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- Ileum and colon perforation following peritoneal dialysis-related peritonitis and high-dose calcium polystyrene sulfonate. [JOURNAL ARTICLE]
- J Formos Med Assoc 2013 Apr 17.
A rare but severe complication, intestinal necrosis, has been reported after sodium polystyrene sulfonate (SPS; Kayexalate) and sorbitol intake. Some case reports described bowel perforation following calcium polystyrene sulfonate (CPS; Kalimate) administration. We report a case of ileum and colon perforation following peritoneal dialysis-related peritonitis and high-dose Kalimate in a 59-year-old female patient. The patient had a history of hypertension, diabetes mellitus, and end-stage renal disease (ESRD). During hospitalization for peritoneal dialysis-related peritonitis, she developed hyperkalemia, and Kalimate was administered orally. However, severe abdominal distension and pain occurred just one day after Kalimate intake. An urgent surgery disclosed several perforations in the ileum and sigmoid colon. Pathology of the resected gut showed transmural necrosis and perforation with basophilic angulated crystals. The patient finally expired during hospitalization due to refractory septic shock.
- Reactions of the tetraoxidosulfate(˙-) and hydroxyl radicals with poly(sodium α-methylstyrene sulfonate). [Journal Article]
- Phys Chem Chem Phys 2013 Apr 14; 15(14):4975-83.
Poly(α-methylstyrene sulfonic acid) (PAMS) represents a class of polymers that can form the protogenic constituent in electrolyte membranes for fuel cells. Oxidative stress is thought to play an important role in the degradation of the fuel cell membranes. Having previously established that damage may be mediated via abstraction of a benzylic hydrogen, we examined model compounds similar to those used before, but with a methyl group at the α-position. We studied the reaction of HO˙ and SO4(˙-), generated by pulse radiolysis, with model compounds in aqueous solution, and measured k = (2 ± 0.5) × 10(10) M(-1) s(-1) and (2 - 3) × 10(10) M(-1) s(-1) for the reaction of HO˙ with PAMS with average molecular weights of 2640 Da (PAMS-2640) and 6440 Da (PAMS-6440), respectively, at room temperature. At low pH, the decay of the hydroxycyclohexadienyl radical thus formed is accompanied by the formation of an absorption band in the visible region of the spectrum, which we tentatively assign to the radical cation of PAMS-2640 and -6440. The radical cation of PAMS-2640, formed by the reaction of SO4(˙-) with k = (6 ± 1) × 10(8) M(-1) s(-1), has a local absorption maximum at 560 nm, with ε560 ≥ 1400 M(-1) cm(-1). For the reaction of HO˙ and SO4(˙-) with the model compound benzenesulfonate, we measured k = (4-5) × 10(9) M(-1) s(-1) and (1.0 ± 0.3) × 10(8) M(-1) s(-1), respectively, while the reaction of SO4(˙-) with PAMS-6440 proceeds with (0.8-1) × 10(9) M(-1) s(-1). The 4-sulfophenoxyl radical was generated via the reaction of N3˙ with 4-hydroxybenzenesulfonate; ε410 ≥ 2300 M(-1) cm(-1). Not unexpectedly, the radical cation of PAMS is longer-lived than that of polystyrene sulfonic acid. Furthermore, fragmentation may result in desulfonation.
- Pretreatment of infant formula with sodium polystyrene sulfonate : focus on optimal amount and contact time. [Journal Article, Research Support, Non-U.S. Gov't]
- Paediatr Drugs 2013 Feb; 15(1):43-8.
In pediatric patients at risk of hyperkalemia there are limited treatment or preventive alternatives for this electrolyte imbalance. Oral or rectal sodium polystyrene sulfonate (SPS) has several potential adverse effects, and dietary potassium restriction may compromise nutrition. Pretreatment of infant formula with SPS has been previously studied with promising efficacy. The optimal dosing and contact time has not been fully elucidated for this practice, nor have brand and generic products been compared.The present study aimed to evaluate the effectiveness of varying amounts of brand and generic SPS for the removal of potassium from formula after 1 and 24 hours.SPS was added to infant formula in four different amounts measured in milliliters to reflect how a parent or caregiver would measure this product at home. After 1 and 24 hours samples were withdrawn and potassium and sodium levels were measured.Potassium decreased in all samples, with the greatest reduction after the addition of 10 mL of SPS. Sodium levels increased in all pretreated samples to a greater extent than the potassium reduction. Contact time of either 1 or 24 hours did not impact the amount of potassium removed or the increase in sodium concentration. There were also no differences found between generic and brand SPS products.The effectiveness of SPS for formula pretreatment appears to have a plateau effect beyond the addition of 20 mL (16.47 g of brand name product, 19.5 g of generic product). This study demonstrates an effective protocol for pretreatment of formula.
- Gastrointestinal adverse events with sodium polystyrene sulfonate (Kayexalate) use: a systematic review. [Journal Article, Review]
- Am J Med 2013 Mar; 126(3):264.e9-24.
Sodium polystyrene sulfonate (Kayexalate; Sanofi-Aventis, Paris, France) is a cation-exchange resin routinely used in the management of hyperkalemia. However, its use has been associated with colonic necrosis and other fatal gastrointestinal adverse events. Although the addition of sorbitol to sodium polystyrene sulfonate preparations was previously believed to be the cause of gastrointestinal injury, recent reports have suggested that sodium polystyrene sulfonate itself may be toxic. Our objective was to systematically review case reports of adverse gastrointestinal events associated with sodium polystyrene sulfonate use.MEDLINE (1948 to July 2011), EMBASE (1980 to July 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (1993 to July 27, 2011), bibliographies of identified articles, and websites of relevant drug agencies and professional associations in the United States and Canada were reviewed to identify eligible reports of adverse gastrointestinal events associated with sodium polystyrene sulfonate use. Causality criteria of the World Health Organization causality assessment system were applied to each report.Thirty reports describing 58 cases (41 preparations containing sorbitol and 17 preparations without sorbitol) of adverse events were identified. The colon was the most common site of injury (n=44; 76%), and transmural necrosis (n=36; 62%) was the most common histopathologic lesion reported. Mortality was reported in 33% of these cases due to gastrointestinal injury.Sodium polystyrene sulfonate use, both with and without sorbitol, may be associated with fatal gastrointestinal injury. Physicians must be cognizant of the risk of these adverse events when prescribing this therapy for the management of hyperkalemia.
- [Special role of phosphate in the stability of the protein to the destruction by polyelectrolyte]. [English Abstract, Journal Article]
- Bioorg Khim 2012 Jul-Aug; 38(4):421-30.
X-ray analysis shows the presence of specific anion-binding sites in proteins for sulfate, citrate and phosphate ions, but the functional role of these anions is not always clear. Thus, it is unknown which of the two types, mono- or divalent phosphate, plays an important role in the stability of proteins to stress effects on cells. In the present work, the influence of phosphate, sulfate, and chloride salt on the stability of lactate dehydrogenase (LDH) to its destruction by poly(styrenesulphonate) (PSS) was investigated by the methods of steady-state kinetics and the own protein fluorescence. The analysis was based on the differences between the influence of phosphate and sulfate ions on the process at two pH values, 6.2 and 7.0, at which the ratio of mono- and divalent phosphate changed, whereas sulfate remained in the divalent form. It was shown that the difference between the influence of phosphate and sulfate ions increased with increasing pH, which indicates that divalent phosphate ions much more effectively stabilized LDH compared to sulfate and monovalent phosphate. The differences in the effect of sulfate and chloride salts on the protein corresponded to differences in ionic strength of their solutions. The study of the own fluorescence of LDH in the complex with PSS showed that the rate of fluorescence quenching and the amplitude of the fast stage significantly decreased with increasing concentration of divalent phosphate in solution, as compared to the same effect in the presence of sulfate anions. The conclusion was made that, from two anion-binding sites in the LDH molecule, the intersubunit center is most important in stabilizing the protein to the destruction by polyelectrolyte, and from two phosphate anions, hydrophosphate HPO4(-2) plays the stabilizing role.
- Novel controllable auxetic effect of linearly elongated supported polyelectrolyte multilayers with amorphous structure. [Journal Article, Research Support, Non-U.S. Gov't]
- Phys Chem Chem Phys 2013 Jan 14; 15(2):483-8.
Polyelectrolyte multilayers (PEMs) deposited on flexible supports are promising candidates for many applications ranging from controlled wettability over stimuli responsive nanovalves to lithography free surface structuring. Since many potential applications involve elongation of these films, we investigated the effect of elongation on the PEM thickness and density with ellipsometry. To our surprise PEM films with known amorphous internal structure show auxetic behavior that depends on the PEM preparation condition. The measured refractive index was compared with simulated values using the Garnet equation to evaluate if the incorporation of water or air causes the observed phenomena.
- Colonic ulceration in a patient with renal disease and hyperkalemia. [Case Reports, Journal Article]
- JAAPA 2012 Oct; 25(10):34, 37-8.
- Divalent-anion salt effects in polyelectrolyte multilayer depositions. [Journal Article, Research Support, U.S. Gov't, Non-P.H.S.]
- Langmuir 2012 Nov 13; 28(45):15831-43.
We systematically investigate the effects of divalent anions on the assembly of polyelectrolyte multilayers by fabricating polystyrene sulfonate (PSS)/polyallylamine hydrochloride (PAH) multilayer films from aqueous solutions containing SO(4)(2-), HPO(4)(2-), or organic dicarboxylate dianions. The chosen concentrations of these anions (i.e., ≤0.05 M) allow us to isolate their effects on the assembly process from those of the polyelectrolyte solubility or solution ionic strength (maintained constant at μ = 1.00 M by added NaCl). Compared to a control film prepared from solutions containing only Cl(-) anions, stratified multilayers deposited in the presence of dianions exhibit increased UV absorbance, thickness, and roughness. From the dependence of film properties on the solution concentration of SO(4)(2-) and number of polyelectrolyte layers deposited, we derive a generic model for the PSS/PAH multilayer formation that involves adsorption of PAH aggregates formed in solution via electrostatic interactions of PAH with bridging dianions. Experiments using HPO(4)(2-) and organic dicarboxylate species of varying structure indicate that the separation, rigidity, and angle between the discrete negatively charged sites in the dianion govern the formation of the PAH aggregates, and therefore also the properties of the multilayer film. A universal linear relationship between film UV absorbance and thickness is observed among all dianion types or concentrations, consistent with the model.
- Polyethylenimine-capped Ag nanoparticle film as a platform for detecting charged dye molecules by surface-enhanced Raman scattering and metal-enhanced fluorescence. [Journal Article, Research Support, Non-U.S. Gov't]
- ACS Appl Mater Interfaces 2012 Oct 24; 4(10):5498-504.
Many drugs are charged molecules and are weak bases or acids having counterions. Their binding to biological surfaces is generally difficult to assess by vibrational spectroscopy. In this work, we demonstrated the potential of surface-enhanced Raman scattering (SERS) conducted using a polyethylenimine (PEI)-capped Ag nanoparticle film for the quantification of an electrostatic adsorption process of charged drug molecules, by using charged dye molecules such as sulforhodamine B (SRB) and rhodamine-123 (R123) as model drugs. It was possible to detect small-sized anions such as SCN(-) at 1 × 10(-9) M by SERS because of the cationic property of PEI. We were subsequently able to detect a prototype anionic dye molecule, SRB, by SERS at a subnanomolar concentration. On the other hand, it was difficult to detect cationic dyes such as R123 because of the electrostatically repulsive interaction with PEI. Nonetheless, we found that even R123 could be detected at subnanomolar concentrations by SERS by depositing an anionic polyelectrolyte such as poly(sodium 4-styrenesulfonate) (PSS) and poly(acrylic acid) (PAA) onto the PEI-capped Ag nanoparticles. Another noteworthy point is that a subnanomolar detection limit can also be achieved by carefully monitoring the fluorescence background in the measured SERS spectra. This was possible because charged dyes were not in contact with Ag but formed ion pairs with either PEI or PSS (PAA), allowing metal-enhanced fluorescence (MEF). The PEI-capped Ag nanoparticle film can thus serve as a useful indicator to detect charged drug molecules by SERS and MEF.
- Electrosteric stabilization and its role in cooperative magnetophoresis of colloidal magnetic nanoparticles. [Journal Article]
- Langmuir 2012 Oct 23; 28(42):14878-91.
A detailed study on the conflicting role that colloid stability plays in magnetophoresis is presented. Magnetic iron oxide particles (MIOPs) that were sterically stabilized via surface modification with poly(sodium 4-styrene sulfonate) of different molecular weights (i.e., 70 and 1000 kDa) were employed as our model system. Both sedimentation kinetics and quartz crystal microbalance with dissipation (QCM-D) measurements suggested that PSS 70 kDa is a better stabilizer as compared to PSS 1000 kDa. This observation is mostly attributed to the bridging flocculation of PSS 1000 kDa decorated MIOPs originated from the extended polymeric conformation layer. Later, a lab-scale high gradient magnetic separation (HGMS) device was designed to study the magnetophoretic collection of MIOPs. Our experimental results revealed that the more colloidally stable the MIOP suspension is, the harder it is to be magnetically isolated by HGMS. At 50 mg/L, naked MIOPs without coating can be easily captured by HGMS at separation efficiency up to 96.9 ± 2.6%. However, the degree of separation dropped quite drastically to 83.1 ± 1.2% and 67.7 ± 4.6%, for MIOPs with PSS 1000k and PSS 70k coating, respectively. This observation clearly implies that polyelectrolyte coating that was usually employed to electrosterically stabilize a colloidal system in turn compromises the magnetic isolation efficiency. By artificially destroying the colloidal stability of the MIOPs with ionic strength increment, the ability for HGMS to recover the most stable suspension (i.e., PSS 70k-coated MIOPs) increased to >86% at 100 mM monovalent ion (Na(+)) or at 10 mM divalent ion (Ca(2+)). This observation has verified the conflicting role of colloidal stability in magnetophoretic separation.