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  • 1
    Electronic Resource
    Electronic Resource
    Induction of the fed pattern of human exocrine pancreatic secretion by nutrients: role of cholecystokinin and neurotensin (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. 902-908 
    Details
    ISSN: 1432-1440
    Keywords: Cholecystokinin ; Gastrointestinal hormones ; Human ; Interdigestive pattern ; Fed pattern ; Pancreatic secretion ; Neurotensin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to assess the role of cholecystokinin and neurotensin in converting the cyclical interdigestive pattern of pancreatic secretion into the non-cyclical fed pattern. Six healthy male volunteers were studied on 4 separate days. During each experiment a mixed liquid meal or solutions of individual nutrients were perfused intraduodenally for 180 min at 2 ml/min. The mixed meal contained 4.3 g glucose, 2.0 g fractionated soya oil, and 1.7 g casein hydrolysate per 100 ml, which delivered a caloric load of 0.9 kcal/min into the duodenum. The isocaloric and isotonic solutions of individual nutrients contained 44.5 g glucose, 17.8 g fractionated soya oil, or 44.5 g hydrolysed serum bovine albumin per liter and delivered 0.36 kcal/min into the duodenum. Duodenal aspirates and blood samples were collected at regular intervals for determination of pancreatic enzyme outputs and plasma levels of cholecystokinin and neurotensin, respectively. The mixed meal converted the cyclical interdigestive secretory pattern into the noncyclical fed pattern whereas none of the three individual nutrients abolished the interdigestive pattern. Not only the mixed meal but also lipid and protein perfusion consistently stimulated cholecystokinin release. Integrated incremental cholecystokinin release amounted to 32.3±9.9 pg/ml × 180 min with the mixed meal, 23.2±6.5 with lipid perfusion (P〈 0.05 versus mixed meal) and 13.4±3.8 with protein perfusion (P〈0.05 versus mixed meal). The carbohydrate solution did not significantly release cholecystokinin. None of the duodenal perfusates raised neurotensin plasma levels. We conclude that (a) intraduodenal delivery of a mixed meal at 0.9 kcal/min converts the interdigestive pattern of pancreatic secretion, (b) cholecystokinin but not neurotensin is involved in converting this pattern in response to low-caloric meals, and (c) a threshold amount of CCK release must be exceeded to convert the secretory pattern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180436
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  • 2
    Electronic Resource
    Electronic Resource
    Caerulein-induced acute pancreatitis in rats: changes in glycoprotein-composition of subcellular membrane systems in acinar cells (1990)
    Springer
    Histochemistry and cell biology 95 (1990), S. 87-96 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Caerulein-induced acute pancreatitis is characterized by the occurrence of two membrane-bound vacuolar systems in acinar cells. Beside digestive enzymes containing secretory vacuoles, lysosomal autophagic structures can be identified at the ultrastructural level. In the present study glycoconjugate patterns of the surrounding membranes were characterized by ultrastructural lectin-binding experiments using five colloidal-gold labeled lectins with distinct sugar specificities. Furthermore, the profile of membrane glycoproteins of isolated vacuolar fractions was studied by SDS-PAGE and lectin-blotting. In pancreatitis, membranes of secretory vacuoles showed a significant lower degree of lectin-binding compared to normal zymogen granules. In contrast, newly appearing autophagic vacuoles in pancreatitis revealed a strong membrane labelling for most lectins used. The pattern of membrane glycoproteins of secretory and autophagic vacuoles as determined by SDS-PAGE and lectin-blotting differed from those of normal zymogen granules resembling the protein profile of smooth microsomes. Since this pattern requires a previous passage through Golgi stacks, it is assumed that the two types of vacuoles derive from Golgi elements. For the pathogenesis of caerulein pancreatitis these vacuolar post-Golgi structures seem to play an important role.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00737232
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  • 3
    Electronic Resource
    Electronic Resource
    Glycoconjugate pattern of membranes in the acinar cell of the rat pancreas (1990)
    Springer
    Histochemistry and cell biology 93 (1990), S. 319-326 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lectin-binding studies were performed at the ultrastructural level to characterize glycoconjugate patterns on membrane systems in pancreatic acinar cells of the rat. Five lectins reacting with different sugar moieties were applied to ultrathin frozen sections: concanavalin A (ConA): glucose, mannose; wheat-germ agglutinin (WGA): N-acetylglucosamine, sialic acid; Ricinus communis agglutinin I (RCA I): galactose; Ulex europaeus agglutinin I (UEA I): l-fucose; soybean agglutinin (SBA): N-acetylgalactosamine). Binding sites of lectins were visualized either by direct conjugation to colloidal gold or by the use of a three-step procedure involving additional immune reactions. The rough endoplasmic reticulum and the nuclear envelope of acinar cells was selectively labelled for ConA. The membranes of the Golgi apparatus bound all lectins applied with an increasing intensity proceeding from the cis-to the trans-Golgi area for SBA, UEA I and WGA. In contrast RCA I selectively labelled the trans-Golgi cisternae. The membranes of condensing vacuoles and zymogen granules were labelled for all lectins used although the density of the label differed between the lectins. In contrast the content of zymogen granules failed to bind SBA and WGA. Lysosomal bodies (membranes and content) revealed binding sites for all lectins used. The plasma membranes were heavily labelled by all lectins except for SBA which showed only a weak binding to the lateral and the apical plasma membrane. These results are in accordance to current biochemical knowledge of the successive steps in the glycosylation of membrane proteins. It could be demonstrated, that the cryo-section technique is suitable for the fine structural localisation of surface glycoconjugates of plasma membranes and internal membranes in pancreatic acinar cells using plant lectins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00266395
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  • 4
    Electronic Resource
    Electronic Resource
    Localization of lysosomal and digestive enzymes in cytoplasmic vacuoles in caerulein-pancreatitis (1990)
    Springer
    Histochemistry and cell biology 94 (1990), S. 161-170 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intracellular localization and enzymatic activities of lysosomal enzymes (cathepsin B,N-acetyl-β-glucosaminidase, and β-glucuronidase) were studied in control rats and after induction of caerulein pancreatitis. In control rats high enzymatic activities were found in the postnuclear 1000g fraction (purified zymogen granules). The corresponding subcellular fraction in pancreatitis animals additionally contained larger secretory vacuoles and autophagosomes and revealed a marked increase in lysosomal enzyme activities. Immunolabelling studies at the ultrastructural level for trypsinogen and cathepsin B demonstrated a colocalization of lysosomal and digestive enzymes in zymogen granules in healthy controls. After induction of pancreatitis immunolabelling still demonstrated a colocalisation of cathepsin B and trypsinogen in secretory granules and newly formed Golgi-derived secretory vacuoles. Concomitantly appearing autophagosomes were, however, only labelled for cathepsin B. It is concluded that segregation of lysosomal and digestive enzymes is incomplete in normal acinar cells resulting in a colocalization in zymogen granules. In pancreatitis colocalization in secretory granules is maintained, whereas only lysosomal enzymes were sufficiently transferred into autophagic vacuoles. No indication for impaired mechanisms of molecular sorting of lysosomal and digestive enzymes in caerulein-induced pancreatitis was found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02440183
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  • 5
    Electronic Resource
    Electronic Resource
    A frontal cortical potential associated with saccades in humans (1992)
    Springer
    Experimental brain research 89 (1992), S. 441-446 
    Details
    ISSN: 1432-1106
    Keywords: EEG ; Saccadic potential ; Frontal eye fields ; Supplementary eye-Movement initiating activity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We describe a frontal EEG potential which begins 25–35 ms before intentional saccadic eye movement. It consists of a 15–20 μvolt monophasic positive waveform with peak during or just after movement, and returns to EEG baseline 150–200 ms after its onset. The waveform is largest at a midline position just anterior to FZ (10–20 system), is independent of visual input such as fixation guides, and is not related to saccade direction or amplitude. The potential is difficult to observe in some subjects and is independent of the “pre-saccadic spike potential”. It may be related to the discharge of single cortical neurons that signal the initiation of saccadic movements, but not their exact metrics; a possible generator is the supplementary eye fields of the dorsomedial prefrontal cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228260
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  • 6
    Electronic Resource
    Electronic Resource
    Henoch-Schönlein purpura with ileitis terminalis (1993)
    Springer
    Journal of molecular medicine 71 (1993), S. 564-567 
    Details
    ISSN: 1432-1440
    Keywords: Henoch-Schonlein purpura ; Ileitis terminalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Gastrointestinal manifestations of Henoch-Schönlein purpura commonly include abdominal pain and gastrointestinal bleeding as well as extraintestinal signs and symptoms. We report here on a 24-year-old man with gastrointestinal pain in whom the classical features of Henoch-Schönlein purpura appeared only 6 days after acute abdominal symptoms. At endoscopic investigation inflammation with aphthous lesions was detected at the terminal ileum, which is a common feature of Crohn's disease. The observation that vasculitic disorders such as Henoch-Schonlein purpura can present with inflammatory lesions at the terminal ileum which are indistinguishable from those of Crohn's disease underlines the potential vasculitic basis of the latter condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00208482
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  • 7
    Electronic Resource
    Electronic Resource
    Endemism in birds of tropical Pacific islands (1992)
    Springer
    Evolutionary ecology 6 (1992), S. 296-306 
    Details
    ISSN: 1573-8477
    Keywords: Archipelagos ; birds ; endemic species ; Pacific Ocean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary I analysed avifaunal data from 30 archipelagos and isolated islands in the tropical Pacific Ocean to examine the effects of geography on endemism. I divided the total bird species list (pelagic and migrant species excluded) for each island group into continental (also found outside of the study area), Pacific (found only within the study area but within more than one archipelago), and endemic (found only within a single archipelago) species and estimated ten variables related to the geography of each archipelago. I used multiple linear regression analysis to relate numbers and proportions of species in each category to the geographical variables. Total land area of an archipelago was the most improtant variable in explaining variation in the number of species in each category, with elevation and isolation also being important. The relationships between the proportions of species in each category and the geographical variables underscore the importance of isolation and the number of large islands in promoting endemism, presumably by allowing both inter- and intra-archipelagal speciation to proceed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02270966
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  • 8
    Electronic Resource
    Electronic Resource
    Stimulation of pancreatic secretory process in the rat by low-molecular weight proteinase inhibitor (1990)
    Springer
    Cell & tissue research 262 (1990), S. 143-148 
    Details
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Proteinase inhibitor-DNA synthesis ; Mitotic activity ; Rat(Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies with rats have shown that a single oral dose of the proteinase inhibitor Camostate (FOY-305) induces release of cholecystokinin (CCK) into the circulation, which lasts for 3 to 6h. This transient endogenous release of hormone results in a depletion of pancreatic enzyme stores within 1 h and an increase in total rate of protein synthesis, which peaks at 6 to 9 h. At the level of individual enzyme biosynthesis a transient decrease in amylase and an increase in trypsinogen and chymotrypsinogen is observed. In the present study the time course of DNA synthesis and the labeling index of 5 populations of pancreatic cells have been analysed following a single oral dose of 50 or 100 mg/kg proteinase inhibitor, using in vivo labeling with 12 μCi/g body weight 3H-thymidine 1 h prior to sacrifice of the animals. DNA synthesis did not change during the initial 12 h following inhibitor feeding and then showed a phasic increase with a peak (20-fold) at 24h and intermediate increases (4- to 5-fold) at 18 and 36 h, respectively. From the 5 pancreatic cell populations studied by autoradiography the labeling indices of interlobular duct cells and islet cells did not change over the entire observation period. Acinar cells, intralobular duct cells and interstitial cells showed a marked increase in labeling index with peak values at 24h, which were 20-fold in acinar cells and 5.5- and 8.5-fold in intralobular duct cells and interstitial cells, respectively. The data demonstrate a significant growth response of pancreatic acinar tissue after a single episode of endogenous CCK-release, which is similar in extent, time course and cellular source as previously demonstrated during persistent stimulation of the pancreas by prolonged infusion of the CCK-analogue caerulein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327755
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