Masatoshi Fujii

New model of acute necrotizing pancreatitis induced by excessive doses of arginine in rats

We examined the biological and histologic characteristics of a new experimental model of acute necrotizing pancreatitis induced by excessive doses of arginine in rats. Rats were given a single intraperitoneal injection of 500 mg/100 g body weight ofl-arginine. At 12–24 hr after the arginine injection, serum levels of amylase, lipase, and anionic trypsin(ogen) reached respective peak values 2, 5, and 20 times those of control rats without arginine and returned to control levels after 24–48 hr. The contents of pancreatic protein, DNA, and digestive enzymes were markedly reduced after the arginine injection and reached their nadirs at 72 hr. After 14 days these levels were almost normal. Histologic examination revealed a number of small vesicles within acinar cells at 6 hr, which were identified as markedly swollen mitochondria by the electron microscope. Other intracellular organelles and nuclei also showed degenerative changes. At 12 hr interstitial edema appeared, and acinar cell necrosis was seen after 24 hr. The extent and severity of necrotic changes of pancreatic exocrine tissue with inflammatory cell infiltration were maximal at 72 hr. At seven days, pancreatic acinar cells began to regenerate, and pancreatic architecture appeared almost normal after 14 days. The present study has demonstrated that the administration of excessive doses of arginine induces a new, noninvasive experimental model of acute necrotizing pancreatitis.

Histologic and biochemical alterations in experimental acute pancreatitis induced by supramaximal caerulein stimulation

SummaryWe studied the histologic and biochemical alterations in experimental acute pancreatitis induced by supramaximal caerulein stimulation in rats. All rats received 4 subcutaneous injections of various doses of caerulein (5–50 μg/kg body weight) at hourly intervals over 3 h, and 9 h after the first injection all animals were killed. Subcutaneous injections of 20 μg/kg body weight of caerulein induced a significant increase in serum amylase activity and histologic evidence of acute interstitial pancreatitis similar to those observed with the 50 μg/kg body weight dosage of caerulein. Therefore, a total of 4 subcutaneous injections of 20 μg/kg body weight of caerulein was chosen to study the time-course of structural and biochemical alterations in caerulein-induced acute pancreatitis. Serum amylase activity reached a maximal value of 10-fold increase over the basal values at 6 h, and then decreased gradually to normal values at 18 h after the first injection. Remarkable interstitial edema and cytoplasmic vacuoles in acinar cells were the earliest histologic alterations. Cellular infiltration was prominent at 9–12 h after the first injection. Although these histologic changes almost completely disappeared after 24 h, the reduction in the number of zymogen granules was still detectable by electron microscopic examination even after 7 days. DNA content in the pancreas showed no significant changes following the induction of acute pancreatitis, whereas a moderate to marked reduction in enzyme content persisted after 7 days. Within 14 days after the initiation of the injections, both structural and biochemical changes had completely disappeared. *** DIRECT SUPPORT *** A00DX035 00005

Acute gastric anisakiasis: 28 cases during the last 10 years.

Anisakiasis is a disease which occurs following eating raw fish infected with anisakis larvae. Many cases have been reported from Japan and from other countries with increasing opportunities of eating raw fish such as “sushi” and “sashimi.” We have reviewed 28 patients with acute gastric anisakiasis during the last 10 years from November 1984 to October 1994. This disease has rarely been detected in persons over 60 years of age and in patients with gastric surgery. Therefore it is postulated that gastric acid secretion influences the activities of anisakis larvae. An alkaline gastric pH could interfere with the toxicity of anisakis larvae.

Effect of Gymnema sylvestre, R.Br. on glucose homeostasis in rats

Effect of Gymnema sylvestre, R.Br. (G. sylvestre; GS4) on glucose homeostasis was studied in rats. In the first set of experiments, the acute effect of GS4 was examined in both non-diabetic and streptozocin (30 mg/kg)-induced mildly diabetic rats. Administration of 1 g/kg body weight of GS4 to 18-h fasted non-diabetic rats significantly attenuated the serum glucose response to oral administration of 1 g/kg glucose. The immunoreactive insulin (IRI) response in GS4-administered rats was lower, but not significantly, than that in control rats. In mildly diabetic rats, a 60 min increment in serum glucose concentrations was significantly reduced by GS4 administration. No IRI response was observed in these diabetic rats irrespective of GS4 administration. In the second set of experiments, the chronic effect of GS4 was examined in mildly diabetic rats. Two weeks after the induction of diabetes, the rats were divided into two groups that had similar impairment of glucose tolerance assessed by an oral glucose loading test. The rats were fed for 32-35 days with either a control diet or a diet supplemented with GS4. After 4 weeks, GS4 showed a tendency to reduce the serum glucose concentrations in the fed state and to improve the glucose tolerance. Gain in body weight, food intake, pancreas weight and the pancreatic contents of IRI, protein, amylase and trypsinogen were unaltered in the GS4-treated group compared with the control. These results suggest the usefulness of G. sylvestre in the treatment of certain classes of non-insulin-dependent diabetes mellitus.

Effect of a new cholecystokinin receptor antagonist loxiglumide on acute pancreatitis in two experimental animal models

We evaluated the effects of a new cholecystokinin (CCK) receptor antagonist, loxiglumide, in a model of mild pancreatitis induced by repeated injections of cerulein and in a severe necrotizing form of pancreatitis induced by retrograde ductal injection of sodium taurocholate (NaTc) in rats. A single subcutaneous injection or oral administration of 50 mg/kg of body weight of loxiglumide almost completely reduced the increases of serum amylase activity and pancreatic wet weight, and caused histologic improvements of the cerulein-induced acute pancreatitis when given 30 min before the first cerulein injection. Loxiglumide was also effective in reducing the elevated serum amylase activity, pancreatic wet weight, and histologic alterations even when administered after the induction of acute pancreatitis. However, loxiglumide offered no apparent beneficial effects when given 30 min before and 3 h after the induction of acute pancreatitis by NaTc as determined by changes in serum amylase activity, pancreatic wet weight, and histology. These results do not necessarily suggest that CCK is not important in the pathogenesis of pancreatitis, but do suggest that the sole blockade of peripheral CCK receptors isineffective against NaTc-induced severe necrotizing pancreatitis.

Loxiglumide. A new proglumide analog with potent cholecystokinin antagonistic activity in the rat pancreas.

D,L-4-(3,4-dichlorobenzoylamino)-5-(N-3-methoxypropyl-pentylami no)-5- oxopentanoic acid (CR 1505; loxiglumide) is a newly developed analog of proglumide. We examined the inhibitory effects of loxiglumide on pancreatic exocrine function in the isolated pancreatic acini and the isolated perfused pancreata of rats. Loxiglumide inhibited cholecystokinin octapeptide (CCK-8)-stimulated amylase release and, similarly, binding of [125I]CCK-8 to isolated rat pancreatic acini. Loxiglumide was about 3000 times more potent than the reference substance proglumide, but was about 1000 times less potent than L-364,718, another new CCK antagonist having benzodiazepine ring, in inhibiting CCK-8-stimulated amylase release. The inhibitory effect of loxiglumide displayed competitive kinetics and was specific for CCK in that the effects of other receptor secretagogues or agents bypassing receptors were not altered. The inhibitory effect of loxiglumide was fully reversible in isolated acini. However, the pancreata perfused with 10 microM loxiglumide for 20 min did not respond to CCK-8 for more than 20 min even after the removal of loxiglumide infusion. In contrast, an immediate increase in pancreatic exocrine secretion was observed after proglumide removal. Loxiglumide appeared to be bound to the receptors on acinar cells in a slowly dissociating state. These results indicate that loxiglumide acts as a potent, competitive, and specific CCK antagonist on the exocrine pancreas and, because of its prolonged inhibitory action, may be useful as a therapeutic agent in pancreatic disease.

The protective effect of the trypsin inhibitor urinastatin on cerulein-induced acute pancreatitis in rats.

We examined the protective effects of the trypsin inhibitor, urinastatin, extracted from human urine in experimental acute pancreatitis in conscious rats. Acute pancreatitis was induced by four subcutaneous injections of 20 μg/kg body weight of cerulein at hourly intervals. Urinastatin at a dose of 50,000 U/kg body weightl6.5 h was given by continuous i.v. infusion beginning 0.5 h before the first cerulein injection and continuing until 3 h after the last one, for a total of 6.5 h. Urinastatin significantly reduced serum levels of amylase, lipase, and anionic trypsin(ogen) but did not affect pancreatic wet weight or protein or enzyme content. Urinastatin also significantly reduced the degree of acinar cell vacuolization, interstitial edema, and cellular infiltration. These results suggest that urinastatin does not block the induction of acute pancreatitis by cerulein but does substantially reduce its seventy.

TYPE IIA EARLY GASTRIC CANCER WITH PROLIFERATION OF XANTHOMA CELLS

Abstract: We report a type IIa early gastric cancer associated with xanthoma cell proliferation in a 61-year-old man. The patient was admitted to our hospital because of a gastric polyp detected at a medical checkup. An irregular protruding lesion with xanthoma cell proliferation was detected endoscopically. Histological examination showed a well differentiated tubular adenocarcinoma in the mucosa associated with xanthoma cell proliferation. The distribution of the xanthoma cells in the stroma corresponded closely with that of the cancer cells. Neither atypism nor mitotic figures were recognized in the xanthoma cells. In an immunohistochemical study, almost all the xanthoma cells were stained positive for α1-antitrypsin, while relatively few exhibited positive S-100 protein staining. Specific monocyte chemotactic and activating factor immunoreactivity was present only in the xanthoma cells, and not in the cancer cells. On the basis of these findings, it was speculated that the gastric cancer cells may have caused the xanthoma cell proliferation via an autocrine mechanism i.e., by a chemical mediator acting in a paracrine or juxtacrine manner.

Oral glucose ingestion stimulates cholecystokinin release in normal subjects and patients with non-insulin-dependent diabetes mellitus

The role of glucose in the regulation of plasma cholecystokinin (CCK) level was investigated in healthy control subjects and patients with non-insulin-dependent diabetes mellitus (NIDDM). Plasma CCK concentration was determined by a specific and sensitive bioassay and by a highly sensitive and reliable double-antibody radioimmunoassay using OAL-656 as an antiserum. In control subjects, ingestion of Trelan G-75 (1,200 mOsm/L,225 mL), which is equivalent to 75 g glucose as metabolic products, caused a rapid and significant increase in plasma CCK bioactivity from 1.3 +/- 0.2 to a peak of 5.8 +/- 0.6 pmol/L and immunoreactive CCK concentration from 1.2 +/- 0.1 to 4.6 +/- 0.6 pmol/L. Ingestion of 75 g glucose in 225 mL water (33.3% solution) increased plasma CCK bioactivity to a similar degree to that observed following Trelan G-75 (peak response, 4.5 +/- 0.4 pmol/L). The same volume of 0.9% NaCl solution or water failed to increase plasma CCK concentration. A smaller dose of glucose (50 b/150 mL water) increased plasma CCK concentration, although the peak level (3.0 +/- 0.5 pmol/L) was less than that observed following 75 g glucose. In patients with NIDDM, Trelan G-75 ingestion increased CCK concentration, but the peak level was lower, albeit insignificantly, than that of normal subjects. When the maximal increment of plasma CCK above the basal value was compared between control and NIDDM subjects, the differences were statistically significant (NIDDM, 3.6 +/- 0.1 pmol/L; control, 5.0 +/- 0.4; P < .01). However, integrated CCK responses to Trelan G-75 in NIDDM (165.8 +/- 15.5 pmol/120 min) were not significantly different from those in control subjects (189.8 +/- 15.9 pmol/120 min). Peak CCK bioactivity occurred within 10 to 30 minutes of ingestion, preceding the increase in glucose and insulin. These results suggest a possible effect of CCK on insulin release in humans, and that the CCK secretory response to glucose in well-controlled diabetic patients is not significantly altered.

Comparative inhibitory effects of pirenzepine and atropine on cholinergic stimulation of exocrine and endocrine rat pancreas

The effects of pirenzepine on carbamylcholine-stimulated exocrine and endocrine pancreatic functions were compared with those of atropine in both the isolated pancreatic acini and the isolated perfused pancreas of rats. In the isolated acini pirenzepine and atropine produced a concentration-dependent inhibition of amylase secretion initiated by carbamylcholine. This inhibition resulted in a rightward shift in the dose-response curve for carbamylcholine-stimulated amylase secretion without altering the maximal increase in amylase secretion. Pirenzepine was, however, approximately 300 times less potent than atropine in inhibiting the stimulated amylase release. A similar difference in potency was observed with respect to carbamylcholine stimulation of pancreatic juice, amylase, and insulin release from the isolated perfused pancreas. The maximal inhibitory concentration of pirenzepine on a maximal effective concentration of pirenzepine on a maximal effective concentration of carbamylcholine for stimulating pancreatic exocrine secretion was 10 microM, whereas that of atropine was 30 nM. The present data define the pirenzepine receptors in the exocrine and endocrine pancreas as low-affinity-type receptors.