摘要:

In a previous study, we reported that the pancreatic wet weight in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, cholecystokinin-A (CCK-A) receptor-defective because of a congenital gene abnormality, was significantly lower than in control rats (Long-Evans Tokushima Otsuka; LETO) from 3 weeks of age. In this study we examined apoptosis of pancreatic acinar cells in OLETF rats at 5 to 6 weeks of age in comparison with that in LET0 rats. We present here direct morphologic evidence of apoptosis in OLETF rats, using a 3′-OH nick end-labeling method for detecting cells with DNAstrand breaks and electron microscopy. Nick end-labeling revealed a sinall number of positively labeled acinar cells in OLETF rats. On electron microscopic examination, small numbers of apoptotic cells were seen in the lobules in OLETF rats but not in LETO rats. These results suggest that apoptosis plays an important role in the destruction of acinar cells of OLETF rats and induces atrophy of the pancreas.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Recent studies provide significant evidence that Cholecystokinin (CCK) is involved in the induction and development of acute pancreatitis in experimental animals. However, the results obtained with specific CCK-A (peripheral) receptor antagonists are still controversial. The present studies were undertaken to evaluate the involvement of endogenous CCK and the CCK-A receptors in the development of severe acute pancreatitis induced in Otsuka Long-Evans Tokushima Fatty (OLETF) rats that have a selective defect in the CCK-A receptor. Three models of severe acute pancreatitis were induced by retrograde intraductal infusion of 4% sodium taurocholate, by the closed duodenal loop, or by a single intraperitoneal injection of 500 mg/100 g body weight of L-arginine in OLETF rats and control Long-Evans Tokushima Otsuka (LETO) rats. Plasma CCK levels rose up to 4- to 14-fold over the preloading values after the onset of acute pancreatitis in all three models in both groups of rats. However, histologic alterations as well as the magnitudes of increase in serum amylase and lipase activity and the pancreatic wet weight were significantly less in the OLETF rats than those in the LETO rats. In addition, 72 h after the onset of arginine pancreatitis, massive destruction of pancreatic parenchyma with a significant reduction in serum amylase and lipase activities and pancreatic wet weight was observed in the LETO rats, whereas these changes were not seen in OLETF rats. These results suggest that endogenous CCK and CCK-A receptors play a role in the development of severe acute pancreatitis in rats.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Fibrocalculous pancreatic diabetes (FCPD) is a form of diabetes associated with tropical chronic calcific pancreatitis, seen mostly in developing countries. FCPD is likely to be a multifactorial disease with both environmental and genetic components. Thereg1A gene encodes a protein associated with regeneration of pancreatic islets and has a sequence identical to that of pancreatic stone protein. Since FCPD is associated with both diabetes and pancreatitis, we tested the hypothesis that FCPD may be the result of mutations in the coding regions of thereg1A gene. Restriction length polymorphisms (RFLPs) and possible sequence variants of thereg1A gene were studied by RFLP analysis, looking for single-stranded conformational polymorphisms (SSCPs) and direct nucleotide sequencing. In 20 patients with FCPD and 20 control subjects, no RFLPs were detected using 10 restriction enzymes. In 50 patients with FCPD and 50 control subjects, no SSCP variants were detected. Finally, direct nucleotide sequencing of thereg1A gene from 30 patients with FCPD did not show any differences from the published humanreg1A gene sequence. In conclusion, it seems unlikely that mutations in the coding region of thereg1A gene are a common cause of FCPD.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Peritoneal metastases are the second most common site of involvement, following the liver, in pancreatic cancer. Thus, we performed peritoneal washing cytology at laparotomy to diagnose accurately the intraperitoneal spread of carcinoma cells to determine the appropriate therapy. Peritoneal washings were collected at laparotomy from 20 Japanese pancreatic carcinoma patients at Nagoya University Hospital between April 1993 and December 1994. From centrifuged deposits, we examined the cytology by three methods as follows. The first method was conventional cytology, including May- Grünwald and Giemsa, Papanicolaou, periodic acid-Schiff, and Alcian blue. The second method was immunocytochemical staining, using antibodies to carbohydrate antigen (CA19–9) and carcinoembryonic antigen. After extracting DNA from the remaining pellet, we studied the last method, detecting K-raspoint mutation, by two-step polymerase chain reaction and restriction fragment length polymorphism analysis. In two cases, peritoneal metastases were macroscopically recognized, and the results of all three methods were positive. In the two other cases, where peritoneal dissemination was not macroscopically recognized, the judgments of conventional cytological study and detecting K-raspoint mutation were negative. However, a few malignant cells were found by the immunocytochemical staining method. Judging from their clinical course, the positively stained cells were suggestive of malignancy. At present, the immunocytochemical staining method is the most sensitive of these three methods in peritoneal washing cytology. However, preserving DNA is suitable for repeated examination, and a modified method can be applied. If the sensitivity increases, the method of detecting K-rashas the potential to become the standard for peritoneal washing cytology in pancreatic cancer.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The present study was designed to examine the role of Ca2+in the regulation of digestive enzyme synthesis, to determine whether changes in intracellular Ca2+stores or cytosolic Ca2+caused the observed effects, and to establish the steps in the pathway of protein synthesis where the regulation occurs. Protein synthesis, polysome size, and the ratio of completed to nascent polypeptides were measured as a function of Ca2+in the intracellular stores and the cytoplasm of pancreatic acinar cells. Rat acini and rabbit pancreatic lobules were incubated in media containing 1 mMCaCl2with the following additives: cholecystokinin (CCK) octapeptide; the inhibitors of microsomal Ca2+ATPase, thapsigargin (THP) and 2,5-di(tertbutyl)-hydroquinone (BHQ); the intracellular Ca2+chelator, l,2-bis(O-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA); an inhibitor of translational initiation, 7-methylguanosine 5'-triphosphate; and an inhibitor of translation elongation, cyclohexamide. THP and BHQ depleted intracellular pools of Ca2+and caused a sustained elevation in cytosolic [Ca2+]. Under these conditions, the polysome size diminished, and the ratio of completed proteins increased twofold relative to nascent polypeptides despite an overall decrease in net protein synthesis (55.3 ± 2.7% of control). These effects paralleled those caused by incubation with 1 nMCCK. Incubation of pancreatic acini with BAPTA plus THP or BHQ depleted the pool [Ca2+] without changing the cytosolic [Ca2+]. In addition, these agents decreased the net protein synthesis (30.1 ± 3.6% compared to control) and polysome size and increased the ratio of completed to nascent polypeptides to 2:1. These results suggest that depletion of intracellular stores of Ca2+without changes in cytosolic [Ca2+] decreases protein synthesis at translational initiation.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Protease inhibitors may have a beneficial effect in acute pancreatitis. The effects of E3123, a new low molecular weight protease inhibitor, on the ultrastructure of isolated pancreatic acini were examined using transmission electron microscopy. Acini supramaximally stimulated with cerulein (10−8M) formed large cytoplasmic vacuoles similar to those generated in the cerulein-induced in vivo model of pancreatitis. Pretreatment of isolated acini with E3123 significantly reduced the size and number of vacuoles associated with cerulein treatment. The distribution of3H-E3123 in acinar cells was examined using a pulse-chase protocol and electron microscopic autoradiography. Cellular levels of3H-E3123 increased about 30-fold in acinar cells treated with cerulein (10−8M) compared to unstimulated controls. In cerulein-treated acini examined after a 5-min chase, 47.4% of the autoradiographic grains were associated with the rough endoplasmic reticulum and 13.2% were associated with zymogen granules. After 30 min of incubation, the grains associated with the endoplasmic reticulum decreased to 18.5% but increased to 26.3% over zymogen granules. Thus, E3123 is taken up by the acinar cell and follows a cellular itinerary similar to that of newly synthesized secretory proteins. One potential conclusion from these studies is that the ability of E3123 to reduce the formation of vacuoles in supramaximally stimulated acini may be due to its inhibition of proteases within the secretory pathway.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Despite the fact that alcoholism is one of the major causes of pancreatitis, the pathogenesis of this disorder remains obscure. Factors such as the pattern of ethanol consumption, diet, and genetic predisposition may be contributing factors. The failure to produce alcoholic pancreatitis in experimental animals suggests that experimental provision of ethanol may only increase the predisposition to pancreatitis. To test this possibility, we developed an assay system using the in vitro model of cerulein-induced pancreatitis. In this system, pancreatic lobules were first exposed to a supraphysiologic concentration (10−6M) of the cholecystokinin analogue, cerulein, after which homogenates were incubated for up to 6 h. Activation of trypsinogen and chymotrypsinogen was observed only in cerulein-treated preparations. We then investigated the effects of the duration of ethanol feeding on cerulein-induced changes in rat pancreas. The pancreata from rats fed ethanol for 9–12 months were more susceptible to cerulein-induced activation of chymotrypsinogen compared to the pancreata from pair-fed control animals. This susceptibility also paralleled morphologic changes, such as dilatation of endoplasmic reticulum, only in the ethanol-fed group. In contrast, during the early stages (up to 3 months) of ethanol consumption, there was resistance (p< 0.01) to cerulein-induced changes. These results suggest that long-term ethanol consumption increases susceptibility to pancreatitis and raises the possibility that a similar mechanism may operate in human alcoholics.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

We studied the effect of oral zinc administration on functional and morphological regeneration of the remnant pancreas after 80% pancreatectomy in dogs. After 80% pancreatectomy, both endo- and exocrine function (assessed by the sum of plasma immunoreactive insulin on the intravenous glucose tolerance test and amylase output on the cerulein-secretin test) markedly deteriorated, the pancreatic regeneration rate (change in weight of the remnant pancreas between the time of surgery and autopsy) was very poor, and the zinc concentration in pancreatic tissue decreased in dogs fed the standard diet. In dogs fed the high-zinc diet, pancreatic function and regeneration rate were significantly improved, and the zinc concentration in pancreatic tissue was maintained. Early cell proliferation (assessed by ornithine decarboxylase activity, DNA synthesis, and proliferating cell nuclear antigen labeling index in the remnant pancreas) after pancreatectomy was significantly enhanced in the high-zinc diet group compared to the standard diet group. Correlation analyses between parameters of early cell proliferation and zinc concentration in pancreatic tissue yielded significant positive correlations, and the zinc concentration in pancreatic tissue was significantly correlated with both endo- and exocrine function and the pancreatic regeneration rate. These results suggest that a high-zinc diet after major pancreatectomy is effective in maintaining the zinc concentration in pancreatic tissue, which not only enhances early cell proliferation in the remnant pancreas but improves pancreatic endo- and exocrine function in the late period, promoting pancreatic regeneration.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Previously we showed that carbohydrate (CHO) in the ileum slowed gastric emptying and increased pancreatic amylase secretion relative to that of other enzymes. Our aim here was to determine if extrinsic innervation of the jejunoileum participates in the CHO-induced ileal modulation of postprandial upper gut function. Six dogs were studied before and 2–3 weeks after in situ neural isolation of the jejunoileum (complete extrinsic denervation). Gastric emptying (GE) and pancreatic amylase secretion were quantitated for 4 h after a 300-ml meal containing3H-PEG (liquid marker) and99mTc sulfur colloid cooked with eggs (solid marker). Coincident with feeding, we started a distal ileal infusion of 150 mMNaCl or 40 mg · min−1CHO. Extrinsic denervation abolished the slowing of GE of liquids and solids and the augmented increase in amylase and trypsin in relation to solid emptying seen in the neurally intact dogs prior to denervation. Denervation also abolished the decrease in total pancreatic exocrine secretion in response to ileal CHO. Increases in plasma concentrations of peptide YY (PYY) were correlated temporally with decreased GE of solids and increased exocrine secretion during ileal CHO in neurally intact dogs, but no increases in PYY release occurred after extrinsic denervation. Extrinsic denervation of the jejunoileum abolished the effect of ileal CHO on GE of liquids and solids, the decrease in total amylase secretion during ileal CHO, and the relative increase in enzyme secretion expressed as total enzyme output per percentage solid marker emptied. Extrinsic innervation of the jejunoileum mediates ileal modulation of GE and the relationship of amylase secretion to GE of solids. The mechanism of this effect may be via neurally mediated release of PYY.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Although surgical procedures that improve pancreatic drainage alleviate abdominal pain in the vast majority of patients with chronic pancreatitis, postoperative absorption and nutritional status are less predictable. The present study was designed to determine the efficacy of pancreatic enzyme supplementation in maintaining postoperative digestion and nutrition in patients who had received the local resection-longitudinal pancreaticojejunostomy (LR-LPJ) procedure for chronic pancreatitis. We evaluated nutritional status and intestinal absorption in 11 patients who had undergone LR-LPJ. The efficacy of postoperative pancreatic enzyme supplementation was studied by measurements of intestinal absorption and nutritional status at baseline, after 4 weeks of individualized daily dosage of pancreatin (Creon), and after an additional 4 weeks of randomization to receive another 4 weeks of pancreatin or placebo. All patients demonstrated abnormal digestion of fat, protein, and total energy at baseline 3 weeks after surgery. Pancreatin supplementation significantly improved the coefficients of absorption of dietary fat and total energy over the next 4 weeks. Between 4 and 8 weeks, pancreatin significantly improved protein absorption and nitrogen balance, whereas placebo substitution worsened the absorption of dietary fat and total energy. Nutritional status was not significantly altered over the 8-week study period, although four patients receiving pancreatin gained more than 3.6 kg body weight. The data suggest that long-term postoperative pancreatic enzyme supplementation is both efficacious and necessary in chronic pancreatitis patients after LR-LPJ.

ISSN:0885-3177    

出版商:OVID    

年代:1997

数据来源: OVID