A Commercial Nonbinding Surface Effectively Reduces Fibrinogen Adsorption but Does Not Prevent Platelet Adhesion to Fibrinogen.

A commercial nonbinding surface effectively prevents protein adsorption; however, the platelet phenotype on this surface has yet to be defined. This study evaluates platelet adhesion and adsorption of several plasma/extracellular matrix (ECM) proteins to the nonbinding surface compared to other commonly used nontreated and high-binding surfaces. Platelet adhesion to uncoated microplates and those coated with fibrinogen or collagen is quantified by colorimetric assay. The binding capacity of the examined surfaces for plasma/ECM proteins is evaluated by measuring the relative and absolute protein adsorption. Compared to other surfaces, the nonbinding surface effectively prevents platelet adsorption, i.e. by 61-93% (Enzyme-Linked Immunosorbent Assay, ELISA), and reduces platelet adhesion, i.e. by 92%, when not coated with any protein. The nonbinding surface also decreases platelet deposition on collagen (up to 31%), but not fibrinogen. The nonbinding surface seems to be more of a low-fouling than nonfouling material, as it is able to reduce fibrinogen adsorption but not prevent platelet adhesion to fibrinogen. This feature should be considered when using the nonbinding surface for in vitro platelet testing.

Impacts of low concentrations of nanoplastics on leaf litter decomposition and food quality for detritivores in streams.

In forested streams, leaf litter decomposition is a vital ecosystem process, governed primarily by aquatic hyphomycetes. These fungi are crucial mediators of nutrients and energy to invertebrates and higher trophic levels. Very little information is available on the impact of low concentrations of different sizes of nanoplastic particles (NPPs) on leaf litter decomposition and aquatic hyphomycetes communities. Besides, NPPs impact on leaf litter nutritional quality and invertebrate feeding behaviour is unknown. We conducted a microcosm assay with varying concentrations (0-25 µg L-1) of small (100 nm; SNPPs) and large (1000 nm; LNPPs) plastic particles to assess their impact on leaf litter decomposition, sporulation rates and community structure of aquatic hyphomycetes. Furthermore, leaf litter was retrieved and fed to invertebrates to assess feeding rates. Our results indicated that leaf litter decomposition, fungal sporulation and abundance were significantly affected by NPPs concentrations and sizes. By contrast, leaf litter nutritional quality was impacted only by sizes. The NPPs, particularly SNPPs, augmented leaf litter polyunsaturated fatty acids (18-31%), consequently improving food quality; however, invertebrates' feeding rates were not impacted. Overall, our study provides novel insights on the risks posed by NPPs with pronounced impact at the basal trophic level.

Treatment of Mild Hyperkalemia in Hospitalized Patients: An Unnecessary Practice?

BACKGROUND: Sodium polystyrene sulfonate (SPS) is one of the most commonly used treatments for mild hyperkalemia. Other treatments include insulin, sodium bicarbonate, and salbutamol, which may be given alone or in combination. The results of research examining treatment effectiveness for mild hyperkalemia (e.g., the ability of SPS to achieve normokalemia) thus far have been inconsistent. Given that the effectiveness of treatment for mild hyperkalemia is debatable, new research is needed. OBJECTIVE: To determine whether treatment of hospitalized patients with mild hyperkalemia (using SPS or another approach, relative to no treatment) was associated with achievement of normokalemia (serum potassium < 5.1 mmol/L). METHODS: For this retrospective, quasi-experimental study, hospitalized patients with index serum potassium level between 5.1 and 6.4 mmol/L were identified. Post-index serum potassium level within 24 hours was dichotomized (< 5.1 or ≥ 5.1 mmol/L). Pre-index serum creatinine and serum potassium levels were recorded as the average of the first 5 values immediately before the index potassium value. For each patient, treatment was categorized as no treatment, SPS treatment, or other treatment strategy. RESULTS: Among the 1944 patients included in the analysis, the average age was 66.8 (standard deviation 13.5) years; 605 (31.1%) of the patients were women and 1339 (68.9%) were men. Logistic regression results indicated that patients who were female and/or had higher pre-index serum potassium were less likely to return to normokalemia within 24 hours after the time of the index serum potassium value. Treatment category was not a statistically significant predictor of the achievement of normokalemia. Most patients with mild hyperkalemia (> 74.5% in each treatment category) achieved normokalemia, whether or not they received treatment. CONCLUSIONS: The findings of this study suggest that although follow-up is required for mild hyperkalemia in hospitalized patients, active treatment may be unnecessary.

CONTEXTE: Le sulfonate de polystyrène de sodium (SPS) est l'un des traitements les plus communément utilisés pour l'hyperkaliémie légère. D'autres traitements comprennent l'insuline, le bicarbonate de sodium et le salbutamol, qui peuvent être administrés seuls ou ensemble. Les résultats des recherches se penchant sur l'efficacité des traitements de l'hyperkaliémie légère (p. ex., la capacité du SPS à rétablir la normokaliémie) sont contradictoires jusqu'à présent. Étant donné que l'efficacité du traitement de l'hyperkaliémie légère est discutable, de nouvelles recherches sont nécessaires. OBJECTIF: Déterminer si le traitement des patients hospitalisés, présentant une hyperkaliémie légère, (à l'aide de SPS ou d'une autre approche, comparativement à l'absence de traitement) était associé à l'atteinte de la normokaliémie (potassium sérique < 5,1 mmol/L). MÉTHODES: Des patients hospitalisés, dont l'indice de concentration sérique de potassium se situait entre 5,1 et 6,4 mmol/L, ont été identifiés pour participer à cette étude rétrospective quasi expérimentale. La concentration sérique de potassium mesurée dans les 24 heures après le diagnostic d'hyperkaliémie légère a été dichotomisée (< 5,1 ou ≥ 5,1 mmol/L). Les indices de concentrations sériques de créatinine et de potassium avant le diagnostic d'hyperkaliémie légère ont été obtenus par la moyenne des cinq premières valeurs situées immédiatement avant celle de la concentration de potassium. Le classement du traitement de chaque patient était le suivant: Aucun traitement, Traitement par SPS ou Autre stratégie de traitement. RÉSULTATS: L'âge moyen des 1944 patients inclus dans l'analyse était de 66,8 ans (écart type 13,5); 605 (31,1 %) d'entre eux étaient des femmes et 1339 (68,9 %) des hommes. Les résultats de la régression logistique indiquaient que les patientes, donc les femmes, qui avaient un indice sérique de potassium plus élevé au moment du diagnostic, avaient moins de chances de retourner à la normokaliémie dans les 24 heures après l'instant de la mesure de la valeur de l'indice sérique de potassium. La catégorie de traitement n'était pas une variable prédictive statistiquement significative de l'atteinte de la normokaliémie. La plupart des patients présentant une hyperkaliémie légère (> 74,5 % dans chaque catégorie de traitement) atteignaient la normokaliémie, qu'ils aient reçu ou non un traitement. CONCLUSIONS: Les résultats de cette étude laissent entendre que, malgré la nécessité d'un suivi des patients hospitalisés en cas d'hyperkaliémie légère, un traitement actif pourrait s'avérer inutile.

[Granulomatous lung disease induced by kayexalate inhalation during immunotherapy for metastatic melanoma]. / Pneumopathie granulomateuse induite par l'inhalation de Kayexalate® sous immunothérapie: Un diagnostic différentiel de progression tumorale et de toxicité pulmonaire spécifique des inhibiteurs de checkpoints immunitaires.

INTRODUCTION: When a patient treated by immune checkpoint inhibitors for metastatic melanoma presents with pulmonary symptoms, several diagnoses are possible. We report a case of acute granulomatous lung disease secondary to repeated kayexalate inhalations, and probably stimulated by immunotherapy. CASE REPORT: A patient treated with pembrolizumab and then ipilimumab presented with fever and acute shortness of breath. His pulmonary symptoms got progressively worse, leading to an acute respiratory distress syndrome. Chest CT displayed a pattern of non-specific organized pneumonia. Pulmonary infection, tumor progression, specific immune-related lung toxicity and immunotherapy-induced sarcoidosis were discussed. Histopathological examination of a lung biopsy showed a foreign body granulomatous macrophage reaction associated with crystalline, basophilic, purple and laminated elements, evoking kayexalate particles. These elements helped rewrite the diagnosis and confirmed a kayexalate-induced granulomatous lung disease secondary to repeated aspiration. The patient's respiratory condition got better following discontinuation of kayexalate together with systemic corticosteroids. Symptoms relapsed with resumption of the immunotherapy but were controlled with the addition of a new course of prolonged systemic corticosteroid therapy. We can hypothesize that immunotherapy played a role in the recurrence of the granulomatous lung reaction, or that there was an association between an aspiration pneumonia and an immunotherapy-induced lung toxicity. CONCLUSION: Facing respiratory symptoms during immunotherapy, the treatment may be the cause, but lung biopsy should be performed rapidly to arrive to a certain diagnosis.

Effect of the polydispersity on the dispersion of polymers through silicas having different morphologies (fully porous and core-shell particles and monoliths).

The effect of the polydispersity of polystyrenes on the dispersion through silicas having different morphologies (fully porous, core-shell particles and monoliths) was investigated. The heights equivalent to a theoretical plate (HETP) of those columns were measured for a small molecule (toluene) and a series of polystyrenes of different sizes in non-adsorbing conditions. The different contributions to the total HETP including polydispersity were determined experimentally. The longitudinal diffusion and the mass transfer resistance term were obtained from peak parking experiments. The eddy dispersion was obtained from models and experiments. The effect of polydispersity on the HETP values (Hpoly) can thus be calculated from the total HETP by substraction of the other contributions. The results were compared to the Knox model which surestimates the Hpoly values for porous and core-shell particles which is usually explained by an overestimation of the polydispersity index (PDI) given by the manufacturer. The PDI of two polymers (P02, Mw= 690 g.mol-1 and P03, Mw=1380 g.mol-1) was verified by liquid chromatography by separating each fraction of the polymer on the silica columns by using adsorbing conditions which are obtained with a mixture of heptane and THF. The PDI obtained are comparable to the PDI given by the manufacturer meaning that the assumptions made by Knox are not entirely valid. A direct method is proposed in this paper in order to determine Hpoly. In this method the excess of spreading as compared with a polymer with only one size corresponding to the average size is studied assuming the polymer size distribution is gaussian. The Hpoly values obtained by the direct method are comparable to the experimental values.

Characterization of Complex Branched Polymers by Multidetector Thermal Field-Flow Fractionation.

Size exclusion chromatography (SEC) for the molar mass analysis of polymers is of limited use for the analysis of branched polymers due to the co-elution of linear and branched molecules with similar hydrodynamic sizes but different molar masses. Thermal field-flow fractionation (ThFFF) in combination with multiple detection methods is a versatile alternative to SEC due to the fact that fractionation is not based entirely on molecular size but the interplay of thermal and translational diffusion that depend on molecular topology and molecular size. Multidetector ThFFF is used to investigate the correlation of branching and molar mass by determining polymer conformations from Mark-Houwink plots and the degrees of branching using functionality plots. The suitability of this approach is demonstrated for a set of 3-, 4-, and 6-arm star polystyrenes as well as a more complex hyperbranched polybutadiene-polystyrene copolymer. It is shown that ThFFF is a powerful tool for the analysis of the radius of gyration and the hydrodynamic radius when coupled online to static light scattering, viscometry, and dynamic light scattering. Shape factors are evaluated as influenced by branching where narrow dispersed star polystyrenes are used as model systems for the analysis of the more complex hyperbranched polybutadiene-polystyrene copolymer.

Syndiospecific Coordination Polymerization of Si-H-Containing Styrenes Catalyzed by Scandium Complex and Synthesis of Styrene-Based Triblock Copolymers.

The controlled syndiospecific polymerization of three Si-H-containing styrenes, that is, 4-(methylhydrosilyl)styrene (FSt-1), 4-(dimethylhydrosilyl)styrene (FSt-2) and 4-(diisopropylhydrosilyl)styrene (FSt-3), is realized in the presence of (C5 Me4 SiMe3 )Sc (CH2 C6 H5 )2 (THF)/[Ph3 C][B(C6 F5 )4 ]. Then a series of FSt-b-styrene-b-FSt triblock copolymers (FSt-St-FSt) are synthesized facilely via a sequential monomer feeding process (FSt-2, styrene, and FSt-2, respectively) during the polymerization. The syndiotactic polystyrene (sPS) block in the middle endows the copolymer with high melting point above 250 °C, whereas the Si-H groups on monomer FSt-2 introduce functional pendants to the end-blocks (with Si-H content of 31-63 mol%). Finally by a mild and high-effective hydrosilylation reaction, novel polar-group functionalized sPS is obtained.

Rectal ulcer due to Kayexalate deposition - an unusual case

SUMMARY Sodium polystyrene sulfonate (PSP) or Kayexalate is a cation-exchange resin, widely used in the management of hyperkalaemia due to renal disease. A rare, yet potentially dangerous, adverse event related to sodium polystyrene sulfonate use is intestinal mucosal injury, especially in the colon. The injury to the gastrointestinal mucosa can range from mild and superficial to wall necrosis and bowel perforation. The mechanism that leads to mucosal damage remains unclear. However, it is believed that sorbitol, commonly given to counteract PSP's tendency to cause constipation, may play an important role in the development of gastrointestinal injury. Other potential risk factors are uraemia or end-stage renal disease, hemodynamic instability, solid organ transplantation, postoperative status and concomitant opioid administration. The authors present a case of diarrhoea and haematochezia after the administration of PSP without sorbitol, in a patient with hyperkalaemia due to acute kidney injury, in the absence of other risk factors. A colonoscopy was performed and revealed a rectal ulcer which histological findings were suggestive of mucosal injury due to Kayexalate deposition. This case supports the concept that this widely used drug can itself, without sorbitol, cause injury to the gastrointestinal wall. Even though this is a rare adverse effect, the widespread use of this medication may put a large population at risk.

RESUMO O polistireno sulfonato de sódio (PSP) ou kayexalato é uma resina de troca iônica, amplamente usada no tratamento da hipercalemia associada à doença renal. Um efeito adverso raro, mas potencialmente grave, dessa terapêutica é a agressão à parede do trato gastrointestinal, principalmente ao nível do cólon, que pode ser ligeira e superficial ou culminar em necrose e perfuração intestinal. O mecanismo pelo qual o PSP lesa a mucosa intestinal não é totalmente conhecido. Contudo, pensa-se que o sorbitol, frequentemente administrado em simultâneo para contrabalançar o efeito obstipante do PSP, possa ter um papel preponderante no desenvolvimento de lesão gastrointestinal. Outros potenciais fatores de risco são a presença de uremia ou doença renal em estágio terminal, instabilidade hemodinâmica, pós-operatório, pós-transplante renal e a administração concomitante de opioides. Os autores descrevem um caso de diarreia e hematoquesias após a administração de PSP sem sorbitol, numa paciente com hipercalemia secundária a lesão renal aguda, sem outros fatores de risco para o desenvolvimento desse efeito adverso. A investigação etiológica com colonoscopia revelou a presença de uma úlcera retal, cujo estudo histológico foi compatível com lesão por deposição de cristais de kayexalato. Este relato incomum reforça o conceito de que este fármaco de uso frequente, mesmo na ausência de sorbitol, pode ser lesivo para a mucosa intestinal. Assim, e apesar de este ser um efeito adverso raro, a utilização difundida do PSP coloca uma vasta população em risco.

Linear solvation energy relationship (LSER) characterization of the normal phase retention mechanism on hypercrosslinked polystyrenes.

Linear solvation energy relationships (LSERs) were applied to retention on hypercrosslinked polystyrene on silica (HC-Tol) to elucidate the type and relative importance of molecular interactions between model solutes and the HC-Tol stationary phase. Classical amino phase and another hypercrosslinked phase (5-HGN) were used as reference columns. On both the HC-Tol and amino, polar interactions predominate and contribute to retention. Solute volume V has no impact on retention on the amino column, while V has a slightly negative influence on retention for the HC-Tol column. The differences in coefficient v between the amino and the HC-Tol columns might explain why the HC-Tol is capable of group-type separations. 5-HGN phase has smaller a and b values compared to HC-Tol, which means that 5-HGN is not as basic or acidic in terms of hydrogen bonds as is HC-Tol. This suggests that the hydrogen bonding character of the HC-Tol phase arises from its silica substrate.

Randomized, Controlled Trial of the Effect of Dietary Potassium Restriction on Nerve Function in CKD.

BACKGROUND AND OBJECTIVES: Neuromuscular complications are almost universal in CKD by the time that a patient commences dialysis. Recent studies have indicated that chronic hyperkalemia may contribute to the development of neuropathy in CKD. This study was undertaken to determine whether dietary restriction of potassium intake may be a neuroprotective factor in CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A 24-month prospective, single-blind, randomized, controlled trial was undertaken in 47 consecutively recruited patients with stages 3 and 4 CKD. The intervention arm (n=23) was prescribed a diet focusing on potassium restriction to meet a monthly serum potassium level of ≤4.5 mEq/L, with oral sodium polystyrene sulfonate provided if dietary advice failed to achieve the target. The control arm (n=24) received dietary advice regarding general nutrition. The primary outcome was the change in the total neuropathy score evaluated by a blinded observer. Secondary outcomes included electrolyte levels, gait speed, neurophysiologic parameters, and health-related quality of life scores. Five patients withdrew before initiation of treatment, and final analysis consisted of n=21 in each group. RESULTS: There was a greater increase in total neuropathy score from baseline to final assessment in the control arm compared with the intervention arm (6.1±6.2-8.6±7.9 controls; 7.8±7.4-8.2±7.5 intervention; change 2.8±3.3-0.4±2.2, respectively; P<0.01). The intervention significantly reduced mean serum potassium compared with controls (4.6±0.1-4.8±0.1 mEq/L mean recorded every 6 months over the trial duration; P=0.03). There were no adverse changes in other nutritional parameters. Improved gait speed was also noted in the intervention arm compared with the control arm, with a mean increase of 0.15±0.17 m/s in the intervention group versus 0.02±0.16 m/s in the control group (P=0.01). CONCLUSIONS: Our results provide important preliminary evidence that dietary potassium restriction confers neuroprotection in CKD and should be confirmed in a larger multicenter trial.

Randomized Clinical Trial of Sodium Polystyrene Sulfonate for the Treatment of Mild Hyperkalemia in CKD.

BACKGROUND AND OBJECTIVES: Hyperkalemia affects up to 10% of patients with CKD. Sodium polystyrene sulfonate has long been prescribed for this condition, although evidence is lacking on its efficacy for the treatment of mild hyperkalemia over several days. This study aimed to evaluate the efficacy of sodium polystyrene sulfonate in the treatment of mild hyperkalemia. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In total, 33 outpatients with CKD and mild hyperkalemia (5.0-5.9 mEq/L) in a single teaching hospital were included in this double-blind randomized clinical trial. We randomly assigned these patients to receive either placebo or sodium polystyrene sulfonate of 30 g orally one time per day for 7 days. The primary outcome was the comparison between study groups of the mean difference of serum potassium levels between the day after the last dose of treatment and baseline. RESULTS: The mean duration of treatment was 6.9 days. Sodium polystyrene sulfonate was superior to placebo in the reduction of serum potassium levels (mean difference between groups, -1.04 mEq/L; 95% confidence interval, -1.37 to -0.71). A higher proportion of patients in the sodium polystyrene sulfonate group attained normokalemia at the end of their treatment compared with those in the placebo group, but the difference did not reach statistical significance (73% versus 38%; P=0.07). There was a trend toward higher rates of electrolytic disturbances and an increase in gastrointestinal side effects in the group receiving sodium polystyrene sulfonate. CONCLUSIONS: Sodium polystyrene sulfonate was superior to placebo in reducing serum potassium over 7 days in patients with mild hyperkalemia and CKD.

Field efficacy of expanded polystyrene and shredded waste polystyrene beads for mosquito control in artificial pools and field trials, Islamic Republic of Iran

Concerns about traditional chemical pesticides has led to increasing research into novel mosquito control methods. This study compared the effectiveness of 2 different types of polystyrene beads for control of mosquito larvae in south-east Islamic Republic of Iran. Simulated field trials were done in artificial pools and field trials were carried out in 2 villages in an indigenous malaria area using WHO-recommended methods. Application of expanded polystyrene beads or shredded, waste polystyrene chips to pool surfaces produced a significant difference between pre-treatment and post-treatment density of mosquitoes [86% and 78% reduction respectively 2 weeks after treatment]. There was no significant difference between the efficacy of the 2 types of material. The use of polystyrene beads as a component of integrated vector management with other supportive measures could assist in the control of mosquito-borne diseases in the Islamic Republic of Iran and neighbouring countries

Impact of polystyrene beads as a mosquito control measure to supplement lymphatic filariasis elimination activities in Socotra Island, Yemen

Lymphatic filariasis [LF] is targeted for worldwide elimination. In Yemen, all mainland implementation units met the WHO criteria for stopping mass drug administration [MDA] after 5 rounds. However, in Socotra Island these criteria were not met. Our study evaluated the efficacy of applying expanded polystyrene beads [EPBs] on the Culex population and the effect on LF transmission. Human and mosquito surveys were conducted in 40 randomly selected households in Hadibo [capital of Socotra] before and after application of EPBs. The EPBs intervention resulted in a reduction in mosquito density of 80% and a 64.3% reduction in microfilaria prevalence. The majority of interviewed households [98%] thought EPBs considerably reduced the mosquito population. After the intervention all collected pools tested negative. Application of EPBs is an effective supplement to MDA for achieving the goal of LF elimination