Telomerase activity in periampullary tumors correlates with aggressive malignancy.

OBJECTIVE: To determine the presence of telomerase activity in a variety of periampullary malignancies and pancreatic diseases and quantify its activity to establish any association with the stage or aggressiveness of malignancy. SUMMARY BACKGROUND DATA: Progressive shortening of telomeres, repetitive DNA sequences at the ends of chromosomes, plays a role in cell senescence. Telomerase catalyzes conservation of telomeric repeats and may promote cell immortality and hence malignancy. It is absent in normal tissues but upregulated in more than 80% of cancers. METHODS: Fresh specimens of 62 periampullary tumors were snap-frozen in liquid nitrogen and adjacent tissue was formalin-fixed for histopathology. The telomerase repeat amplification protocol (TRAP) was used to obtain telomerase DNA products. These were separated with gel electrophoresis, stained with SYBR green, and quantified by densitometry. Findings were confirmed with a fluorometric TRAP assay in which fluorescent primers specific for telomerase were selectively amplified in its presence. RESULTS: Telomerase activity was upregulated in 26 of 33 periampullary malignancies (79%): 17 of 21 pancreatic adenocarcinomas (81%), 2 of 2 cholangiocarcinomas, 2 of 2 duodenal carcinomas, and 5 of 8 ampullary carcinomas (63%). Poorly differentiated periampullary tumors had significantly higher telomerase activity than well-differentiated tumors, and tumors larger than 2 cm had significantly higher telomerase activity than those 2 cm or smaller. Pancreatic ductal adenocarcinomas with lymph node metastases had significantly greater activity than node-negative cancers. Two of 11 intraductal papillary mucinous tumors were positive for telomerase activity, but only in foci of invasive carcinoma. Chronic pancreatitis (n = 7), serous cystadenomas (n = 5), benign mucinous cystic neoplasms (n = 4), neuroendocrine cancer (n = 1), and acinar cell carcinoma (n = 1) had no detectable telomerase activity. CONCLUSION: Telomerase activity is common in periampullary carcinomas. The magnitude of activity correlates with aggressiveness in pancreatic adenocarcinoma and may prove useful as a molecular index for biologic staging.

Regional effects of nafamostat, a novel potent protease and complement inhibitor, on severe necrotizing pancreatitis.

BACKGROUND: We evaluated the effect of the novel protease inhibitor nafamostat on rat necrotizing pancreatitis through different routes of administration. METHODS: Three hours after the induction of severe pancreatitis, the rats received intravenous gabexate or intravenous or local mesenteric intra-arterial nafamostat. At 9 hours, ascites and bronchoalveolar lavage fluid were collected for the evaluation of capillary leakage (Evans blue extravasation). Pancreas and lung were excised for histologic features, myeloperoxidase, and trypsinogen activation peptide. Twenty-four hour survival was evaluated. RESULTS: Only the intravenous infusion of nafamostat significantly reduced myeloperoxidase (11.7 +/- 2.3 vs 18.3 +/- 1.8 mU/mg; P <.05) and capillary leakage in lungs (Evans blue dye, 1.6 +/- 0.3 vs 2.6 +/- 0.3; P <.05). Only intra-arterial infusion of nafamostat significantly diminished capillary peritoneal leakage (Evans blue dye, 3.6 +/- 0.9 vs 9.4 +/- 0.4; P <.01). Typsinogen activation peptide levels were significantly reduced in all groups, but only intra-arterial infusion did so to baseline. Histologic inflammation in the pancreas was most significantly reduced after intra-arterial infusion (0.92 +/- 0.08 vs 2.91 +/- 0.06; P <.05). No form of protease inhibition reduced mortality rates. CONCLUSIONS: The effects of protease inhibition depend on the route of administration. Nafamostat has maximal effects on the pancreas and peritoneal capillary leakage when delivered by way of local intra-arterial infusion, and shows a greater reduction of lung leukocyte infiltration and capillary leakage by the intravenous route. Nafamostat is more effective than gabexate.

Ten-year experience with 733 pancreatic resections: changing indications, older patients, and decreasing length of hospitalization.

HYPOTHESIS: Experience with pancreatic resection for the last 10 years has resulted in new trends in patient characteristics and, for pancreaticoduodenectomy (PD), a decrease in the length of stay (LOS). This decrease is due in part to the implementation of case management and clinical pathways. DESIGN: Retrospective case series of patients undergoing pancreatic resection. SETTING: A university-affiliated, tertiary care referral center. PATIENTS: The study comprised 733 consecutive patients undergoing pancreatic resection for benign or malignant disease at the Massachusetts General Hospital in Boston from April 1990 to March 2000. INTERVENTIONS: Of the 733 pancreatic resections, 489 were PD; 190, distal pancreatectomy; 40, total pancreatectomy; and 14, middle-segment pancreatectomy. MAIN OUTCOME MEASURES: Length of stay; occurrence of delayed gastric emptying, pancreatic fistula, reoperation, readmission, or other complications; mortality; and comparison of patients in 3 periods according to the implementation of case management (July 1995) and clinical pathways (September 1998). RESULTS: For PD, patients in group 1 (April 1990 to June 1995) were significantly younger (mean +/- SD, 57 +/- 15 years) than those in group 2 (July 1995 to August 1998; mean +/- SD, 62 +/- 13 years) and group 3 (September 1998 to October 2000; mean +/- SD, 65 +/- 13 years)(P <.01). Over time, the proportion of PD for cystic tumors increased from 9.9% to 20% (P =.01), and the proportion of PD for chronic pancreatitis decreased from 23% to 10% (P <.01). Use of pylorus-preserving PD decreased from 45% to 0% (P <.001). Delayed gastric emptying decreased from 17% to 6.1% (P <.01). Pancreatic fistula, reoperation, and mortality were unchanged. Length of stay for PD decreased from 16.1 +/- 0.6 to 9.5 +/- 0.4 days (mean +/- SE) (P <.001). Multivariate analysis showed that period, case volume, pylorus-preserving PD, and presence of complications are all independent predictors of LOS (P <.05 for all). For distal pancreatectomy, patients in groups 2 and 3 were older than those in group 1 (mean +/- SD, 57 +/-14 vs 52 +/- 17 years) (P <.05). Resections for cystic tumors increased from 26% to 52% (P <.05), and resections for chronic pancreatitis decreased from 32% to 14% (P =.06). Median LOS decreased from 9 days to 6. For total pancreatectomy, resections for cystic tumors increased from 18% to 43%. Median LOS decreased from 14.5 days to 11. For all resections, case volume increased from 4 resections per month in 1990 to 5.8 in 1995 and 12 in 2000 (r = 0.83; P <.001). CONCLUSIONS: Older patients are increasingly being selected for pancreatic resection. This reflects an increasing frequency of operations performed for cystic tumors and fewer for chronic pancreatitis. With the exception of delayed gastric emptying, complications and mortality have remained the same or decreased slightly during the past 10 years. However, there has been a significant decrease in LOS; this is the result of implementation of case management and clinical pathways, increasing case volume, decreasing incidence of delayed gastric emptying, and decreasing use of pylorus-preserving PD.

Effect of a selective rise in hepatic artery insulin on hepatic glucose production in the conscious dog.

In the present study we compared the hepatic effects of a selective increase in hepatic sinusoidal insulin brought about by insulin infusion into the hepatic artery with those resulting from insulin infusion into the portal vein. A pancreatic clamp was used to control the endocrine pancreas in conscious overnight-fasted dogs. In the control period, insulin was infused via peripheral vein and the portal vein. After the 40-min basal period, there was a 180-min test period during which the peripheral insulin infusion was stopped and an additional 1.2 pmol. kg-1. min-1 of insulin was infused into the hepatic artery (HART, n = 5) or the portal vein (PORT, n = 5, data published previously). In the HART group, the calculated hepatic sinusoidal insulin level increased from 99 +/- 20 (basal) to 165 +/- 21 pmol/l (last 30 min). The calculated hepatic artery insulin concentration rose from 50 +/- 8 (basal) to 289 +/- 19 pmol/l (last 30 min). However, the overall arterial (50 +/- 8 pmol/l) and portal vein insulin levels (118 +/- 24 pmol/l) did not change over the course of the experiment. In the PORT group, the calculated hepatic sinusoidal insulin level increased from 94 +/- 30 (basal) to 156 +/- 33 pmol/l (last 30 min). The portal insulin rose from 108 +/- 42 (basal) to 192 +/- 42 pmol/l (last 30 min), whereas the overall arterial insulin (54 +/- 6 pmol/l) was unaltered during the study. In both groups hepatic sinusoidal glucagon levels remained unchanged, and euglycemia was maintained by peripheral glucose infusion. In the HART group, net hepatic glucose output (NHGO) was suppressed from 9.6 +/- 2.1 micromol. kg-1. min-1 (basal) to 4.6 +/- 1.0 micromol. kg-1. min-1 (15 min) and eventually fell to 3.5 +/- 0.8 micromol. kg-1. min-1 (last 30 min, P < 0.05). In the PORT group, NHGO dropped quickly (P < 0.05) from 10.0 +/- 0.9 (basal) to 7.8 +/- 1.6 (15 min) and eventually reached 3.1 +/- 1.1 micromol. kg-1. min-1 (last 30 min). Thus NHGO decreases in response to a selective increase in hepatic sinusoidal insulin, regardless of whether it comes about because of hyperinsulinemia in the hepatic artery or portal vein.

A comparison of the effects of selective increases in peripheral or portal insulin on hepatic glucose production in the conscious dog.

We investigated the mechanisms by which peripheral or portal insulin can independently alter liver glucose production. Isotopic ([3-3H]glucose) and arteriovenous difference methods were used in conscious overnight-fasted dogs. A pancreatic clamp (somatostatin plus basal insulin and basal glucagon infusions) was used to control the endocrine pancreas. After a 40-min basal period, a 180-min experimental period followed in which selective increases in peripheral (PERI group, n = 5) or portal-vein (PORT group, n = 5) insulin were induced. In control dogs (CONT group, n = 10), insulin was not increased. Glucagon levels were fixed in all studies, and basal euglycemia was maintained by peripheral glucose infusion in the two experimental groups. In the PERI group, arterial insulin rose from 36 +/- 12 to 120 +/- 12 pmol/l, while portal insulin was unaltered. In the PORT group, portal insulin rose from 108 +/- 42 to 192 +/- 42 pmol/l, while arterial insulin was unaltered. Neither arterial nor portal insulin changed from basal in the CONT group. With a selective rise in peripheral insulin, the net hepatic glucose output (NHGO; basal, 11.8 +/- 0.7 micromol x kg-1 x min-1) did not change initially (11.8 +/- 2.1 micromol x kg-1 x min-1, 30 min after the insulin increase), but eventually fell (P < 0.05 ) to 6.1 +/- 0.9 micromol x kg-1 x min-1 (last 30 min). With a selective rise in portal insulin, NHGO dropped quickly (P < 0.05) from 10.0 +/- 0.9 to 5.6 +/- 0.6 micromol x kg-1 x min-1 (30 min after the insulin increase) and eventually reached 3.1 +/- 1.1 micromol x kg-1 x min-1 (last 30 min). When insulin levels were not increased (CONT group), NHGO dropped progressively from 10.1 +/- 0.6 to 8.3 +/- 0.6 micromol x kg-1 x min-1 (last 30 min). Conclusions drawn from the net hepatic glucose balance data were confirmed by the tracer data. Net hepatic gluconeogenic substrate uptake (three carbon precursors) fell 2.0 micromol x kg-1 x min-1 in the PERI group, but rose 1.2 micromol x kg-1 x min-1 in the PORT group and 1.2 micromol x kg-1 x min-1 in the CONT group. A selective 84 pmol/l rise in arterial insulin was thus associated with a fall in NHGO of approximately 50%, which took 1 h to manifest. Conversely, a selective 84 pmol/l rise in portal insulin was associated with a 50% fall in NHGO, which occurred quickly (15 min). From the control data, it is evident that in either case approximately 30% of the fall in NHGO was due to a drift down in baseline and that 70% was due to the rise in insulin. In conclusion, an increment in portal insulin had a rapid inhibitory effect on NHGO, caused by the suppression of glycogenolysis, while an equal increment in arterial insulin produced an equally potent but slower effect that resulted from a small increase in hepatic sinusoidal insulin, from a suppression of gluconeogenic precursor uptake by the liver, and from a redirection of glycogenolytic carbon to lactate rather than glucose.