Synthesis of an alginate–poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with low salt sensitivity and high pH sensitivity

2006 ◽  
Vol 101 (5) ◽  
pp. 2927-2937 ◽  
Author(s):  
G. Bagheri Marandi ◽  
N. Sharifnia ◽  
H. Hosseinzadeh
Keyword(s):  
Salt Sensitivity ◽  
Ph Sensitivity ◽  
Sodium Acrylate ◽  
Superabsorbent Hydrogel ◽  
High Ph ◽  
Low Salt

Abstract 495: A Novel Test for Low Salt Sensitivity: Angiotensin type-II Receptor Recruitment After Dopamine-1 Receptor Stimulation in Urine-Derived Renal Proximal Tubule Cells

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
John J Gildea ◽  
Staci A Keene ◽  
Dylan T Lahiff ◽  
Robert E Van Sciver ◽  
Cynthia D Schoeffel ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Flow Cytometry ◽  
Clinical Study ◽  
Salt Sensitivity ◽  
High Salt ◽  
Salt Diet ◽  
Independent Events ◽  
Angiotensin Type 2 Receptor ◽  
Low Salt ◽  
Angiotensin Type

Salt-sensitivity of blood pressure is an inappropriate increase in blood pressure following high salt intake. Subjects in our clinical study were typed according to their salt-sensitivity status into 3 categories: High-Salt-Sensitive (HSS; ≥ 7 mmHg increase in mean arterial pressure (MAP) on a high salt diet of 300 mEq of sodium, 17% prevalence), Low-Salt-Sensitive (LSS:, who paradoxically showed a ≥ 7 mmHg increase in MAP on a low salt diet of 10 mEq of sodium, 11% prevalence), and Salt-Resistant (SR, individuals who showed no significant increase in blood pressure on either diet, 72% prevalence). We previously demonstrated that LSS subjects show increased recruitment of the natriuretic dopamine-1 receptor (D1R) to the plasma membrane following a salt stimulation as compared to HSS subjects. Stimulation of the D1R in RPTC with fenoldopam (dopaminergic agonist) results in recruitment of the natriuretic angiotensin type-2 receptor (AT2R) to the cell surface. We hypothesized that LSS individuals may also demonstrate an enhanced AT2R RPTC membrane recruitment compared to HSS individuals when challenged with fenoldopam. In order to gain access to fresh RPTC from each subject, we isolated exfoliated RPTC from randomly voided urine from SR, LSS, and HSS subjects from our clinical study. We measured three subjects from each category with a minimum of three voids for each subject. We counted individual cells as independent events using both the confocal microscope (n=245) and the flow cytometer (n=5344). We found an inverse correlation between AT2R recruitment and the degree of salt-sensitivity of blood pressure. Fenoldopam stimulated AT2R recruitment as measured by confocal microscopy (y = -0.0047x + 0.4966, R2 = 0.2488, P<0.0001) and flow cytometry (y =-0.057x + 1.5645, R2=0.2912, P=0.0185). Flow cytometry provided a more sensitive diagnostic for LSS than HSS subjects. AT2R recruitment was more predictive of LSS than HSS. AT2R recruitment may be used as a rapid method to test for LSS individuals who need to be identified and encouraged to increase their sodium intake in order to avoid paradoxical hypertension.

Polyethylenimine wrapped mesoporous silica loaded benzotriazole with high pH-sensitivity for assembling self-healing anti-corrosive coatings

2020 ◽  
Vol 253 ◽  
pp. 123425 ◽  
Author(s):  
Jiaxin Wen ◽  
Jinglei Lei ◽  
Jinlong Chen ◽  
Lei Liu ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Ph Sensitivity ◽  
Self Healing ◽  
High Ph

Synthesis and absorbency of gelatin-graft-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with saltand pH-responsiveness properties

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Ali Pourjavadi ◽  
Mohammad Sadeghi ◽  
Mohammad Mahmodi Hashemi ◽  
Hossein Hosseinzadeh
Keyword(s):  
Weight Ratio ◽  
Ammonium Persulfate ◽  
Switching Behavior ◽  
Polymerization Reaction ◽  
Sodium Acrylate ◽  
Swelling Kinetics ◽  
Superabsorbent Hydrogel ◽  
Swelling Capacity ◽  
Bioactive Agents ◽  
Kinetics Of

AbstractIn this article, we synthesize a novel gelatin-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and acrylamide (AAm) onto gelatin backbones. The polymerization reaction was carried out in an aqueous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N'-methylene bisacrylamide (MBA) as a crosslinker. The hydrogel structures were confirmed by FTIR spectroscopy. The effect of grafting variables, i.e. concentration of MBA and APS, AA/AAm weight ratio, and reaction time and temperature, was systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The swelling behavior of these absorbent polymers was also investigated in various salt solutions. Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1.0 and 13.0. It showed a reversible pH-responsive behavior at pHs 2.0 and 7.0. This on-off switching behavior makes the synthesized hydrogels an excellent candidate for controlled delivery of bioactive agents. Finally, the swelling kinetics of the synthesized hydrogels with various particle sizes was preliminarily investigated.

scholarly journals High Salt Intake Increases Copeptin but Salt Sensitivity Is Associated with Fluid Induced Reduction of Copeptin in Women

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Irina Tasevska ◽  
Sofia Enhörning ◽  
Philippe Burri ◽  
Olle Melander
Keyword(s):  
Body Weight ◽  
Salt Intake ◽  
Salt Sensitivity ◽  
High Salt ◽  
Dietary Salt ◽  
Urinary Volume ◽  
Salt Consumption ◽  
High Salt Intake ◽  
Low Salt ◽  
Induced Changes

This study investigated if copeptin is affected by high salt intake and whether any salt-induced changes in copeptin are related to the degree of salt sensitivity. The study was performed on 20 men and 19 women. In addition to meals containing 50 mmol NaCl daily, capsules containing 100 mmol NaCl and corresponding placebo capsules were administered during 4 weeks each, in random order. Measurements of 24 h blood pressure, body weight, 24 h urinary volume, and fasting plasma copeptin were performed at high and low salt consumption. Copeptin increased after a high compared to low dietary salt consumption in all subjects 3,59 ± 2,28 versus 3,12 ± 1,95 (P= 0,02). Copeptin correlated inversely with urinary volume, at both low (r= −0,42;P= 0,001) and high (r= −0,60;P< 0,001) salt consumption, as well as with the change in body weight (r= −0,53;P< 0,001). Systolic salt sensitivity was inversely correlated with salt-induced changes of copeptin, only in females (r= −0,58;P= 0,017). As suppression of copeptin on high versus low salt intake was associated with systolic salt sensitivity in women, our data suggest that high fluid intake and fluid retention may contribute to salt sensitivity.

Modeling Equilibrium Swelling of a Dual pH- and Temperature-Responsive Core/Shell Hydrogel

2016 ◽  
Vol 08 (03) ◽  
pp. 1650039 ◽  
Author(s):  
N. Hamzavi ◽  
A. D. Drozdov ◽  
Y. Gu ◽  
E. Birgersson
Keyword(s):  
Ph Sensitivity ◽  
Core Shell ◽  
Polymer Gel ◽  
Stimuli Responsive ◽  
Degree Of Ionization ◽  
High Ph ◽  
The Core ◽  
Ionic Core ◽  
Ph Values ◽  
Equilibrium Swelling

The equilibrium swelling of a dual stimuli-responsive core/shell hydrogel is studied by a thermodynamic model. This hydrogel shows thermo-sensitivity as well as pH-sensitivity. The model captures the inhomogeneous swelling of core/shell hydrogels and also, accounts for temperature and pH sensitivity. The predictions of this model are verified with the swelling experiments of a core/shell microgel comprising poly N-isopropyl acrylamide (pNIPAM) and acrylic acid (AAc). The model calculates the equilibrium swelling within the ionic core and the neutral shell. Simulation results can reproduce the equilibrium swelling-temperature curves of this microgel at different pH values considering the delay in the volume phase transition temperature (VPTT) of the ionic polymer gel (pNIPAM-co-AAc) in the core. Two transition points are found in the equilibrium swelling behavior of the hydrogel akin to the VPTTs of the core and shell domains at high pH values of bath solutions. Likewise, the degree of ionization in the core domain is predicted to have a two-step transition behavior corresponding to the VPTTs of the core and shell domains at high pH values of bath solutions. It is shown that the equilibrium swelling of the ionic core is mainly influenced by the electrostatic repulsion between bound charges rather than the ionic pressure. Furthermore, it is determined that the maximum radial stress occurs at the core/shell interface and reaches its maximum value about the VPTT of the core.

Abstract 32: A Rapid Method for Clinical Diagnosis of Salt Sensitivity of Blood Pressure

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
John J Gildea ◽  
Dylan T Lahiff ◽  
Staci A Keene ◽  
Robert E Van Sciver ◽  
Robert M Carey ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Flow Cytometry ◽  
Confocal Microscopy ◽  
Salt Sensitivity ◽  
Sensitivity Index ◽  
Flow Cytometry Analysis ◽  
Salt Diet ◽  
Low Salt ◽  
Microscopy Analysis ◽  
Confocal Microscopy Analysis

Salt-sensitivity of blood pressure (BP) is a cardiovascular risk that affects 25% of the world’s population due to its resulting hypertension, although independent of BP. Salt-sensitivity is detected with a two week controlled diet, which is difficult to administer in the clinical setting. We therefore developed a rapid method of diagnosis based on exfoliated renal proximal tubule cells (RPTC) in urine. Subjects were divided into 3 salt sensitivity index categories: High-Salt-Sensitive (HSS; ≥ 7 mmHg increase in mean arterial pressure (MAP) on a high salt diet of 300 mEq of sodium, 17%prevalence), Low-Salt-Sensitive (LSS; ≥ 7 mmHg increase in MAP on a low salt diet of 10 mEq of sodium, 11% prevalence) and Salt Resistant (SR; ≤ 7 mmHg increase in MAP on both high and low salt diets, 72% prevalence) (Carey et al., in review). Three individuals were analyzed in each category on a minimum of 3 separate occasions. Cells were isolated from urine using centrifugation and measured for dopamine-1 receptor (D1R) plasma membrane recruitment using fluorescently-labeled antibodies under a confocal microscope as well as in a flow cytometer. Confocal microscopy analysis (total of 100 RPTCs for the 9 subjects) showed a negative correlation between salt-sensitivity index and D1R surface recruitment in RPTCs in their response to salt stimulation (y = -0.0073x + 0.5248, p = 0.0159). Flow cytometry analysis (total of 4938 RPTCs for the 9 subjects) also demonstrated a negative correlation between salt-induced D1R recruitment and salt-sensitivity (y = -2.547x + 239.97, p < 0.0001). Flow cytometry analysis showed a greater degree of separation amongst the subjects than confocal microscopy analysis, and would allow for a rapid diagnostic use of exfoliated renal cells in urine. Cryopreserved RPTCs (viability = 57.16% ± 9.15%, n = 12) compare favorably with cell viability from freshly voided urine cells and were still capable of eliciting intracellular sodium-mediated D1R recruitment. Cryopreservation thus enables batch collection, transport and processing of specimens between sites. We expect these procedures to provide a novel and convenient method of diagnosing the salt-sensitivity index in humans.

The circularly permuted yellow fluorescent protein cpYFP that has been used as a superoxide probe is highly responsive to pH but not superoxide in mitochondria: implications for the existence of superoxide ‘flashes’

2011 ◽  
Vol 437 (3) ◽  
pp. 381-387 ◽  
Author(s):  
Markus Schwarzländer ◽  
David C. Logan ◽  
Mark D. Fricker ◽  
Lee J. Sweetlove
Keyword(s):  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Ph Sensitivity ◽  
Detectable Effect ◽  
High Ph ◽  
Pharmacological Manipulation ◽  
The Matrix

The properties of a cpYFP [circularly permuted YFP (yellow fluorescent protein)] reported to act as a superoxide sensor have been re-examined in Arabidopsis mitochondria. We have found that the probe has high pH sensitivity and that dynamics in the cpYFP signal disappeared when the matrix pH was clamped by nigericin. In contrast, genetic and pharmacological manipulation of matrix superoxide had no detectable effect on the cpYFP signal. These findings question the existence of superoxide flashes in mitochondria.

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