study examined the effects of endogenous cholecystokinin (CCK) released by bombesin and FOY-305 (a synthetic inhibitor of trypsin on pancreatic regeneration in rats).

SUMMARY BACKGROUND DATA

Trophic gut hormones (CCK and bombesin) stimulate the growth of the normal rat pancreas. However, the influence of endogenous gut hormones on pancreatic regeneration is unclear.

METHODS

Male Fisher rats (n = 6 to 8 per group) were fed a protein-free diet and given ethionine (700 mg/kg intraperitoneally daily) for 8 to 9 days to induce degeneration of the pancreas. Regeneration was stimulated by giving the rats a regular chow diet. The effects of bombesin (10 micrograms/kg three times a day for 7 days) or FOY-305 (200 mg/kg daily for 8 days) on the process of regeneration were examined.

RESULTS

At the end of the degeneration phase, there was near-total destruction of pancreatic acinar cells. Both bombesin and FOY-305 stimulated pancreatic regeneration. Growth measurements (weight and total content of DNA and protein) were significantly increased (p < 0.05) in the bombesin- and FOY-305-treated rats compared with controls. Histologic examination revealed widespread repopulation of the pancreas with acinar cells in the bombesin- and FOY-305-treated groups. The stimulating effects of both bombesin and FOY-305 on pancreatic regeneration were blocked completely by the CCK-receptor antagonist L-364,718. Growth measurements were not significantly increased in the groups of control rats or rats given L-364,718 alone.

CONCLUSIONS

These results show that bombesin and FOY-305 significantly stimulated pancreatic regeneration. Because the stimulating effects of bombesin and FOY-305 on regeneration were blocked by the specific CCK-receptor antagonist L-364,718, it was concluded that this effect was mediated by endogenous CCK.