Tissue factor, angiogenesis and thrombosis in pancreatic cancer

4001

Background: Coagulation proteins are commonly activated in pancreatic cancer and are closely linked to regulation of angiogenesis. We investigated tumor cell expression of tissue factor (TF), the prime initiator of coagulation, and its association with parameters of angiogenesis, venous thromboembolism (VTE) and survival. Methods: Tissue cores from a bi-institutional retrospective series of patients consecutively resected between January 1994 and February 2002 and followed for a median period of 16 months were used to build a pancreatic cancer tissue microarray. TF expression was graded semiquantitatively using immunohistochemistry (IHC)(grade 0:negative, grade 1: 1- 33% positive, grade 2: 34- 66% positive and grade 3: > 66% cells positive) in pancreatic intraductal dysplasia (n=5) and resected pancreatic cancer (n=122). Study endpoints included correlation of TF with VEGF expression by IHC, microvessel density (MVD), clinical VTE and survival in resected patients. Patients with history of VTE, on anticoagulation or with inadequate follow-up were excluded from analysis of VTE outcomes (n=33). Results: TF expression was observed in all specimens with intraductal dysplasia and 108 resected pancreatic cancers (89%) but not in uninvolved pancreas. Sixty-six patients (54%) with resected pancreatic cancer were found to have high TF expression (defined as ≥ grade 2, the median score), and 56 patients (46%) had low or no TF expression. Tumors with high TF expression were more likely to also express VEGF (80% versus 27% with low TF expression, p<0.0001). Tumors with high TF expression had a higher median MVD (8 versus 5/tissue core with low TF expression, p=0.01). Resected patients with high TF expression had a VTE rate of 20% compared to 5.5% in patients with low TF expression (p=0.04). Median survival in tumors with high TF was 17.9 months versus 12.6 months in those with low TF (p=0.16). Conclusions: TF expression appears to occur early in pancreatic cancer pathogenesis. This is the first report describing an association of TF expression with VEGF expression, increased MVD and clinical VTE in resected pancreatic cancer, confirming the linkage of thrombosis and angiogenesis. Targeting TF in pancreatic cancer could affect both neoplastic and thrombotic outcomes.

No significant financial relationships to disclose.

O(6)-Methylguanine-DNA methyltransferase promoter hypermethylation shifts the p53 mutational spectrum in non-small cell lung cancer

The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) removes mutagenic adducts from the O6 position of guanine, thereby protecting the genome against G to A transition mutations. MGMT is inactivated by promoter hypermethylation in many human cancers and has been associated with G to A mutations in K-ras in colorectal cancer. We hypothesized that MGMT promoter hypermethylation would be associated with an increase in G to A transitions in the p53 gene in non-small cell lung cancer (NSCLC). p53 mutations were detected by both dideoxy sequencing and p53 GeneChip analysis in 92 patients with primary NSCLC. Methylation of the promoter region of the MGMT gene was determined using methylation-specific PCR and was present in 27 of 92 (29%) tumors. Hypermethylation of the MGMT promoter was more common in adenocarcinoma than in other histological types of NSCLC and was also more common in poorly differentiated tumors. MGMT promoter hypermethylation was present significantly more often in tumors with a G to A mutation in p53 (9 of 14; 64%) than in tumors with other types of p53 mutations (11 of 41; 27%; P = 0.02) or in tumors with wild-type p53 (7 of 37; 18%; P = 0.006). MGMT promoter hypermethylation was also strongly associated with G to A transitions at CpG sites. Inactivation of the MGMT gene by promoter hypermethylation alters the pattern of p53 mutation in NSCLC.

Surgical therapy of iatrogenic lesions of biliary tract

Iatrogenic injuries of the biliary tract have increased in incidence over the past decade with the introduction of laparoscopic cholecystectomy. Although a number of factors have been identified with a higher risk of injury (male gender, complicated gallstone disease, aberrant anatomy) and a number of technical steps have been emphasized to avoid these injuries, the incidence of bile duct injuries has reached a steady-state at least double the rate observed with open cholecystectomy. Most patients sustaining a bile duct injury are recognized in the weeks following laparoscopic cholecystectomy. Careful preoperative preparation should include control of sepsis by draining any bile collections or fistulas and complete cholangiography. Long-term results are best achieved in specialized hepatobiliary centers performing biliary reconstruction with a Roux-en-Y hepaticojejunostomy. Success rates over 90% have been reported from several centers to date with intermediate follow-up.

Cigarette smoking is strongly associated with mutation of the K-ras gene in patients with primary adenocarcinoma of the lung

BACKGROUND

The majority of lung carcinoma cases occur in current or former smokers. K-ras gene mutations are common in lung adenocarcinoma and have been associated with cigarette smoking, asbestos exposure, and female gender.

METHODS

In the current study, the authors examined the contribution of cigarette smoking to K-ras gene mutations in patients with primary lung adenocarcinoma. Smoking histories were obtained from 106 prospectively enrolled patients with primary adenocarcinoma of the lung.

RESULTS

K-ras mutations were detected in the primary tumor using an allele-specific ligation assay. Ninety-two of the 106 patients (87%) with lung adenocarcinoma were smokers. Nonsmokers with this tumor were more likely to be women (11 of 14; 79%), whereas the majority of smokers (57%) were men. K-ras mutations were detected in 40 of 106 tumors (38%) and were significantly more common in smokers compared with nonsmokers (43% vs. 0%; P = 0.001).

CONCLUSIONS

The results of the current study confirm and extend previous observations that smokers with adenocarcinoma of the lung are more likely to have K-ras mutant tumors compared with nonsmokers. The strong link between cigarette smoking and K-ras mutations in adenocarcinoma of the lung supports the role of specific tobacco carcinogens in the etiology of this malignancy.

p53 overexpression and K-ras gene mutations in primary sclerosing cholangitis-associated biliary tract cancer

Cholangiocarcinoma occurs frequently in patients with primary sclerosing cholangitis (PSC). We evaluated the incidence and prognostic significance of p53 protein overexpression and K-ras gene mutations in patients with biliary tract cancer and PSC. p53 protein expression was determined in specimens from 12 patients with biliary tract cancer, using the antibody, D07. K-ras mutations were detected using DNA sequencing and a mutation ligation assay. Accumulation of p53 protein was detected in 6 of 12 tumors (50%). K-ras mutations were detected in 4 of 12 tumors (33%). Overall survival in patients with p53-negative tumors was significantly longer (P < 0.05) than that in patients with p53-positive (mutant) tumors. Similarly, overall survival was significantly longer (P < 0.05) in the absence of a K-ras mutation than in patients with a tumor containing a K-ras mutation. Mean interval from the time of diagnosis of PSC until the diagnosis of biliary tract cancer was significantly shorter (P < 0.05) in patients with p53 overexpression than in those patients without p53 overexpression (2 versus 47 months). p53 overexpression and K-ras mutations occur commonly in patients with PSC and biliary tract cancer and are associated with a shortened survival. Patients with longstanding PSC are less likely to have these genetic alterations and may have a better prognosis.

p53 overexpression and K-ras gene mutations in primary sclerosing cholangitis-associated biliary tract cancer

Cholangiocarcinoma occurs frequently in patients with primary sclerosing cholangitis (PSC). We evaluated the incidence and prognostic significance of p53 protein overexpression and K-ras gene mutations in patients with biliary tract cancer and PSC. p53 protein expression was determined in specimens from 12 patients with biliary tract cancer, using the antibody, D07. K-ras mutations were detected using DNA sequencing and a mutation ligation assay. Accumulation of p53 protein was detected in 6 of 12 tumors (50%). K-ras mutations were detected in 4 of 12 tumors (33%). Overall survival in patients with p53-negative tumors was significantly longer (P < 0.05) than that in patients with p53-positive (mutant) tumors. Similarly, overall survival was significantly longer (P < 0.05) in the absence of a K-ras mutation than in patients with a tumor containing a K-ras mutation. Mean interval from the time of diagnosis of PSC until the diagnosis of biliary tract cancer was significantly shorter (P < 0.05) in patients with p53 overexpression than in those patients without p53 overexpression (2 versus 47 months). p53 overexpression and K-ras mutations occur commonly in patients with PSC and biliary tract cancer and are associated with a shortened survival. Patients with longstanding PSC are less likely to have these genetic alterations and may have a better prognosis.

Increased loss of chromosome 9p21 but not p16 inactivation in primary non-small cell lung cancer from smokers

Epidemiological studies have demonstrated a causal association between tobacco use and carcinoma of the lung, and some genetic targets of the carcinogens in cigarette smoke have been defined recently. We further examined the effect of cigarette smoking on the frequency of allelic losses on chromosome 9p21 and the incidence of p16 inactivation. Chromosomal loss at 9p21-24 was determined by microsatellite analysis using 14 markers in 47 patients with non-small cell lung cancer. In addition, p16 gene inactivation was determined by DNA sequence analysis, methylation-specific PCR, and immunohistochemistry. Tumors from a group of nonsmokers (n = 14) were compared with tumors from a group of smokers (n = 33) matched for cell type, tumor stage, and gender. Allelic loss encompassing the p16 locus was present significantly (P = 0.01) more often in smokers (23 of 33 smokers, 70%) than in nonsmokers (4 of 14 nonsmokers, 28%). No significant differences in the frequency of p16 inactivation were observed between smokers and nonsmokers (45% versus 36%). However, homozygous deletion of the p16 gene locus and point mutation of p16 gene were only observed in tumors from smokers, whereas the p16 gene was inactivated in tumors from nonsmokers only through promoter hypermethylation. Thus, inactivation of the p16 gene is a common event in all non-small cell lung cancer, but the mechanism of gene alteration differs between smokers and nonsmokers. The significant link between tobacco and loss of the p16 locus identifies additional genetic targets of smoking in the pathogenesis of lung cancer.

Chromosomal alterations in lung adenocarcinoma from smokers and nonsmokers

The etiology of lung tumors arising in nonsmokers remains unclear. Although mutations in the K-ras and p53 genes have been reported to be significantly higher in smoking-related lung carcinomas, in the present study we performed a more comprehensive analysis in search of additional genetic changes between lung adenocarcinoma from tobacco- and non-tobacco-exposed patients. We selected a matched cohort of 18 lifetime nonsmoking and 27 smoking patients diagnosed with primary adenocarcinoma of the lung and searched for chromosomal alterations in each tumor by testing normal and tumor tissue with 54 highly polymorphic microsatellite markers located on 28 different chromosomal arms. Allelic losses or gains at chromosomal arms 3p (37 versus 6%), 6q (46 versus 12%), 9p (65 versus 22%), 16p (28 versus 0%), 17p (45 versus 11%), and 19p (58 versus 16%) were present significantly more often in adenocarcinomas from smokers than from nonsmokers. Chromosomal arms showing allelic imbalance in lung tumors from nonsmokers were rare but occurred more often at 19q (22%), 12p (22%), and 9p (22%). The FAL (fractional allelic loss or gain) is defined as the percentage of chromosomal arm losses/gains among the total informative chromosomal arms. Tumors from smokers harbored higher levels of FAL (13 (48%) of 27 showed FAL > or = 0.3) compared with the lung tumors from the nonsmoker patients (2 (11%) of 18 showed FAL > or = 0.3; P = 0.02; odds ratio, 0.13; 95% confidence interval, 0.01-0.79). Our data demonstrate that widespread chromosomal abnormalities are frequent in lung adenocarcinoma from smokers, whereas these abnormalities are infrequent in such tumors arising in nonsmokers. These observations support the notion that lung cancers in nonsmokers arise through genetic alterations distinct from the common events observed in tumors from smokers.

Immunohistochemistry and molecular detection of nodal micrometastases in pancreatic cancer

PURPOSE

Assays based on polymerase chain reaction (PCR) demonstrate mutated Kiras in the regional nodes of a majority of patients with node-negative stage I or II (T(1-3), N(0), M(0)) pancreatic adenocarcinoma. The hypothesis that the presence of mutated Kiras equates with micrometastases has not been validated by detailed histologic examination nor has an impact on survival been demonstrated.

METHODS

We examined the paraffin blocks of the primary tumor and regional lymph nodes from all 30 patients from 1984 to 1998 with resected pN(0) stage I or II pancreatic adenocarcinoma. DNA was analyzed for mutations in codon 12 of the Kiras oncogene by PCR and restriction digest with BstN1 (RFLP). All nodes were examined by histology of 4 hematoxylin and eosin-stained step sections and immunohistochemistry (HPE/IHC) with AE3/AE1 epithelial cell marker antibody.

RESULTS

Examination of the regional lymph nodes of the 30 patients demonstrated nodal metastases in 9 (30%) by step-section histology alone, 14 (46.7%) by HPE/IHC, 19 (63.3%) by PCR/RFLP, and 25 (83.3%) by a combination of PCR/RFLP and HPE/IHC. Seven cases were HPE/IHC positive yet PCR/RFLP negative while 10 cases were PCR/RFLP positive and HPE/IHC negative. Median survival (months) did not differ if nodes were negative or positive by HPE/IHC (20.5 vs 17.5) or PCR/RFLP (20.0 vs 19.0) or a combination of these techniques (25 vs 18.5).

CONCLUSIONS

A great majority (83.3%) of patients with pathologic stage I or II pancreatic cancer had metastases in their regional nodes. Step-sectioning with immunohistochemistry and PCR/RFLP are complementary tests in detection of metastatic cancer cells. Nodal micrometastases did not adversely influence survival.

Cholangiocarcinoma

Despite overall advances in the ability to diagnose and treat patients with cholangiocarcinoma, the prognosis for patients with this malignancy remains poor. Further improvements in the survival of patients with cholangiocarcinoma will come with the early diagnosis of these lesions. New molecular techniques should improve the ability to screen high-risk patients, such as those with primary sclerosing cholangitis, hepatolithiasis, choledochal cysts, and ulcerative colitis. Improvements in imaging will continue, and spiral CT scanning, duplex ultrasonography, MR imaging and, perhaps, PET scans will improve the ability to stage patients with cholangiocarcinoma noninvasively. Complete surgical resection remains the only curative treatment for malignancies of the biliary tract. Aggressive surgical approaches are likely to continue, and the challenge remains in being able to perform these procedures safely in jaundiced and sometimes septic patients. For patients with unresectable lesions, the optimal form of palliation, whether surgical or nonsurgical, remains to be defined. Finally, multicenter, prospective, randomized trials of chemoradiation need to be performed to delineate an effective adjuvant therapy more precisely, and to improve the overall prognosis of patients with cholangiocarcinoma.

Microsatellite instability at AAAG repeat sequences in respiratory tract cancers

We surveyed the occurrence of novel alleles at microsatellite sequences in non-small cell lung cancers (NSCLC) using 61 tetranucleotide repeat markers. The presence of at least one new allele, consistent with microsatellite instability (MSI), was observed in 26 of 61 (43%) markers involving 30 of 47 (64%) NSCLC. Twelve of the 26 markers detected new alleles in 2 or more tumors and 11 of these 12 markers contained an AAAG repeat sequence. Using this panel of 12 markers, MSI was detected in 24 of 47 (51%) NSCLC and 10 of 18 (56%) head and neck cancers but was only observed in 8 of 38 (21%) bladder cancers and 3 of 25 (12%) kidney cancers. Our results suggested that about 50% of respiratory tract cancers exhibited microsatellite instability predominantly at AAAG sequences. This distinct type of instability was termed EMAST for elevated microsatellite alterations at selected tetranucleotide repeats. The identification of markers with EMAST should have potential application for the molecular detection of respiratory tract cancers.

p21WAF1 expression is associated with improved survival after adjuvant chemoradiation for pancreatic cancer

BACKGROUND

Cell cycle arrest after DNA damage is partly mediated through the transcriptional activation of p21(WAF1) by the p53 tumor suppressor gene. p21(WAF1) and p53 are both critical in maintaining cell cycle control in response to DNA damage from radiation or chemotherapy. Therefore, we examined the role of p21(WAF1) and p53 in the determination of outcome for patients who receive radiation and/or chemotherapy for pancreatic cancer.

METHODS

p21(WAF1) and p53 protein expression were determined (with the use of immunohistochemistry) in specimens from 90 patients with pancreatic cancer. Forty-four patients underwent surgical resection, and 46 patients had either locally unresectable tumors (n = 9 patients) or distant metastases (n = 37 patients). Seventy-three percent of the patients who underwent resection and 63% of the patients who did not undergo resection received radiation and/or chemotherapy.

RESULTS

p21(WAF1) expression was present in 48 of 86 tumors (56%) and was significantly (P<.05) associated with advanced tumor stage. Median survival among patients with resected pancreatic cancer who received adjuvant chemoradiation with p21(WAF1)-positive tumors was significantly longer than in patients with no p21(WAF1) staining (25 vs. 11 months; P = .01). Fifty of 89 tumors (56%) stained positive for p53 protein. p53 overexpression was associated with decreased survival in patients who did not undergo resection.

CONCLUSIONS

Normal p21(WAF1) expression may be necessary for a beneficial response to current adjuvant chemoradiation protocols for pancreatic cancer. Alternate strategies for adjuvant therapy should be explored for patients with pancreatic cancer who lack functional p21(WAF1).

Alcohol consumption and cigarette smoking increase the frequency of p53 mutations in non-small cell lung cancer

Epidemiological studies have demonstrated a strong association between tobacco use and lung cancer; however, the genetic targets of these carcinogens and the role of other environmental agents in this process have yet to be defined. We examined the contribution of alcohol use and cigarette smoking top53 gene mutations in patients with non-small cell lung cancer. Mutations of the p53 gene were detected by sequence analysis in 105 patients with non-small cell lung cancer. Patient characteristics significantly associated with p53 gene mutations were determined using logistic regression. Mutations in the p53 gene were present in 53% of the patients (56 of 105). p53 mutations were more common in patients who used alcohol than in patients who consumed less than one drink per day (72 versus 39%; P = 0.003), and were detected more often smokers than nonsmokers (58% versus 10%, P = 0.02). Mutations in the p53 gene were present more often (P = 0.01) in alcohol drinkers who smoked cigarettes [76% (31 of 41)], than in nondrinkers (<1 drink per day) who smoked cigarettes [42% (20 of 48)] or in nondrinkers who did not smoke [14% (1 of 7)]. In conclusion, alcohol consumption and tobacco use are both associated with p53 mutations in non-small cell lung cancer. The link between exposure to both alcohol and tobacco and p53 mutations raises the possibility that alcohol may enhance the mutagenic effects of cigarette smoke in the lung.

Iron deficiency diminishes gallbladder neuronal nitric oxide synthase

BACKGROUND

Iron deficiency has been demonstrated in the prairie dog to result in cholesterol crystal formation and altered biliary motility. Gallbladder filling and emptying are influenced by both inhibitory and excitatory stimuli, with nitric oxide (NO) playing a key role in normal relaxation. Iron is a cofactor for nitric oxide synthase. Therefore, we tested the hypothesis that iron deficiency would result in diminished levels of gallbladder neuronal nitric oxide synthase (nNOS) but would not influence the gallbladder's response to excitatory stimuli.

MATERIALS AND METHODS

Twenty adult female prairie dogs were fed either an iron-supplemented (Fe(+)) (200 ppm) control diet (n = 10) or an iron-deficient (Fe-) (8 ppm) diet (n = 10) for 8 weeks. Fasting gallbladder volume was measured. Gallbladder muscle strips were harvested for response to excitatory stimuli and measurement of nNOS protein levels by Western blotting. Muscle strip response to a spectrum of doses of cholecystokinin, acetylcholine, and electrical field stimuli was determined, and the areas under the response curves were calculated.

RESULTS

Gallbladder volume increased in the iron-deficient prairie dogs compared with the iron-supplemented group (1.45 +/- 0.27 mL vs 0.80 +/- 0.13 mL, P < 0.05). Iron deficiency diminished the ratio of gallbladder nNOS to beta-actin protein levels (0.05 +/- 0.01 vs 3.48 +/- 1.02, P < 0.05) but resulted in a normal response to excitatory stimuli.

CONCLUSIONS

We conclude that diminished gallbladder neuronal nitric oxide synthase contributes to the gallbladder stasis that occurs with iron deficiency. This phenomenon may contribute to the increased incidence of gallstones in premenopausal women.

Microsatellite instability at selected tetranucleotide repeats is associated with p53 mutations in non-small cell lung cancer

Microsatellite alterations are useful clonal markers for the early detection of cancer. An increase in microsatellite instability has been observed at certain tetranucleotide repeat markers (AAAGn) in lung, head and neck, and bladder cancer. However, the genetic mechanism underlying these elevated microsatellite alterations at selected tetranucleotide repeat (EMAST) tumors is still unknown. The p53 gene plays an important role in maintaining genome integrity by repairing damaged DNA. Therefore, we tested 88 non-small cell lung cancers with a panel of 13 microsatellite markers previously shown to exhibit frequent instability and also performed p53 sequence analysis in these tumors. Thirty-one of these 88 cancers (35%) demonstrated a novel allele [EMAST(+)] in > or =1 of these 13 microsatellite markers. p53 mutations were detected in 50 of 88 (57%) cancers and were significantly (P = 0.001) more common in EMAST(+) tumors (25 of 31; 81%) than in EMAST(-) tumors (25 of 57; 44%). Among squamous cell cancers, p53 mutations were detected significantly (P = 0.04) more frequently in EMAST(+) tumors (17 of 19; 89%) than in EMAST(-) tumors (10 of 18; 55%). Similarly, among primary adenocarcinomas, p53 mutations were present in 67% of the EMAST(+) tumors and in 35% of EMAST(-) adenocarcinomas. None of the 31 EMAST(+) tumors demonstrated high frequency microsatellite instability when examined with a reference panel of five mono- and dinucleotide markers. Primary lung cancers with microsatellite alterations at selected tetranucleotide repeats have a high frequency of p53 mutations and do not display a phenotype consistent with defects in mismatch repair.

The potential of molecular screening

Clonal genetic alterations such as tumor suppressor, gene mutations, or microsatellite instability are a hallmark of human cancer. These genetic alterations can be detected in clinical samples using DNA amplification techniques and used for early detection of cancer. This article reviews molecular-based approaches for screening of malignancies commonly encountered by the practicing general surgeon.

Extended subcostal hinge incision for right hepatic lobectomy

The safe performance of a right hepatic lobectomy requires adequate exposure of the hepatic veins and of the suprahepatic vena cava. An extended subcostal or midline incision is commonly used to provide exposure for this operation. The technique for an extended subcostal incision that uses the natural hinge mechanism of the rib cage to provide exposure to the right upper quadrant is described. This approach provides adequate exposure during a difficult hepatectomy, avoiding the need for a thoracotomy or sternotomy.

Diagnosis and management of cholangiocarcinoma in primary sclerosing cholangitis

Cholangiocarcinoma remains difficult to diagnose and is a major cause of death in patients with primary sclerosing cholangitis. Recently serum carcinoembryonic antigen and carbohydrate antigen 19-9 (CA 19-9) levels have been reported to improve diagnostic accuracy in patients with cholangiocarcinoma and primary sclerosing cholangitis. We reviewed our experience with cholangiocarcinoma complicating primary sclerosing cholangitis to identify clinical factors associated with cholangiocarcinoma in patients with primary sclerosing cholangitis and to determine the appropriate management of patients with confirmed or suspected cholangiocarcinoma. Between 1984 and 1997, 25 patients (18%) were diagnosed with cholangiocarcinoma among 139 patients with primary sclerosing cholangitis. The diagnosis of primary sclerosing cholangitis was made coincident with the diagnosis of cholangiocarcinoma in 12 patients and preceded it by a mean of 62 months in the remaining 13 patients. The incidence of inflammatory bowel disease was higher (P <0.05) in patients with cholangiocarcinoma (80% vs. 61%). Nine patients (36%) with cholangiocarcinoma were managed with either extrahepatic bile duct resection and/or partial hepatic resection (n = 5) or liver transplantation (n = 4), and the remaining 16 patients were unresectable at presentation. Serum CA 19-9 was elevated in all six patients with cholangiocarcinoma who were analyzed and in none of the eight patients without cholangiocarcinoma who were tested (P <0.01). Actuarial 1- and 3-year survival rates in the resected patients (56% and 28%, respectively) were significantly longer (P <0. 02) than in the unresected patients (13% and 0%, respectively). The 10-year actuarial mortality rates for cholangiocarcinoma among all 139 patients was 25%. In summary, cholangiocarcinoma was the leading cause of death in patients with primary sclerosing cholangitis and was often diagnosed concurrently with or within months of its diagnosis. Early liver transplantation for patients with primary sclerosing cholangitis will not reduce the incidence of cholangiocarcinoma-related mortality in these patients.

Utility of magnetic resonance cholangiography in the evaluation of biliary obstruction

BACKGROUND

Evaluation of suspected biliary obstruction has traditionally involved a variety of imaging modalities including ultrasound, CT, and invasive cholangiography. These techniques have limitations because of poor visualization of intraductal stones (ultrasound and CT) and the need for an invasive procedure (ERCP and percutaneous transhepatic cholangiography). Magnetic resonance cholangiography (MRC) is a noninvasive imaging modality that provides good visualization of the hepatobiliary system. The aim of the present study was to determine the utility of MRC in evaluating patients with suspected biliary obstruction.

STUDY DESIGN

One hundred forty-three patients were identified with suspected acute biliary obstruction and underwent MRC. Patient selection was based on clinical criteria including an elevation in serum liver chemistries or evidence of biliary ductal dilatation on conventional imaging. MRC was performed using a half-Fourier acquisition single-shot turbo spin-echo sequence involving single breath-hold rapid image acquisition. A final diagnosis was determined in each patient based on invasive cholangiography, findings at surgery, and clinical course.

RESULTS

Of the 143 patients, 73 had an obstructing biliary lesion. A malignant process was identified in 25 patients with final diagnoses of pancreatic cancer (n = 15), ampullary cancer (n = 4), cholangiocarcinoma (n = 3), and hepatic or nodal metastases (n = 3). MRC correctly identified biliary obstruction in all these patients and accurately identified the level of biliary obstruction in 24 of 25 patients. Based on the MRC images alone, a malignant process was suspected in 21 of the 25 patients. Forty patients were found to have common bile duct stones and eight patients had a benign distal bile duct stricture. MRC correctly identified common bile duct stones in 37 patients with one false-positive exam (sensitivity = 92%; specificity = 99%). MRC also correctly identified distal biliary strictures in eight patients. In the remaining 70 patients, no definite biliary obstruction was identified by MRC, and in all patients the absence of mechanical obstruction was confirmed by invasive cholangiography or overall clinical course.

CONCLUSIONS

This study demonstrates that MRC is able to accurately identify the level and cause of biliary obstruction in both malignant and benign disease. MRC may prove to be an important noninvasive tool in preoperative evaluation of patients with suspected biliary obstruction and identification of patients most likely to benefit from an invasive radiologic or surgical procedure.

Rapid p53 sequence analysis in primary lung cancer using an oligonucleotide probe array

The p53 gene was sequenced in 100 primary human lung cancers by using direct dideoxynucleotide cycle sequencing and compared with sequence analysis by using the p53 GeneChip assay. Differences in sequence analysis between the two techniques were further evaluated to determine the accuracy and limitations of each method. p53 mutations were either detected by using both techniques or, if only detected by one technique, were confirmed by using mutation-specific oligonucleotide hybridization. Dideoxynucleotide sequencing of the conserved regions of the p53 gene (exons 5-9) detected 76% of the mutations within this region of the gene. The GeneChip p53 assay detected 81% of all (exons 2-11) mutations, including 80% of the mutations within the conserved regions of the gene. The GeneChip assay detected 46 of 52 missense mutations (88%), but 0 of 5 frameshift mutations. The specificity of direct sequencing and of the p53 GeneChip assay at detecting p53 mutations were 100% and 98%, respectively. The GeneChip p53 assay is a rapid and reasonably accurate approach for detecting p53 mutations; however, neither direct sequencing nor the p53 GeneChip are infallible at p53 mutation detection.

Chromosome 9p21 loss and p16 inactivation in primary sclerosing cholangitis-associated cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma is a frequent complication of primary sclerosing cholangitis and is a leading cause of mortality in patients with this disease. The tumor suppressor gene p16 is commonly inactivated in many neoplasms; however, the role of p16 in the pathogenesis of cholangiocarcinoma is unclear. Therefore, we examined the role of p16 inactivation in the pathogenesis of cholangiocarcinoma associated with primary sclerosing cholangitis.

MATERIALS AND METHODS

Paraffin-embedded sections from 10 patients who developed cholangiocarcinoma in the setting of primary sclerosing cholangitis were examined. Chromosomal loss at 9p21 was determined using microsatellite analysis. Methylation of a CpG island in the promoter region of the p16 gene was determined using methylation-specific polymerase chain reaction. p16 inactivation was also determined using immunohistochemistry.

RESULTS

Allelic loss at chromosome 9p21 was present in 9 of 10 tumors (90%). Methylation of the p16 promoter was present in 2 of the 8 tumors examined (25%). Four of seven tumors (57%) analyzed by immunohistochemistry demonstrated an absence of p16 nuclear staining.

CONCLUSIONS

Loss of chromosome 9p21 and inactivation of the p16 tumor suppressor gene are common events in primary sclerosing cholangitis-associated cholangiocarcinoma and may play a role in the high incidence of cholangiocarcinoma in patients with primary sclerosing cholangitis.

Biliary tract surgery

The use of the laparoscope in biliary tract surgery continues to play a major role in improving the operative management of patients with biliary diseases. Laparascopic cholecystectomy has been safely performed as a day-case procedure and has lowered the morbidity of cholecystectomy in the setting of acute cholecystitis. Laparoscopic common bile duct exploration allows cholecystectomy and the removal of common bile duct stones to be performed during the same procedure, thereby decreasing hospital stay. Several new noninvasive modalities have been recently developed to image the biliary tract. In addition, laparoscopic ultrasound has led to rapid intraoperative imaging of the extrahepatic biliary tree. The long-term results of laparoscopic bile duct injuries have been better defined during the past several years. Finally, the role of surgical resection for gallbladder cancer detected during or after laparoscopic cholecystectomy has recently been evaluated.

Molecular detection of tumor cells in bronchoalveolar lavage fluid from patients with early stage lung cancer

BACKGROUND

Conventional cytologic analysis of sputum is an insensitive test for the diagnosis of non-small-cell lung cancer (NSCLC). We have recently demonstrated that polymerase chain reaction (PCR)-based molecular methods are more sensitive than cytologic analysis in diagnosing bladder cancer. In this study, we examined whether molecular assays could identify cancer cells in bronchoalveolar lavage (BAL) fluid.

METHODS

Tumor-specific oncogene mutations, CpG-island methylation status, and microsatellite alterations in the DNA of cells in BAL fluid from 50 consecutive patients with resectable (stages I through IIIa) NSCLC were assessed by use of four PCR-based techniques.

RESULTS

Of 50 tumors, 28 contained a p53 mutation, and the identical mutation was detected with a plaque hybridization assay in the BAL fluid of 39% (11 of 28) of the corresponding patients. Eight of 19 adenocarcinomas contained a K-ras mutation, and the identical mutation was detected with a mutation ligation assay in the BAL fluid of 50% (four of eight) of the corresponding patients. The p16 gene was methylated in 19 of 50 tumors, and methylated p16 alleles were detected in the BAL fluid of 63% (12 of 19) of the corresponding patients. Microsatellite instability in at least one marker was detected with a panel of 15 markers frequently altered in NSCLC in 23 of 50 tumors; the identical alteration was detected in the BAL fluid of 14% (three of 22) of the corresponding patients. When all four techniques were used, mutations or microsatellite instability was detected in the paired BAL fluid of 23 (53%) of the 43 patients with tumors carrying a genetic alteration.

CONCLUSION

Although still limited by sensitivity, molecular diagnostic strategies can detect the presence of neoplastic cells in the proximal airway of patients with surgically resectable NSCLC.

The changing face of mesenteric infarction

Intestinal infarction remains a devastating event despite improvements in clinical recognition as well as diagnostic and therapeutic modalities. Recent changes in the etiology of this disease have not been examined. A retrospective review of 121 consecutive patients over a 6-year period was undertaken. Twenty-three patients died without operation, and mortality in the remaining 98 patients was 50 per cent. The only significant predictor of mortality was an elevated serum lactate at the time of diagnosis. Thirty-one patients (26%) developed infarction while hospitalized for another disease process; excluding patients with obstruction as the etiology of infarction caused this number to rise to 39 per cent. Nonocclusive mesenteric infarction was the most common disease process. The increased incidence of nonocclusive mesenteric infarction is likely due to the development of intestinal ischemia in already systemically ill patients. Nearly half of all cases of intestinal infarction due to nonobstructive causes develop in already hospitalized patients. The development of unexplained acidosis in a postoperative or critically ill patient should prompt a search for a reversible cause of mesenteric ischemia. Intestinal infarction may represent another example of the multisystem organ failure syndrome.

Primary sclerosing cholangitis: resect, dilate, or transplant?

OBJECTIVE

The current study examines the results of extrahepatic biliary resection, nonoperative endoscopic biliary dilation with or without percutaneous stenting, and liver transplantation in the management of patients with primary sclerosing cholangitis (PSC).

SUMMARY BACKGROUND DATA

Primary sclerosing cholangitis is a progressive inflammatory disease leading to secondary biliary cirrhosis. The most effective management of sclerosing cholangitis before the onset of cirrhosis remains unclear.

METHODS

From 1980 to 1994, 146 patients with PSC were managed with either resection of the extrahepatic bile ducts and long-term transhepatic stenting (50 patients), nonoperative endoscopic biliary dilation with or without percutaneous stenting (54 patients), medical therapy (28 patients), and/or liver transplantation (21 patients).

RESULTS

Procedure-related morbidity and mortality rates were similar between surgically resected and nonoperatively managed patients. In noncirrhotic patients, the serum bilirubin level was significantly (p < 0.05) reduced from preoperative levels (8.3+/-1.5 mg/dL) 1 (1.7+/-0.4 mg/dL) and 3 (2.7+/-0.9 mg/ dL) years after resection, but not after endoscopic or percutaneous management. For noncirrhotic PSC patients, overall 5-year survival (85% vs. 59%) and survival until death or transplantation (82% vs. 46%) were significantly longer (p < 0.05) after resection than after nonoperative dilation with or without stenting. For cirrhotic patients, survival after liver transplantation was longer than after resection or nonoperative dilation with or without stenting. Five patients developed cholangiocarcinoma, including three (6%) of the nonoperatively managed patients but none of the resected patients.

CONCLUSIONS

In carefully selected noncirrhotic patients with PSC, resection and long-term stenting remains a good option. Patients with cirrhosis should undergo liver transplantation.

Analysis of PTEN/MMAC1 alterations in aerodigestive tract tumors

PTEN/MMAC1 is a candidate tumor suppressor gene recently identified at chromosomal band 10q23. It is mutated in sporadic brain, breast, and prostate cancer and in the germ line of patients with hereditary Cowden disease. We searched for genetic alterations of the PTEN/MMAC1 gene in 39 primary head and neck cancers (HNSCCs), 42 primary non-small cell lung cancers (NSCLCs), 80 pancreatic cancer xenografts, and 37 cell lines and xenografts from colon, lung, and gastric cancers. Microsatellite analysis revealed loss of heterozygosity at markers near the gene in 41% of primary HNSCCs, 50% of NSCLCs, and 39% of the pancreatic cancers. Three cases of HNSCCs displayed homozygous deletion involving the gene. We sequenced the entire coding region of the PTEN/MMAC1 gene in the remaining tumors displaying loss of heterozygosity and found one terminating mutation in a HNSCC sample. Thus, a second inactivation event was observed in 4 of 39 primary HNSCC cases. By use of a protein truncation assay, one terminating mutation was also identified in one of eight NSCLC cell lines. Our results suggest that PTEN/MMAC1 gene inactivation plays a role in the genesis of some tumor types.

Detailed deletion mapping at chromosome 9p21 in non-small cell lung cancer by microsatellite analysis and fluorescence in situ hybridization

We examined 82 cases of primary non-small cell lung cancer (NSCLC) for loss of heterozygosity (LOH) at the chromosome 9p21-24 region using 16 microsatellite markers. A total of 52 tumors (63%) displayed LOH, and 25 of these cases displayed LOH for all markers. Two cases had small hemizygous losses confined to the p16 gene and more distal markers, whereas 3 cases had loss proximal to p16 and extended through marker D9S126. This latter region has recently been described as another minimal region of loss at 9p21 in lung cancer. However, homozygous deletion of the p16 gene was observed in 18 of 85 cases, with only 5 cases having large deletions extended into the D9S126 region. Furthermore, we did not observe homozygous deletion at the 9p21 region that excluded the p16 gene. Fluorescence in situ hybridization (FISH) analysis using genomic probes spanning either the p16 or Hel-N1 (located at D9S126) gene was performed in 14 tumors. The results from FISH correlated with the chromosomal mapping data, suggesting that the p16 region is the major target of deletion at chromosome 9p21 in primary NSCLC.

Normal polymorphism in the incomplete trinucleotide repeat of the arginine-rich protein gene

The arginine-rich protein (ARP) gene was recently cloned and localized to human chromosome band 3p21. Recent reports have suggested that ARP is mutated in a high percentage of different human tumors. We amplified and sequenced the multiple arginine coding area of the ARP gene in primary head and neck, non-small cell lung, and renal cell cancers. We found a high frequency of genetic changes in this region, including a single base pair substitution and deletions of arginine repeats in primary tumors. However, these changes were always present in matched normal controls. Thus, the variations in the ARP trinucleotide repeat region represent normal polymorphisms rather than tumor-specific mutations.

Comparison of oncogene mutation detection and telomerase activity for the molecular staging of non-small cell lung cancer

Novel oncogene mutation detection techniques have demonstrated that standard histopathological examination may fail to detect clinically significant metastatic cancer cells. Recently, telomerase activity has been detected in most immortal cell lines and human tumors, potentially providing a novel diagnostic marker. We compared standard histopathological examination with the telomeric repeat amplification protocol assay and either a p53 plaque hybridization or a K-ras mutation ligation assay in the lymph nodes of 12 patents with surgically resectable non-small cell lung cancer. Telomerase activity was detected in 10 of 10 (100%) evaluable tumors. Eight of 9 (89%) histopathologically positive lymph nodes were telomerase positive, and 26 of 48 (54%) histopathologically negative lymph nodes were telomerase positive. In comparison, oligonucleotide plaque hybridization detected metastases in all 3 histopathologically positive nodes and in 3 of 27 histopathologically negative nodes. Similarly, the K-ras mutation ligation assay detected metastases in all 6 histopathologically positive lymph nodes examined and in 1 of 21 histopathologically negative lymph nodes. Thus, most of the "positive" nodes by telomerase assay did not harbor occult neoplastic cells that shared the same genetic alteration as the primary tumor. The high rate of false positives associated with the telomeric repeat amplification protocol assay limits its role in staging lymph nodes in patients with non-small cell lung cancer.

Detection of telomerase activity in oral rinses from head and neck squamous cell carcinoma patients

Telomerase is a ribonucleoprotein that maintains telomere length and whose activity is associated with escape from cellular senescence. Telomerase activity has been found in germline, immortalized, and malignant tumor cells. Using a modified PCR-based assay for telomerase activity, 26 of 35 (80%) primary, fresh, head and neck squamous cell cancer specimens and 3 of 6 head and neck squamous dysplastic lesions possessed telomerase activity. In addition, 14 of 44 (32%) oral rinses from a separate group of head and neck squamous cell cancer patients contained detectable telomerase activity, whereas 1 of 22 (5%) oral rinses from normal control patients exhibited telomerase activity. Telomerase activity in oral rinses was compared with corresponding activity in paired primary tumor samples for 19 cases: 7 of 19 demonstrated activity in both tumor and oral rinse, 2 of 19 lacked activity in both tumor and oral rinse, 10 of 19 tumors demonstrated activity that could not be detected in corresponding oral rinses, and there were no examples of positive oral rinses with corresponding negative tumors. Although currently limited in its sensitivity, analysis of telomerase activity in oral rinses represents a novel method to detect the presence of cancer cells shed in the upper aerodigestive tract.

p16 and p16 beta are potent growth suppressors of head and neck squamous carcinoma cells in vitro

p16 (CDKN2/MTS1/p16INK4a) is frequently deleted, methylated, or mutated in many malignancies including squamous cell carcinoma of the head and neck (HNSCC). p16 beta is an alternative transcript derived from a newly described exon (exon 1 beta) located more than 15 kb 5' to exon 1 of p16. Moreover, the p16 beta transcript theoretically encodes a protein distinct from p16 derived from a divergent reading frame putatively initiated in exon 1 beta. To test the contribution of both of these transcripts in carcinogenesis, full-length cDNA of p16 and p16 beta were cloned in separate vector constructs and then transfected into HNSCC cell lines characterized for p16 status (p16[+/+], p16[mut/-], and p16[methylated]). Transfection of either p16 or p16 beta resulted in marked growth inhibition in all three HNSCC lines tested, regardless of p16 status. However, p16 beta but not p16 inhibited the growth of HeLa cells, a cell line with inactive pRB due to expression of E7 papillomavirus protein. Moreover, transfection of all three HNSCC lines with either p16 or p16 beta resulted in a marked increase in cells in G0-G1 consistent with a cell cycle arrest in G1. These data are consistent with the hypothesis that p16 and p16 beta are growth-inhibitory genes active in HNSCC and that both act by blocking progression through the G1-S transition of the cell cycle. Furthermore, the suppressive effects of p16 beta on HeLa growth suggest that p16 beta mediates its effect independently from pRB.

Hypercalcemia decreases bile flow and increases biliary calcium in the prairie dog

BACKGROUND

Biliary calcium is known to play an important role in the pathogenesis of gallstones. Calcium salts are present in all pigment gallstones and are also present in the core of most, if not all, cholesterol gallstones.

METHODS

The effects of acute hypercalcemia on bile flow and biliary calcium secretion were examined in 22 prairie dogs during intravenous taurocholate infusion (0, 1.0, 2.25, and 4.5 mumol/kg/min).

RESULTS

Bile flow was linearly correlated with bile acid output in both control (y = 7.62x + 13.5, r = 0.98) and hypercalcemic (y = 7.00x + 10.4, r = 0.96) animals. At lower bile acid outputs (< 3.0 mumol/kg/min), biliary ionized calcium output per increment bile acid output was significantly increased in hypercalcemic animals (0.016 versus 0.011 mumol Ca++ mumol taurocholate, p < 0.001). Bile ionized calcium concentrations approximated Gibbs-Donnan predicted values only at low bile flow rate.

CONCLUSIONS

Hypercalcemia decreases bile flow and increases biliary ionized calcium concentration in the prairie dog. These effects favor the precipitation of calcium salts in bile.

Characterization of a small vesicular cholesterol carrier in human gallbladder bile

OBJECTIVE

Cholesterol phospholipid vesicles play an important role in the nucleation of cholesterol in bile. Recent studies have identified an additional vesicle population in human bile. In this study, the role of these small vesicles as cholesterol carriers was examined.

METHODS

Gallbladder bile was obtained from 60 patients at cholecystectomy. Large vesicles, small vesicles, lamellae, and mixed micelles were separated using gel filtration chromatography.

RESULTS

Small vesicles were present in bile from the majority of patients both with and without cholesterol gallstones, whereas the void volume vesicle fraction was found almost exclusively in bile from patients with cholesterol gallstones. Both large vesicular and small vesicular cholesterol increased as total bile cholesterol concentration increased; however, the cholesterol-phospholipid ratio in the large vesicle fraction from patients with cholesterol stones was significantly greater than the ratio in small vesicles (1.6 +/- 0.3 vs. 1.0 < or = 0.1, p < 0.05). Whole bile cholesterol crystal appearance time was correlated significantly with the percentage of cholesterol transported by large vesicles (r = 0.63, p < 0.001) but not with the percentage of cholesterol present in small vesicles. Finally, large vesicles isolated by gel filtration chromatography formed cholesterol crystals faster than small vesicles (5.3 +/- 2 vs. 17.4 +/- 4 days, p < 0.01).

CONCLUSIONS

These data suggest that a heterogenous population of vesicles is present in human gallbladder bile. As bile becomes saturated with cholesterol, it increasingly is solubilized by both small and large vesicles. The small vesicles have relatively less cholesterol and are more stable than the larger variety, from which cholesterol is most likely to precipitate.

Cholesterol nucleates rapidly from mixed micelles in the prairie dog

Current theory suggests that the nucleation of cholesterol in human bile requires the aggregation and fusion of cholesterol-enriched phospholipid vesicles. This theory is based on observations which do not exclude the precipitation of cholesterol from mixed micelles. The present study examines the role of mixed micelles and vesicles in the formation of cholesterol monohydrate crystals in the prairie dog. The intermicellar bile salt concentration of prairie dog gallbladder bile was determined using equilibrium dialysis. Model bile equivalent to gallbladder bile from cholesterol-fed prairie dogs was used as dialysant yielding the intermicellar (dialysate) concentration of 9 mM. Cholesterol carriers in gallbladder bile from 11 cholesterol-fed animals were then separated by Sephacryl S200 gel filtration chromatography using eluant buffer containing the intermicellar bile salt concentration. Gel filtration chromatography of fresh bile demonstrated that 100% of cholesterol was carried in the mixed micellar fraction with no vesicles observed in any of the 11 animals. The gallbladder bile nucleation time was 2.0 +/- 0.3 days for the cholesterol-fed animals. Gel filtration chromatography immediately after nucleation again revealed a single mixed micellar peak. These data indicate that cholesterol is carried exclusively in and nucleates rapidly from mixed micelles in the cholesterol-fed prairie dog and that cholesterol-phospholipid vesicles are not required in this process.

The effect of erythromycin on motility of the duodenum, sphincter of Oddi, and gallbladder in the prairie dog

BACKGROUND

Interdigestive motility of the stomach, duodenum, sphincter of Oddi, and gallbladder is mediated through the migrating myoelectric complex and the action of motilin. Erythromycin, a motilin agonist, has recently been studied as a gastrointestinal and biliary prokinetic agent. We hypothesized that erythromycin would increase interdigestive duodenal and sphincter of Oddi motility in a dose-dependent manner.

METHODS

In 10 anesthetized prairie dogs we determined the motility responses of the duodenum, sphincter of Oddi, and gallbladder to erythromycin infusion during a three-log dosing regimen and correlated activity with serum concentrations of the drug.

RESULTS

Erythromycin administered at 0.01 and 0.1 mg/kg had no effect on duodenal or sphincter motility. At 1.0 and 10 mg/kg, duodenal motility index increased by 451% +/- 114% and 1070% +/- 480%, respectively, when compared with baseline values, (p < 0.05). Sphincter of Oddi motility index increased by 122% +/- 38% and 323% +/- 99%, respectively, at these same doses of erythromycin (p < 0.05). Gallbladder pressure did not change significantly during erythromycin infusion. Erythromycin serum concentration at 1.0 mg/kg was 1.0 +/- 0.7 micrograms/ml.

CONCLUSIONS

These data suggest that erythromycin stimulates interdigestive motility of the duodenum and sphincter of Oddi in a dose-dependent manner at otherwise subtherapeutic concentrations of the drug.

Distribution of phosphatidylcholine molecular species between mixed micelles and phospholipid-cholesterol vesicles in human gallbladder bile: dependence on acyl chain length and unsaturation

The partitioning of phosphatidylcholine (PC) molecular species between mixed micelles and vesicles was studied in each of seven human gallbladder biles. Biles were fractionated by Sephacryl S-300 SF gel filtration chromatography, and PC species in the micellar and vesicular fractions were quantitated by high performance liquid chromatography. Micelles were enriched in species containing unsaturated acyl groups (e.g., 16:1-18:2, 18:1-18:2, and 18:1-18:3); vesicles were enriched in more highly saturated species (e.g., 16:0-16:1, 16:0-18:1, and 18:0-18:1). Separate multivariate analyses for each bile demonstrated that the distribution of PC species between vesicles and micelles was related to the degree of sn-1 and sn-2 unsaturation, and sn-1, but not sn-2, chain length. In addition, the tendency to partition into the micellar phase was particularly marked when unsaturation was present at both the sn-1 and sn-2 positions. When this interaction was included in the multivariate analyses, the regression models accounted for virtually all of the variation in PC partitioning (for each of the seven patients r2 = 0.92-0.98, P less than 0.03). These results suggest that the partitioning of PC species between micelles and vesicles is strictly determined by sn-1 chain length and the degree of unsaturation at both the sn-1 and sn-2 positions. In light of recent reports that fatty acyl composition influences the cholesterol content of vesicles and micelles in model biles, these results raise the possibility that diet-induced alterations in the phospholipid species and the relative proportions of biliary lipid particles may influence the cholesterol-carrying capacity of bile.

Effect of cholecystectomy on gallbladder bile composition

Human bile samples are commonly used in biliary research; however, the optimal sampling technique is not known. The current study examines whether bile obtained prior to operative manipulation of the gallbladder differs in composition from samples obtained after cholecystectomy. Gallbladder bile samples were obtained from 26 patients undergoing cholecystectomy. An initial sample was obtained prior to manipulation or devascularization of the gallbladder, and a second sample was obtained after the removal of the gallbladder from the operative field. Gallbladder bile pH and total protein were significantly increased in the postcholecystectomy samples. Bile obtained after cholecystectomy also contained significantly less phospholipid. Gallbladder bile cholesterol, total bile acids, bilirubin, ionized and total calcium, cholesterol saturation index, and total lipids were similar between techniques. These results indicate that manipulation of the gallbladder during cholecystectomy produces alterations in gallbladder bile composition. These results also emphasize the need for consistent sampling technique when obtaining samples for biliary research.

Effect of octreotide on sphincter of Oddi and gallbladder motility in prairie dogs

Somatostatin and its synthetic analogue, octreotide, inhibit gallbladder emptying and cause gallstones. Whether octreotide-induced alterations in sphincter of Oddi motility contribute to this process is unknown. We, therefore, examined the effect of octreotide on fasting and protein-stimulated sphincter of Oddi motility. In 25 anesthetized prairie dogs, sphincter of Oddi motility and gallbladder pressure were monitored during the intravenous administration of octreotide, cholecystokinin (CCK) octapeptide, atropine, the intraduodenal administration of casein, and combinations of these agents. Intravenous octreotide decreased fasting sphincter of Oddi motility index both with (59 +/- 19 vs. 84 +/- 28, P less than 0.05) and without (137 +/- 31 vs. 227 +/- 42, P less than 0.05) prior cholinergic blockade with atropine. Octreotide also prevented the increases in sphincter of Oddi motility and gallbladder pressure seen with intraduodenal casein. Exogenous CCK increased sphincter of Oddi motility index and gallbladder pressure despite the simultaneous administration of octreotide alone (357 +/- 109 vs. 137 +/- 31, P less than 0.07, and 11.2 +/- 1.0 mmHg vs. 9.6 +/- 0.6 mmHg, P less than 0.05) or the combination of octreotide and atropine (317 +/- 69 vs. 59 +/- 19, P less than 0.05, and 10.1 +/- 1.6 mmHg vs. 8.5 +/- 1.4 mmHg, P less than 0.05). We conclude that both a cholinergic and an octreotide-sensitive noncholinergic pathway stimulate fasting sphincter of Oddi motility in the prairie dog.

Short-term fasting increases biliary calcium and bilirubin

Fasting has been associated clinically with the development of gallbladder sludge and pigment gallstones, both of which are composed primarily of calcium bilirubinate. Although fasting has been demonstrated to increase the cholesterol saturation of bile, its effect on biliary calcium and bilirubin has not been investigated. We, therefore, tested the hypothesis that short-term fasting would increase gallbladder bile calcium and bilirubin levels. Fifteen prairie dogs were studied. Seven animals were not fasted, whereas eight were fasted for 16 hr prior to acute experiments. Gallbladder and hepatic bile samples were obtained and analyzed for calcium, bilirubin, pH, and biliary lipids. Gallbladder bile ionized calcium levels were significantly increased in fasted animals (1.7 +/- 0.2 mM) compared to those in nonfasted animals (1.1 +/- 0.1 mM). Similarly, total calcium (4.3 +/- 0.5 mM vs 2.3 +/- 0.3 mM), total bilirubin (63 +/- 12 microM vs 29 +/- 8 microM), and bilirubin monoglucuronide (58 +/- 10 microM vs 22 +/- 8 microM) were significantly increased in the fasted group. Fasted animals were also noted to have an increased biliary cholesterol saturation index (0.57 +/- 0.04 vs 0.36 +/- 0.03) and decreased biliary pH (6.9 +/- 0.1 vs 7.6 +/- 0.1). These data indicate that in the prairie dog short-term fasting results in significant alterations in gallbladder bile composition. The increased concentrations of gallbladder calcium and bilirubin observed in these experiments may account, in part, for the formation of pigment gallstones and gallbladder sludge seen clinically with prolonged fasting.

Why does somatostatin cause gallstones?

Long-term administration of the somatostatin analogue, octreotide, is complicated by gallstone formation. Somatostatin is known to inhibit hepatic bile secretion and gallbladder emptying. However, the effect of octreotide on gallbladder bile composition remains unknown. Therefore, we tested the hypothesis that octretide would alter hepatic bile composition and cause gallbladder stasis, thereby increasing gallbladder bile solute concentrations. Fourteen control prairie dogs received daily saline injections, whereas 10 animals received 1 micrograms of octreotide subcutaneously three times per day for 5 days. Cholecystectomy and common bile duct cannulation were then performed. Octreotide increased hepatic bile concentrations of bilirubin monoglucuronide (p less than 0.05), total bilirubin (p less than 0.05), and total protein (p less than 0.01). Rsa, an index of gallbladder stasis, was decreased (p less than 0.01) in the octreotide group. Gallbladder bile total calcium (p less than 0.05), bilirubin monoglucuronide (p less than 0.05), total bilirubin (p less than 0.01), total protein (p less than 0.05), and total lipids (p less than 0.05) were increased in the octreotide group. Animals receiving octreotide also had decreased hepatic (p less than 0.05) and gallbladder (p less than 0.001) bile pH. No differences in cholesterol saturation index were observed. These data suggest that in the prairie dog, octreotide (1) alters hepatic bile composition, (2) causes gallbladder stasis, and (3) increases gallbladder bile calcium, bilirubin, protein, lipid, and hydrogen ion concentrations. We conclude that octreotide causes alterations in gallbladder bile composition that increase the likelihood of cholesterol and calcium bilirubinate precipitation.

A history of the bilioenteric anastomosis

The bilioenteric anastomosis has played an integral role in the surgical management of biliary tract disease during the past century. A wide variety of techniques for suturing a portion of the biliary tract to the digestive tract have been described since von Winiwarter's first cholecystoenterostomy. Many types of biliary stents have also been developed, although their exact role remains controversial. Many advances in preoperative and postoperative care have contributed to the low morbidity and mortality of current reconstructive biliary tract surgery.