scholarly journals A quantitative immuno-electronmicroscopic study of amylase and chymotrypsinogen in peri- and tele-insular cells of the rat exocrine pancreas.

1986 ◽  
Vol 34 (2) ◽  
pp. 203-207 ◽  
Author(s):  
G Posthuma ◽  
J W Slot ◽  
H J Geuze
Keyword(s):  
Protein A ◽  
Density Ratio ◽  
Zymogen Granules ◽  
Experimental Conditions ◽  
Pancreatic Cells ◽  
Rat Exocrine Pancreas ◽  
Biochemical Measurements ◽  
Ultrathin Cryosections ◽  
Density Ratios ◽  
Induced Changes

Malaisse-Lagae demonstrated in 1975 that peri-insular (PI) cells and tele-insular (TI) cells produce amylase (Am) and chymotrypsinogen (Ch) in a different ratio. These biochemical measurements are in contradiction with recent observations of Bendayan (1985), who found that the Am/Ch ratio measured with the protein A-gold technique applied to ultrathin Epon sections was the same in PI and TI cells. We have previously shown (Posthuma et al., 1984) that experimentally induced changes in Am and Ch content of rat pancreas are quantitatively reflected by immuno-gold labeling of zymogen granules in cryosections. Here we applied the same technique to compare the Am/Ch labeling density ratios in PI and TI pancreatic cells. To ascertain constancy of experimental conditions, we used ultrathin cryosections from tissue blocks consisting of TI and PI tissue elements. Consecutive sections of these blocks were alternatively immunolabeled for Am and Ch, using protein A-gold as marker. The density of gold particles over zymogen granules of both PI and TI cells was measured. It appeared that the Am/Ch labeling density ratio was significantly lower in PI than in TI cells. This difference resulted from a lower Am labeling as well as higher Ch labeling density over zymogen granules in PI cells.

scholarly journals Quantitative immunocytochemical localization of pancreatic secretory proteins in subcellular compartments of the rat acinar cell.

1980 ◽  
Vol 28 (2) ◽  
pp. 149-160 ◽  
Author(s):  
M Bendayan ◽  
J Roth ◽  
A Perrelet ◽  
L Orci
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Protein A ◽  
Secretory Proteins ◽  
Zymogen Granules ◽  
Thin Sections ◽  
Intracellular Compartments ◽  
Rat Exocrine Pancreas ◽  
Acinar Lumen ◽  
Cellular Compartments

The recently developed protein A-gold technique for the detection of intracellular antigenic sites on thin sections was utilized to localize nine different secretory proteins in the rat exocrine pancreas. Amylase, chymotrypsinogen, trypsinogen, lipase, elastase, carboxypeptidases A and B, RNase and DNase, were detected at the level of the rough endoplasmic reticulum, the Golgi area, and the zymogen granules of the acinar cells, as well as in the acinar lumen. A quantitative evaluation of the labeling showed that its intensity was not identical for all enzymes studied nor in all cellular compartments analyzed. An increasing gradient of the labeling from the rough endoplasmic reticulum to the Golgi and to the zymogen granules was found for amylase, carboxypeptidases A and B, chymotrypsinogen, trypsinogen, and RNase, while a comparable low degree of labeling in the Golgi apparatus and in the zymogen granules was observed for DNase, lipase, and elastase. These results suggest that the nine enzymes are processed through the same intracellular compartments, but that they may be concentrated to different degrees in the zymogen granules before being released in the acinar lumen.

scholarly journals Immunocytochemical localization of kallikrein in the rat exocrine pancreas.

1982 ◽  
Vol 30 (1) ◽  
pp. 58-66 ◽  
Author(s):  
M Bendayan ◽  
T B Orstavik
Keyword(s):  
Secretory Pathway ◽  
Protein A ◽  
Pancreatic Tissue ◽  
Pancreatic Acinar Cells ◽  
Zymogen Granules ◽  
Rat Exocrine Pancreas ◽  
Pancreatic Exocrine ◽  
Embedding Medium ◽  
Lowicryl K4m ◽  
Acinar Lumen

The subcellular localization of kallikrein was studied in the rat pancreas using the immunocytochemical protein A-gold technique. Kallikrein was found at the level of the rough endoplasmic reticulum (RER), Golgi cisternae, condensing vacuoles, and zymogen granules of the pancreatic acinar cells as well as in the acinar lumen. The effect of various tissue processings on the immunocytochemical labeling of kallikrein was evaluated using pancreatic tissue fixed in glutaraldehyde and embedded in Epon, Lowicryl K4M, or glycol methacrylate (GMA). Compared to the results obtained with Epon, Lowicryl allowed improved resolution and specificity in the immunocytochemical labeling, while GMA retained greater amounts of kallikrein antigenicity leading to a higher intensity in the labeling; since it also gave a good ultrastructural preservation, GMA appeared to be the superior embedding medium for the localization of kallikrein. The quantitative evaluation of the labeling obtained under the three embedding conditions showed the presence of an increasing concentration gradient along the RER-Golgi-granule secretory pathway, suggesting that, like other pancreatic exocrine enzymes, kallikrein is synthesized in the RER, processed through the Golgi apparatus, and packed in the zymogen granules before being released into the acinar lumen.

Differences in the Interactions of Lupus Anticoagulant IgG with Human Prothrombin and Bovine Prothrombin

1995 ◽  
Vol 73 (04) ◽  
pp. 668-674 ◽  
Author(s):  
L Vijaya Mohan Rao ◽  
An D Hoang ◽  
Samuel I Rapaport
Keyword(s):  
Western Blot ◽  
Lupus Anticoagulant ◽  
Protein A ◽  
Phospholipid Complex ◽  
Experimental Conditions ◽  
Bovine Plasma ◽  
Activation System ◽  
Rate Limiting ◽  
Substantial Extent ◽  
Prothrombin Activation

SummaryLupus anticoagulant (LA) IgGs have been reported to inhibit more effectively and consistently the Xa/Va/phospholipid complex-catalyzed activation of human prothrombin than the Xa/Va/phospholipid complex-catalyzed activation of bovine prothrombin. This led us to carry out studies to determine whether the ability to inhibit the activation of prothrombin of LA IgGs, separated from the plasma of 15 patients by protein A affinity chromatography, could be related to the ability of the LA IgGs to bind to prothrombin under various experimental conditions. Of 14 LA IgG preparations tested all prolonged to a variable but substantial extent the dilute Russell’s viper venom time (dRVVT) of human plasma but only minimally prolonged the dRVVT of bovine plasma. In a purified prothrombin activation system with a rate limiting concentration of phospholipid, all 15 LA IgG preparations inhibited the activation of human prothrombin with the majority showing >50% of inhibition. In contrast, only one LA IgG markedly inhibited (>50%) the activation of bovine prothrombin and five others moderately inhibited (25-40%) the activation of bovine prothrombin. Nevertheless, the majority of LA IgG preparations bound to immobilized bovine prothrombin on a Western blot and also to immobilized bovine prothrombin on a microtiter well. In an ELISA in which phosphatidylserine (PS) was immobilized on microtiter wells, bovine prothrombin supported the binding of 10 of 15 LA IgG preparations to PS. However, the extent of binding was lower than that observed with human prothrombin. In experiments with 125I-human prothrombin or 125I-bovine prothrombin in a solution containing Ca2+, the addition of PS/PC vesicles enhanced the binding of both human and bovine prothrombin to some LA IgG preparations. The enhanced binding was particularly evident for bovine prothrombin. Although seemingly related for some preparations, the ability of a LA IgG to bind to bovine prothrombin, either in the presence or absence of PS, and the ability of that LA IgG to inhibit the activation of bovine prothrombin was not consistently related for all preparations.

Secretagogue-induced changes in subcellular Ca2+ distribution in isolated pancreatic acini

1981 ◽  
Vol 240 (2) ◽  
pp. G130-G140
Author(s):  
R. L. Dormer ◽  
J. A. Williams
Keyword(s):  
Atomic Absorption Spectrometry ◽  
High Speed ◽  
Microsomal Fraction ◽  
Absorption Spectrometry ◽  
Subcellular Fractionation ◽  
Differential Centrifugation ◽  
Zymogen Granules ◽  
Pancreatic Acini ◽  
Induced Changes ◽  
Stimulation Of

In a prior study, we demonstrated that pancreatic secretagogues increased both the uptake into and washout of 45Ca2+ from isolated mouse pancreatic acini. The net result of these processes was an initial fall in total acinar cell Ca2+ content. In the present study, we have employed subcellular fractionation of acini under conditions that minimized posthomogenization redistribution of Ca2+ in order to localize those organelles involved in intracellular Ca2+ fluxes. Homogenization and differential centrifugation of acini, preloaded with 45Ca2+ and subjected to a period of washout, showed that carbachol induced an increased loss of 45Ca2+ from all fractions isolated. The high-speed microsomal fraction lost 45Ca2+ to a greater extent than did whole acini; measurement of total Ca2+ by atomic absorption spectrometry showed a net loss of Ca2+ from this fraction. Purification of the lower-speed fractions indicated that carbachol increased 45Ca2+ exchange with both zymogen granules and mitochondria, but net Ca2+ levels in these organelles were unchanged. It was concluded that stimulation of pancreatic acini by carbachol results in the release of calcium from a microsomal compartment leading to a rise in cytoplasmic Ca2+, increased exchange with granule and mitochondrial Ca2+, and increased efflux of Ca2+ from the cell.

scholarly journals Localization of protein disulfide isomerase on plasma membranes of rat exocrine pancreatic cells.

1988 ◽  
Vol 36 (8) ◽  
pp. 1069-1074 ◽  
Author(s):  
S Akagi ◽  
A Yamamoto ◽  
T Yoshimori ◽  
R Masaki ◽  
R Ogawa ◽  
...  
Keyword(s):  
Protein Disulfide Isomerase ◽  
Plasma Membranes ◽  
Secretory Granules ◽  
Amorphous Material ◽  
Protein A ◽  
Disulfide Isomerase ◽  
Gold Particles ◽  
Pancreatic Cells ◽  
Acinar Lumen ◽  
Protein Disulfide

We investigated immunocytochemically the ultrastructural localization of protein disulfide isomerase (PDI) in rat pancreatic exocrine cells by use of the post-embedding protein A-gold technique. We found that not only the endoplasmic reticulum (ER) and nuclear envelope but also the trans-Golgi cisternae, secretory granules, and plasma membranes were heavily labeled with gold particles. Labeling density of the gold particles in the rough ER and plasma membranes of the exocrine pancreatic cells was twofold and twentyfold greater, respectively, than that of hepatocytes. In the acinar lumen, amorphous material presumably corresponding to the secreted zymogens was also labeled with gold particles. These results suggest that in rat exocrine pancreatic cells a significant amount of PDI is transported to the plasma membrane and secreted to the acinar lumen.

Equation of State’s Crossover Enhancement of Pseudopotential Lattice Boltzmann Modeling of CO2 Flow in Homogeneous Porous Media

Fluids ◽  
2021 ◽  
Vol 6 (12) ◽  
pp. 434
Author(s):  
Assetbek Ashirbekov ◽  
Bagdagul Kabdenova ◽  
Ernesto Monaco ◽  
Luis R. Rojas-Solórzano
Keyword(s):  
Porous Medium ◽  
Lattice Boltzmann ◽  
Multiphase Flows ◽  
Equations Of State ◽  
Density Ratio ◽  
Narrow Channel ◽  
Lattice Boltzmann Model ◽  
High Density Ratio ◽  
Homogeneous Porous Medium ◽  
Density Ratios

The original Shan-Chen’s pseudopotential Lattice Boltzmann Model (LBM) has continuously evolved during the past two decades. However, despite its capability to simulate multiphase flows, the model still faces challenges when applied to multicomponent-multiphase flows in complex geometries with a moderately high-density ratio. Furthermore, classical cubic equations of state usually incorporated into the model cannot accurately predict fluid thermodynamics in the near-critical region. This paper addresses these issues by incorporating a crossover Peng–Robinson equation of state into LBM and further improving the model to consider the density and the critical temperature differences between the CO2 and water during the injection of the CO2 in a water-saturated 2D homogeneous porous medium. The numerical model is first validated by analyzing the supercritical CO2 penetration into a single narrow channel initially filled with H2O, depicting the fundamental role of the driving pressure gradient to overcome the capillary resistance in near one and higher density ratios. Significant differences are observed by extending the model to the injection of CO2 into a 2D homogeneous porous medium when using a flat versus a curved inlet velocity profile.

A Numerical Study of Flow and Heat Transfer in Rotating Rectangular Channels AR=4 With 45 deg Rib Turbulators by Reynolds Stress Turbulence Model

2003 ◽  
Vol 125 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Mohammad Al-Qahtani ◽  
Hamn-Ching Chen ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Secondary Flow ◽  
Density Ratio ◽  
Convective Transport ◽  
High Density ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Rectangular Channels ◽  
Density Ratios

Computations were performed to study three-dimensional turbulent flow and heat transfer in stationary and rotating 45 deg ribbed rectangular channels for which experimental heat transfer data were available. The channel aspect ratio (AR) is 4:1, the rib height-to-hydraulic diameter ratio e/Dh is 0.078 and the rib-pitch-to-height ratio P/e is 10. The rotation number and inlet coolant-to-wall density ratios, Δρ/ρ, were varied from 0.0 to 0.28 and from 0.122 to 0.40, respectively, while the Reynolds number was fixed at 10,000. Also, two channel orientations (β=90deg and 135 deg from the rotation direction) were investigated with focus on the high rotation and high density ratios effects on the heat transfer characteristics of the 135 deg orientation. These results show that, for high rotation and high density ratio, the rotation induced secondary flow overpowered the rib induced secondary flow and thus change significantly the heat transfer characteristics compared to the low rotation low density ratio case. A multi-block Reynolds-Averaged Navier-Stokes (RANS) method was employed in conjunction with a near-wall second-moment turbulence closure. In the present method, the convective transport equations for momentum, energy, and turbulence quantities are solved in curvilinear, body-fitted coordinates using the finite-analytic method.

Film Cooling of the Gas Turbine Endwall by Discrete-Hole Injection

1996 ◽  
Vol 118 (2) ◽  
pp. 278-284 ◽  
Author(s):  
M. Y. Jabbari ◽  
K. C. Marston ◽  
E. R. G. Eckert ◽  
R. J. Goldstein
Keyword(s):  
Film Cooling ◽  
Density Ratio ◽  
Reynolds Numbers ◽  
Hole Injection ◽  
Qualitative Information ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Density Ratios

Film cooling performance for injection through discrete holes in the endwall of a turbine blade is investigated. The effectiveness is measured at 60 locations in the region covered by injection. Three nominal blowing rates, two density ratios, and two approaching flow Reynolds numbers are examined. Analysis of the data reveals that even 60 locations are insufficient for the determination of the field of film cooling effectiveness with its strong local variations. Visualization of the traces of the coolant jets on the endwall surface, using ammonium-diazo-paper, provides useful qualitative information for the interpretation of the measurements, revealing the paths and interaction of the jets, which change with blowing rate and density ratio.

scholarly journals Immunocytochemical assays of amylase and chymotrypsinogen in rat pancreas secretory granules. Efficacy of using immunogold-labeled ultrathin cryosections to estimate relative protein concentrations.

1984 ◽  
Vol 32 (10) ◽  
pp. 1028-1034 ◽  
Author(s):  
G Posthuma ◽  
J W Slot ◽  
H J Geuze
Keyword(s):  
Secretory Granules ◽  
Relative Concentration ◽  
Data Sets ◽  
Zymogen Granule ◽  
Protein Levels ◽  
Pancreatic Cells ◽  
Intracellular Proteins ◽  
Ultrathin Cryosections ◽  
Respective Protein ◽  
Normal Laboratory

An exploration was conducted as to whether the relative concentration of two intracellular proteins could be evaluated quantitatively from their labeling densities in ultrathin cryosections labeled with the immunogold technique. As a model rat pancreatic cells were used in which the content of amylase (Am) and chymotrypsinogen (Ch) was experimentally altered. Rats were fed either normal laboratory chow or food containing soybean trypsin inhibitor (STI), which affects the Am/Ch ratio in the tissues. The changes in Am and Ch protein levels and enzyme activities were measured biochemically in cell suspension homogenates or in zymogen granule fractions. Within 5 days a maximal change in the Am/Ch was observed as a result of adaptation to the STI diet. The Am/Ch ratio determined biochemically was compared with that from counts of gold particles bound to the respective protein in immunogold-labeled cryosections. The two data sets matched fairly well, indicating that the intensity of the immunoreaction is a reliable reflection of antigen concentration in this system.

Tropomyosin-Troponin-Induced Changes in the Partitioning of Free Energy Release of Actomyosin-Catalyzed ATP Hydrolysis as Measured by ATP-Phosphate Exchange

1980 ◽  
Vol 35 (5-6) ◽  
pp. 431-438 ◽  
Author(s):  
Peter Dancker
Keyword(s):  
Free Energy ◽  
Atpase Activity ◽  
Energy Release ◽  
Atp Hydrolysis ◽  
Free Energy Change ◽  
Energy Change ◽  
Experimental Conditions ◽  
Mean Values ◽  
Induced Changes ◽  
Phosphate Exchange

Abstract ATPase activity and ATP-Pi exchange of unregulated (without tropomyosin-troponin) and regulated (with tropomyosin-troponin) acto-HMM were measured in media containing 0.2 mg/ml actin, HMM, and (when present) tropomyosin-troponin, 2 mM MgCl2, 10 m M KCl, 2 mM NaN3, 10 mM Pi(pH 7.0), 3 mM ATP. The following mean values for ATPase activity and for the rate of incorporation of P, into ATP (each per mg HMM and per min) were obtained: unregulated acto-HMM 0.33 nmol Pi and 0.33 nmol Pi, regulated acto-HMM 0.54 nmol Pi and 1.06 nmol P*. The ratio of P4 incorporation rate to ATPase activity was 1.01 × 10-3 for unregulated and 2.02 × 10-3 for regulated acto-HMM. From these ratios and from the overall free energy change of ATP hydrolysis it was calculated that under the prevailing experimental conditions in unregulated acto-HMM 62% and in regulated acto-HMM 66% of the free energy change of ATP hydrolysis occurs after the release of phosphate from actomyosin. It is probably this part of the free energy change that is used by the muscle for the performance of work.

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