[Autoimmune pancreatitis with normal IgG4-Levels: 4 case reports and review of the literature]. / Autoimmune Pankreatitis bei normalem IgG4: 4 Fallberichte und Literaturübersicht.

We report four cases of autoimmune pancreatitis in an 18-, a 22- and a 26-year-old male patient and a 20-year-old female patient. The 20-year-old female patient was admitted to the hospital with upper abdominal pain and jaundice, the 18-year-old patient with recurrent acute pancreatitis and cholestasis, the 26-year-old patient with right upper abdominal pain for four weeks and laboratory findings suggesting an acute pancreatitis. The 22-year-old patient presented with painless jaundice. EUS-guided fine needle aspiration was performed in all patients. The cytological findings and the EUS were decisive for the diagnosis of autoimmune pancreatitis in all four cases. In contrast, no patient showed elevated IgG4, or antibodies for carboanhydrase-II, for lactoferrin, or rheumatoid factor, serum markers reported to be positive in autoimmune pancreatitis. All patients were treated successfully with steroids, one patient relapsed after discontinuing the steroid medication and required renewed therapy. These case reports demonstrate that autoimmune pancreatitis should be considered in the differential diagnosis in cases of pancreatitis and/or jaundice also in western countries. As demonstrated, the diagnosis should not be based solely on the elevation of IgG4 or autoantibodies.

Primary precutting versus conventional over-the-wire sphincterotomy for bile duct access: a prospective randomized study.

BACKGROUND AND STUDY AIMS: Precut is a well-known technique that is used if repeated attempts at common bile duct (CBD) cannulation fail. Opinions on the complication rate of precut are conflicting, however. The aim of the present study was to compare the efficacy and complication rate of precut used as a primary method of CBD access with the efficacy and safety of the conventional technique. PATIENTS AND METHODS: During the 19-month study period, consecutive patients who were scheduled for first-time endoscopic sphincterotomy (ES) for a variety of biliary disorders were randomized into two groups: patients in group A underwent conventional wire-guided biliary cannulation followed by ES (with precut being performed only when this failed); in patients in group B precut was used as a primary technique to gain biliary access, followed by wire-guided ES. We used a specially designed, modified Erlangen type of sphincterotome for precutting. RESULTS: A total of 291 patients (100 men, 191 women; mean +/- SD age 65 +/- 17.5 years) were recruited: 146 patients were assigned to group A (conventional approach) and 145 to group B (primary precut approach). The indications for ES were comparable in the two groups. In group A, wire-guided cannulation of the CBD failed in 42 patients. Secondary precut was successful in 41 of these patients, leading to an overall success rate of 99.3 %. In group B, the ES success rate using primary precut was 100 % at the first attempt. The mean time to successful deep CBD cannulation was 8.3 +/- 2.1 minutes in group A and 6.9 +/- 1.8 minutes in group B ( P < 0.001). The incidence of mild to moderate pancreatitis was similar in the two groups (2.9 % in group A vs. 2.1 % in group B, P > 0.05). Mild bleeding occurred in only one patient (from group A) and this was controlled by epinephrine injection. None of the study patients developed severe pancreatitis or perforation. CONCLUSIONS: In experienced hands, an approach using primary precut appears to be at least as successful and safe as a conventional approach using guide-wire-based CBD cannulation followed by ES, and might also be a quicker method.

Impact of endoscopic ultrasound for evaluation of submucosal lesions in gastrointestinal tract.

BACKGROUND: Endoscopic ultrasound is widely used following endoscopy for evaluation of suspected submucosal lesions and may guide further management of patients. PATIENTS AND METHOD: A total of 181 consecutive patients with suspected submucosal lesion in the upper gastrointestinal tract were diagnosed by endoscopic ultrasound between 1990-97. We evaluated: 1) the potential of endoscopic ultrasound criteria to predict histological type of submucosal lesions in 69 patients with available histology, 2) the ability of endoscopic ultrasound alone or with clinical presentation, to predict malignancy in 86 patients with available histology or follow-up of >12 months. RESULTS: Sensitivity and specificity for diagnosing 44 gastrointestinal stromal tumours were 95 and 72%, respectively, while 25 miscellaneous lesions were diagnosed correctly in only 56% by endoscopic ultrasound. Diagnosis of malignancy, using any two of three endoscopic ultrasound criteria (heterogeneous echotexture, size >3 cm, irregular margins) showed a sensitivity of 80% and specificity of 77%, giving accurate endoscopic ultrasound diagnosis in 16/20 malignant and 51/66 benign submucosal lesion. Heterogeneous echotexture, size >3 cm, and irregular margins showed a relative risk of 7.2, 5.4 and 4.6, respectively, for presence of malignancy. The presence of symptoms, potentially suggesting malignancy (dysphagia, gastrointestinal bleeding, pain and weight loss), had a relative risk of 4.2, however this did not increase the accuracy of diagnosing malignancy based on endoscopic ultrasound criteria alone. CONCLUSION: The accuracy of endoultrasound is high in diagnosing gastrointestinal stromal tumours, which show a significant potential of malignancy. Endoscopic ultrasound morphology appears to be helpful in selection of patients for surgical or conservative treatment. The accuracy of endoscopic ultrasound in differential diagnosis of non-gastrointestinal stromal tumour lesions is limited.

CCKB/gastrin receptors mediate changes in sodium and potassium absorption in the isolated perfused rat kidney.

BACKGROUND: To evaluate the function of cholecystokinin B (CCKB)/gastrin receptors in the rat kidney, we identified the receptors by Northern blot and localized the receptors by immunohistochemistry. The functional effects of gastrin were studied under standardized in vitro conditions using the isolated perfused kidney. METHODS: Rat kidneys were mounted in an organ bath by attaching the renal artery to a perfusion system. A catheter was inserted into the renal vein and the ureter to collect samples that were analyzed for the concentrations of electrolytes. After a preperfusion period, gastrin-17-I was given via the renal artery (10-8 to 10-6 mol/L). Subsequently, hemodynamic parameters (for example, perfusate flow) and changes in sodium and potassium absorption were determined. All data were subjected to a nonparametric analysis of variance and, in case of significant results, to subsequent paired comparisons by the a posteriori Wilcoxon test. RESULTS: Northern blot analysis detected CCKB receptor transcripts in total RNA isolated from kidneys. Immunohistochemistry localized CCKB receptors on tubules and collecting duct cells. Compared with controls, gastrin (10-6 mol/L) caused a decrease in the fractional sodium reabsorption (basal 80%, 10 minutes after application of gastrin 71%, after 20 minutes 62%, P < 0.05). This effect was inhibited by the CCKB receptor antagonist L-365,260. Gastrin decreased urinary potassium excretion at 10-8 and 10-6 mol/L [maximal decrease at 10-6 mol/L from baseline values (100%) to 49% after 10 minutes and to 69% after 20 minutes, P < 0.05, N = 6]. This effect was also abolished by the CCKB receptor antagonist L-365,260. Gastrin (10-6 mol/L) reduced perfusate flow by 31% (P < 0.05). CONCLUSIONS: CCKB receptors are expressed in the rat kidney on tubules and collecting ducts. These receptors mediate changes in renal potassium and sodium absorption. In addition, gastrin causes a decrease in perfusate flow, indicating that CCKB receptors might also modulate vascular resistance in the kidney.

[Receptors for cholecystokinin and gastrin]. / Rezeptoren für Cholezystokinin und Gastrin.

Cholecystokinin (CCK) and gastrin belong to one family of gastrointestinal peptides that regulate a variety of functions in the gastrointestinal tract and in the central nervous system. On the basis of pharmacological, physiological and molecular studies, receptors for these peptides can be divided into at least two different types: CCKA- and CCKB-receptors. CCKA- and CCKB-receptors are both G-protein coupled receptors and are highly conserved between species. Molecular techniques have revealed a distinct species- and tissue-specific variation in receptor expression and pharmacology. In addition, previously unknown targets for CCK and gastrin such as the kidney were identified. This review discusses the physiological functions of the hormones CCK and gastrin and their receptors. The molecular structure of these receptors and the results of recent structure-function analysis are reviewed.

Human pancreatic cancer cell lines express the CCKB receptor.

BACKGROUND/AIMS: The gastrointestinal peptide gastrin might be a stimulatory effector of the growth of human pancreatic cancer cell lines. Several authors suggest that this effect is mediated by CCKB receptors. However, no studies have examined human pancreatic cells for CCKB receptor expression. The study was designed to evaluate cell lines from human pancreatic cancer (n = 6), or normal pancreatic ducts (n = 2), pancreatic tumor and control tissues (n = 9) for CCKB receptor expression. METHODOLOGY: RNA from cell lines and tissues was subject to DNAse digestion, reverse transcription and amplification using CCKB receptor cDNA sequence specific oligonucleotides via polymerase chain reaction (PCR). After confirmation of CCKB receptor sequence, the products were examined using southern blot analysis. The relative expression was determined by photodensitometrical quantification and normalization to the housekeeping gene beta-actin. RESULTS: Six pancreatic tumor cell lines expressed the CCKB receptor. Amplification of CCKB receptor cDNA from 2 cell lines derived from non-malignant human pancreatic duct cell lines resulted in products with a significantly lower copy number. Tissues like stomach and brain served as positive controls. CONCLUSIONS: These results provide evidence that most human pancreatic cancer cell lines of ductal origin express CCKB receptor mRNA. Malignant pancreatic tissue may overexpress these receptors in comparison with normal tissue.

Pancreaticoduodenal artery aneurysm--a life-threatening cause of gastrointestinal hemorrhage: case report and review of the literature.

Gastrointestinal bleeding caused by erosion of a pancreaticoduodenal artery aneurysm in patients with pancreatitis is a rare but potentially life threatening disease. In this case report, the successful treatment of a patient bleeding from a ruptured pancreaticoduodenal artery aneurysm is described. A review of the literature of reported cases discusses the value of early angiographic intervention in patients with unexplained gastrointestinal hemorrhage and suspected rupture of an aneurysm.

Evidence for CCK(B) receptors in the guinea-pig kidney: localization and characterization by [125I]gastrin binding studies and by RT-PCR.

Two types of receptors for gastrin and cholecystokinin (CCK) have been identified in the gastrointestinal tract and in the central nervous system: CCK(A) and CCK(B) receptors. Here we report evidence for the expression of CCK(B) receptors in the guinea-pig kidney. Specific binding sites for [125I]gastrin were detected in sections of the guinea-pig kidney: Binding was saturable, pH-, temperature- and time-dependent, and specific for gastrin-related peptides. The potencies for inhibition of binding of [125I]gastrin were CCK-8 > gastrin 17-I > CCK(B) receptor antagonist L-365,260 > des(SO3)CCK-8 > CCK(A) receptor antagonist L-364,718. Autoradiography demonstrated specific [125I]gastrin binding to medullary collecting ducts and to a much lesser extent to glomeruli, but not over other structures. CCK(B) receptor cDNA fragments were amplified by RT-PCR from total kidney, isolated tubuli and from tissues known to express CCK(B) receptors such as stomach and brain. The kidney might therefore be a previously unidentified site of action for gastrin and cholecystokinin-related peptides.

Gastrin/cholecystokinin type B receptors in the kidney: molecular, pharmacological, functional characterization, and localization.

BACKGROUND: Gastrin/cholecystokinin type B receptors (CCKBRs) can be found on parietal cells and smooth muscle cells and are the predominant brain CCK receptors. Recent cloning studies indicate that this is receptor type might also be expressed in the kidney. MATERIALS AND METHODS: We used Northern blot analysis in guinea pig. kidney and reverse transcriptase polymerase chain reaction (RT-PCR) in several murine kidney cells lines to evaluate this organ for the expression of the CCKBRs. The receptor was pharmacologically characterized by displacement experiments using [125I]-BH-CCKs and various agonists and antagonists. Polyclonal antibodies vs. the CCKBRs were raised in chicken, and immunohistochemistry on tissue sections was used to localize the receptor within the organ. The effect of gastrin on renal cell growth was measured using proximal tubulus (MCT) cells, which were cultured with gastrin (10-9 M) for 24-72 h. Cell counts and [3H]-thymidine incorporation experiments were performed. RESULTS: CCKBR transcripts can be detected in kidney RNA (tubules > glomeruli > interstitium). RT-PCR revealed CCKBR transcripts in proximal tubules (MCT cells) and in mesangium (MMC). The medullary thick ascending limb of Henle's loop and several control tissues such as liver and muscle were negative. Displacement experiments using [125I]-BH-CCK and various agonists and antagonists identified binding sites with typical CCKBR pharmacology. CCKBRs were localized in the proximal tubulus, distal collecting ducts and mesangium cells. Treatment of rested MCT cells with gastrin 17-1 induced cell proliferation and [3H]-thymidine incorporation by at least 40% compared with normal growth (P < 0.05). CONCLUSION: These results show for the first time that CCKBRs are present in selected areas of the kidney, and strongly confirm our previous observation that this organ expresses binding sites for [125I]-gastrin. Furthermore, gastrin might act as a growth factor in the kidney.

Characterization of CCK receptors in stomach smooth muscle: evidence for two subtypes.

Cholecystokinin (CCK) and related peptides such as gastrin are important regulators of gastric smooth muscle contraction. Several studies have shown that these effects of CCK and gastrin are mediated by CCK(B) receptors. However, recent studies suggest the expression of an additional CCK receptor subtype distinct from CCK(B) receptors in this tissue. This study was designed to distinguish between CCK(A) and CCK(B) receptors on guinea-pig stomach smooth muscle cells and to evaluate these cells for additional receptor subtypes. We cloned these receptors by hybridization screening of a guinea-pig smooth muscle cDNA library using 32P random primed labeled cDNA probes from the recently cloned rat CCK(A) and CCK(B) receptor coding regions. In addition to clones representing the CCK(B) subtype, clones of CCK(A) receptor subtype, but no additional CCK receptor subtypes, could be identified. All isolated clones displayed highly homologous nucleotide sequences in comparison to previously characterized CCK(A) and CCK(B) receptors from different species. The results of cDNA hybridization at different levels of stringency and Southern blot analysis using guinea-pig genomic DNA suggest that it is unlikely that additional CCK receptors despite CCK(A) and CCK(B) receptors exist in stomach smooth muscle.

Molecular cloning, functional expression, and chromosomal localization of the human cholecystokinin type A receptor.

The results presented here describe for the first time the molecular cloning of the human CCKA-R. Expression of the recombinant receptor shows the expected subtype pharmacology and coupling to phosphoinositide hydrolysis reported for the native human CCKA-R. This knowledge will enhance our understanding of its distribution, pharmacology, and structure and will improve our understanding of its physiological role in the gastrointestinal and nervous systems in humans. Ultimately, this should hasten the understanding and therapy of gastrointestinal and neuropsychiatric disorders.

Cholecystokinin receptor family. Molecular cloning, structure, and functional expression in rat, guinea pig, and human.

A review of the literature encompassing numerous pharmacological, physiological, and biochemical studies indicates the presence of at least four CCK receptor types, CCKA, CCKB, gastrin, and CG-4 receptors. Multiple subtypes of the CCKAR have been postulated to account for the differences in pharmacology or affinity cross-linking of CCKARs between pancreas and gallbladder and the presence of high and low affinity CCKARs on pancreatic acini. Multiple subtypes of the CCKBR have been postulated to explain the differences in pharmacology and physiology between gastric and gallbladder smooth muscle CCKBRs. We recently cloned and functionally expressed both the CCKAR and the CCKBR from rat, guinea pig, and human. The CCKAR and CCKBR are 48% homologous and constitute a family of receptors within the guanine nucleotide-binding regulatory protein-coupled superfamily of receptors. Each receptor is highly conserved between species. A single cDNA encoding a single protein is present in both pancreas and gallbladder and can account for both high and low affinity CCKARs found on pancreatic acini when transfected into COS-7 cells. A single cDNA encoding a single CCKBR protein is present in both the central nervous system and the periphery including the gastrointestinal system. Therefore, the gastrin receptor is actually a CCKBR present on parietal cells. Genomic and cDNA library hybridization as well as Northern and Southern hybridization studies among rat, guinea pig, and human species identifies only two members of the CCK receptor family, CCKAR and CCKBR. Although these studies do not identify other closely related members of the CCK receptor family, they do not rule out the existence of other less closely related members. Furthermore, differences in tissue and species-specific posttranslational processing, receptor coupling, and associated membrane protein and lipid heterogeneity may be among some of the other factors that may account for the phenotypic expression of more receptor subtypes than molecular studies would predict.

Guinea pig gallbladder and pancreas possess identical CCK-A receptor subtypes: receptor cloning and expression.

Cholecystokinin (CCK) receptors mediate pancreatic acinar secretion and gallbladder contraction. Pharmacological and functional studies in pancreas and gallbladder demonstrate a CCK-A receptor subtype in both tissues. However, some pharmacological studies and affinity cross-linking studies of CCK receptors on pancreatic acini and gallbladder suggest that these two tissues possess two different subtypes of the CCK-A receptor. We cloned these receptors in guinea pig using a cDNA clone of the CCK-A receptor from rat pancreas. The guinea pig gallbladder CCK-A receptor was cloned by hybridization screening of a gallbladder cDNA library using a cDNA probe from the rat CCK-A receptor coding region. The guinea pig pancreas CCK-A receptor cDNA was cloned via the polymerase chain reaction using primers corresponding to the guinea pig gallbladder CCK-A receptor 5'- and 3'-noncoding regions. CCK-A receptor clones from guinea pig pancreas and gallbladder had identical nucleotide sequences, which were 80% homologous to the rat CCK-A receptor cDNA sequence. The deduced amino acid sequence from guinea pig CCK-A receptors was 89% homologous to the rat CCK-A receptor sequence. Dose-inhibition binding studies of transiently expressed receptors by CCK agonists and antagonists exhibited a CCK-A receptor pharmacologically similar to the rat CCK-A receptor. These studies indicate that the CCK-A receptors in guinea pig pancreas and gallbladder are identical and do not support previous proposals that they may represent different receptor subtypes.

Molecular cloning, functional expression and chromosomal localization of the human cholecystokinin type A receptor.

The cholecystokinin (CCK) family of peptides and receptors are present throughout the brain and gastrointestinal tract and can be pharmacologically subdivided into two subtypes: CCKA and CCKB. Little is known about the localization, pharmacology and function of CCKA receptors (CCKAR) in humans. We used the rat CCKAR cDNA to isolate the human CCK receptor cDNA homologue from human gallbladder which encodes a unique 428 amino acid protein having > 90% homology to the rat and guinea pig CCKAR. Expression of the recombinant CCKAR in COS-7 cells displayed a pharmacological profile characteristic of a CCKAR subtype and mediated agonist stimulated increase in total inositol phosphates. Northern hybridization identified a transcript measuring 6 Kb. The human CCKAR gene maps to chromosome 4. These results describe for the first time the molecular cloning, expression and chromosomal localization of the human CCKA receptor.

Molecular cloning of the human brain and gastric cholecystokinin receptor: structure, functional expression and chromosomal localization.

The receptors for the brain and gastrointestinal peptide, cholecystokinin, can be classified into CCKA and CCKB subtypes. Having recently cloned the rat CCKB receptor, we used it's cDNA to isolate the human CCKB receptor homologue from brain and stomach which encodes a 447 amino acid protein with 90% identity to both rat CCKB and canine gastrin receptors. Northern hybridization identifies transcripts from stomach, pancreas, brain and gallbladder. The CCKB receptor gene maps to chromosome 11. Expression of the receptor cDNA in COS-7 cells was characteristic of a CCKB receptor subtype pharmacology. These data confirm that we have cloned a novel gene for the human brain and stomach CCKB receptor.

Brain and gastrointestinal cholecystokinin receptor family: structure and functional expression.

Cholecystokinin was one of the first gastrointestinal peptides discovered in the mammalian brain. In the central nervous system there is evidence for CCKA and CCKB receptor subtypes. The CCKA receptors occur in a few localized areas of the central and peripheral nervous systems where they modulate feeding and dopamine-induced behavior. CCKB receptors occur throughout the central nervous system where they modulate anxiety, analgesia, arousal, and neuroleptic activity. We have recently purified and cloned a CCKA receptor cDNA from rat pancreas that allowed isolation of an identical cDNA from rat brain by using the polymerase chain reaction. Using low-stringency hybridization screening of cDNA libraries from rat brain and AR42-J cells, which possess large numbers of CCKB receptors, we identified previously unreported cDNAs, the sequence of which were identical in both tissues. The cDNA sequence encodes a 452-amino acid protein that is 48% identical to the CCKA receptor and contains seven transmembrane domains characteristics of guanine nucleotide-binding regulatory protein-coupled receptors. COS-7 cells transfected with this cDNA expressed binding sites for agonists and antagonists characteristic of a CCKB receptor subtype. We conclude that this cDNA isolated from rat brain and AR42-J cells is a receptor of the CCKB subtype and that the respective cDNAs for both CCKA and CCKB are identical in the brain and gastrointestinal system.

Purification, molecular cloning, and functional expression of the cholecystokinin receptor from rat pancreas.

The cholecystokinin (CCK) family of peptides and their receptors are widely distributed throughout the gastrointestinal and central nervous systems where they regulate secretion, motility, growth, anxiety, and satiety. The CCK receptors can be subdivided into at least two subtypes, CCKA and CCKB on the basis of pharmacological studies. We report here the purification of the CCKA receptor to homogeneity from rat pancreas by using ion-exchange and multiple affinity chromatographic separations. This allowed partial peptide sequencing after chemical/enzymatic cleavage and synthesis of degenerate oligonucleotide primers. These primers were used for initial cloning of the cDNA from rat pancreas by PCR. The predicted protein sequence of the cDNA clone contained the five partial peptide sequences obtained from the purified protein. Seven putative transmembrane domains suggest its membership in the guanine nucleotide-binding regulatory protein-coupled receptor superfamily. In vitro transcripts of the cDNA clone were functionally expressed in Xenopus oocytes and displayed the expected agonist and antagonist specificity.