Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036421 (PSS)
 10,989 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms that control intracellular pH (pHi) in vascular smooth muscle are not fully understood. These studies were performed to determine the identity and relative importance of the sarcolemmal transport systems that mediate net acid efflux in primary cultured vascular smooth muscle cells from canine femoral artery. In HEPES- or HCO3(-)-buffered physiological salt solution (HEPES-PSS, HCO3(-)-PSS), recovery from an acute acid load was totally dependent on external Na+. 5-[N-ethyl-N-isopropyl]amiloride (EIPA, 50 microM) inhibited pHi recovery 100 and 68% in HEPES-PSS and HCO3(-)-PSS, respectively. EIPA-insensitive pHi recovery in HCO3(-)-PSS was inhibited 48% by 4,4'-diisothyocyanostilbene-2,2'-disulfonic acid (DIDS). An outwardly directed H+ gradient stimulated amiloride-sensitive 22Na+ uptake, and an inwardly directed HCO3- gradient stimulated amiloride-insensitive 22Na+ uptake. The latter was inhibited by DIDS or prior depletion of cell Cl-. In HEPES-PSS, resting pHi was 7.17 +/- 0.03, was not affected by DIDS, but was lowered by EIPA or by removing extracellular Na+. In HCO3(-)-PSS, resting pHi was 7.25 +/- 0.02 (P less than 0.05) and was not affected by EIPA. Removing extracellular Na+ in the presence of EIPA decreased pHi in HCO3(-)-PSS but not in HEPES-PSS. DIDS lowered resting pHi in HCO3(-)-PSS, after which EIPA further lowered pHi. We conclude that acid efflux from these cells is mediated by a Na(+)-H+ exchanger and a Na(+)-dependent Cl(-)-HCO3- exchanger. In HEPES-PSS, acid efflux via the Na(+)-H+ exchanger maintains resting pHi. In HCO3(-)-PSS, additional acid efflux via the Na(+)-dependent Cl(-)-HCO3- exchanger results in a higher pHi. Although the Na(+)-H+ exchanger is primarily responsible for acid efflux after an acute acid load, the Na(+)-dependent Cl(-)-HCO3- exchanger is responsible for acid efflux under physiological conditions.
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PMID:Na(+)-H+ and Na(+)-dependent Cl(-)-HCO3- exchange control pHi in vascular smooth muscle. 216 79

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

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

A new approach of encapsulation of proteins in polyelectrolyte microcapsules has been developed using porous calcium carbonate microparticles as microsupports for layer-by-layer (LbL) polyelectrolyte assembling. Two different ways were used to prepare protein-loaded CaCO3 microparticles: (i) physical adsorption--adsorption of proteins from the solutions onto preformed CaCO3 microparticles, and (ii) coprecipitation--protein capture by CaCO3 microparticles in the process of growth from the mixture of aqueous solutions of CaCl2 and Na2CO3. The latter was found to be about five times more effective than the former (approximately 100 vs approximately 20 mug of captured protein per 1 mg of CaCO3). The procedure is rather mild; the revealed enzymatic activity of alpha-chymotrypsin captured initially by CaCO3 particles during their growth and then recovered after particle dissolution in EDTA was found to be about 85% compared to the native enzyme. Core decomposition and removal after assembly of the required number of polyelectrolyte layers resulted in release of protein into the interior of polyelectrolyte microcapsules (PAH/PSS)5 thus excluding the encapsulated material from direct contact with the surrounding. The advantage of the suggested approach is the possibility to control easily the concentration of protein inside the microcapsules and to minimize the protein immobilization within the capsule walls. Moreover, it is rather universal and may be used for encapsulation of a wide range of macromolecular compounds and bioactive species.
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PMID:Protein-calcium carbonate coprecipitation: a tool for protein encapsulation. 1593 74

Combination of adsorption by porous CaCO(3) microparticles and encapsulation by polyelectrolyte multilayers via the layer-by-layer (LbL) self-assembly was proposed for sustained drug release. Firstly, porous calcium carbonate microparticles with an average diameter of 5 microm were prepared for loading a model drug, ibuprofen (IBU). Adsorption of IBU into the pores was characterized by ultraviolet (UV), infrared (IR), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) experiment and X-ray diffraction (XRD). The adsorbed IBU amount Gamma was 45.1mg/g for one-time adsorption and increased with increasing adsorption times. Finally, multilayer films of protamine sulfate (PRO) and sodium poly(styrene sulfonate) (PSS) were formed on the IBU-loaded CaCO(3) microparticles by the layer-by-layer self-assembly. Amorphous IBU loaded in the pores of the CaCO(3) microparticles had a rapider release in the gastric fluid and a slower release in the intestinal fluid, compared with the bare IBU crystals. Polyelectrolyte multilayers assembled on the drug-loaded particles by the LbL reduced the release rate in both fluids. In this work, polymer/inorganic hybrid core-shell microcapsules were fabricated for controlled release of poorly water-soluble drugs. The porous inorganic particles are useful to load drugs in amorphous state and the polyelectrolyte multilayer films coated on the particle assuage the initial burst release.
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PMID:Combination of adsorption by porous CaCO3 microparticles and encapsulation by polyelectrolyte multilayer films for sustained drug delivery. 1635 36

Besides the classical atom/ion/molecule based mechanism, nonclassical crystallization provides a nanoparticle-based crystallization pathway toward single crystals. However, there is a lack of experimentally established strategies for engineering a range of crystalline microstructures from common nanoparticles by nonclassical crystallization. We demonstrate that a commercial random copolymer polyelectrolyte poly(4-styrene sulfonate)-co-(maleic acid) (PSS-co-MA) considerably guides crystallization of calcium carbonate (CC) with a high versatility. The bioinspired nonclassical crystallization protocol yielded a series of calcite microstructures. Calcite single crystals obtained at low supersaturation show a pseudo-dodecahedral shape with curved faces, whereas increasing supersaturation generated calcite mesocrystals with pseudo-octahedral shapes and scalloped surfaces. Further increase of supersaturation induced the formation of polycrystalline multilayered and hollow spheres. In the initial growth stage of all these microstructures, amorphous CC nanoparticles formed as the early product. Remarkably, microparticles with minimal primitive (P)-surface were captured as the prominent intermediate indicative of liquidlike behavior. Moreover, nanogranular structures exist broadly in the as-synthesized crystals. These results demonstrate that the polyelectrolyte can effectively stabilize the amorphous CC nanoparticle precursors, impart control over the evolution from amorphous precursors via a liquid aggregate through P-surface intermediates to the final crystals, and thus allow the morphogenesis. Simple variation of calcium and polyeletrolyte concentrations enables a systematic control over the size and morphology of particles among pseudo-dodecahedra, pseudo-octahedra, multilayered spheres, and hollow spheres, which are expressed in a morphology diagram. A unifying nanoparticle aggregation formation mechanism was suggested to explain the morphogenesis by the combination of nonclassical crystallization and surface area minimization principles.
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PMID:Polyelectrolyte-directed nanoparticle aggregation: systematic morphogenesis of calcium carbonate by nonclassical crystallization. 1957 17

Shape-controlled synthesis of calcium carbonate with specific polymorphs can be achieved by the assistance of organic additives. In this study, highly uniform nanosized calcium carbonate spheres were synthesized by a fast precipitation method in the presence of a simple polymer, poly(styrene sulfonate) (PSS). The polymorph of the synthesized calcium carbonate products changes from pure calcite in PSS-free reactions to vaterite in PSS-containing (1-50 g/L) reactions. The effect of PSS on the formation of vaterite can be attributed to the two aspects: decrease of driving force by reducing the interfacial energy, and phase stabilization effect caused by the adsorbed PSS. A higher PSS concentration (50 g/L) results in highly uniform vaterite nanospheres of 400-500 nm in diameter. Furthermore, PSS is found more effective to induce the formation of vaterite in the Ca(2+)-rich reaction condition (Ca(2+):CO(3)(2-)=5:1) than in the CO(3)(2-)-rich conditions (Ca(2+):CO(3)(2-)=1:5). It has also been found that different mixing mode of the calcium and carbonate precursor solutions has a significant influence on the size distribution of the products. Finally, with a controlled anion-exchange method, the as-prepared vaterite nanospheres can be easily transformed to hollow hydroxyapatite spheres, which exhibit great potential to be used as the drug carriers due to their considerably high surface area and biocompatibility.
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PMID:Fast precipitation of uniform CaCO3 nanospheres and their transformation to hollow hydroxyapatite nanospheres. 2084 64

Polyelectrolyte microcapsules with avidin-poly(styrene sulfonate) (PSS) membrane were prepared by a layer-by-layer deposition technique. The uptake and release of biotin-labeled fluorescein (b-FITC) as well as immobilization of biotin-labeled glucose oxidase (b-GOx) to the microcapsule were studied. The polyelectrolyte microcapsules were prepared by coating the surface of calcium carbonate (CaCO(3)) microparticles with an avidin/PSS multilayer membrane, followed by dissolution of CaCO(3) core in an ethylenediaminetetraacetic acid solution. Inner and outer poly(allylamine)/PSS films were required to isolate the microcapsules, whereas microcapsules could not be formed without the support. The uptake of b-FITC into the microcapsule was highly enhanced through a strong binding of b-FITC to avidin as compared with the uptake of biotin-free FITC. Release of b-FITC from the microcapsule was accelerated upon addition of biotin due to a competitive binding of the added biotin to the binding site of avidin. Similarly, the surface of microcapsule was modified with b-GOx with retaining its catalytic activity.
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PMID:Avidin/PSS membrane microcapsules with biotin-binding activity. 2159 84

Calcium carbonate particles with a novel bowknot-like superstructure were fabricated in the presence of poly(sodium 4-styrene sulfate) (PSS) and under the assistance of ultrasonication during the initial reaction stage. X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and field-emission scanning electron microscopy (FE-SEM) equipped with energy-dispersive X-ray (EDX) were used to characterize the particles. Results demonstrated that the bowknot-like calcium carbonate particles were mainly composed of amorphous calcium carbonate (ACC) and some amounts of calcite and vaterite. Ultrasound irradiation associated with the presence of PSS affects the mesoscale crystallization, resulting in stepwise growth of the earlier bundles to the bowknot. Morphology evolution and dissolution of the bowknot particle were observed in different media, confirming that PSS and Ca(2+) ions in the solutions could accelerate and resist the transformation process, respectively. In the presence of PSS, ACC prefers to transform into vaterite.
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PMID:Preparation and structure evolution of bowknot-like calcium carbonate particles in the presence of poly(sodium 4-styrene sulfate). 2286 60

Hypoparathyroidism in systemic sclerosis is extremely rare with only a single case reported till date. Idiopathic hypoparathyroidism with systemic sclerosis was diagnosed in a 59-year-old gentleman who had presented with recurrent seizures, instability of gait, skin thickening and tightening over both legs and forearms, and arthritis. Examination was significant for positive Trousseau sign and cerebellar ataxia. Evaluation revealed bilateral symmetrical cerebellar and basal ganglia calcification, sensorineural deafness, low serum calcium, elevated serum phosphorus, normal magnesium, normal vitamin D, low plasma parathyroid hormone, high titer of thyroid peroxidase antibody, positive centromere pattern antinuclear antibody, strongly positive anti-topoisomerase-1 (Scl-70) antibody, nonvisualization of parathyroids on neck ultrasonography and skin biopsy suggestive of hyperkeratosis, increased collagen in dermis, and perivascular lymphomononuclear cell infiltration compatible with scleroderma. Last evaluated 10 months after the diagnosis, his ataxia had improved, he remained seizure-free, Trousseau sign was negative, and he had low-normal calcium calcium with calcium carbonate and calcitriol supplementation and switch from phenytoin to valproate. Further studies are warranted to study the use of serum calcium as a screening test for hypoparathyroidism in patients with systemic sclerosis.
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PMID:Idiopathic hypoparathyroidism and systemic sclerosis: An association likely missed. 2356 41


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