BACKGROUND: We assessed the usefulness of magnetic resonance imaging (MRI) in identifying nonmalignant intraductal papillary mucinous tumors (IPMTs) of the pancreas. METHODS: Thirty-three patients with branch duct-type IPMT diagnosed by endoscopic retrograde cholangiopancreatography were prospectively examined with magnetic resonance cholangiopancreatography followed by dynamic gadolinium-enhanced MRI examinations, and patients with no findings suggestive of malignancy, including a solid mass, mural nodules, a main pancreatic duct wider than 5 mm in diameter, and stenosis of the main pancreatic duct, were prospectively followed up with sequential MRI examinations once or twice a year. RESULTS: Twenty-six (79%) patients showed no findings suggestive of malignancy in the initial MRI examination. The diameter (mean +/- standard error) of the main pancreatic duct was 3.9 +/- 0.7 mm and that of the ectatic branch pancreatic duct was 36.0 +/- 9.1 mm. Twenty-three patients were prospectively followed for more than 36 months and 22 of them showed no findings suggestive of malignancy during follow-up periods ranging from 39 to 77 months (mean = 55 months). CONCLUSION: MRI was useful to identify nonmalignant IPMTs of the branch duct type, and close follow-up observation with serial MRI examinations may be appropriate in the management of such patients.

Adenocarcinoma, Mucinous↗

PubMedDate not supplied

Presence of immunoreactive endothelin in human saliva and rat parotid gland.

The presence of immunoreactive endothelin (IR-ET) in human saliva and rat parotid gland was investigated by radioimmunoassay. The IR-ET concentration (mean +/- SEM) in saliva taken from normal volunteers was 2.0 +/- 0.2 pmol/l (n = 15). The IR-ET concentration in rat parotid gland was 19.2 +/- 2.2 fmol/g wet weight (n = 10). Fast protein liquid chromatography (FPLC) of human saliva extract revealed 6 peaks; one peak eluting in the void volume, one in a position between ET-1 and -3, and the other four in the positions of synthetic ET-1, -2, -3 and big ET(1-38), respectively. A similar pattern of rat parotid gland extract was noted with FPLC, except that there was no peak after the void volume. Presence of endothelin, a potent growth factor, in saliva and salivary gland points to a role in maintaining the integrity of the oral and gastrointestinal tract mucosa.

Animals↗

PubMedDate not supplied

Induction of pancreatic islet cell tumors in rats by repeated intravenous administration of 4-hydroxyaminoquinoline 1-oxide.

The inducibility of pancreatic islet cell tumors by administration of 4-hydroxyaminoquinoline 1-oxide (4HAQO) was investigated in male 6-week-old Sprague-Dawley rats. Rats were given 4HAQO intravenously at a weekly dose of 5 mg/kg 4 times (group 1) or a single dose of 10 mg/kg (group 2). Control rats received the vehicle alone (group 3). Fifty-six weeks after the first 4HAQO administration, all surviving animals were killed and the pancreas was examined histopathologically, immunohistochemically and ultrastructurally. The incidences and multiplicities of islet cell tumors in groups 1, 2, and 3 were 52.3% (p < 0.05 vs group 2, p < 0.01 vs group 3), 19.2% and 0%, and 0.70/animal (p < 0.05 vs group 2, p < 0.01 vs group 3), 0.23 and 0, respectively. Islet cell carcinomas were induced only in group 1, accounting for 6/44 (26%) tumors. Islet cell hyperplasias were found in 61.4% (p < 0.05 vs group 3), 42.3% and 10.0% of groups 1, 2, and 3, with multiplicities of 0.95 (p < 0.05 vs groups 2 and 3), 0.54 and 0.20, respectively. As compared with normal islets from control subjects, islet cell tumors showed an increase in the number of insulin positive cells associated with cytological features indicative of enhanced insulin synthesis and secretion, and a decrease in the number of glucagon positive cells without ultrastructural signs of modified secretory activity. Thus our results indicate that repeated intravenous administration of 4HAQO to rats is useful for the induction of islet cell tumors at high incidence.

4-Hydroxyaminoquinoline-1-oxide↗