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  • 1
    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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  • 2
    Electronic Resource
    Electronic Resource
    Immunohistochemical demonstration of villin in the normal human pancreas and in chronic pancreatitis (1991)
    Springer
    Histochemistry and cell biology 95 (1991), S. 383-390 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Human pancreatic tissue was investigated by immunohistochemistry using a polyclonal antibody against the actin binding protein villin, which participates in the formation of actin filament bundles in the microvilli. In cells of the different parts of the pancreatic duct system as well as in the acinar cells villin immunoreactivity was located mainly at the apical cell surface. This was confirmed by the ultrastructural demonstration of microvilli on the surface of duct and acinar cells, which exhibited the typical actin bundles. In chronic pancreatitis the staining for villin in duct-like structures of degenerative pancreatic tissue was irregular or even absent. This correlated with the electron microscopic observation of duct-like structures known as tubular complexes composed of cells devoid of microvilli at the apical cell surface. At the light microscopical level degenerative structures without lumen and of unknown origin showed a strong staining for villin at their basal cell surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00266966
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  • 3
    Electronic Resource
    Electronic Resource
    Licht- und elektronenmikroskopische Untersuchung der Langerhansschen Inseln von Nutria (Myocastor coypus), mit besonderer Berücksichtigung der neuroinsulären Komplexe (1971)
    Springer
    Cell & tissue research 113 (1971), S. 216-229 
    Details
    ISSN: 1432-0878
    Keywords: Islet of Langerhans ; Nutria ; Islet innervation ; Neuro-insular complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Inselorgan von Nutria (Myocastor coypus), einem wasserlebenden, pflanzenfressenden Säuger, wurde bei neugeborenen und erwachsenen Tieren licht- und elektronenmikroskopisch untersucht. 1. Bei neugeborenen Nutria ist das Inselorgan noch nicht voll ausdifferenziert, alle Stadien der Embryonalentwicklung werden angetroffen. Lichtmikroskopisch sind die Inselzellen nur spärlich granuliert; elektronenmikroskopisch gelingt der Nachweis von 2 Zelltypen nicht, da die Sekretgranula gleichartig aufgebaut sind. 2. Die Langerhansschen Inseln von erwachsenen Nutria bestehen aus gewundenen, zweizeiligen Bändern von B-Zellen, die A-Zellen liegen in der Einzahl dazwischen eingestreut. Die A∶B-Relation beträgt 1∶9. Im Feinbau ihrer Zellorganellen und Sekretgranula stimmen die Inselzellen von Nutria weitgehend mit denen des Meerschweinchens überein. 3. Die Inseln von neugeborenen und erwachsenen Tieren enthalten zahlreiche Nervenfasern und zugehörige Schwannsche Zellen, die in der Nachbarschaft der Kapillaren liegen und häufig von deren Basalmembran umhüllt sind. 4. Eine Sonderform der Zusammenlagerung von Nervengewebe und Inselgewebe stellen die neuro-insulären Komplexe, bei denen vegetative Ganglienzellen und Inselzellen in einem gemeinsamen Zellverband vereinigt sind. Die Ganglienzellen treten durch Synapsen untereinander in Verbindung, sie grenzen außerdem mit ihren Ausläufern ohne Zwischenschaltung von Bindegewebe an die Inselzellen. In dieser Grenzzone werden ebenfalls synaptische Endigungen an den Inselzellen beobachtet.
    Notes: Summary The Langerhans islet organ of Nutria has been studied in the light and electron microscopes. 1. In the pancreas of new born Nutria all stages of embryonic differentiation of the islets are still encountered. The islet cells are only scarcely granulated, and ultrastructural differentiation of two types of islet cells according to the size or density of secretory granules is not yet possible. 2. The islets in adult Nutria consist of tortuous bands of B cells with A cells scattered singly among the bands. The A∶B cell number ratio is 1∶9. The fine structural appearances of the secretory granules in A and B islet cells in Nutria correspond respectively to those of A and B islet cells in the guinea pig. 3. The islets of new born and adult Nutria contain numerous nerve fibers and associated Schwann cells, which presumably are located along the islet capillaries. Synaptic contact of nerve fibers with both types of islet cells has been encountered. 4. The close association of nerve cells with islet cells and the fine structural appearance of both elements in the neuro-insular complexes is described. Different ganglionic cells are joined by axo-somatic and axo-dendritic synapses. The incidence of synaptic contacts between nerve cells and islet cells is not greater in the neuro-insular complexes than in the islets of Langerhans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339417
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  • 4
    Electronic Resource
    Electronic Resource
    Fine structural distribution of microtubules in pancreatic B cells of the rat (1975)
    Springer
    Cell & tissue research 164 (1975), S. 261-269 
    Details
    ISSN: 1432-0878
    Keywords: Pancreatic B cell ; Microtubules ; Secretory Process ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of microtubules has been studied in pancreatic B cells of normal rats and in animals infused with glucose for various periods of time. An array of microtubules extends from the outer nuclear membrane to the plasma membrane coursing in all directions of the cytoplasmic space. Microtubules are found between profiles of the endoplasmic reticulum, cisternae of the Golgi complex and in close proximity to mitochondria and secretion granules. Insertion of microtubules in the plasma membrane is best studied in tangential sections through the plane of the membrane, the fixation of microtubules might involve microfilaments and desmosomes. The possible role of microtubules in the different phases of the secretory process is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218978
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  • 5
    Electronic Resource
    Electronic Resource
    In-vivo stimulation of rat pancreatic acinar cells by infusion of secretin (1985)
    Springer
    Cell & tissue research 242 (1985), S. 633-639 
    Details
    ISSN: 1432-0878
    Keywords: Secretin ; Pancreas ; Enzyme secretion ; Protein synthesis ; Fine structure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Infusion of synthetic secretin in conscious unrestricted rats for periods up to 24 h was used to study the structural and functional adaptation of pancreatic acinar cells to this secretagogue. Initial dose-response studies established 16 clinical units (CU) per kg and h (corresponding to 4.64 ug x kg-1 x h-1) as optimal dose for persistent stimulation of enzyme discharge. Infusion of this dose led to a slow but progressive depletion of enzyme stores with minimal content by 12 h stimulation. As a result of persistent stimulation total protein synthesis in the acinar cells increased after a lag period of 3 h and reached maximal values 90% above controls by 6 and 12 h secretin infusion. No structural equivalent for pronounced fluid and bicarbonate secretion was observed for either acinar or duct cells over the entire dose range (1 to 64 CU x kg-1 x h-1) and infusion period (1–24 h), except an increased number of coated vesicles in duct cells. Discharge of enzymes from acinar cells was paralleled by a high frequency of exocytotic images at the luminal plasma membrane and was accompanied by the occurrence of membrane fragments in the luminal space, especially after 3 and 6 h secretin infusion. An increased number of lysosomal bodies at these time points especially in the vicinity of the Golgi complex was interpreted in relation to membrane recycling following massive exocytosis. This pattern of structural and functional adaptation of acinar cells following secretin infusion corresponds to previously described changes following caerulein and carbamylcholine stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225430
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  • 6
    Electronic Resource
    Electronic Resource
    In-vivo stimulation of rat pancreatic acinar cells by infusion of secretin (1985)
    Springer
    Cell & tissue research 242 (1985), S. 641-644 
    Details
    ISSN: 1432-0878
    Keywords: Secretin ; Pancreas ; Protein synthesis ; Enzyme synthesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intravenous infusion of synthetic secretin for periods up to 24 h in conscious rats was combined with invitro amino acid incorporation in isolated pancreatic lobules and high-resolution separation of individual enzyme proteins by two-dimensional isoelectric focusing and SDS gel electrophoresis. With this method persistent changes in the biosynthesis of ten enzyme and isoenzyme proteins can be studied as a result of prolonged secretin stimulation. Three major patterns of response were observed: progressive increases in the synthetic rates were found in six out of ten enzyme proteins with most pronounced changes in the synthetic rates of lipase (4.10-fold increase), two forms of proelastase (2.80-fold increase, respectively), the two acidic forms of trypsinogen and chymotrypsinogen (2.60-and 2.40-fold increase, respectively), and of ribonuclease (2.30-fold increase). Only moderate changes (1.30- to 1.90-fold increase) occured in the synthetic rates of four isoenzymatic forms of procarboxypeptidase and the basic forms of chymotrypsinogen and trypsinogen, respectively. No absolute change in the rate of synthesis was observed in both forms of amylase. These data obtained after secretin stimulation differ significantly from previous results after caerulein stimulation, but it is not clear so far whether this is due to differential effects of the two second messengers released by each of the hormones on the level of transcription or translation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225431
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  • 7
    Electronic Resource
    Electronic Resource
    Growth of rat pancreatic acinar cells quantitated with a monoclonal antibody against the proliferating cell nuclear antigen (1994)
    Springer
    Cell & tissue research 276 (1994), S. 603-609 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas, exocrine ; Acinar cells ; Proliferation ; Proliferating cell nuclear antigen (PCNA) ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The monoclonal antibody PC10 raised against the proliferating cell nuclear antigen (PCNA) was used to study acinar cell replication in the pancreas of rats under different functional conditions. In Western blots, the antibody recognized a single band of 37 kDa in pancreatic homogenates indicating its specificity in this particular species and organ. Three conditions of growth were chosen for immunohistochemical analysis: pancreatic preand postnatal development, pancreatic regeneration after injury, and cholecystokinin-stimulated acinar cell proliferation. The time course of acinar cell replication under each condition was the same as that obtained after tritiated thymidine incorporation with subsequent autoradiography, indicating that the percentage of PCNA-positive cells reflects the pool of cycling cells in the models investigated. However, the absolute number of PCNA-positive cells was two to ten times higher than comparable labeling indices from 3H-thymidine autoradiography. This finding might reflect the half life of PCNA, which exceeds the duration of the S-phase. Thus, PCNA-positive cells not only represent S-phase cells, but also cells that have recently completed the cell cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343959
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  • 8
    Electronic Resource
    Electronic Resource
    Stimulation of pancreatic secretory process in the rat by low-molecular weight proteinase inhibitor (1987)
    Springer
    Cell & tissue research 247 (1987), S. 187-193 
    Details
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Proteinase inhibitor ; Feedback regulation ; Cholecystokinin ; Fine structure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Application of a single dose of a new type of proteinase inhibitor camostate (FOY-305) via orogastric tube was used in rats to study the dose-response relationship of resulting pancreatic stimulation. Doses up to 10 mg/ kg failed to elicit any response, while significant decrease in enzyme content and increase in serum CCK-levels were observed with doses ranging from 25 to 400 mg/kg. A single dose of 100 mg/kg was selected for a time-sequence analysis, which revealed a 60 to 70% depletion of enzyme stores persisting over 6 h and reverting to control levels by 12 h. Peak increases in serum CCK-levels (15-fold above the elevation observed after regular food intake) were found after 30 min and persisted as an 8-to 10-fold elevation for at least 3 h, then declined to control levels by 9 h. This prolonged endogenous hormone release and resulting pancreatic stimulation were also verified in a separate group of animals in which volume, protein, and enzyme output were measured after cannulation of the pancreatic duct. While volume secretion was not altered by feeding a single dose of 100 mg/kg FOY-305, protein and enzyme output increased 2-to 3-fold over a period of 7 h. Fine-structural analysis of the pancreas demonstrated efficient depletion of zymogen granules from acinar cells with all doses between 50 and 400 mg/kg, accompanied by the appearance of membrane material in the acinar lumina at 3 and 6 h. The same transient increase in the number of lysosomal bodies predominantly containing mitochondria with all doses above 50 mg/kg was interpreted as increased organelle turnover due to persisting hormonal stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216561
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  • 9
    Electronic Resource
    Electronic Resource
    Time course and cellular site of mitotic activity in the exocrine pancreas of the rat during sustained hormone stimulation (1987)
    Springer
    Cell & tissue research 247 (1987), S. 385-391 
    Details
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Caerulein ; DNA synthesis ; Mitotic activity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies from our laboratory indicate that the adaptive response of the exocrine pancreas of the rat to prolonged stimulation with optimal doses of caerulein (0.25 μg × kg-1 × h-1) follows a characteristic time course in which each step in the secretory pathway is activated. The immediate response is the depletion of zymogen-granule stores followed by coordinate and anticoordinate changes in individual rates of (pro-)enzyme synthesis after a lag period of 2 h. The sum of such changes leads to an increase in total rate of protein synthesis by 3 h which is combined with acceleration of intracellular transport packaging and granule discharge. In the present study the time course of DNA synthesis and the labeling index of five populations of pancreatic cells have been analyzed after caerulein stimulation for periods ranging from 6 to 72 h, using in vivo labeling with 1 μCi/g 3H-thymidine 1 h prior to sacrifice of the animals. DNA synthesis did not change during the initial 18 h in spite of persistent stimulation indicated by a 80% reduction of enzyme content. Following this lag period a sharp rise in DNA synthesis 20- to 25-fold above control levels was observed, which decreased by 48 h to reach control levels by 72 h. Increase in DNA synthesis was most pronounced in animals with lowest enzyme content in the pancreas. From the five cell populations studied by autoradiography interlobular duct cells and islet cells had no significant increase in labeling index at any time of stimulation. Acinar cells, intralobular duct cells and interstitial cells showed a marked increase in labeling index after a latent period of 18 h with peak values at 36 h 30 to 50 times higher in intralobular duct and acinar cells, respectively, and 4 times higher in interstitial cells. The increased labeling indices in all three cell populations reverted to lower values at 48 h and reached control values by 72 h. The data indicate a phasic and limited growth response of the rat exocrine pancreas to persistent stimulation with acinar cells as the major contributing cell population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218320
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  • 10
    Electronic Resource
    Electronic Resource
    Stimulation of pancreatic secretory process in the rat by low-molecular weight proteinase inhibitor (1987)
    Springer
    Cell & tissue research 249 (1987), S. 63-67 
    Details
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Proteinase inhibitor ; Cholecystokinin ; Protein synthesis ; Enzyme synthesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Oral application of a single dose of a new synthetic proteinase inhibitor Camostate (Foy-305) in male Wistar rats was carried out together with studies of in vitro amino acid incorporation followed by separation of proteins by two-dimensional gel electrophoresis. The aim of this experiment was to analyze changes produced by the inhibitor in total protein and individual enzyme biosynthesis. Administration of 100 mg/kg Foy-305 resulted in significant inhibition of total pancreatic protein synthesis, without changes in fractional rates for individual enzymes. 50 mg/kg Foy-305 induced a 10-fold elevation of cholecystokinin (CCK) levels in serum; this persisted for 3 h and led to a significant increase in the total rate of protein synthesis with peak values at 6 and 9 h (78% and 84% above control levels, respectively), returning to control by 15h. Changes in fractional rates of synthesis occurred with a latency of 6 h and were restricted to amylase and the anionic form of trypsinogen and chymotrypsinogen. Amylase biosynthesis decreased by about 40% from control levels at 9 h to return to control levels by 15 h. Increased synthesis of trypsinogen and chymotrypsinogen was observed; this was also phasic. The results show similar enzyme-specific regulation as previously described for exogenous CCK stimulation and for the adaptation of the pancreas to diets enriched in protein. They demonstrate the effectiveness of pulsatory endogenous hormone release in the regulation of protein synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215419
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