摘要:

The cytosolic glutathione S-transferases (GSTs) are a family of phase II detoxifying isoenzymes that catalyze the interaction of the tripeptide thiol glutathione (GSH) with a wide variety of reactive and often toxic or carcinogenic electrophilic substrates. Pancreatic GSTs, however, have only been partially characterized. In this study, pancreatic cytosolic GSTs from male Fisher 344 rats were semipurified by affinity chromatography and then analyzed for isoenzyme content by chromatofocusing (fast protein liquid chromatography) and for sub-unit content by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. In addition, polyclonal rabbit antisera were produced against homodimeric isoenzymes purified from rat liver and kidney, including the α class isoenzymes 1-1 and 2-2, the μ class isoenzyme 4-4, and the π class isoenzyme 7-7. These antisera were used in immunohistochemical (IHC) studies of the distribution of the pancreatic GSTs. A range of 0.5 1.6% of the total protein in rat pancreatic cytosol was found to be GST protein. The most abundant subunits present were the IT subunit 7 and μ subunits 3 and 4. Using modified methodology, smaller amounts of the a subunit 2 and the μ subunit 6 were detected, whereas very small amounts of the α subunits 1 and 8 were present. The IHC demonstrated that the GSTs were in large part limited to the duct system of the exocrinee pancreas, with positive staining of endothelial cells and stroma observed for the α and μ subunits. Isoenzymes containing the a subunit 2 were preferentially expressed in centroacinar cells and small ductules, whereas those containing the μ subunit 4 and the π subunit 7 were more prevalent within larger ductules and ducts. The lumens of the largest ducts also contained the two subunits 4 and 7. It is concluded that the acinar cells of the exocrine pancreas may lack the protection against electrophilic toxic and carcinogenic agents provided by the ductular system by GSTs.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Previous studies reported different frequencies of p53 expression between Japanese and Americans or Europeans. The present study was designed to clarify whether there is a significant difference in p53 expression and its clinical implications between Chinese and Japanese patients with primary invasive ductal carcinoma (IDC) of the pancreas. p53 expression was studied in 39 Chinese and 47 Japanese patients, and immunostaining with the SAB method was performed using anti-p53 monoclonal antibody (DO-1) in formalin-fixed and paraffin-embedded specimens. Clinical data were analyzed according to the International Union Against Cancer classification. p53 expression was seen in 71.8% of Chinese and in 48.9% of Japanese patients with IDCs of the pancreas (p <0.05). The Chinese patients were significantly younger than the Japanese ones (p <0.05), but there were no significant corre lations between p53 immunoreactivity and age, gender, stage, and histopathological grade in separate analyses of the Chinese and Japanese patients. A comparison between them showed that in patients younger than 55 and 65 years old, the incidence of p53 expression was markedly lower in Japanese than in Chinese (p <0.05). In Japanese patients, those with a p53-positive pancreatic cancer had a significantly lower survival rate than those with a p53-negative tumor, but there was no correlation between p53 expression and the prognosis of Chinese patients. The frequency of p53 expression in IDC of the pancreas is higher in Chinese than in Japanese patients, and the effect of p53 expression on prognosis is different between Chinese and Japanese patients.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Oxidative stress has been proposed to play a role in the early events of acute pancreatitis, and metallothionein (MT) can provide protection against oxidative stress. Using transgenic mice, we characterized the effects of depletion of MT-I and -II, or overexpression of MT-I, on pancreatic responses during cerulein-induced acute pancreatitis. In MT-I/-II knockout mice, repeated injections of cerulein caused (a) higher serum amylase levels at 3 and 7 h after the initiation of acute pancreatitis; (b) earlier and stronger upregulation of oxidative stress-responsive genes, including heme oxygenase (HO)-l andc-fos; and (c) exacerbated tissue damage (edema and polymorphonuclear neutrophil infiltration) compared with nontransgenic 129/SvCPJ mice. Total pancreatic glutathione (GSH + GSSG) content was similar between the knockout and nontransgenic 129/SvCPJ mice. Interestingly, during acute pancreatitis, CD-1 mice pretreated with L-buthionine-[S,R]-sulfoximine (BSO), which dramatically depleted pancreatic GSH, also had more severe pancreatitis, based on the same three criteria listed above, relative to untreated controls. No effects were observed with BSO treatment alone. Finally, during cerulein-induced acute pancreatitis, MT-I overexpressing transgenic mice (>20-fold increase in pancreatic MT-I content) had lower serum a-amylase levels between 7 and 24 h and delayed upregulation of HO-I mRNA levels, but no difference inc-fosmRNA induction relative to the appropriate strain of nontransgenic mice. Diminished tissue damage (particularly cellular necrosis) was noted in these MT-I overexpressing transgenic mice. Total pancreatic GSH content was similar in these transgenic and nontransgenic mice during cerulein-induced acute pancreatitis. These studies suggest that pancreatic MT can function as an intracellular antioxidant as does GSH and that these intracellular antioxidants play a protective role during cerulein-induced acute pancreatitis.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Primary cultures of bovine pancreatic duct epithelial cells grown on permeable supports exhibit electrogenic transepithelial ion transport. The short-circuit current (Iscgenerated by unstimulated duct cell monolayers and the increase in Iscelicited by increased levels of cyclic adenosine monophos-phate (CAMP) were greater in monolayers bathed by bicarbonate-containing solution compared with monolayers bathed by nominally bicarbonate-free solution. An inhibitor of epithelial sodium channels (amiloride, 10 μM) had no effect on Iscwhereas a CI−channel blocker, N-phenylanthranilic acid (DPC; 1 mM), reduced the forskolin-stimulated Iscby −50% in the absence or presence of bicarbonate. Bumetanide (an inhibitor of Na+, K+, 2CI−cotransport activity; 10 FM) reduced forskolin-stimulated Iscby 49 ± 6% in bicarbonate-free bathing solution and by only 18 ± 1% in bicarbonate-containing solution. Measurements of unidirectional36CI- flux across short-circuited ductal monolayers in a bicarbonate-containing solution revealed that net C1- secretion accounted for the Iscduring se-cretin stimulation. However, the basal Iscand the Iscmeasured during exposure to secretin plus bumetanide were significantly greater than net CI- flux. The permeability coefficient for [14C]acetate (a surrogate tracer for bicarbonate) measured in the secretory direction was −1.5-fold greater than the permeability coefficient measured in the absorptive direction, indicating net secretion. These results suggest that primary cultures of bovine pancreatic duct epithelial cells secrete both CI- and HCO−3.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The pancreatic regenerating gene (reg I) is expressed in the exocrine pancreas and is involved in islet regeneration.reg Iprotein has been shown to be mitogenic to p- and ductal cell lines, but not mature islets. In this study, we tested the effect of two isolates ofreg Ion primary cultures of ductal cells. Rat pancreatic ductal cells were isolated by collagenase digestion and isolated colonies were maintained in culture. The cells were proven to be ductal in origin by their morphology and by immunofluorescent staining with epithelial markers.reg Iwas isolated from human pancreatic extracts or from the rat acinar cell line AR42J by sequential ammonium sulfate precipitation and acid precipitation. Cells were cultured with doses ofreg Ifor 72 h, pulsed with 10 μM bromodeoxyuridine (BrdU) for 2 h. After fixation, nuclei were double-stained with propidium iodide and BrdU monoclonal antibody. The percentages of nuclei positive for BrdU were calculated from at least five colonies per group. A 10-nM concentration of humanreg Iincreased BrdU incorporation by 2.3-fold over controls, ratreg Iincreased it by 1.4-fold (p <0.05). When compared to their effects on the ductal cell line ARIP, both human and ratreg Iwere 100 times more potent on the primary cultures of ductal cells. We conclude that human and ratreg Iproteins are mitogenic to primary cultures of ductal cells. Although principally a product of the acinar cell,reg Iappears to be a stimulus of ductal cell growth and, in this fashion, may modulate the expansion of the pancreatic ductal population during islet regeneration.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Preparation of pancreatic duct epithelial cells from adult organs is possible by limited digestion and outgrowth of cells. These primary cells are mitotically active for only a short period. Therefore transfection with SV40 large-T antigen is one method to obtain an immortalized cell clone. Because the transfection efficacy of primary cells with conventional vectors is comparatively low, our aim was to develop conditions with improved transfection rates. Best transfection rates (˜6% of the resting cells) were obtained by using the BES buffered saline (BBS) calcium phosphate (Ca-P) coprecipitation technique at low pH. By using these optimized transfection parameters, primary cultures of human pancreatic duct epithelial cells were successfully transfected with the plasmid pSV3neo, bearing the large- and small-T antigen of SV40. A G 418 resistant clone (E4) was maintained in culture for 14 months before reaching terminal crisis.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The aim of this study was to document the natural history of chronic hereditary pancreatitis and to compare its evolution to that of chronic alcoholic pancreatitis. Twelve subjects with chronic hereditary pancreatitis were followed up for a mean duration of 15.8 years (range, 1-23) and compared to subjects with chronic alcoholic pancreatitis who were followed up from 1972 to 1980. The subjects with chronic hereditary pancreatitis, when compared to those with chronic alcoholic pancreatitis, were found to have an earlier onset of symptoms (10.5 vs. 46.0 years, p <0.05); a significant delay in diagnosis (14.3 vs. 3 years); a similar prevalence of pancreatic calcification (58 vs. 57%); a similar amount of pancreatic insufficiency; both endocrine (50 vs. 70%) and exocrine 42 vs. 38%); and a higher prevalence of pseudocysts (33 vs. 10%. p <0.05). Only one pancreatic adenocarcinoma was diagnosed in a patient with chronic alcoholic pancreatitis. Apart from the earlier onset and the delay in diagnosis, chronic hereditary pancreatitis has a natural history similar to that of chronic alcoholic pancreatitis. The disease is progressive with a high incidence of complications, but all subjects were alive after follow-up.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Secretory synovial-type PLA2(sPLA2-II) in peripheral blood is known to be associated with systemic complications in patients with severe diseases. Being the pacemaking enzyme in eicosanoid synthesis, sPLA2-II is a mediator of the inflammatory response and plays a role in host defense against bacterial infection. We evaluated the clinical role of systemic sPLA2-II in bacterial infection of pancreatic necroses in severe acute pancreatitis. In 58 patients with acute pancreatitis, pancreatic and sPLA,-I and sPLA2-II were measured daily for the first 14 days of hospital treatment by a time-resolved fluoroimmunoassay. All 36 patients with necrotizing pancreatitis underwent regular fine needle aspiration (FNA) to monitor bacterial infection. In 10 patients, infected necroses were found on FNA and postoperative examination. On admission and at most days throughout the observation period, systemic sPLA2-II was significantly higher in patients with infected necroses than in patients with sterile necroses or interstitial pancreatitis. This difference was not found for sPLA,-I, but values were higher in necrotizing pancreatitis than in interstitial pancreatitis at the first 2 days of hospital treatment. If sPLA,-II was >300 ng/ml on 2 successive days within the first 4 days, infected necroses could be predicted with a sensitivity of 89%, a specificity of 8856, and a negative predictive value of 95%. Systemic sPLA2-II has the potential to identify patients at risk of bacterial infection of pancreatic necroses and its routine measurement may therefore, in combination with FNA2offer a valuable tool in monitoring patients with acute necrotizing pancreatitis.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The etiology of nonalcoholic chronic pancreatitis, occurring in tropical regions, is unknown. Although environmental factors may play a role in its pathogenesis, a specific genetic predisposition may be necessary. The genetic mutation responsible for hereditary pancreatitis was described recently. Unlike in patients with hereditary pancreatitis, we found a lack of the R117H mutation in the cationic trypsinogen gene in all patients with tropical pancreatitis from Bangladesh.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Alterations in pancreatic cell function and morphology are characteristics of pancreatic compromise in various pathophysiological conditions. The present review focuses on potential patterns of pancreatic cell death, apoptosis, and/or oncosis, after different experimental challenges, to understand their potential significance in the pathogenesis of pancreatic injury. Apoptosis is not only present during maintenance of pancreatic homeostasis but can also be initiated by extrinsic and intrinsic factors. Pancreatic cell oncosis is another pattern of cell death, occurring in pancreatic injury. The proportion of apoptosis and oncosis may depend on the severity of pancreatic cell compromise, the properties of the challenge, animal strain, and time course. The role of various inflammatory mediators and adhesion molecules, the use of transgenic animals, and the significance of apoptosis and oncosis in acute and chronic pancreatic injury are discussed. Molecular biology of pancreatic cell death provides valuable information to simplify the understanding of mechanisms in clinical pancreatic diseases and may also introduce potential modes of pharmacological management.

ISSN:0885-3177    

出版商:OVID    

年代:1998

数据来源: OVID