scholarly journals Transport of sodium, potassium, and calcium across rabbit polymorphonuclear leukocyte membranes. Effect of chemotactic factor.

1977 ◽  
Vol 73 (2) ◽  
pp. 428-444 ◽  
Author(s):  
P H Naccache ◽  
H J Showell ◽  
E L Becker ◽  
R I Sha'afi
Keyword(s):  
Plasma Membrane ◽  
Steady State ◽  
Polymorphonuclear Leukocyte ◽  
Silicone Oil ◽  
State Level ◽  
Extracellular Calcium ◽  
Chemotactic Factor ◽  
Extracellular Potassium ◽  
Steady State Level ◽  
Centrifugation Technique

The transport properties of the rabbit peritoneal polymorphonuclear leukocyte (PMN) plasma membrane to Na+, K+, and Ca2+ have been characterized. The use of a silicone oil centrifugation technique provided a rapid and reliable method for measuring ion fluxes in these cells. Na+ and K+ movements across PMN membranes were found to be rapid. The value for the unifirectional steady-state fluxes (in meq/liter cell X min) were of the order of 3.0 for Na+ and 7.4 for K+. Ouabian inhibited both K+ influx and Na+ efflux, the latter being also dependent on the presence of extracellular potassium. The rate constant (in min-1) for 45Ca influx was found to be .05 and that for 45Ca efflux .04. The synthetic chemotactic factor formyl-methionyl-leucyl-phenylalanine (FMLP) was found to affect the fluxes of Na+, K+, and Ca2+ at concentrations as low as 10(-10)M. FMLP induced a large and rapid increase in the permeability of the PMN plasma membrane to 22Na. Smaller and delayed enhancements of 42K influx and 22Na efflux were also noted. Some evidence that the latter findings are a consequence of the increased 22Na influx is presented. 45Ca influx and efflux were also stimulated by FMLP. In the presence of 0.25 mM extracellular calcium, FMLP induced an increase in the steady-state level of cell-associated 45Ca. In the presence of .01 mM extracellular calcium, however, a transient decrease in the steady-state level of cell-associated 45Ca was induced by FMLP. The curves relating the concentration of FMLP to its effects on cation fluxes are very similar to those found for its enhancement of migration.

Tacrolimus initial steady state level in post-transplant cyclophosphamide-based GvHD prophylaxis regimens

2021 ◽  
Author(s):  
Janny M. Yao ◽  
Dongyun Yang ◽  
Mary C. Clark ◽  
Salman Otoukesh ◽  
Thai Cao ◽  
...  
Keyword(s):  
Steady State ◽  
State Level ◽  
Steady State Level ◽  
Post Transplant ◽  
Gvhd Prophylaxis

Ascorbate and glutathione homeostasis in vascular smooth muscle cells: cooperation with endothelial cells

1998 ◽  
Vol 275 (4) ◽  
pp. C1031-C1039 ◽  
Author(s):  
Ilia Voskoboinik ◽  
Karin Söderholm ◽  
Ian A. Cotgreave
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Steady State ◽  
Smooth Muscle Cells ◽  
Umbilical Vein ◽  
State Level ◽  
Muscle Cells ◽  
Free Access ◽  
Steady State Level ◽  
Human Umbilical Vein

Human umbilical vein smooth muscle cells (HUVSMCs) utilize extracellular cystine, glutathione (GSH), and N-acetylcysteine (NAC) to synthesize cellular GSH. Extracellular cystine was effective from 5 μM, whereas GSH and NAC were required at 100 μM for comparable effects. The efficacy of extracellular GSH was dependent on de novo GSH synthesis, indicating a dependence on cellular γ-glutamyltransferase (glutamyl transpeptidase). Coculture of syngenetic HUVSMCs and corresponding human umbilical vein endothelial cells (HUVECs) on porous supports restricted cystine- or GSH-stimulated synthesis of HUVSMC GSH when supplied on the “luminal” endothelial side. Thus HUVSMC GSH rapidly attained a steady-state level below that achieved in the absence of interposed HUVECs. HUVSMCs also readily utilize both reduced ascorbate (AA) and oxidized dehydroascorbate (DHAA) over the range 50–500 μM. Phloretin effectively blocked both AA- and DHAA-stimulated assimilation of intracellular AA, indicating a role for a glucose transporter in their transport. Uptake of extracellular AA was also sensitive to extracellular, but not intracellular, thiol depletion. When AA was applied to the endothelial side of the coculture model, assimilation of intracellular AA in HUVSMCs was restricted to a steady-state level below that achieved by free access.

scholarly journals The steady-state level of Mg-protoporphyrin IX is not a determinant of plastid-to-nucleus signaling in Arabidopsis

2008 ◽  
Vol 105 (39) ◽  
pp. 15184-15189 ◽  
Author(s):  
N. Mochizuki ◽  
R. Tanaka ◽  
A. Tanaka ◽  
T. Masuda ◽  
A. Nagatani
Keyword(s):  
Steady State ◽  
Protoporphyrin Ix ◽  
State Level ◽  
Steady State Level

scholarly journals Effect of Nedocromil Sodium on Polymorphonuclear Leukocyte Plasma Membrane

1994 ◽  
Vol 3 (7) ◽  
pp. S21-S24 ◽  
Author(s):  
A. Kantar ◽  
N. Oggiano ◽  
P. L. Giorgi ◽  
G. V. Coppa ◽  
R. Gabbianelli ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Steady State ◽  
Membrane Fluidity ◽  
Fluorescence Anisotropy ◽  
Polymorphonuclear Leukocyte ◽  
Polymorphonuclear Leukocytes ◽  
Plasma Membranes ◽  
Nedocromil Sodium ◽  
Plasma Membrane Fluidity ◽  
Steady State Fluorescence

The effect of nedocromil sodium on the plasma membrane fluidity of polymorphonuclear leukocytes (PMNs) was investigated by measuring steady-state fluorescence anisotropy of 1-[4-trimethylammonium-phenyl]-6-phenyl- 1,3,5-hexatriene (TMA-DPH) incorporated in the membrane. Our results show that nedocromil sodium 300 μM significantly decreased membrane fluidity of PMNs. The decrease in membrane fluidity of PMNs induced by fMLP was abolished in the presence of nedocromil sodium. These data suggest that nedocromil sodium interferes with the plasma membranes of PMNs and modulates their activities.

scholarly journals Expression of human beta-secretase in the mouse brain increases the steady-state level of beta-amyloid

2002 ◽  
Vol 80 (5) ◽  
pp. 799-806 ◽  
Author(s):  
Ursula Bodendorf ◽  
Simone Danner ◽  
Frauke Fischer ◽  
Muriel Stefani ◽  
Christine Sturchler-Pierrat ◽  
...  
Keyword(s):  
Steady State ◽  
Mouse Brain ◽  
State Level ◽  
Beta Amyloid ◽  
Steady State Level ◽  
Beta Secretase

Expression of a gene for mouse eucaryotic elongation factor Tu during murine erythroleukemic cell differentiation

1987 ◽  
Vol 7 (11) ◽  
pp. 3929-3936
Author(s):  
W W Roth ◽  
P W Bragg ◽  
M V Corrias ◽  
N S Reddy ◽  
J N Dholakia ◽  
...  
Keyword(s):  
Steady State ◽  
Genomic Library ◽  
Elongation Factor ◽  
State Level ◽  
Genomic Clone ◽  
Elongation Factor Tu ◽  
Steady State Level ◽  
Similar Reduction ◽  
S1 Nuclease ◽  
Murine Erythroleukemia

The eucaryotic elongation factor Tu (eEF-Tu) is a single polypeptide with an approximate Mr of 53,000. During protein synthesis eEF-Tu promotes the binding of aminoacyl-tRNA to the ribosome. To study the expression of the gene(s) for this factor, a genomic clone was isolated that contains a mouse eEF-Tu gene. We screened a phage genomic library with a synthetic oligonucleotide probe complementary to a region of the Saccharomyces cerevisiae and Artemia sp. eEF-Tu genes which codes for an area that is highly conserved between both yeast and Artemia sp. eEF-Tu. From approximately 75,000 phage plaques we obtained five isolates with apparently identical inserts. All five clones contained a 3.8-kilobase EcoRI fragment that hybridized to additional oligonucleotide probes corresponding to different conserved regions of eEF-Tu. We sequenced the 5' end of one genomic clone and determined the length of the cloned fragment that was protected by eEF-Tu mRNA in S1 nuclease protection assays. A quantitative S1 nuclease protection assay was used to compare the relative steady-state levels of eEF-Tu mRNA in total mRNA in total RNA isolated from hexamethylene-bisacetamide-induced murine erythroleukemia cells. The results show a dramatic reduction in the steady-state level of eEF-Tu mRNA as differentiation proceeds. A similar reduction in transcription of eEF-Tu mRNA was observed in isolated nuclei. Finally, we examined the in vivo synthesis of eEF-Tu during differentiation and found that it declined in a manner parallel to the decline in the steady-state level of eEF-Tu mRNA. In addition, we have isolated and sequenced a cDNA clone for mouse eEF-Tu. The derived amino acid sequence is compared with sequences from other eucaryotes.

Cytosolic Ca2+ dynamics in hamster ascending thin limb of Henle's loop

1995 ◽  
Vol 268 (6) ◽  
pp. F1148-F1153 ◽  
Author(s):  
N. Takahashi ◽  
Y. Kondo ◽  
O. Ito ◽  
Y. Igarashi ◽  
K. Omata ◽  
...  
Keyword(s):  
Steady State ◽  
Intracellular Calcium ◽  
State Level ◽  
Steady State Level ◽  
Subsequent Reduction ◽  
Fura 2 ◽  
Henle's Loop ◽  
K Concentration ◽  
Thin Limb

Intracellular calcium plays an important role in the regulation of Cl- reabsorption in the ascending thin limb of Henle's loop (ATL). To elucidate the cytosolic Ca2+ dynamics in the ATL, intracellular Ca2+ concentration activity ([Ca2+]i) was measured in the in vitro microperfused hamster ATL using fura 2. Basal [Ca2+]i was 89.1 +/- 7.3 nM (n = 9 tubules). Removal of Ca2+ from the peritubular solution decreased [Ca2+]i from 89.1 +/- 7.3 to 64.1 +/- 7.1 nM in 2 min (n = 9, P < 0.05), whereas [Ca2+]i did not change after removal of Ca2+ from the luminal solution. Addition of 1 mM NaCN to the bath increased [Ca2+]i. This effect was completely abolished by the elimination of ambient Ca2+. Trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) in the bath reversibly increased [Ca2+]i, whereas addition of 1 mM ouabain to the bath decreased [Ca2+]i. Rates of changes in [Ca2+]i after removal and replacement of basolateral Ca2+ were not affected by removal of Na+, K+, or Cl- from the bath, whereas nicardipine decreased these parameters. Increasing bath K+ from 5 to 100 mM decreased [Ca2+]i from 69.3 +/- 5.8 to 50.8 +/- 5.0 nM in 1 min (n = 6, P < 0.05). Subsequent reduction of K+ from 100 to 5 mM increased [Ca2+]i to 174.0 +/- 30.8 nM in 1 min, followed by a gradual decrease in [Ca2+]i to a steady-state level of 74.2 +/- 8.0 nM in 2 min. Changes in basolateral K+ concentration did not affect [Ca2+]i in the absence of ambient Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)

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