Progressive Redistribution Research Articles

Ca2+-induced redistribution of Ca2+/calmodulin-dependent protein kinase II associated with an endoplasmic reticulum stress response in vascular smooth muscle.

The relation between CaM kinase II activity and high Ca2+-mediated stress responses was studied in cultured vascular smooth muscle cells. Treatment with ionomycin (1 microM) for 5 min caused a significant loss of CaM kinase II activity in whole cell homegenates and prominent vesiculation of the endoplasmic reticulum (ER). Similar losses of CaM kinase II activity were observed in the soluble lysate as assessed by activity measurements and Western blotting. Examination of the post-lysate particulate fraction showed that the loss of CaM kinase II from the soluble lysate was accompanied by a redistribution of CaM kinase II to this fraction. The ionomycin-mediated response was limited to this concentration (1 microM); lower concentrations of ionomycin as well as stimulation with angiotensin II (1 microM) orATP (100 microM) did not cause a shift in CaM kinase II distribution. Treatment with neither the CaM kinase II inhibitor KN-93 nor the phosphatase inhibitor okadaic acid altered the ionomycin-induced redistribution indicating that CaM kinase II activation and/or phosphorylation was not part of the mechanism. The response, however, was eliminated when the cells were treated in Ca2+-free medium. Washout of ionomycin led to only a partial restoration of the kinase activity in the soluble fraction after 10 min. Immunofluorescence microscopy of resting cells indicated colocalization of antibodies to CaM kinase II and an ER protein marker. ER vesiculation induced by ionomycin coincided with a parallel redistribution of CaM kinase II and ER marker proteins. These data link ionomycin-induced ER restructuring to a progressive redistribution of CaM kinase II protein to an insoluble particulate fraction and loss of cellular CaM kinase II activity. We propose that redistribution of CaM kinase II and loss of cellular activity are components of a common Ca2+-overload induced cellular stress response in cells.

THE EFFECTS OF ECLOGITIC HETEROGENEITIES ON UPPER MANTLE MELTING

THE EFFECTS OF ECLOGITIC HETEROGENEITIES ON UPPER MANTLE MELTING

Ajustement et accumulation: la Turquie

ABSTRACT Contrary to the predictions of structural adjustment policies, the opening up of Turkey to the external market has increased profits in the tradeable sector more rapidly than in the non-tradeable one. This article examines the various factors that affect the investments of private companies in the tradeable and non-tradeable sectors. The analysis of the relationship between the redistribution of incomes and investment decisions shows that a regressive redistribution did not affect the tradeable sector. The author suggests that a progressive redistribution could have a positive impact on the growth of investments in the non-tradeable sector.

29Si mas nmr study of the Al/Si ordering process in potassium doped-cordierites

This paper deals with the MAS NMR study of the Al/Si ordering process taking place in K-doped cordierites (compared to pure cordierite sample) by annealing at 1150 °C. A progressive redistribution of Al/Si is observed. This leads to the ordered orthorhombic form for pure cordierite, whereas such a perfect ordered structure cannot be reached with K-doped cordierites. Ce travail concerne l'étude par RMN à Angle Magique du 29 Si du processus de mise en ordre Al/Si, mis en oeuvre dans les cordiérites dopées au K (par comparaison avec la cordiérite pure), lors d'un recuit prolongé à la température de 1150 °C. Une redistribution progressive en Al et Si est observée. Celle-ci tend vers un ordre parfait avec un nombre de ponts Al-O-Al Nul (symétrie orthorhombique) pour la cordiérite pure. Pour les cordierites dopées, l'insertion d'alcalin rend cet ordre impossible.

Ion microscopic imaging of calcium during 1,25-dihydroxyvitamin D-mediated intestinal absorption.

A combination of ion microscopic and conventional radionuclide techniques was employed to investigate the temporal-spatial dynamics of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-stimulated intestinal calcium (Ca) absorption. At varying times following the administration of a single intravenous dose of 1,25(OH)2D3 to vitamin D-deficient chicks, transepithelial transport and tissue retention of Ca were quantitated in vivo, using the ligated duodenal loop technique and 47Ca as the tracer. The localization of Ca in the intestinal tissue during absorption was monitored by ion microscopy, using the stable Ca isotope, 44Ca, as the absorbed species. There was little transepithelial absorption of Ca in the vitamin D-deficient animals despite a substantial tissue accumulation of luminally derived Ca, the latter localizing predominantly in the brush border region of the enterocyte, as shown by the 44Ca-ion microscopic images. The early (30 min-1 h) response to 1,25(OH)2D3 was an increased tissue uptake of luminal 47Ca, which also primarily associated with the brush border region, again as shown by ion microscopy. At 2-4 h after the 1,25(OH)2D3 dose, there was a progressive redistribution of Ca from the brush border region throughout the cytoplasm and into the lamina propria. At 8-16 h, 47Ca absorption was maximal and 44Ca was sparsely distributed in the intestinal tissue. 47Ca absorption gradually declined and reached pre-dose levels by 72 h. At this time, tissue 44Ca was again largely limited to the brush border region. These results provide support for the multiple actions of 1,25(OH)2D3 on the intestinal Ca absorption process. The ion microscopic images provided unique information on the specific time-dependent changes in the tissue localization of Ca during the process of its intestinal absorption as affected by 1,25(OH)2D3.

Nodal Na +-channel displacement is associated with nerve-conduction slowing in the chronically diabetic BB/W rat: Prevention by aldose reductase inhibition

Chronic nerve conduction slowing in experimental diabetic neuropathy has been associated with decreased nodal Na + permeability and an ultrastructurally identifiable loss of axo-glial junctions, which comprise the paranodal voltage channel barrier separating nodal Na + channels from paranodal K + channels. In human and experimental diabetic neuropathy these structural changes of the paranodal apparatus correlate closely with the nerve conduction defect. The present immunocytochemical study of the α-subunit of the Na + channel examined whether the breach of the voltage channel barrier may account for a shift in the distribution of Na + channels explaining decreased nodal Na + permeability. Biobreeding Wistar (BB/W) rats diabetic for 4–8 months showed a progressive redistribution of nodal Na + channels across the paranodal barrier into the paranodal and internodal domains which was associated with chronic nerve conduction slowing. The present data suggest that structural damage to the paranodal barrier system in diabetic nerve facilitates the lateral displacement of Na + channels from the nodal axolemma thereby diminishing their nodal density and the nodal Na + permeability associated with the chronic nerve conduction defect in experimental diabetes. These abnormalities were prevented by the treatment with an aldose reductase inhibitor, belonging to a class of drugs that, in neuropathic patients, improves nerve-conduction velocity and repairs axo-glial dysjunction of the paranodal apparatus.

Agonist-induced internalization and recycling of the glucagon-like peptide-1 receptor in transfected fibroblasts and in insulinomas

Glucagon-like peptide-1 (GLP-1) is the most potent stimulator of glucose-induced insulin secretion and its pancreatic beta-cell receptor is a member of a new subfamily of G-protein-coupled receptors which includes the receptors for vasoactive intestinal polypeptide, secretin and glucagon. Here we studied agonist-induced GLP-1 receptor internalization in receptor-transfected Chinese hamster lung fibroblasts using three different approaches. First, iodinated GLP-1 bound at 4 degrees C to transfected cells was internalized with a t 1/2 of 2-3 min following warming up of the cells to 37 degrees C. Secondly, exposure to GLP-1 induced a shift in the distribution of the receptors from plasma membrane-enriched to endosomes-enriched membrane fractions, as assessed by Western blot detection of the receptors using specific antibodies. Thirdly, continuous exposure of GLP-1 receptor-expressing cells to iodinated GLP-1 led to a linear accumulation of peptide degradation products in the medium following a lag time of 20-30 min, indicating a continuous cycling of the receptor between the plasma membrane and endosomal compartments. Potassium depletion and hypertonicity inhibited transferrin endocytosis, a process known to occur via coated pit formation, as well as GLP-1 receptor endocytosis. In contrast to GLP-1, the antagonist exendin-(9-39) did not lead to receptor endocytosis. Surface re-expression following one round of GLP-1 receptor endocytosis occurred with a half-time of about 15 min. The difference in internalization and surface re-expression rates led to a progressive redistribution of the receptor in intracellular compartments upon continuous exposure to GLP-1. Finally, endogenous GLP-1 receptors expressed by insulinoma cells were also found to be internalized upon agonist binding. Together our data demonstrate that the GLP-1 receptor is internalized upon agonist binding by a route similar to that taken by single transmembrane segment receptors. The characterization of the pathway and kinetics of GLP-1-induced receptor endocytosis will be helpful towards understanding the role of internalization and recycling in the control of signal transduction by this receptor.

The impact of a capital investment on a subregional level: Research note on an extended input‐output approach

An extended input‐output approach is proposed to investigate the possible subregional impact of a capital investment in mining activity. The approach is different from previous attempts in a sense that households are regarded as endogenous variables and they are broken down into three categories. This will in principle allow for an evaluation of changes in income distribution in the subregion. The results show that no significant progressive redistribution of earned income may be expected from such a capital investment.

Progressive redistribution of alcohol dehydrogenase during vitellogenesis in Drosophila melanogaster: characterization of ADH-positive bodies in mature oocytes.

The use of monoclonal antibodies against Drosophila alcohol dehydrogenase (ADH) provides a powerful tool in the analysis of the tissue and temporal patterns of Adh gene expression. Immunocytochemical techniques at the light- and electron-microscopic levels have been used to determine the distribution of ADH in the ovarian follicles of D. melanogaster during oogenesis. In the early stages of oogenesis, small amounts of ADH are detectable in the cystocytes. At the beginning of vitellogenesis (S7), ADH appears to be located mainly in the nurse cells. From stage S9 onwards, the ADH protein is evenly distributed in the ooplasm until the later stages of oogenesis (S13-14), when multiple ADH-positive bodies of varying size appear in the ooplasm. This change in distribution is a result of the compartmentalization of the ADH protein within the glycogen yolk or beta-spheres. Yolk becomes enclosed within the lumen of the primitive gut during embryonic development, and thus our results suggest a mechanism for the transfer of maternally-inherited enzymes to the gut lumen via yolk spheres.

Social Democratic Corporatism and Economic Growth

Recent papers by Lange and Garrett and by Jackman have debated whether the political and economic power of the Left has had a sustained impact on the economic growth of relatively affluent capitalist democracies since 1973. This paper indicates that, consistent with theory and research by Lange and Garrett, they have had such an impact. Economic growth between 1974 and 1980-1982 accelerated where both unions were organizationally strong and Left parties were strong participants in governments; and this finding is not an artifact of a 1970s oil boom in Social Democratic Norway. In addition, it is robust in the presence of several key control variables drawn from economic theory. These variables indicate that less affluent and slower growers tended to catch up, and that capital formation tended to accelerate growth while progressive governmental redistribution of income tended to dampen it.

Spatial and temporal expression of cell surface galactosyltransferase during mouse spermatogenesis and epididymal maturation

We have previously shown that sperm-egg recognition in the mouse is mediated by the binding of galactosyltransferase (GalTase) on the sperm surface to its appropriate glycoside substrate in the egg zona pellucida [L. C. Lopez, E. M. Bayna, D. Litoff, N. L. Shaper, J. H. Shaper, and B. D. Shur (1985) J. Cell Biol. 101, 1501–1510] . In the present study, we have defined the spatial and temporal expression of surface GalTase during spermatogenesis and epididymal maturation. Purified populations of spermatogenic cells were isolated by unit gravity sedimentation, and surface GalTase expression was determined by indirect immunofluorescence and by direct enzymatic assay. GalTase is present on the surface of all spermatogenic cells assayed. During differentiation, there is a progressive redistribution of GalTase from an initially diffuse and uniform localization on the surface of primary spermatocytes to a restricted plasma membrane domain overlying the dorsal aspect of the mature acrosome. This apparent redistribution of surface GalTase was confirmed by direct enzymatic assays, which show that surface GalTase activity, normalized per cell, remains relatively constant throughout spermatogenesis, despite a drastic reduction in cell surface area. When normalized to the relevant cell surface area, the GalTase concentration per square micrometer increases 77-fold from pachytene spermatocytes to cauda epididymal sperm. Cell surface GalTase is thought to be a cytoskeletally associated transmembrane protein [N. L. Shaper, P. L. Mann, and J. H. Shaper (1985) J. Cell Biochem. 28, 229–239] ; consequently we examined whether cytoskeletal components may be involved in the redistribution of GalTase during spermatogenesis. β-Tubulin, monomeric actin, and filamentous actin were found to be present during spermatogenesis, as assayed by indirect immunofluorescence and by Western immunoblotting. α-Actinin and vinculin were not detectable under these conditions and served as negative controls. During spermatogenesis, the distribution of tubulin coincides with the appearance of the mitotic spindle, flagellum, and manchette. On the other hand, the distribution of filamentous actin coincides with surface GalTase, suggesting that actin-containing microfilaments may participate in the redistribution of surface GalTase during spermatogenesis.

The development of loops, trains and tails in a self-avoiding terminally attached molecule

The configuration of self-avoiding polymer molecules terminally attached to a rigid boundary is resolved into loop, train and tail components on the basis of a convolution integral analysis. The expectation lengths (lloop), (ltrain) and (ltail) and the component fractions are determined as functions of chain length and chain-plane interaction. In the case of zero chain-plane attraction thre is good quantitative agreement with Monte Carlo estimates, although the predicted dependence of (lloop) upon chain length appears too strong. Results are also presented for hard sphere sequences as a function of chain-plane attraction when it is found that there is a progressive redistribution amongst loop and tail states, the train exponent remaining essentially unmodified over the range of interactions investigated. Exponent representations are proposed and compared with earlier analyses. The various component structures are discussed in terms of the interplay of entropic and energetic processes at the boundary.

引張残留応力場からき裂が伝ぱんする場合の溶接残留応力場の再分布に関する研究

An experimental investigation was conducted to clarify the behavior of residual stress redistribution caused by fatigue crack propagation itself initially through compressive residual stress field. Test specimens were prepared from HT80 steel plate and two parallel welds comprising one pass along each side of the specimen were applied by electron beam welding to induce centrally located compressive residual stress field.The results obtained from fatigue crack propagation tests were reviewed comparing with the results from sawcut simulating a propagating crack. While the crack propagated in the initial compressive residual stress field, the initial distribution of residual stress was maintained until the crack tip reached tensile field in the vicinity of the weld bead. However, as the crack propagated beyond compressive field and crack tip entered into the tensile field, accompaning the residual crack opening just behind of the crack tip, progressive redistribution of residual stress was occurred.

Transcellular transport of polymeric IgA in the rat hepatocyte: biochemical and morphological characterization of the transport pathway.

Polymeric IgA (pIgA) is transported by liver parenchymal cells (hepatocytes) from blood to bile via a receptor-mediated process. We have studied the intracellular pathway taken by a TEPC15 mouse myeloma pIgA. When from 1 microgram to 1 mg 125I-pIgA was injected into the saphenous vein of a rat, 36% was transported as intact protein into the bile over a 3-h period. The concentration of transported 125I-pIgA was maximal in bile 30-60 min after injection, and approximately 80% of the total 125I-pIgA ultimately transported had been secreted into bile by 90 min. A horseradish peroxidase-pIgA conjugate (125I-pIgA-HRP) was transported to a similar extent and with kinetics similar to that of unconjugated 125I-pIgA and was therefore used to visualize the transport pathway. Peroxidase cytochemistry of livers fixed in situ 2.5 to 10 min after 125I-pIgA-HRP injection demonstrated a progressive redistribution of labeled structures from the sinusoidal area to intermediate and bile canalicular regions of the hepatocyte cytoplasm. Although conjugate-containing structures began accumulating in the bile canalicular region at these early times, no conjugate was present in bile until 20 min. From 7.5 to 45 min after injection approximately 30% of the labeled structures were in regions that contained Golgi complexes and lysosomes; however, we found no evidence that either organelle contained 125I-pIgA-HRP. At least 85% of all positive structures in the hepatocyte were vesicles of 110-160-nm median diameters, with the remaining structures accounted for by tubules and multivesicular bodies. Vesicles in the bile canalicular region tended to be larger than those in the sinusoidal region. Serial sectioning showed that the 125I-pIgA-HRP-containing structures were relatively simple (predominantly vesicular) and that extensive interconnections did not exist between structures in the sinusoidal and bile canalicular regions.

Effect of iron on the stability of macrophage lysosomes.

Mouse peritoneal macrophages exposed to 60 microM Fe3+ in culture showed a pronounced decline in survival rate and an enhanced capacity for lipid peroxidation, as estimated by the formation of malondialdehyde. The iron-exposed cells contain secondary lysosomes loaded with iron as demonstrated by transmission electron microscopy, energy dispersive X-ray micro-analysis and the sulphide-silver method. The macrophages concentrated within their lysosomes the weak base acridine orange (AO) when the latter was added to the medium in a low concentration (1:10(5)). When cells were viewed under continuous illumination with short wave blue light in a fluorescence microscope, AO-exposed cells initially showed a brilliant red granular fluorescence and subsequently a progressive redistribution of AO into the cell sap and the nucleus with resultant green fluorescence. This redistribution of AO was associated with the disappearance of the normal granular reaction product pattern of the lysosomal marker enzyme acid phosphatase (AP), as demonstrated with a Gomori-type reaction, and later with cell death. The redistribution of AO and AP from the lysosomal vacuome to the cell sap under the influence of blue light occurred markedly more rapidly in macrophages containing iron loaded lysosomes than in control cells. The findings indicate that the presence of iron in lysosomes decreases the proton-retaining ability of their bordering membranes, possibly by way of enhanced metal (iron) catalyzed lipid peroxidation. It appears that leakage of AO signifies destabilization of the lysosomal membrane.

Regional distribution of pulmonary blood volume: An index of pulmonary capillary wedge pressure determined from blood pool scintigraphy

Progressive redistribution of pulmonary blood flow to the lung apices occurs with increasing degrees of left ventricular failure, and correlates with increasing pulmonary capillary wedge pressure (PCWP). If similar changes in pulmonary blood volume (PBV) occur, then technetium-99m equilibrium blood pool scintigraphy, by assessing relative distribution of PBV, may allow prediction of PCWP. Therefore 30 patients being monitored with pulmonary artery balloon flotation catheters underwent imaging. PCWP was compared with the average radioactive count density arising from apical (A) and basal (B) regions of interest within the right lung, expressed as an AB ratio. Correlation was strong for patients imaged erect, either posteriorly (r = 0.864, p = 0.001) or in the 45 ° left anterior oblique position (r = 0.842, p = 0.001), and only slightly less impressive for patients imaged supine (r = 0.678, p = 0.001). Especially when imaging was performed with patients erect, an AB ratio greater than unity identified with high sensitivity (100%) and specificity (83 to 88%) an abnormally elevated PCWP (> 12 mm Hg). Moreover, directional changes in the AB ratio reflected concomitant changes in PCWP after intervention. Thus, analysis of lung AB radioactive count ratios obtained by equilibrium blood pool scintigraphy may be used to evaluate PCWP.

Progressive Taxation, Redistribution, and Labor Supply

The analysis of the effect of progression on labor supply is extended to a model with many consumers. The condition for progression to increase labor supply, given constant aggregate tax revenue, is derived and shown to depend on the income effects resulting from redistribution. It is then shown that the optimal linear income tax schedule involves a degree of progression which on the margin does reduce labor supply.

Effect of perfusion pressure distal to a coronary stenosis on transmural myocardial blood flow.

We tested the hypothesis that reductions of perfusion pressure distal to a flow-limiting coronary artery stenosis can directly impair perfusion of the subendocardial myocardium. Dogs were instrumented with an electromagnetic flowmeter probe and a variable occluder on the proximal left circumflex coronary artery. Coronary perfusion pressure was measured with a catheter distal to the occluder. Coronary autoregulation was abolished by intraarterial infusion of adenosine to produce maximal coronary vasodilation. The transmural distribution of myocardial blood flow was measured with radioactive microspheres during unimpeded arterial inflow, when the occluder was progressively narrowed to reduce distal coronary pressure to approximately 70%, 50% and 35% of the control coronary perfusion pressure, and during total coronary occlusion. Heart rate, left ventricular diastolic pressure and the fraction of coronary artery flow during systole remained constant throughout the study. Progressive reductions of coronary perfusion pressure were accompanied by direct reductions of the subendocardial/subepicardial blood flow ratio (r = 0.83). Examination of the relationship between myocardial blood flow and coronary perfusion pressure showed that blood flow decreased linearly with perfusion pressure, with flow ceasing at a positive pressure (zero-flow pressure). Blood flow data from four transmural myocardial layers from epicardium to endocardium showed that this zero-flow pressure increased progressively from 10 +/- 2.1 mm Hg in the subepicardium to 18 +/- 2.3 mm Hg in the subendocardium (p less than -.01). Consequently, as coronary pressure was reduced, the zero-flow pressure represented a progressively greater fraction of coronary pressure in the subendocardium than in the subepicardium. This effect appeared to account for the progressive redistribution of blood flow away from the subendocardium that occurred as coronary pressure was decreased. Myocardial vascular resistance did not change as a result of changes in coronary perfusion pressure.

Equity in Transit Finance: Distribution of Transit Subsidy Benefits and Costs Among Income Classes

Abstract Transit subsidies in the United States increased eleven-fold between 1970 and 1979. One of the key justifications of this growth was the belief that the poor would be the primary beneficiaries. The purpose of this article is to determine to what extent the poor have in fact benefited and to what extent they have born the tax costs of subsidies. To ascertain the net distributional effect, this study allocates the benefits and tax burdens of transit subsidies among income classes. User benefits are apportioned to income classes on the basis of the income distribution of the riders of each of the various types of transit service and the degree to which each type of service is subsidized. The distribution of tax costs is calculated from the mix of taxes used to finance transit subsidies and the percentage contribution from each level of government. Overall, it is found that transit subsidization redistributes income from high-income to low-income classes but that it is not very effective in targeting benefits to the poor. The current transit program is therefore not primarily justifiable on the ground of progressive redistribution. Although it would be possible to increase progressivity, the necessary modifications in the program might conflict with other objectives of transportation policy.

Proliferative and migratory activity of glial cells in the partially deafferented hippocampus.

The proliferative response of the glial cell population of the adult rat hippocampus deafferented by unilateral lesion of the entorhinal cortex was studied using 3H-thymidine autoradiography. Two experimental paradigms were used, involving: (1) intraventricular 3H-thymidine injection at a number of post-lesion intervals with sacrifice six hours later and (2) intraventricular injection at 30 hours post-lesion with sacrifice at 6, 96, or 192 hours later. The first increase in the number of labeled glial cells was obtained at 20 hours post-lesion and was confined to areas of degenerating axons. By 30 hours a large and uniformly dense proliferative response was observed throughout the ipsilateral, and medial aspects of the contralateral, hippocampus encompassing both deafferented and intact regions. Cell division continued through 50 and 65 hours post-lesion particularly in directly deafferented regions, but diminished to control levels by 80 hours. Although oligodendroglia and astrocyte-like cells were sometimes found to have incorporated the label the most common proliferative element within the hippocampus corresponded to previous light microscopic descriptions of "microglial" cells. The experiments using thymidine injection given at the peak proliferative period followed by survival periods of varying lengths indicated that a progressive redistribution of labeled nuclei occurred resulting in an accumulation of labeled cells in the zones of deafferentation. Multiple division of cells within these areas as well as the migration of nuclei from non-deafferented regions was found to contribute to this effect. The possible involvement of glial proliferation with other morphological effects of deafferentation, including the sprouting response of intact afferents, is discussed.