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Biomedical subjects

H A Reber

Publications and source records attributed to H A Reber.

At least 19 recordsLinked to original sources
PubMed2006

Unfavourable prognosis associated with K-ras gene mutation in pancreatic cancer surgical margins.

BACKGROUND: Despite intent to cure surgery with negative resection margins, locoregional recurrence is common in pancreatic cancer. AIMS: To determine whether detection of K-ras gene mutation in the histologically negative surgical margins of pancreatic cancer reflects unrecognised disease. PATIENTS: Seventy patients who underwent curative resection for pancreatic ductal adenocarcinoma were evaluated. METHODS: All patients had surgical resection margins (pancreatic transection and retroperitoneal) that were histologically free of invasive cancer. DNA was extracted from these paraffin embedded surgical margins and assessed by quantitative real time polymerase chain reaction to detect the K-ras gene mutation at codon 12. Detection of K-ras mutation was correlated with standard clinicopathological factors. RESULTS: K-ras mutation was detected in histologically negative surgical margins of 37 of 70 (53%) patients. A significant difference in overall survival was demonstrated between patients with margins that were K-ras mutation positive compared with negative (median 15 v 55 months, respectively; p = 0.0008). By univariate and multivariate analyses, detection of K-ras mutation in the margins was a significant prognostic factor for poor survival (hazard ratio (HR) 2.8 (95% confidence interval (CI) 1.5-5.3), p = 0.0009; and HR 2.8 (95% CI 1.4-5.5), p = 0.004, respectively). CONCLUSIONS: Detection of cells harbouring K-ras mutation in histologically negative surgical margins of pancreatic cancer may represent unrecognised disease and correlates with poor disease outcome. The study demonstrates that molecular-genetic evaluation of surgical resection margins can improve pathological staging and prognostic evaluation of patients with pancreatic ductal adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Identification of genes differentially induced by hypoxia in pancreatic cancer cells.

A hypoxic microenvironment is characteristic of many solid tumors, including pancreatic cancer, the fifth leading cause of cancer death in the United States. Hypoxia causes the stabilization of the HIF-1 (hypoxia-inducible factor-1) transcription factor and the induction of many genes that promote angiogenesis, tumor growth, and metastasis. We performed representational difference analysis (RDA) using mRNA extracted from hypoxic and normoxic Capan-2, a human pancreatic cancer cell line. cDNAs corresponding to hypoxia-inducible genes were cloned and sequenced. We identified GPI/NLK/AMF (glucose phosphate isomerase/neuroleukin/autocrine motility factor) as a hypoxic inducible gene. In addition, hexokinase II and DEC1/Stra13, genes known to be hypoxia inducible in other systems, were found to be hypoxia inducible in our pancreatic cancer system. We thus identified three genes that are induced by hypoxia in a human pancreatic cancer, including GPI/NLK/AMF, which was not previously known to be hypoxia inducible in any other system. These genes may provide new targets for diagnosis and treatment of pancreatic cancer.

Basic Helix-Loop-Helix Proteins↗
PubMed2001

Peroxisome proliferator-activated receptor gamma induces pancreatic cancer cell apoptosis.

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) decreases the growth of certain cancer cells. In the present study, we found that six different human pancreatic cancer cell lines (AsPC-1, BxPC-3, Capan-2, HPAF-II, MIA PaCa-2, and PANC-1) expressed PPAR-gamma m-RNA and synthesized the protein. The endogenous and exogenous PPAR-gamma ligands 15-deoxy-d12,14-prostaglandin J(2) (15-PGJ(2)) and ciglitazone decreased cell number, cell viability, and increased floating/attached ratio, in a time- and dose-dependent fashion. 15-PGJ(2) increased intracellular nucleosome concentration after 6 h, but did not increase caspase-3 activity even after 96 h. Combined treatment with both 15-PGJ(2) and the caspase-3 inhibitor DEVD-CHO had no effect on cell viability, but the general caspase inhibitor ZVAD-FMK reduced 15-PGJ(2)-induced apoptosis. We concluded that the six human pancreatic cancer cells tested all expressed PPAR-gamma receptor, and treatment with PPAR-gamma agonists decreased cell viability and growth in a time- and dose-dependent manner. These effects were partially mediated by induction of caspase-3 independent apoptosis.

Apoptosis↗
PubMed2001

G protein-coupled receptor signaling in human ductal pancreatic cancer cells: neurotensin responsiveness and mitogenic stimulation.

Neuropeptides and their corresponding G protein-coupled receptors (GPCRs) are increasingly implicated in the autocrine/paracrine stimulation of growth of human cancers. We report that neurotensin induced rapid Ca2+ mobilization from intracellular stores followed by Ca2+ influx in five human ductal pancreatic cancer cell lines: HPAF-II, Capan-1, Capan-2, PANC-1, and MIA PaCa-2. In addition, most cell lines exhibited Ca2+ responses to multiple neuropeptides including bombesin, bradykinin, cholecystokinin, and vasopressin and to bioactive lipids, including lysophosphatidic acid (LPA), that also act via GPCRs. The well-differentiated line HPAF-II responded to at least seven independent GPCR agonists. The concentrations of neurotensin required to induce half-maximal effects (EC50) in HPAF-II and PANC-1 cells were 5 and 8nM, respectively. Digital fluorescence image analysis to measure Ca2+ responses in single cells revealed that 90% or more of HPAF-II and PANC-1 cells responded to 10nM neurotensin. Addition of neurotensin to PANC-1 cells also induced rapid and dose-dependent extracellular-regulated protein kinase (ERK-1 and ERK-2) activation and subsequently, stimulated DNA synthesis. The signaling complexity of GPCRs uncovered by these studies reveals a new aspect in the biology of human pancreatic cancer and could offer the basis for new approaches to the treatment of this disease.

Bombesin↗
PubMed2001

Platelet activating factor antagonism reduces the systemic inflammatory response in a murine model of acute pancreatitis.

BACKGROUND: The platelet activating factor (PAF) antagonist, Lexipafant, has been used in experimental models and clinical trials to treat severe acute pancreatitis (AP). The purpose of this study was to determine whether Lexipafant reduces the local and systemic components of AP in a murine model of mild, edematous AP. MATERIALS AND METHODS: Forty-eight female Swiss-Webster mice were divided into four groups. Group 1 received 50 microl of saline ip every hour for 6 h (sham). Group 2 received saline treatment, plus Lexipafant (25 mg/kg dose ip, every 3 h starting 1 h after the first saline injection) (sham/Lex). Group 3 received cerulein (50 microg/kg dose ip, every hour for 6 h) (AP). Group 4 received AP, plus therapeutic treatment with Lexipafant (AP/Lex). Animals were sacrificed 3 h after the last injection. Serum cytokine levels were determined by ELISA. Standard assays were performed for serum amylase activity and lung myeloperoxidase activity (MPO). Histology was scored by two blinded investigators. RESULTS: Serum cytokines (TNFalpha, IL-1beta), lung MPO, and serum amylase activity were reduced by PAF antagonism. Histology showed a trend toward improvement with Lexipafant, but did not reach statistical significance. CONCLUSION: The PAF antagonism reduces the severity of systemic inflammation when given after the induction of mild AP in mice. These results suggest that Lexipafant may be useful in the treatment of mild pancreatitis after its clinical onset.

Acute Disease↗
PubMed2001

Pancreatic surgery.

Recent advances have been made in both laparoscopic and endoscopic techniques for diagnosing and treating pancreatic neoplasms. These advances are reviewed. In addition to the traditional methods of pancreatic resection (eg, standard Whipple and pylorus-preserving Whipple), several other techniques have been described and are discussed (eg, median pancreatectomy and extended pancreatectomy). The morbidity and mortality rates of pancreatic operations have diminished, but significant complications still occur (eg, delayed gastric emptying, pancreatic fistula, and biliary strictures). These are discussed. In managing acute and chronic pancreatitis, less invasive and more conservative approaches are being advocated.

Journal Article↗
PubMed2001

An improved clinical model of orthotopic pancreatic cancer in immunocompetent Lewis rats.

The study of pancreatic cancer (PaCa) requires orthotopic, clinically relevant animal models. The aims of this study were to establish an orthotopic model of ductal pancreatic adenocarcinoma in immunocompetent Lewis rats and to develop a scoring system to quantify local tumor infiltration and distant metastasis. Cells (10(7)) of the rat ductal PaCa cell line DSL-6A/C1 were injected s.c. into donor rats. After 8 weeks, either three (IPL-3) or five (IPL-5) fragments (1 mm3) of the resulting s.c. tumors were microsurgically implanted into the pancreas of recipient rats. In another series of animals, 10(7) DSL-6A/C1 cells were directly injected (INJ) into the pancreas. All animals were monitored daily until death or for 16 weeks. At autopsy, volume of primary tumors and ascites, local and systemic tumor spread, and histologic phenotype were assessed. IPL-5 resulted in significantly larger tumors (12,224 +/- 1,933 mm3), more local infiltration and systemic spread (score: 18.3 +/- 2.0 points), severe clinical tumor disease, and lethality (50%) in comparison to the other induction techniques (IPL-3: 283 +/- 115 mm3/3.5 +/- 0.8 points/0; INJ: 752 +/- 207 mm3/4.3 +/- 0.8 points/8%). Histologic examination revealed moderately to well-differentiated ductal tumors, surrounded by dense stroma. Intraperitoneal tumor dissemination in the INJ group occurred simultaneous with primary tumor growth, indicating PaCa cell spread during injection. Orthotopic implantation of five DSL-6A/C1 tumor fragments into the rat pancreas provides a valid clinical model of ductal pancreatic adenocarcinoma in immunocompetent rodents for preclinical treatment studies. The dissemination score we used permitted quantification of local and systemic tumor spread.

Adenocarcinoma↗
PubMed2001

Real-time quantitative PCR of telomerase mRNA is useful for the differentiation of benign and malignant pancreatic disorders.

The presence of telomerase activity has been proposed as a specific and sensitive marker for malignant tissue, and positivity rates of up to 95% have been reported in pancreatic cancer. In the present study telomerase activity analysis was reevaluated in 29 pancreatic cancer tissues compared with 36 chronic pancreatitis tissues and 21 normal controls, and a study was made of whether malignant and benign pancreatic disorders can be better differentiated using a novel technique real-time quantitative PCR analysis-analyzing telomerase mRNA expression. Telomerase activity was present in 35% (10 of 29) of pancreatic cancer samples, 3% (one of 36) of chronic pancreatitis samples, and none of the normal pancreatic tissue samples in the TRAP assay. Real-time quantitative PCR analysis revealed the presence of telomerase mRNA expression in 50% (10 of 20) of normal, 86% (31 of 36) of chronic pancreatitis, and 90% (26 of 29) of pancreatic cancer samples. However, quantification of the expression data revealed that the relative increase above normal was 5.5 (range, 3.5-8.6) for chronic pancreatitis and 23.9 (range, 18.6-30.7) for pancreatic cancer samples (p < 0.01). No relationship was found between telomerase activity and the fold increase of telomerase mRNA above normal and gender, patient age, tumor stage, or tumor grade. These data indicate that detection of telomerase activity using the TRAP assay has limitations in differentiating benign and malignant pancreatic disorders. However, telomerase mRNA analysis by real-time quantitative PCR analysis allows a highly sensitive detection and differentiation of pancreatic cancer from normal pancreas and chronic pancreatitis and thereby may serve as a new reliable, easy, and effective diagnostic tool for cancer diagnosis.

Adult↗
PubMed2001

Solid and papillary epithelial neoplasms of the pancreas: aggressive resection for cure.

Solid and papillary epithelial neoplasms of the pancreas (SPENP) are extremely rare and usually affect young women. We retrospectively reviewed our experience with pancreatic neoplasms from 1986 to the present and identified nine patients with SPENP. All nine patients were female with a mean age of 32 years (range 16-66). All patients presented with gastrointestinal complaints including pain, mass, dyspepsia, or bloating and were subsequently diagnosed with a tumor of the pancreas by CT scan. All patients underwent surgical resection. Two patients had tumors located in the head of the pancreas and underwent a pancreaticoduodenectomy. The remainder had tumors located in the tail of the pancreas and underwent distal pancreatectomy. Pathology demonstrated solid and papillary or solid and cystic pseudopapillary neoplasm of the pancreas. Three tumors were positive for both vimentin and alpha-1 antitrypsin on immunohistochemical studies, and three were positive for neuron-specific enolase. All nine patients underwent curative resection and are alive without any evidence of recurrence with a mean follow-up of 5.4 years. SPENP is considered to be a low-grade malignancy with an excellent prognosis. Prompt diagnosis and surgical resection can result in cure.

Adolescent↗
PubMed2000

Primary duodenal adenocarcinoma: a 40-year experience.

HYPOTHESIS: In patients with duodenal adenocarcinoma, certain pathologic features of the tumor will have prognostic significance. DESIGN: Retrospective case series. PATIENTS: Forty-nine patients diagnosed with duodenal adenocarcinoma between 1957 and 1998. RESULTS: The tumors of 31 (63%) of the 49 patients underwent resection, 18 (37%) had surgical palliation or underwent biopsy. Mean (+/- SEM) survival for all patients was 49 +/- 9 months. The patients whose tumors were resected had longer survival than those who underwent palliation (mean +/- SEM, 66 +/- 13 months vs 18 +/- 6 months, P =.02). Multivariate analysis revealed large tumor size (P =.01), transmural invasion (P =.004), and moderate to poor tumor grade (P =.03) were negatively correlated with survival. Lymph node status did not influence survival. CONCLUSIONS: Our 40-year experience with duodenal adenocarcinoma demonstrates that large tumor size, advanced histological grade, and transmural invasion are associated with decreased survival. These results underscore the importance of early diagnosis, and suggest the presence of nodal spread is not a contraindication to resection.

Adenocarcinoma↗
PubMed2000

Complicated enterocutaneous fistulas: failure of octreotide to improve healing.

Octreotide has been promoted as a potential aid during closure of enterocutaneous fistulas (ECFs) on the basis of clinical and experimental evidence that it can reduce gastrointestinal secretions. We retrospectively reviewed the records of patients admitted with ECF to our tertiary referral center to ascertain whether use of octreotide affected fistula duration, length of hospitalization, closure rate, and morbidity. Of 60 patients diagnosed and treated for ECF over a 4-year period, 13 underwent a therapeutic trial with octreotide. Thirteen patients from the group who did not receive octreotide were matched by cause, location, and output of the fistula, age, and primary diagnosis to the treatment group. Octreotide was administered in therapeutic dosage for a mean course of 57 +/- 29 days, resulting in a substantial acute decrease (84.7 +/- 4.8%) in fistula output. Prolonged therapy nevertheless failed to affect the outcome parameters studied, particularly fistula duration, spontaneous closure rate, and length of hospitalization. There was a significantly higher incidence of septic and thrombotic complications associated with octreotide use. In this patient population with complicated ECFs, use of octreotide showed no benefit and was associated with increased morbidity.

Cutaneous Fistula↗
PubMed2000

Animal models of exocrine pancreatic cancer.

Clinically and biologically relevant animal models are mandatory to further evaluate both the pathophysiology and novel strategies for diagnosis and treatment of exocrine pancreatic cancer. This review briefly summarizes the features of human pancreatic cancer in order to define requirements for animal models of the disease. The described model systems in rodents include pancreatic cancer induced by chemicals, pancreatic cancer in transgenic, and immunodeficient animals.

Animals↗
PubMed2000

Endoscopic measurement of pancreatic tissue perfusion in patients with chronic pancreatitis and control patients.

BACKGROUND: Pancreatic blood flow is diminished in experimental models of acute and chronic pancreatitis. We attempted to develop a safe and reliable technique for its measurement in patients and to examine blood flow in patients with chronic pancreatitis and in control subjects. METHOD: Pancreatic blood flow was measured using the hydrogen gas clearance technique and an endoscopically placed platinum ductal electrode. Pancreatic blood flow was measured in 12 patients with chronic pancreatitis diagnosed clinically and radiographically, and in 11 control patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) for non-pancreatic pathology. RESULTS: Patients with chronic pancreatitis had a significantly lower pancreatic blood flow compared with control patients (51.5 versus 91.7 mL/min/100 gm, p < 0.01). With secretin stimulation pancreatic blood flow increased in two control patients, whereas this notable rise was not seen in three patients with chronic pancreatitis. CONCLUSIONS: Measurement of pancreatic blood flow with an endoscopically placed electrode is relatively safe and simple to perform. The scarring and vascular fibrosis associated histologically with chronic pancreatitis is reflected in lower pancreatic blood flow.

Adult↗
PubMed2000

Pancreatic surgery.

Several important advances in pancreatic surgery have been made over the past year. As in other areas of general surgery, laparoscopic techniques are being used with increasing frequency, but their real value remains to be determined. Methods to stage pancreatic cancer, perform palliative bypass, relieve pain, and perform distal pancreatic resections have been described. Using more conventional surgical approaches, data continue to accumulate about pylorus preserving pancreaticoduodenectomy as an alternative to the standard operation. The survival benefit of extended pancreatic resection for pancreatic cancer remains dubious. Studies continue to demonstrate lower morbidity and mortality rates for pancreaticoduodenectomy performed at high-volume centers. In the arena of chronic pancreatitis, pain relief is still the most common reason for surgical treatment, and the efficacy of various operations has been assessed by some new studies. Data continue to show that aggressive surgical treatment for infected necrosis leads to improved survival in patients with severe acute pancreatitis.

Journal Article↗
PubMed2000

The spectrum of mucin-producing adenocarcinoma of the pancreas.

The clinical distinction between cystic and mucinous carcinomas of the pancreas has been poorly defined. Therefore we sought to stratify the entity known as pancreatic mucinous adenocarcinoma based on pathologic and clinical criteria. Clinical data and pathology specimens were reviewed for patients (n = 40) who had been diagnosed as having mucin-producing pancreatic adenocarcinoma and had undergone either resection or intraoperative biopsy of their pancreatic tumor during a 40-year period at the UCLA Medical Center. Based on histologic criteria, three distinct classes of pancreatic adenocarcinoma were identified: mucinous noncystic (colloid) adenocarcinoma (group I), mucinous cystadenocarcinoma (group II), and ductal adenocarcinoma (group III). Based on clinical behavior, groups I and III were indistinguishable. Compared to patients from groups I and III, those from group II were younger, more likely to be female, and had a better prognosis. Among mucin-producing adenocarcinomas of the pancreas, mucinous noncystic adenocarcinoma and ductal adenocarcinoma share similar clinical features, whereas true cystic lesions represent a distinct clinical entity.

Adenocarcinoma, Mucinous↗