Effect of Chitosan on Rheological, Mechanical, and Adhesive Properties of Pectin-Calcium Gel.

In the present study, chitosan was included in the pectin ionotropic gel to improve its mechanical and bioadhesive properties. Pectin-chitosan gels P-Ch0, P-Ch1, P-Ch2, and P-Ch3 of chitosan weight fractions of 0.00, 0.25, 0.50, and 0.75 were prepared and characterized by dynamic rheological tests, penetration tests, and serosal adhesion ex vivo assays. The storage modulus (G') and loss modulus (G″) values, gel hardness, and elasticity of P-Ch1 were significantly higher than those of P-Ch0 gel. However, a further increase in the content of chitosan in the gel significantly reduced these parameters. The inclusion of chitosan into the pectin gel led to a decrease in weight and an increase in hardness during incubation in Hanks' solution at pH 5.0, 7.4, and 8.0. The adhesion of P-Ch1 and P-Ch2 to rat intestinal serosa ex vivo was 1.3 and 1.7 times stronger, whereas that of P-Ch3 was similar to that of a P-Ch0 gel. Pre-incubation in Hanks' solution at pH 5.0 and 7.4 reduced the adhesivity of gels; however, the adhesivity of P-Ch1 and P-Ch2 exceeded that of P-Ch0 and P-Ch3. Thus, serosal adhesion combined with higher mechanical stability in a wide pH range appeared to be advantages of the inclusion of chitosan into pectin gel.

Serosal Adhesion Ex Vivo of Hydrogels Prepared from Apple Pectin Cross-Linked with Fe3+ Ions.

The study aims to investigate the adhesion of a hydrogel made of cross-linked low-methyl esterified pectin to rat intestinal serosa ex vivo. The adhesivity of the FeP hydrogel, which was cross-linked by Fe3+ cations, exceeded that of hydrogels cross-linked by Ca2+, Zn2+, and Al3+ cations. The concentration of the cross-linking cation failed to influence the adhesion of the pectin hydrogel to the serosa. The mechanical properties and surface microrelief of the pectin hydrogel were influenced by the type and concentration of the cross-linking cations. Fe3+ cations form a harder and more elastic gel than Ca2+ cations. Scanning electron microscopy analysis revealed the characteristic surface pattern of FeP hydrogel and its denser internal structure compared to Ca2+ cross-linked hydrogel. The effect of the salt composition of the adhesion medium was shown since the FeP hydrogel's adhesion to the serosa was lower in physiological solutions than in water, and adhesion in Hanks' solution was higher than in phosphate buffered saline. Serum proteins and peritoneal leukocytes did not interfere with the serosal adhesion of the FeP hydrogel. Pre-incubation in Hanks' solution for 24 h significantly reduced the adhesion of the FeP hydrogel to the serosa, regardless of the pH of the incubation. Thus, serosal adhesion combined with excellent stability and mechanical properties in physiological environments appeared to be advantages of the FeP hydrogel, demonstrating it to be a promising bioadhesive for tissue engineering.

Effect of Cross-Linking Cations on In Vitro Biocompatibility of Apple Pectin Gel Beads.

The study aimed to compare the in vitro biocompatibility of pectin gels formed by different cross-linking cations. Hydrogel beads named CaPG, ZnPG, FePG, and AlPG were prepared from 4% solutions of apple pectin using ionotropic gelling with CaCl2, ZnCl2, FeCl3, and AlCl3, respectively. Cations influenced the gel strength of the wet gel beads in the following order (least strong) Ca2+ < Zn2+ < Fe3+~Al3+ (most strong). The swelling degree of the CaPG beads after 24 h of incubation in the RPMI-1640 medium was 104%, whereas the ZnPG, FePG, and AlPG beads swelled by 76, 108, and 134%, respectively. The strength of the pectin gel decreased significantly after incubation in the RPMI-1640 medium for 24 h, regardless of the cross-linking cation, although the FePG beads remained the strongest. All the pectin beads adsorbed serum proteins to a low degree, however the serum protein adsorption by the ZnPG and FePG beads (1.46 ± 0.87 and 1.35 ± 0.19 µg/mm2) was more than the CaPG and AlPG beads (0.31 ± 0.36 and 0.44 ± 0.25 µg/mm2). All the pectin beads reduced the production of TNF-α and IL-10 by hPBMCs in response to LPS stimulation. The IL-1ß response of cells to LPS was significantly reduced by the CaPG, ZnPG, and FePG beads, whereas the AlPG beads enhanced it twofold. The CaPG, FePG, and AlPG beads had no cytotoxicity. The viability of hPBMCs and human fibroblasts incubated with ZnPG beads was 5.3 and 7.2%, respectively. Thus, the use of different cross-linking cations changed the properties of the pectin gel, which is important for biocompatibility.

Pyroptosis is a drug target for prevention of adverse cardiac remodeling: The crosstalk between pyroptosis, apoptosis, and autophagy.

Acute myocardial infarction (AMI) is one of the main reasons of cardiovascular disease-related death. The introduction of percutaneous coronary intervention to clinical practice dramatically decreased the mortality rate in AMI. Adverse cardiac remodeling is a serious problem in cardiology. An increase in the effectiveness of AMI treatment and prevention of adverse cardiac remodeling is difficult to achieve without understanding the mechanisms of reperfusion cardiac injury and cardiac remodeling. Inhibition of pyroptosis prevents the development of postinfarction and pressure overload-induced cardiac remodeling, and mitigates cardiomyopathy induced by diabetes and metabolic syndrome. Therefore, it is reasonable to hypothesize that the pyroptosis inhibitors may find a role in clinical practice for treatment of AMI and prevention of cardiac remodeling, diabetes and metabolic syndrome-triggered cardiomyopathy. It was demonstrated that pyroptosis interacts closely with apoptosis and autophagy. Pyroptosis could be inhibited by nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 inhibitors, caspase-1 inhibitors, microRNA, angiotensin-converting enzyme inhibitors, angiotensin Ⅱ receptor blockers, and traditional Chinese herbal medicines.

Polysaccharides of Salsola passerina: Extraction, Structural Characterization and Antioxidant Activity.

The above-ground part of the Salsola passerine was found to contain ~13% (w/w) of polysaccharides extractable with water and aqueous solutions of ammonium oxalate and sodium carbonate. The fractions extracted with aqueous sodium carbonate solutions had the highest yield. The polysaccharides of majority fractions are characterized by similar monosaccharide composition; namely, galacturonic acid and arabinose residues are the principal components of their carbohydrate chains. The present study focused on the determination of antioxidant activity of the extracted polysaccharide fractions and elucidation of the structure of polysaccharides using nuclear magnetic resonance (NMR) spectroscopy. Homogalacturonan (HG), consisting of 1,4-linked residues of α-D-galactopyranosyluronic acid (GalpA), rhamnogalacturonan-I (RG-I), which contains a diglycosyl repeating unit with a strictly alternating sequence of 1,4-linked D-GalpA and 1,2-linked L-rhamnopyranose (Rhap) residues in the backbone, and arabinan, were identified as the structural units of the obtained polysaccharides. HMBC spectra showed that arabinan consisted of alternating regions formed by 3,5-substituted and 1,5-linked arabinofuranose residues, but there was no alternation of these residues in the arabinan structure. Polysaccharide fractions scavenged the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical at 0.2-1.8 mg/mL. The correlation analysis showed that the DPPH scavenging activity of polysaccharide fractions was associated with the content of phenolic compounds (PCs).

Swelling, Protein Adsorption, and Biocompatibility In Vitro of Gel Beads Prepared from Pectin of Hogweed Heracleum sosnówskyi Manden in Comparison with Gel Beads from Apple Pectin.

The study aims to develop gel beads with improved functional properties and biocompatibility from hogweed (HS) pectin. HS4 and AP4 gel beads were prepared from the HS pectin and apple pectin (AP) using gelling with calcium ions. HS4 and AP4 gel beads swelled in PBS in dependence on pH. The swelling degree of HS4 and AP4 gel beads was 191 and 136%, respectively, in PBS at pH 7.4. The hardness of HS4 and AP4 gel beads reduced 8.2 and 60 times, respectively, compared with the initial value after 24 h incubation. Both pectin gel beads swelled less in Hanks' solution than in PBS and swelled less in Hanks' solution containing peritoneal macrophages than in cell-free Hanks' solution. Serum protein adsorption by HS4 and AP4 gel beads was 118 ± 44 and 196 ± 68 µg/cm2 after 24 h of incubation. Both pectin gel beads demonstrated low rates of hemolysis and complement activation. However, HS4 gel beads inhibited the LPS-stimulated secretion of TNF-α and the expression of TLR4 and NF-κB by macrophages, whereas AP4 gel beads stimulated the inflammatory response of macrophages. HS4 gel beads adsorbed 1.3 times more LPS and adhered to 1.6 times more macrophages than AP4 gel beads. Thus, HS pectin gel has advantages over AP gel concerning swelling behavior, protein adsorption, and biocompatibility.

Characterization and Biocompatibility Properties In Vitro of Gel Beads Based on the Pectin and κ-Carrageenan.

This study aimed to investigate the influence of kappa (κ)-carrageenan on the initial stages of the foreign body response against pectin gel. Pectin-carrageenan (P-Car) gel beads were prepared from the apple pectin and κ-carrageenan using gelling with calcium ions. The inclusion of 0.5% κ-carrageenan (Car0.5) in the 1.5 (P1.5) and 2% pectin (P2) gel formulations decreased the gel strength by 2.5 times. Car0.5 was found to increase the swelling of P2 gel beads in the cell culture medium. P2 gel beads adsorbed 30-42 mg/g of bovine serum albumin (BSA) depending on pH. P2-Car0.2, P2-Car0.5, and P1.5-Car0.5 beads reduced BSA adsorption by 3.1, 5.2, and 4.0 times compared to P2 beads, respectively, at pH 7. The P1.5-Car0.5 beads activated complement and induced the haemolysis less than gel beads of pure pectin. Moreover, P1.5-Car0.5 gel beads allowed less adhesion of mouse peritoneal macrophages, TNF-α production, and NF-κB activation than the pure pectin gel beads. There were no differences in TLR4 and ICAM-1 levels in macrophages treated with P and P-Car gel beads. P2-Car0.5 hydrogel demonstrated lower adhesion to serous membrane than P2 hydrogel. Thus, the data obtained indicate that the inclusion of κ-carrageenan in the apple pectin gel improves its biocompatibility.

Isolation, Chemical Characterization and Antioxidant Activity of Pectic Polysaccharides of Fireweed (Epilobium angustifolium L.).

The aim of this study was to isolate pectins with antioxidant activity from the leaves of Epilobium angustifolium L. Two pectins, EA-4.0 and EA-0.8, with galacturonic acid contents of 88 and 91% were isolated from the leaves of E. angustifolium L. by the treatment of plant raw materials with aqueous hydrochloric acid at pH 4.0 and 0.8, respectively. EA-4.0 and EA-0.8 were found to scavenge the DPPH radical in a concentration-dependent manner at 17-133 µg/mL, whereas commercial apple pectin scavenged at 0.5-2 mg/mL. The antioxidant activity of EA-4.0 was the highest and exceeded the activity of EA-0.8 and a commercial apple pectin by 2 and 39 times (IC50-0.050, 0.109 and 1.961 mg/mL), respectively. Pectins EA-4.0 and EA-0.8 were found to possess superoxide radical scavenging activity, with IC50s equal to 0.27 and 0.97 mg/mL, respectively. Correlation analysis of the composition and activity of 32 polysaccharide fractions obtained by enzyme hydrolysis and anionic exchange chromatography revealed that the antioxidant capacity of fireweed pectins is mainly due to phenolics and is partially associated with xylogalacturonan chains. The data obtained demonstrate that pectic polysaccharides appeared to be bioactive components of fireweed leaves with high antioxidant activity, which depend on pH at their extraction.

Lipophilic Metabolites from Five-Needle Pines, Pinus armandii and Pinus kwangtungensis, Exhibiting Antibacterial Activity.

Lipophilic extractive metabolites from needles and defoliated twigs of Pinus armandii and P. kwangtungensis were studied by GC/MS. Needles of P. armandii contained predominantly 15-O-functionalized labdane type acids (anticopalic acid), fatty acids, nonacosan-10-ol, sterols, nonacosan-10-ol and sterol saponifiable esters, and acylglycerols, while P. kwangtungensis needles contained no anticopalic acid, but more trinorlabdane (14,15,16-trinor-8(17)-labdene-13,19-dioic acid) and other labdane type acids, nonacosan-10-ol and its saponifiable esters. The major compounds in the P. armandii defoliated twig extract were abietane and isopimarane type acids, fatty acids, sterols, labdanoids (cis-abienol), cembranoids (isocembrol and 4-epi-isocembrol), saponifiable sterol esters, and acylglycerols. The same extract of P. kwangtungensis contained larger quantities of fatty acids, caryophyllene oxide, serratanoids, sterols, saponifiable sterol esters, and acylglycerols, but lesser amounts of abietane and isopimarane type acids, cis-abienol, and lacked cembranoids. Both twig and needle extracts of P. armandii and P. kwangtungensis, as well as the extracts' fractions, significantly inhibited the growth of Gram-negative bacteria Serratia marcescens with MIC of 0.1 mg ml-1 , while in most cases they slightly stimulated the growth of Gram-positive bacteria Bacillus subtilis at the same concentrations. Thus, lipophilic extractive compounds from the needles and defoliated twigs of both pines are prospective for the development of antiseptics against Gram-negative bacteria.

ALK2 inhibitors display beneficial effects in preclinical models of ACVR1 mutant diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine glioma (DIPG) is a lethal childhood brainstem tumour, with a quarter of patients harbouring somatic mutations in ACVR1, encoding the serine/threonine kinase ALK2. Despite being an amenable drug target, little has been done to-date to systematically evaluate the role of ACVR1 in DIPG, nor to screen currently available inhibitors in patient-derived tumour models. Here we show the dependence of DIPG cells on the mutant receptor, and the preclinical efficacy of two distinct chemotypes of ALK2 inhibitor in vitro and in vivo. We demonstrate the pyrazolo[1,5-a]pyrimidine LDN-193189 and the pyridine LDN-214117 to be orally bioavailable and well-tolerated, with good brain penetration. Treatment of immunodeprived mice bearing orthotopic xenografts of H3.3K27M, ACVR1R206H mutant HSJD-DIPG-007 cells with 25 mg/kg LDN-193189 or LDN-214117 for 28 days extended survival compared with vehicle controls. Development of ALK2 inhibitors with improved potency, selectivity and advantageous pharmacokinetic properties may play an important role in therapy for DIPG patients.

Mechanical properties of the pectin hydrogels and inflammation response to their subcutaneous implantation.

We studied the influence of the mechanical properties of pectin hydrogels on acute inflammation and tissue repair after subcutaneous implantation. We used hard and soft pectin hydrogels. The results of histology and the analysis of serum-level cytokines demonstrated that the intensity of acute inflammation increased with increasing hardness of the pectin hydrogels. We also showed that the pectin hydrogels did not inhibit tissue repair. The results of the morphometric and texture analysis of the pectin hydrogels showed that the in vivo biodegradation kinetics of hard hydrogels were greater than those of soft pectin hydrogels. We also observed that on the surface of the hard and soft pectin hydrogels, a network of collagen fibers was formed. The surface of the pectin hydrogel was shown to prevent the adhesion of infiltrating inflammatory cells. The results of the in vitro experiments demonstrated that pectin hydrogels inhibited the functional activity of macrophages and minimally activated the complement system. Therefore, we showed that soft pectin hydrogels have low proinflammatory potential and can be used in surgery as a barrier material as prevention of adhesions in the abdominal cavity. The hard pectin hydrogel can be used in tissue engineering. The hard pectin hydrogels can be used in the reconstruction of skin because are overpopulated with collagen fibers and contribute to the formation of new connective tissue, their elasticity is comparable to the skin and can be adjusted. They are biodegradable, and no additional manipulation is required to remove them.

The Possibility of Preventive and Therapeutic Use of Green Tea Catechins in Prostate Cancer.

BACKGROUND: Prostate cancer is one of the most frequent types of cancer. Despite the existence of various treatment strategies, treatment of prostate cancer still presents serious difficulties (especially in advanced stages). Polyphenols have been extensively assessed in terms of their potential use for prostate cancer treatment and prevention. Catechins are among the most well-known polyphenols in this respect. OBJECTIVE: In this review, we summarize clinical study results concerning catechin applications with regard to prostate cancer treatment and prevention. We discuss some of the main mechanisms of the anticarcinogenic action of catechins. CONCLUSION: The main mechanisms of the anticarcinogenic action of catechins are subdivided into two major types: (i) direct action on cancer cells and (ii) indirect effect based on catechins's impact on the microenvironment of cancer cells, particularly in relation to the immune system. At this level catechins might reduce tumor-associated inflammation and immune tolerance.

Pectin gelling in acidic gastric condition increases rheological properties of gastric digesta and reduces glycaemic response in mice.

The rheological characteristics and transit time of gastric digesta and the postprandial glycaemic response in mice orally administered with water (control) or pectin solutions supplemented (AP-Ca) or not supplemented (AP) with CaCO3 were elucidated. AP and AP-Ca increased viscosity, storage and loss moduluses (G' and G'') of mice gastric digesta. The gelling capacity of AP-Ca in acidic gastric conditions appeared to provide a greater enhancement of gastric digesta viscosity compared with AP. The postprandial blood glucose concentration was lower in mice orally administered with AP or AP-Ca compared with control mice. The transit time of gastric digesta and the blood glucose concentration were affected in mice orally administered with AP during the early postprandial period. The effect of AP-Ca on the gastric digesta rheology and transit time was stronger than that of AP. Both of the pectin solutions failed to reduce food intake in mice.

Swelling behavior and satiating effect of the gel microparticles obtained from callus cultures pectins.

Gel microparticles were prepared from pectins of campion (SVCgel) and duckweed (LMCgel) callus cultures, as well as from commercial apple pectin (APgel) by emulsion dehydration techniques with successive ionotropic gelation. The morphology and swelling behavior of the microparticles were determined after successive incubation in simulated gastric (SGF), intestinal (SIF), and colonic (SCF) fluids. Both SVCgel and LMCgel microparticles were found to swell in SGF and SIF gradually, and at oral administration decreased food intake by laboratory mice during the first 5 h of free-feeding. The SVCgel microparticles demonstrated the higher stability in SCF within 24 h than LMCgel ones. Only the SVCgel microparticles were shown to decrease food intake by 24% during the 21 h of free-feeding and decreased body weight of mice by 4% during 24 h after oral administration. The APgel microparticles lost their shape in SIF, then fully disintegrated after 0.5 h of incubation in SCF, and failed to affect food intake or mice body weight. The data obtained indicated that sustainability and swelling of the gel microparticles from the SVC pectin in the colonic fluid may provide the stronger satiating effect compared to that of the LMCgel microparticles.

Preparation and release characteristics of mesalazine loaded calcium pectin-silica gel beads based on callus cultures pectins for colon-targeted drug delivery.

The aim of this work is to produce calcium pectin-silica gel beads containing mesalazine as a drug model in order to control the drug release in the colon. The mesalazine loaded calcium pectin-silica gel beads were prepared using the ionotropic gelation method. Energy-dispersive X-ray analysis revealed that increasing the Na2SiO3 concentration led to an increase of the silicon content on the surface and in the cross-sections of the beads. The addition of Na2SiO3 to the gel formulations made from the duckweed callus culture pectin led to a decrease in the swelling degree that appeared to be related to the higher gel strength of these beads. The beads made from pectins of campion and duckweed callus cultures with adding of 22.2 mg/ml of Na2SiO3 showed the lowest release of mesalazine in simulated gastric and intestinal fluids. An increase in the reaction time up to 60 min during incubation in the cross-linking solution of CaCl2 led to a slower release of drug from the beads. An elevated release of mesalazine was achieved in the simulated colonic fluid. Prepared calcium pectin-silica gel beads containing mesalazine as a drug model can be proposed for controlled drug release in the colon.

Mechanical properties, structure, bioadhesion, and biocompatibility of pectin hydrogels.

The surface structure, biocompatibility, textural, and adhesive properties of calcium hydrogels derived from 1, 2, and 4% solutions of apple pectin were examined in this study. An increase in the pectin concentration in hydrogels was shown to improve their stability toward elastic and plastic deformation. The elasticity of pectin hydrogels, measured as Young's modulus, ranged from 6 to 100 kPa. The mechanical properties of the pectin hydrogels were shown to correspond to those of soft tissues. The characterization of surface roughness in terms of the roughness profile (Ra) and the root-mean-square deviation of the roughness profile (Rq) indicated an increased roughness profile for hydrogels depending on their pectin concentration. The adhesion of AU2% and AU4% hydrogels to the serosa abdominal wall, liver, and colon was higher than that of the AU1% hydrogel. The adhesion of macrophages and the non-specific adsorption of blood plasma proteins were found to increase as the pectin concentration in the hydrogels increased. The rate of degradation of all hydrogels was higher in phosphate buffered saline (PBS) than that in DMEM and a fibroblast cell monolayer. The pectin hydrogel was also found to have a low cytotoxicity. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2572-2581, 2017.

Composition and Bioactivity of Lipophilic Metabolites from Needles and Twigs of Korean and Siberian Pines (Pinus koraiensis Siebold & Zucc. and Pinus sibirica Du Tour).

Lipophilic extractive metabolites in different parts of the shoot system (needles and defoliated twigs) of Korean pine, Pinus koraiensis, and Siberian pine, Pinus sibirica, were studied by GC/MS. Korean pine needles comprised mainly bornyl p-coumarate, heterocyclic 15-O-functionalized labdane type acids (lambertianic acid), 10-nonacosanol, sterols and their esters. While Siberian pine needles contained less bornyl p-coumarate, lambertianic acid, sterols and their esters, but were richer in other 15-O-functionalized labdane type acids. The major components of the twig extract of P. koraiensis were lambertianic acid, abietane and isopimarane type acids, cembrane type alcohols, 8-O-functionalized labdanoids, sterols, sterol esters, and acylglycerols. The same extract of P. sibirica differed in larger amounts of other 15-O-functionalized labdane type acids and pinolenic acid glycerides, but in less quantities of cembranoids and 8-O-functionalized labdanoids. The labdane type pinusolic acid was detected for the first time in Korean pine. P. koraiensis was found to be unique in the genus for an ability to synthesize phyllocladane diterpenoids. The content of bound Δ5 -unsaturated polymethylene-interrupted fatty acids in the twig extracts of the both pines was similar or superior to that in their seed oil. Among the pines' metabolites tested isocembrol was strongest in inhibition of both α-glucosidase (IC50 2.9 µg/ml) and NO production in activated macrophages (IC50 3.6 µg/ml).

In vitro gastrointestinal-resistant pectin hydrogel particles for ß-glucuronidase adsorption.

Pectin hydrogel particles (PHPs) were prepared by ionotropic gelation of low methylesterified pectin of Tanacetum vulgare L. with calcium ions. Wet PHPs prepared from TVF exhibited a smaller diameter and the lower weight as well as exhibited the best textural properties in terms of hardness and elasticity compared to the PHPs prepared from commercial low methylesterified pectin (CU701) used for comparison. Upon air drying, PHPs prepared from CU701 became small and dense microspheres whereas the dry PHPs prepared from TVF exhibited a drop-like shape. The morphology of dry PHPs determined by scanning electron microscopy revealed that the surface of the TVF beads exhibited fibred structures, whereas the PHPs prepared from CU701 exhibited a smooth surface. The characterization of surface roughness using atomic force microscopy indicated less roughness profile of the PHPs prepared from TVF than CU701. PHPs prepared from TVF were found to possess in vitro resistance to successive incubations in simulated gastric (SGF), intestinal (SIF), and colonic fluid (SCF) at 37 °C for 2, 4 and 18 h, respectively. The PHPs prepared from CU701 swelled in SGF and then lost their spherical shape and were fully disintegrated after 4 h of incubation in SIF. The PHPs from TVF, which were subjected to treatment with SGF, SIF and SCF, were found to adsorb microbial ß-glucuronidase (ßG) in vitro. The data obtained offered the prospect for the development of the PHPs from TVF as sorbents of colonic ßG for the inhibition of re-absorption of estrogens.

Preparation and biocompatibility evaluation of pectin and chitosan cryogels for biomedical application.

Today, there is a need for the development of biomaterials with novel properties for biomedical purposes. The biocompatibility of materials is a key factor in determining its possible use in biomedicine. In this study, composite cryogels were obtained based on pectin and chitosan using ionic cryotropic gelation. For cryogel preparation, apple pectin (AP), Heracleum L. pectin (HP), and chitosan samples with different physical and chemical characteristics were used. The properties of pectin-chitosan cryogels were found to depend on the structural features and physicochemical characteristics of the pectin and chitosan within them. The addition of chitosan to cryogels can increase their mechanical strength, cause change in surface morphology, increase the degradation time, and enhance adhesion to biological tissues. Cryogels based on AP were less immunogenic when compared with cryogels from HP. Cryogels based on AP and HP were hemocompatible and the percentage of red blood cells hemolysis was less than 5%. Unlike cryogels based on HP, which exhibited moderate cytotoxicity, cryogels based on AP exhibited light cytotoxicity. Based on the results of low immunogenicity, light cytotoxicity data as well as a low level of hemolysis of composite cryogels based on AP and chitosan are biocompatible and can potentially be used in biomedicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 547-556, 2017.

Radionuclide Assessment of Cardiac Function and Dyssynchrony in Children with Idiopathic Ventricular Tachycardia.

BACKGROUND: The aim of the study was to evaluate the impact of idiopathic ventricular tachycardia and premature ventricular beats on cardiac function and dyssynchrony and to elucidate relationships between data of scintigraphic and intracardiac electrophysiology studies (EPSs). METHODS: The study comprised 64 patients with idiopathic ventricular arrhythmias (VAs; median age of 14 years ranging from 8 to 18 years). The control group comprised 20 patients (median age of 12 ranging from 7 to 16 years) without cardiac arrhythmias. EPS and radiofrequency ablation (RFA) procedure for VA were performed in 21 children according to indications. The functional state of both ventricles was assessed by gated blood pool single photon emission computer tomography (GBP-SPECT) before and after RFA in all patients. RESULTS: Patients with VA had local areas of asynchronous myocardial contraction (AMC). Compared with the control group, VA patients had significantly higher values of end-diastolic volume, end-systolic volume, and lower contractility indices. Negative association was found between total numbers of AMC areas and cardiac contractility indices. Ectopic foci localization, determined based on EPS data, was associated with AMC areas topography based on GBP-SPECT. RFA procedure significantly improved cardiac contractility indices; AMC areas completely disappeared or decreased compared with the preoperative conditions. CONCLUSION: In VA patients, AMC areas were localized mostly in the right ventricle. Comparison of the results of GBP-SPECT and EPS studies showed a relationship between AMC localizations and ectopic foci topography. The fact that AMC areas disappeared after RFA supports the hypothesis stating that the presence of AMC areas is a scintigraphic symptom of ectopic focus.