Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1832588 (PSS)
 2,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The pH-sensitive dye 2',7'-bis-(2-carboxyethyl)-5 (and -6)-carboxyfluorescein (BCECF) was used to measure intracellular pH (pHi) in segments of rat resistance vessels (internal diameter about 200 microns) with the vessels mounted in a myograph for simultaneous measurements of isometric contraction. 2. BCECF loaded slowly into the vessels over 1 h and did not affect the maximal contractility of the vessels. There was a loss of dye with time which, however, was very slow when the segments were only excited for 2 s/min, suggesting that the loss was mainly due to dye bleaching with only a very slow leak. 3. The ratio of the emissions (at 540 nm) with excitation at 495 and 450 nm was calibrated in terms of pH using the K+-H+ ionophore nigericin. This calibration gave a pHi value of 7.15 +/- 0.02 (n = 20), suggesting that hydrogen ions are not in electrochemical equilibrium in these vascular smooth muscles which have a membrane potential of about -60 mV. 4. Addition of 10 mM-NH4Cl caused a transient alkalinization and wash-out of 10 mM-NH4Cl a transient acidification. Increasing CO2 with maintained bicarbonate caused a rapid acidification followed by an incomplete recovery. Removal of CO2 and bicarbonate (HEPES-buffered solution) with constant extracellular pH caused a transient alkalinization but steady-state pHi was not significantly altered. 5. In bicarbonate-free buffer the Na+-H+ exchange blocker 5-(N-ethyl-N-isopropyl) amiloride (EIPA) and sodium-free conditions caused a slow acidification. In bicarbonate buffer (PSS) EIPA had no detectable effect after 10 min but the anion exchange blocker diisothio-cyanatostilbenedisulphonic acid (DIDS) caused a small acidification over that time course. 6. The rate of recovery after an acid load was about 50% lower in HEPES buffer compared to PSS and it was inhibited by EIPA. In PSS amiloride and EIPA each had a small inhibitory effect on the pH recovery after an acid load. DIDS also inhibited the recovery from an acid load in PSS and this effect was additive to that of EIPA. DIDS and EIPA also had additive inhibitory effects on the 22Na+ influx stimulated by the acid loading, while in HEPES buffer DIDS had no effect on either pH recovery or 22Na+ influx. These results suggest that a Na+-H+ exchange and an influx of bicarbonate coupled to sodium influx are of importance for pHi control in these vessels.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Intracellular pH regulation in resting and contracting segments of rat mesenteric resistance vessels. 297 24

Cl- efflux into various incubation media (PSS) was studied in pieces of rabbit aortae loaded with 36Cl. Replacement of HCO3-/CO2 by HEPES/O2 in the PSS increased the rate of Cl- efflux by a factor of 2.4. This effect was suppressed in Cl(-)-free PSS containing isethionate, propionate, or benzenesulfonate, but not in NO3(-)-PSS, or Br(-)-PSS. The stimulant effect of HCO3- withdrawal on Cl-efflux was reduced by 140 microM DIDS, but not by 1 mM furosemide. The Cl- efflux was temperature-dependent (Q10 = 2.3-2.5), and it was not affected on depolarisation by high [K+]o. The [Cl-]i of rabbit aorta determined by uptake studies with 36Cl, decreased slightly (by 15%) below controls in PSS containing 140 microM DIDS, but drastically (from 32.6 to 13.5 mM, i.e. by 59%) in PSS containing 1 mM furosemide. Withdrawal of HCO3-/CO2 depolarized rabbit pulmonary artery in standard PSS and in Br(-)-PSS or NO3(-)-PSS, but not in benzenesulfonate-PSS. The pHi of rabbit aorta determined by the distribution of (14C)-DMO, increased in Cl(-)-free PSS containing isethionate or glucuronate. It is concluded that transport mechanisms play a major role in the distribution of Cl- in vascular smooth muscle, and that a membrane anion carrier operates in this tissue which can transport Cl- and HCO3- across the cell membrane. This mechanism seems to be involved in the regulation of pHi. However, the known high [Cl-]i of vascular smooth muscle is rather mediated by the furosemide-sensitive Na-K-Cl cotransport than by this anion carrier.
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PMID:A chloride-bicarbonate exchanging anion carrier in vascular smooth muscle of the rabbit. 361 72

Eight rat lungs were perfused in an in vitro circuit with a blood-PS solution and then with a perfluorocarbon emulsion (perfluorotributylamine, FC-43). With perfusion flow constant, the hypoxic pulmonary vasoconstrictor (HPV) response was measured as changes in pulmonary artery pressure when F1,O2 was changed to 0.1, 0.06, 0.04, 0.03, 0.02 and zero with FI,CO2 of 0.05. The hypoxic response to an FI,O2 of 0.03, with the blood-PSS perfusate, was an increase from baseline pressure of 93.5 +/- 18% and, with the perfluorocarbon perfusate was 67.5 +/- 18%; these values were not significantly different (P greater than 0.2). A stimulus-response relationship was obtained with the FC-43 perfusate by plotting the response as a percentage of the maximum response (R%max) against the logarithm of the alveolar oxygen tension. The equation for the linear portion of the response was R%max = 257.9-140.2 X log (10) PA,O2 and r = 0.78. The PA,O2 corresponding to half of the maximum response (ED50) was 30.4 mmHg. The present study demonstrated that HPV is maintained in isolated rat lungs perfused with an FC-43 emulsion. The stimulus-response relationship as well as the ED50 with the FC-43 is similar to earlier results with blood perfusate. Lung oedema was not found after perfusion with the FC-43 emulsion.
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PMID:Hypoxic pulmonary vasoconstriction in isolated rat lungs perfused with perfluorocarbon emulsion. 406 Nov 15

Isolated porcine coronary arteries contracted transiently when exposed to 20 mM Na salts of organic acids (acetate, propionate, butyrate and lactate) at constant external pH (pH0 = 7.4). The peak of these phasic contractions, completely inhibited by 1 mM amiloride, amounted to about 10% of that elicited by depolarization with 50 mM K0. The slope of the relaxing branch of the phasic contractions induced by 20 mM acetate in HEPES buffered physiological salt solution decreased from 1.05 +/- 0.12 to 0.49 +/- 0.07 mN/min (S.E.M.; n = 14), when Na0 was reduced from 137 to 20 mM. In Na free HEPES-buffered PSS only sustained contractions were obtained. The EC50 values for the concentration-response curves for contractions induced by K-propionate (2-20 mM) in Tris-PSS were 8.2 +/- 0.5 mM, n = 6. After total isoosmotic replacement of external Na+ by sucrose in bicarbonate-buffered PSS, contractions induced by 20 mM K-propionate had the same height as those induced with 50 mM K0+. Longlasting exposure to 0 Ca0 PSS did not affect significantly contractions induced by 20 mM propionate. During an exposure to procaine (10(-4) M) acetate-induced contractions were transiently and significantly enhanced, when induced in bicarbonate buffered PSS, but not in HEPES buffered PSS. In normally polarized PCA preparations 20 mM NH4+ induced both sustained relaxations and polyphasic responses; in depolarized PCA preparations only polyphasic responses were evoked. The time course of the polyphasic responses to application and removal of weak bases (NH(4+)-pulse technique) or to removal and reintroduction of CO2/HCO3- paralleled exactly the expected pHi perturbations, as they have been described in a great variety of cells and tissues, alkalinization leading however to relaxation, acidification to contraction. In presence of NH4+, a transient relaxation (phase 1) was immediately followed by an overshooting contraction (phase 2); at removal of NH4+ a rebound contraction (phase 3) was observed, reaching a peak and changing thereafter to a relaxation (phase 4), the slope of which was sensitive to variation of the external Na0 concentration. These mechanical effects were abolished by 1 hr exposure to 0 Ca PSS. Phase 2 was enhanced 2-5 fold in presence of TEA, Ba ions, Na3 VO4 or beta-methyldigoxin. Contractile responses of PCA preparations activated by various agonists (acetylcholine, histamine and serotonin) to pHi manipulations were similar and generally amplified when compared to unactivated preparations.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of manipulations of cytoplasmic pH on the mechanical responses of isolated porcine coronary arteries. 769 Dec 15

The main barrier for gas permeation across ionically cross-linked Langmuir-Blodgett (LB) bilayers, made from a 5,11,17,23,29,35-hexakis[( N, N, N-trimethylamonium)-N-methyl-37,38,39,40,41,42-hexakis-n-hexamedecyloxy-calix[6]arene hexachloride (1) and poly(sodium 4-styrenesulfonate) (PSS), has been determined by measuring the effects of NaCl on the thickness of the PSS layer encased between the calixarene layers and the permeation characteristics of the resulting membrane. Specifically, the fact that NaCl increases the uptake of PSS by the LB film and increases the permeance of these membranes toward N2 and CO2 but not He provides compelling evidence that the main barrier for permeation is the calixarene layers and not the PSS layer that is encased between them. The effects of NaCl on ionic cross-linking, surface pressure, and surface viscosities are discussed.
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PMID:Probing the gas permeability of an ionically cross-linked Langmuir-Blodgett bilayer with a "touch" of salt. 1846 79

In this paper, we report the development of synthetic CaO-based sorbents via a fast precipitation method with the assistance of sodium poly(styrenesulfonate) (PSS). The effect of PSS on physical properties of the CaO sorbents and their CO2 capture performance were investigated. The presence of PSS dispersed the CaO particles effectively as well as increased their specific surface area and pore volume remarkably. The obtained porous spherical structure facilitated CO2 to diffuse and react with inner CaO effectively, resulting in a significant improvement in initial CO2 carbonation capacity. A proper amount of Mg(2+) precursor solution was doped during a fast precipitation process to gain CaO-based sorbents with a high anti-sintering property, which maintained the porous spherical structure with the high specific surface area. CaO-based sorbents derived from a MgxCa1-xCO3 precursor existed in the form of CaO and MgO. The homogeneous distribution of MgO in the CaO-based sorbents effectively prevented the CaO crystallite from growing and sintering, further resulting in the favorable long-term durability with carbonation capacity of about 52.0% after 30 carbonation/calcination cycles.
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PMID:Porous spherical CaO-based sorbents via PSS-assisted fast precipitation for CO2 capture. 2525 9

Ergonomics has been a very important activity in the design process. However, ergonomics rarely includes the environmental requirements into the design of products. The article proposes and presents the Eco-Ergo model through its application to a real-world product, a washing machine, to allow designers and ergonomists to establish product design requirements in order to minimise environmental impacts related to user-product interaction during the use stage. This model uses a visual language of representation, Blueprinting-based, that helps designers explore problems they have not previously considered during the market research when a wide variety of products with different interaction elements is analysed. The application of this model allows direct efforts and attention on the user analysis phase in the most influential user's actions on the environmental performance of energy-related products during use, establishing ergonomics requirements related to users behaviour at the initial design phase. Practitioner summary: This study provides a proposal to incorporate ergonomics into the practice of eco-design through the use of human factors in the establishment of initial eco-design requirements. This blueprint-based model combines an empirical and theoretical approach, based on the product test developed by designers, ergonomists and environmentalists. Abbreviations: CO2: carbon dioxide; DBIM: design behaviour intervention model; DfSB: design for sustainable behaviour; DwI Method: design with intent method; LCA: life cycle assessment; LCD: liquid cristal display; MJ: megajoule; MTM: methods-time measurement; PSS: product-service system; RPM: revolutions per minute.
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PMID:Introducing ergonomics requirements in the eco-design of energy-related products from users' behaviour approach. 3090 20