April 1 9 9 5 Pancreatic Disorders A 3 6 5

• SIGNIFICANCE OF SELECTIVE ARTERIAL CALCIUM INJECTION TEST (SACI TEST) FOR PREOPERATIVE LOCALIZATION OF OCCULT INSULINOMAS M.Kato, M.Imamura, R.Doi, N.Okada, Y.Shimada, R.Hosotani and J.Miyazaki*. First Dept. of Surgery, Kyoto Univ., Kyoto, Japan, and *Dept. of Disease-Related Gene Regulation Research, Tokyo Univ., Tokyo, Japan.

Preoperative determination of the localization of small insulinoma is sometimes difficult by the routine imaging techniques. To manifest the accurate localization of occult insulinomas, we have attempted the selective arterial calcium injection test (SACI test) when selective abdominal arteriography was done. Briefly, calcium is rapidly injected into the pancreas-feeding arteries (superior mesenteric, gastroduodenal and splenic), respectively; and blood samples are simultaneously obtained from the hepatic vein to detect the increase of serum IRI. In the current study, we summarize the results of SACI test in the latest 5 patients. Further, we demonstrate the in vitro response of the insulinoma cells to the extracellular calcium challenge by using primary-cultured cells from insulinoma. Clinical Reports: Among 5 patients, the localization of insulinoma of 3 cases was defined by ultrasonography and/or CT. In 2 cases, tumor was not visualized by the imaging techniques, despite the clinical symptom s indicated insulinoma. In all 5 cases, the positive SACI test clearly displayed the localizat ion of insulinomas. In Vitro Experiments: Human insulinoma ceils were obtained from 3 patients.' MIN6 cells were derived from transgenic mice. MIN6 cells (a pancreatic B cell line) were used as control, of which insulin response to various stimuli including glucose resembles that of normal islets. The insulin : secretory dynamics in response to extracellular calcium ([CaZ+]o) were observed using perifusion system. Second, the change of cytosolic free calcium level ([Ca2+]i) was monitored by fluorometry using Fura2, Results: In insulinoma cells, when [CaZ+]o was changed from 2.54 mM tol0 mM, the insulin secretion was dramatically increased within 2 min (3-10 fold of the basal at maximum), and rapidly returned to the basal level. At the same time, [Ca2+]kwas immediately elevated and reached to the peak within 1 min when [CaZ+]o was switched to high concentration. On the other hand, in MIN6 cells, the insulin secretion and [Ca2+]i level was constant when [Ca2+]o level was elevated. Conclusions: SACI test was useful in the diagnosis of insulinomas. The results in in vitro experiments followed the clinical results of SACI test. The positive response of insulinoma to SACI test is probably due to the different response of insulinoma cells to the extracellular calcium challenge when compared with normal B cells. The role of [Ca2+]i may be important in mechanistic implication of SACI test:

EFFECT OF a -TOCOPHEROL ON CERULEIN-INDUCED ACUTE PANCREATITIS IN MICE. Y.T. KIM, Y.B. YOON, C.Y. KIM Depar tment o f Internal Medicine and Liver Research Inst i tute, Seoul National Universi ty College of Medicine, Seoul, Korea

Studies in animals suggest tha t oxygen-der ived free radicals may be impor tant in the pathogenesis of acute pancreat i t is . Because a - t o c o p h e r o l is an e f fec t i ve an t iox idan t in stabi l iz ing unsatura ted lipids against auto-oxidat ion, we invest igated whether oxygen radicals play some role in cel lular injury of cerulein- induced acute pancreati t is in mouse and whether a - tocophero l could amel iorate the course of pancreat i t is. Cerulein was introduced into the peritoneal cavi ty in a high dose of 50 ug /kg /h r over a period of 6 hours, a - tocophero l was given in a dose 10 m g / k g / d a y over a period of 4 days. Mice t rea ted wi th a - t o c o p h e r o l were found to have lower serum amylase levels compared wi th mice t reated wi th cerulein alone. However there was not a significant di f ference in the degree of pancreatic edema between the pancreat i t is group and the a - t o c o p h e r o l group. Pancreatic malondialdehide (MDA) levels of the pancratit is group were elevated more than those of the control group. In conclusion, oxygen radicals play some role in ce l lu lar in jury o f ceru le in - induced acute pancreati t is in mice, and a - tocophero l amel iorates the course of pancreati t is.

ANALYSIS OF 252 CASES OF MUCIN-PRODUCING TUMOR OF THE PANCREAS. W. Kimura. N. Sasahira, T. Yoshikawa, T. Muto. First Department of Surgery, the University of Tokyo, Japan

Background: Although there have been recent reports of mucin-producing tumor of the pancreas, there has been no thor- ough clinicopathological analysis of a large number of cases.

Methods: Two hundred thirty seven cases of mucin-produc- ing tumor of the pancreas from Japanese, European and American reports, together with 15 cases at the First Department of Surgery, University of Tokyo, were analyzed clinicopathologically.

Results: Mucin-producing tumor of the pancreas was found in 176 males and 76 females (M:F=2.3:1). The mean age was 66.0 years. Jaundice and diabetes mellitus were found in 20% and 19% of the cases, respectively. A past history of panereatitis was found in 14%. The tumor was most frequently (62%) found in the head of the pancreas. Pathologically, hyperplasia was found in 10 cases, adenoma in 44, borderline benign or malignant lesion in 4 cases, and adenocarcinoma in 157 cases. Among the 157 malignant cases, non-infiltrative carcinoma was found in 65 cases, infiltration of the pancreas in 26 cases and infiltration of other organs in 18 cases. Postoperative survival curve by the Kaplan-Meier method was better in cases without infiltration than in cases with infiltration and was significantly worse in cases in which the tumor was larger than 6 cm, With regard to the type of duct dilatation, histological findings in cases of main pancreatic duct type or combined type were significantly more malignant than those in branch type. Serum tumor markers such as CEA or CA 19-9 were not effective in dif- ferentiating between benign and malignant, or in determining the degree of cancerous spread. Cytology of the pancreatic juice and biopsy of the tumor were slightly more effective for the diagnosis.

Conclusions: Mucin-producing tumor has unique clinico- pathological characteristics compared to normal pancreatic duct ceil carcinoma and mucinous cystadenocarcinoma. Postoperative prognosis was better in tumors smaller than 6 cm and without infil- tration. Methods for distinguishing benign from malignant lesions or for determining cancerous spread should be established.

DEMONSTRATION OF GLUCORESPONSIVE ISLET-INNERVATING NEURONS IN THE GUINEA PIG PANCREAS. A. Kirchgessner and M.-T. Liu. Department of Anatomy and Cell Biology, Columbia Univ. P & S, New York, NY.

Pancreatic secretion is modulated by the activity of pancreatic neurons; however, nothing is known about the projections of these cells, although it is widely assumed that they innervate both the islets and acini. In the current study, islet-innervating neurons were visualized by injecting the retrograde tracer, FluoroGold (FG) into individual islets in vitro. The preparations were cultured overnight, and intracellular recordings were made with Neurobiotin-filled microelectrodes from the FG-labeled pancreatic neurons to characterize the islet-projecting cells. The effects of D-glucose on these neurons were also examined. Only a small subset of pancreatic neurons (~5%) were found to project to the islets. The islet- innervating neurons were phasic cells that fired one to three action potentials at the onset of a current pulse. The somata of islet-innervating neurons were smooth and extended a single long process that entered the FG-injected islet and additional nearby islets; a single pancreatic neuron, therefore, can innervate more than one islet. Microejection of glucose onto impaled FG-labeled neurons evoked bursts of fast EPSP-like activity. Because the fast response to glucose resembled the nicotinic fast EPSPs produced by fiber tract stimulation, the effects of glucose on the stimulus- evoked fast EPSP were studied. When preparations were superfused with glucose (20 mM), the amplitude of the evoked fast EPSP was increased (27.2_+7.9%). The response to glucose was specific, since it was mimicked by galactose, but not by xylose. In order to determine whether the site of action of glucose is presynaptic or postsynaptic, we investigated the effect of glucose on responses of pancreatic neurons to nicotine (postsynaptic). Superfused glucose increased the amplitude of the response to microejected nicotine (45.7+14.2%). These results suggest that glucose acts postsynaptically to potentiate the effects of nicotinic stimulation. Our observations suggest, that in addition to its direct effect on 13 cells, glucose also enhances pancreatic ganglionic transmission. Glucose could thus recruit intrapancreatic secretomotor neurons to potentiate (or otherwise modify) its insulinotropic response. Such an action would explain the ability of the ganglion blocker, hexamethonium, to partially inhibit the secretion of insulin evoked by ACh. Supported by NIH grant NS 01582 and the American Diabetes Association.