Temperature Influences the Postelectroporation Permeability State of the Skin

2004 ◽  
Vol 93 (4) ◽  
pp. 908-915 ◽  
Author(s):  
S. Narasimha Murthy ◽  
Arindam Sen ◽  
Ya-Li Zhao ◽  
Sek Wen Hui
Keyword(s):  
Permeability State

pH influences the postpulse permeability state of skin after electroporation

2003 ◽  
Vol 93 (1) ◽  
pp. 49-57 ◽  
Author(s):  
S.Narasimha Murthy ◽  
Arindam Sen ◽  
Ya-Li Zhao ◽  
Sek Wen Hui
Keyword(s):  
Permeability State

Disturbed Endothelial Blood-Bone Marrow-Barrier In Nox4 Deficient Mice

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1169-1169
Author(s):  
Maren Weisser ◽  
Kerstin B. Kaufmann ◽  
Tomer Itkin ◽  
Linping Chen-Wichmann ◽  
Tsvee Lapidot ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Endothelial Cells ◽  
Stem Cell ◽  
Steady State ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Knock Out ◽  
Deficient Mice ◽  
Permeability State

Abstract Reactive oxygen species (ROS) have been implicated in the regulation of stemness of hematopoietic stem cells (HSC). HSC with long-term repopulating capabilities are characterized by low ROS levels, whereas increased ROS levels correlate with lineage specification and differentiation. Several tightly regulated sources of ROS production are well known among which are the NADPH oxidases (Nox). HSC are known to express Nox1, Nox2 and Nox4, however, their role in maintenance of stem cell potential or in the activation of differentiation programs are poorly understood. While Nox2 is activated in response to various extrinsic and intrinsic stimuli, mainly during infection and inflammation, Nox4 is constitutively active and is considered to be responsible for steady-state ROS production. Consequently, Nox4 deficiency might lower ROS levels at steady-state hematopoiesis and thereby could have an impact on HSC physiology. In this work we studied HSC homeostasis in Nox4 knock-out mice. Analysis of the hematopoietic stem and progenitor cell (HSPC) pool in the bone marrow (BM) revealed no significant differences in the levels of Lineage marker negative (Lin-) Sca-1+ ckit+ (LSK) and LSK-SLAM (LSK CD150+ CD48-) cells in Nox4 deficient mice compared to wild type (WT) C57BL/6J mice. HSPC frequency upon primary and secondary BM transplantation was comparable between Nox4 deficient and WT mice. In addition, the frequency of colony forming cells in the BM under steady-state conditions did not differ between both mouse groups. However, Nox4 deficient mice possess more functional HSCs as observed in in vivo competitive repopulating unit (CRU) assays. Lin- cells derived from Nox4 knock out (KO) mice showed an increased CRU frequency and superior multilineage engraftment upon secondary transplantation. Surprisingly, ROS levels in different HSPC subsets of NOX4 KO mice were comparable to WT cells, implying that the absence of Nox4 in HSCs does not have a major intrinsic impact on HSC physiology via ROS. Therefore, the increased levels of functional HSCs observed in our studies may suggest a contribution of the BM microenvironment to steady-state hematopoiesis in the BM of Nox4 KO animals. Recent observations suggest a regulation of the BM stem cell pool by BM endothelial cells, in particular by the permeability state of the blood-bone marrow-barrier (Itkin T et al., ASH Annual Meeting Abstracts, 2012). Endothelial cells interact with HSCs predominantly via paracrine effects and control stem cell retention, egress and homing as well as stem cell activation. As Nox4 is highly expressed in endothelial cells and is involved in angiogenesis, we reasoned that the absence of NOX4 could affect HSC homeostasis through altered BM endothelium properties and barrier permeability state. Indeed, in preliminary assays we found reduced short-term homing of BM mononuclear cells into the BM of Nox4 deficient mice as compared to wild type hosts. Furthermore, in vivo administration of Evans Blue dye revealed reduced dye penetration into Nox4-/- BM compared to wild type mice upon intravenous injection. Taken together, these data indicate a reduced endothelial permeability in Nox4 KO mice. Ongoing experiments aim at further characterization of the Nox4-/- phenotype in BM sinusoidal and arteriolar endothelial cells, the impact of Nox4 deletion on BM hematopoietic and mesenchymal stem cells, and in deciphering the role of Nox4 in the bone marrow microenvironment. Disclosures: No relevant conflicts of interest to declare.

Palestine and the Arab State System: Permeability, State Consolidation and the Intifada

1991 ◽  
Vol 24 (3) ◽  
pp. 595-621 ◽  
Author(s):  
Rex Brynen
Keyword(s):  
State Formation ◽  
State System ◽  
Arab State ◽  
The Political ◽  
Territorial State ◽  
Arab States ◽  
Permeability State

AbstractThis article examines the sensitivity of Arab states to the political and ideological repercussions of the Palestine issue by focussing upon Egypt, Syria and Jordan. It suggests that the policies of Arab regimes towards the Palestine issue have been substantially shaped by historical patterns of state formation, and by the gradual consolidation of the Arab state system. This has served to “harden” the Arab territorial state, creating conditions under which Arab states are increasingly (if only partially) insulated from the transnational effects of the Palestinian-Israeli conflict.

scholarly journals Partial agonists and antagonists reveal a second permeability state of human lymphocyte P2Z/P2X7channel

1998 ◽  
Vol 275 (5) ◽  
pp. C1224-C1231 ◽  
Author(s):  
J. S. Wiley ◽  
C. E. Gargett ◽  
W. Zhang ◽  
M. B. Snook ◽  
G. P. Jamieson
Keyword(s):  
Partial Agonist ◽  
Second Step ◽  
Rt Pcr ◽  
Time Resolved ◽  
Inorganic Cations ◽  
Partial Agonists ◽  
Channel Opening ◽  
Permeability Increase ◽  
Kinetics Of ◽  
Permeability State

Extracellular ATP is known to trigger apoptosis of thymocytes and lymphocytes through a P2Z receptor at which ATP is a partial agonist, giving only 70% of the maximum response of 3′- O-(4-benzoyl)benzoyl-adenosine 5′-triphosphate (BzATP), a full agonist. This cytolytic receptor and its associated ion channel are Ca2+ (and Ba2+) selective but also pass molecules up to the size of ethidium cation (314 Da). RT-PCR showed identity between lymphocyte P2Z and the hP2X7 gene recently cloned from human monocytes. When human leukemic B lymphocytes were incubated with ATP and133Ba2+, an immediate influx of isotope occurred. It was augmented by 45% when ATP was added 10 min before isotope. Time-resolved flow cytometry was used to examine kinetics of ethidium uptake in cells incubated with BzATP or the partial agonists ATP, 2-methylthioadenosine 5′-triphosphate, or adenosine 5′- O-(3-thiotriphosphate). Maximally effective concentrations of BzATP (50 μM) induced immediate uptake of ethidium at a rate linear with time. In contrast, a delay was observed (30 s) before ethidium uptake commenced after addition of maximally effective ATP concentrations (500 μM) at 37°C, and the delay was longer at 24°C. ATP addition 2–10 min before ethidium abolished the delay. The delay was longer with other partial agonists and inversely related to maximal flux produced by agonist. A delay was also observed for submaximal BzATP concentrations (10–20 μM). P2Z/P2X7 inhibitors, KN-62 and 5-( N, N-hexamethylene)-amiloride, reduced the rate of agonist-induced ethidium uptake and lengthened the delay. The results support a model in which agonists for P2Z/P2X7 receptor mediate an immediate channel opening allowing passage of small inorganic cations, followed by a slow further permeability increase allowing passage of larger permeant cations like ethidium. The rate of the second step depends on time and temperature and the efficacy and concentration of agonist and is slowed by antagonists, suggesting it depends on the fraction of P2Z/P2X7 channels held in the initial open state.

Electroporation: High frequency of occurrence of a transient high-permeability state in erythrocytes and intact yeast

FEBS Letters ◽  
1988 ◽  
Vol 229 (1) ◽  
pp. 30-34 ◽  
Author(s):  
James C. Weaver ◽  
Gail I. Harrison ◽  
Jonathan G. Bliss ◽  
Judith R. Mourant ◽  
Kevin T. Powell
Keyword(s):  
High Frequency ◽  
Frequency Of Occurrence ◽  
High Permeability ◽  
Permeability State

Effect of superior vena caval hypertension on alloxan-induced lung injury in dogs

1990 ◽  
Vol 68 (2) ◽  
pp. 478-483 ◽  
Author(s):  
F. Ando ◽  
M. Arakawa ◽  
K. Kambara ◽  
H. Miyazaki ◽  
T. Segawa ◽  
...  
Keyword(s):  
Time Course ◽  
Low Dose ◽  
Superior Vena ◽  
Gravimetric Method ◽  
Base Line ◽  
Lung Water ◽  
Superior Vena Caval ◽  
Anesthetized Dogs ◽  
Water Accumulation ◽  
Permeability State

To investigate how fast and to what extent superior vena caval hypertension (SVCH) increases lung water in acute increased-permeability state, we studied the time course of lung water accumulation for 3 h in anesthetized dogs under different treatments: 1) controls without intervention (5 dogs), 2) SVCH alone (5 dogs), 3) mild lung microvascular injury induced by low-dose alloxan (75 mg/kg) alone (5 dogs), and 4) SVCH coupled with low-dose alloxan (5 dogs). Neither low-dose alloxan alone nor SVCH alone [superior vena caval pressure (Psvc) = 11.0 +/- 3.1 (SD) mmHg] increased lung water significantly. The SVCH coupled with low-dose alloxan (Psvc = 11.3 +/- 2.7 mmHg) doubled extravascular lung thermal volume measured by the thermal-dye dilution technique within 1 h (5.3 +/- 0.9 ml/kg at base line and 10.9 +/- 4.7 ml/kg at 1 h), then remained unchanged (12.5 +/- 5.7 ml/kg at 3 h). This increase in lung water was confirmed by gravimetric method (5.69 +/- 1.71 g/g blood-free dry wt). We conclude that SVCH is one of the factors that may promote lung water accumulation in increased-permeability state.

scholarly journals Studies of Cardiac Muscle with a High Permeability to Calcium Produced by Treatment with Ethylenediaminetetraacetic Acid

1971 ◽  
Vol 58 (1) ◽  
pp. 71-93 ◽  
Author(s):  
Saul Winegard
Keyword(s):  
Action Potentials ◽  
Ethylenediaminetetraacetic Acid ◽  
Ringer Solution ◽  
Resting Potential ◽  
Free Calcium ◽  
Krebs Solution ◽  
Half Maximum ◽  
High Permeability ◽  
Frog Ventricle ◽  
Permeability State

Thin strips of frog ventricle were isolated and bathed for 15 min in a solution containing 140 mM KCl, 5 mM Na2ATP, 3 mM EDTA, and 10 mM Tris buffer at pH 7.0. The muscle was then exposed to contracture solutions containing 140 mM KCl, 5 mM Na2ATP, 1 mM MgCl2, 10 mM Tris, 3 mM EGTA, and CaCl2 in amounts to produce concentrations of free calcium from 10-4.8 M to 10-9 M. The muscles developed some tension at approximately 10-8 M, and maximum tension was achieved in 10-5 M Ca++. They relaxed in Ca++ concentrations less than 10-8 M. The development of tension by the EDTA-treated muscles was normalized by comparison with twitch tension at a stimulation rate of 9 per min before exposure to EDTA. In 10-5 M Ca++ tension was always several times the twitch tension and was greater than the contracture tension of a frog ventricular strip in KCl low Na-Ringer. Tension equal to half-maximum was produced at approximately 10-6.2 M Ca++. Intracellular recording of membrane potential indicated that after EDTA treatment the resting potential of cells in Ringer solution with 10-5 M Ca or less was between 5 and 20 mv. Contracture solutions did not produce tension without prior treatment with EDTA. The high permeability of the membrane produced by EDTA was reversed and the normal resting and action potentials restored in 1 mM Ca-Ringer. Similar studies of EDTA-treated rabbit right ventricular papillary muscle produced a similar tension vs. Ca++ concentration relation, and the high permeability state reversed with exposure to normal Krebs solution.

scholarly journals Bed Permeability State Prediction Model of Sintering Process Based on Data Mining Technology

2016 ◽  
Vol 56 (12) ◽  
pp. 2113-2117 ◽  
Author(s):  
Xiaoxian Huang ◽  
Xiaohui Fan ◽  
Xuling Chen ◽  
Guiming Yang ◽  
Min Gan
Keyword(s):  
Data Mining ◽  
Prediction Model ◽  
Sintering Process ◽  
Mining Technology ◽  
State Prediction ◽  
Permeability State
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