Are integrin alpha(2)beta(1), glycoprotein Ib and vWf levels correlated with their contributions to platelet adhesion on collagen under high-shear flow?

Platelets in flowing blood at high-shear stress are recruited to exposed subendothelial collagen of injured vessels by GPIb-von Willebrand factor (vWf) and integrin alpha(2)beta(1) (alpha(2)beta(1))-collagen interactions. Platelet adhesion to type I collagen depends mainly on the alpha(2)beta(1)-collagen interaction and that to type III collagen depends on the GPIb-vWf interaction due to vWf's weak affinity for type I collagen. Contributions of these two interactions would differ depending on expressions of alpha(2)beta(1), vWf, or GPIb. We quantitated platelet adhesion to low- and high-density collagen under high-shear flow conditions in the presence of anti-alpha(2)beta(1) (Gi9) and anti-GPIb (NNKY5-5) antibodies to determine if their inhibitory effects were correlated with the amounts of alpha(2)beta(1), GPIb and vWf. Gi9 inhibition of adhesion to type I collagen was decreased in platelets with more integrin alpha(2)beta(1). Gi9 and NNKY5-5 are more inhibitory against adhesion to low-density type III and I, respectively. Higher alpha(2)beta(1) expression decreases adhesion to low-density type III and increases Gi9 inhibition of adhesion to high-density type III, suggesting crosstalk between the alpha(2)beta(1)-collagen and GPIb-vWf interactions in adhesion to type III. Integrin alpha(2)beta(1)-collagen and GPIb-vWf interactions both contribute to platelet adhesion to collagen under high-shear flow. In adhesion under high-shear stress, the two interactions would compensate for each other, when there is a deficiency in one or the other. The alpha(2)beta(1)-collagen interaction was also suggested to have an inhibitory effect on platelet adhesion to type III collagen, through a yet undefined mechanism.

Carcinoid tumor of the Vater's papilla presenting with chronic pancreatitis--a case report--.

Carcinoid tumors are common in the duodenum except for in the Vater's papilla [1-9]. We report here a case of carcinoid tumor arising in the Vater's papilla with repeated episods of pancreatitis. The patient is a 28 year-old-woman who had repeated abdominal pain with elevated serum amylase and had been treated as chronic pancreatitis. Computed tomography (CT) revealed a slight dilatation of the main pancreatic duct from the pancreatic head to the tail, and mild swelling of the pancreas. A submucosal tumor measuring 1.3 cm in diameter was detected in the ampulla of Vater by esophagogastroduodenscopy (EGD), and total papillectomy was performed under the suspicious of carcinoid tumor. The tumor was not encapsulated, 1.0 cm in diameter, undefined, and whitish in color. Histologically monomorphic tumor cells with lightly eosinophlic cytoplasm and round nuclei proliferate in trabecular and solid patterns. Immunohistochemically tumor cells were positive for neuron-specific enolase, chromogranin A and synaptophysin, and the tumor was diagnosed as carcinoid tumor. It should be noted that carcinoid tumor in the ampulla may occur with initial signs of acute or chronic pancreatitis.

Role of CCK-A receptor for pancreatic function in mice: a study in CCK-A receptor knockout mice.

INTRODUCTION: The cholecystokinin (CCK) family of peptides and receptors is present throughout the brain and gastrointestinal tract. The CCK receptors can be pharmacologically subdivided into two subtypes: CCK-A and CCK-B. CCK-A receptor is enriched in the pancreas of mice. AIMS: To determine pancreatic functions in a CCK-A receptor deficient mouse mutant generated by gene targeting in embryonic stem cells. The targeting vector contained lacZ and neo insertions in exon 2. METHODOLOGY: To examine exocrine functions, amylase release from the dispersed acini in vitro was examined. In the in vivo study, the mixture of bile-pancreatic juice was collected, and amylase, bicarbonate, and bile acid outputs were determined after the administration of various stimulants. The cystic duct of the gallbladder and the pylorus were ligated to exclude the involvement of gallbladder contraction and gastric acid. Pancreatic enzyme content was measured, and histologic examinations by HE and lacZ staining were conducted. To examine endocrine functions, oral glucose tolerance test (2 g/kg) was determined. RESULTS: The body weight, pancreatic wet weight, and enzyme content in the pancreas were similar among the three genotypes. Amylase release in vivo and in vitro and bicarbonate secretion in vivo were not stimulated by CCK-8 in CCK-AR (-/-) mice, whereas the responses to other stimulants were substantial in (-/-) mice. Administration of secretin did not increase bicarbonate secretion regardless of genotype. A normal glucose tolerance was observed in (-/-) mice. Acinar cells, islets, and duct cells were stained by lacZ, and HE staining revealed no pathologic findings. CONCLUSION: The CCK-A receptor is important for pancreatic exocrine secretion, but not essential for maintaining glucose concentration and pancreatic growth in mice.

Enhanced gastric emptying of a liquid gastric load in mice lacking cholecystokinin-B receptor: a study of CCK-A,B, and AB receptor gene knockout mice.

BACKGROUND: Although cholecystokinin (CCK) has been shown to inhibit gastric emptying via CCK-A receptors (CCK-ARs), the role of CCK-B receptors (CCK-BRs) has not been verified. We examined whether gastric emptying of a nonnutrient liquid load was modified in CCK-AR, BR, and ARBR gene knockout mice. METHODS: A liquid gastric load prepared with phenol red was administered via an orogastric tube (0.15 ml/mouse). The animals were killed by decapitation, and gastric emptying was estimated at 10 and 30 min after ingestion. The effects of the sulfated form of CCK-8 (CCK-8S) and of graded doses of atropine were examined. In addition, a proton pump inhibitor was administered to wild-type mice to examine the contribution of gastric acid to emptying. RESULTS: Gastric emptying was significantly enhanced in mice lacking CCK-BR, as compared with wild-type and CCK-AR(-/-) mice. CCK-8S inhibited gastric emptying in mice with CCK-AR, but not in mice without CCK-AR. A proton pump inhibitor did not affect gastric emptying. Atropine dose dependently inhibited gastric emptying in all genotypes. The thickness of smooth muscle was comparable for all genotypes. CONCLUSIONS: The gastric emptying of a nonnutrient liquid load was enhanced in mice without CCK-BR, although the precise mechanism is not known. Although cholecystokinin (CCK) has been shown to inhibit gastric emptying via CCK-A receptors (CCK-ARs), the role of CCK-B receptors (CCK-BRs) has not been verified. We examined whether gastric emptying of a nonnutrient liquid load was modified in CCK-AR, BR, and ARBR gene knockout mice.

Unilateral progressive multiple sclerosing hemangioma in a young female successfully treated by pneumonectomy: report of a case.

A 25-year-old woman had been followed for 7 years after multiple pulmonary nodules were detected in both the upper and lower lobes of the left lung on chest X-ray when she was 17 years of age. These pulmonary nodules were gradually increasing in size and, at 25 years of age, transbronchofiberscopic biopsy suggested the possibility of adenocarcinoma. Left pneumonectomy was performed. The diagnosis of multiple tumors was confirmed as sclerosing hemangioma by postoperative histopathological examination of the resected lung. The patient has remained well for 2 years to date after resection.

Confocal laser microscopy of chondrocytes that received gene transfer using in vitro electroporation.

To develop a gene therapy for osteopathies, this study was conducted to establish a method of transferring the BMP gene, a bone formation factor, to cells and administering the cells with BMP expression to patients with osteopathies. Although virus vectors are frequently used for gene transfer, there has been reported a death case of gene therapy using the adenovirus vector. Therefore, various efforts have been made to prevent such complications. In the present study, we used electroporation by which gene transfer can be efficiently performed without inducing severe complications after electric perforation of the cell membrane. Human bone tissues were initially collected intraoperatively, and BMP-2 and Smad4 genes were cloned and integrated into GFP and DsRed plasmid vectors. Using in vitro electroporation, these plasmid vectors were transferred to the cultured chondrocytes (KTN-1) derived from human herniated intervertebral disk. Confocal laser microscopy revealed that the BMP gene was successfully transferred to the nucleus of chondrocytes in the presence of Smad. Since electroporation facilitated human gene transfer to the target cells, gene therapy using electroporation may facilitate individualized treatment for patients.

Effect of AGEs on human disc herniation: intervertebral disc hernia is also effected by AGEs.

Currently, extracellular matrix MMP has been discussed in relation to the extrusion and spontaneous regression of the herniated mass observed in lumbar disc herniation. However, the question remains as to whether degenerated protein is really the cause of this condition's pathogenesis. We confirmed immunologically by means of electron microscopy that extrusion is caused by the AGEs (advanced glycation end products)-induced cross-linking of collagen, and that spontaneous regression is due to AGE receptors on macrophages. Further, AGEs were found to be already exposed during histogenesis, suggesting a relation to apoptosis. In lumbar disc herniation and aging, glucose-derived AGEs cross-link proteins and cause vascular tissue damage.

Pancreatic hypertrophy in Ki-ras-induced actin-interacting protein gene knockout mice.

OBJECTIVES: Pancreatic functions were determined in a Ki-ras-induced actin-interacting protein (KRAP)-deficient (-/-) mouse mutant. METHODS: Pancreatic enzyme, protein, and DNA contents were measured, and histological examinations were conducted. The mixture of bile-pancreatic juice was collected, and amylase and bile acid outputs were determined. Oral glucose tolerance test was determined. Moreover, the gene expression of KRAP was determined in cholecystokinin (CCK)-A(1) receptor (-/-) mice. RESULTS: The body weight was smaller, and the ratio of pancreatic wet weight/body weight was higher in KRAP(-/-) mice compared with wild-type mice. The enzyme contents, but not DNA content, in the pancreas of KRAP(-/-) mice were higher than those of wild-type mice. Histological examination revealed the increase in the number of zymogen granules in the pancreatic acinar cells of KRAP(-/-) mice. Amylase secretions in response to CCK-octapeptide sulfate were significantly higher in KRAP(-/-) than wild-type mice, whereas the basal secretion did not differ between the 2 genotypes. A normal glucose tolerance was observed in KRAP(-/-) mice. The gene expression of KRAP in CCK-A(1) receptor (-/-) mice was significantly lower than in wild-type mice. CONCLUSIONS: The lack and/or decrease in KRAP level in the pancreas may promote the pancreatic growth and hypertrophy.

Pancreatic acinar cell carcinoma extending into the common bile and main pancreatic ducts.

Acinar cell carcinoma (ACC) of the pancreas is relatively rare, accounting for only approximately 1% of all exocrine pancreatic tumors. A 69-year-old man was found to have a mass lesion measuring approximately 4 cm in diameter in the pancreatic head on ultrasound, abdominal dynamic CT, and percutaneous transhepatic cholangiography. Magnetic resonance cholangiopancreatography showed defect of the lower common bile duct (CBD) due to obstruction by the tumor cast. Histopathologically, the pancreatic head tumor invaded the main pancreatic duct (MPD) and CBD with extension into the CBD in a form of tumor cast. The tumor cells consisted of a solid proliferation with abundant eosinophilic cytoplasm and round nuclei in an acinar and trabecular fashion. A 55-year-old man with upper abdominal pain and nausea, had a cystic lesion approximately 3 cm in size in the pancreatic tail on CT. Histopathologically, the tumor was encapsulated by fibrous capsule and had extensive central necrosis with solid areas in the tumor periphery, and invaded with extension into the MPD in a form of tumor cast. The tumor cells resembled acinar cells in solid growths. Two resected cases of ACC with unusual tumor extension into the CBD and the MPD, respectively, are reported.

Signet-ring cell carcinoma of the ampulla of Vater: report of a case.

An 83-year-old man was admitted to our hospital complaining of general fatigue, fever, and obstructive jaundice. Percutaneous transhepatic bile duct drainage was performed. Gastroduodenal fiberscopy revealed carcinoma of the ampulla of Vater, and early gastric cancer was suspected. A pancreatoduodenectomy with lymph node dissection was performed. Although a biopsy specimen from the gastric lesion was suspected to be well-differentiated adenocarcinoma, no cancerous lesion was found in a specimen resected from the stomach. The histopathologic findings of the ampullary lesion were compatible with a diagnosis of signet-ring cell carcinoma. This is a rare lesion, and a review of the literature revealed only three previous similar cases.

Amylase secretion from dispersed human pancreatic acini: neither cholecystokinin a nor cholecystokinin B receptors mediate amylase secretion in vitro.

INTRODUCTION: In humans, cholecystokinin (CCK) stimulates pancreatic secretion, and CCK-A receptor antagonists prevent it in vivo. However, the human pancreas has been reported to express mainly CCK-B receptors. AIM: To elucidate this discrepancy. METHODOLOGY: We prepared dispersed acini from human pancreas and examined whether various doses of CCK stimulated the release of amylase, in comparison with the effects of neuromedin C, carbamylcholine, and secretin. RESULTS: Human pancreatic acini did not respond to any dose of CCK or secretin. Amylase release was stimulated by carbamylcholine and neuromedin C dose-dependently and was inhibited by respective antagonists. The localizations of CCK receptors in the human duodenum were determined. High concentrations of CCK-A receptors were detected in the mucosa as well as in smooth muscle of the duodenum by microautoradiography. CONCLUSION: In conclusion, human pancreatic acinar cells are responsible for carbamylcholine and neuromedin C but not for secretin. Neither CCK-A nor CCK-B receptor mediates amylase release from human pancreatic acini in vitro. Pancreatic secretion in humans in vivo may be regulated indirectly by CCK (via CCK-A receptors).

Different effects of oral administration of synthetic trypsin inhibitor on the pancreas between cholecystokinin-A receptor gene knockout mice and wild type mice.

The synthetic trypsin inhibitor camostat has been used for the treatment of acute and chronic pancreatitis in Japan based on the evidences obtained from a rat experimental model. However, rats differ from other rodents and from humans in terms of lacking a gallbladder and no response of pancreatic bicarbonate secretion to cholecystokinin (CCK). In the present study, we determined whether oral administration of camostat showed a trophic effect in mice as observed in rats and whether the trophic effect, if substantial, was mediated via the CCK-A receptor, using CCK-A receptor gene targeting mice. The chow containing 0.1% camostat was fed to 8-month-old mice. Three- and seven-day treatments with camostat did not affect pancreatic wet weight in CCK-A receptor (+/-) mice. After 14-day treatment, the ratio of pancreatic wet weight/body weight was significantly lower in CCK-A receptor (-/-) than (+/+) mice. The protein and chymotrypsin contents were lower and amylase content was higher in CCK-A receptor (-/-) mice, compared to (+/+) mice. No pathological findings were observed by histological examination. Camostat has a trophic effect on the pancreas in mice and this effect is mediated via the CCK-A receptor, but is less potent than in rats.