Reconstructing the microstructure of polyimide-silicalite mixed-matrix membranes and their particle connectivity using FIB-SEM tomography.

Properties of a composite material made of a continuous matrix and particles often depend on microscopic details, such as contacts between particles. Focusing on processing raw focused-ion beam scanning electron microscope (FIB-SEM) tomography data, we reconstructed three mixed-matrix membrane samples made of 6FDA-ODA polyimide and silicalite-1 particles. In the first step of image processing, backscattered electron (BSE) and secondary electron (SE) signals were mixed in a ratio that was expected to obtain a segmented 3D image with a realistic volume fraction of silicalite-1. Second, after spatial alignment of the stacked FIB-SEM data, the 3D image was smoothed using adaptive median and anisotropic nonlinear diffusion filters. Third, the image was segmented using the power watershed method coupled with a seeding algorithm based on geodesic reconstruction from the markers. If the resulting volume fraction did not match the target value quantified by chemical analysis of the sample, the BSE and SE signals were mixed in another ratio and the procedure was repeated until the target volume fraction was achieved. Otherwise, the segmented 3D image (replica) was accepted and its microstructure was thoroughly characterized with special attention paid to connectivity of the silicalite phase. In terms of the phase connectivity, Monte Carlo simulations based on the pure-phase permeability values enabled us to calculate the effective permeability tensor, the main diagonal elements of which were compared with the experimental permeability. In line with the hypothesis proposed in our recent paper (Capek, P. et al. (2014) Comput. Mater. Sci. 89, 142-156), the results confirmed that the existence of particle clusters was a key microstructural feature determining effective permeability.

Serum levels of matrix metalloproteinases 2 and 9 and TGFBR2 gene screening in patients with ascending aortic dilatation.

Development of ascending aortic dilatation (AAD) in about 10 % of patients operated for aortic valve disease (AVD) is probably based on intrinsic pathology of the aortic wall. This may involve an abnormality in the process of extracellular matrix remodelling. The present study evaluated the serum levels of specific metalloproteinases (MMP-2 and MMP-9) and investigated the gene for transforming growth factor receptor 2 (TGFBR2) in 28 patients with AVD associated with AAD (mean age 60.6 years), in 29 patients (68.9 years) with AVD without AAD, and in 30 healthy controls (45.3 years). The serum levels of MMPs were determined by ELISA. Further, we focused on genetic screening of the TGFBR2 gene. Plasma MMP-2 concentrations were significantly higher in the groups of patients compared to the controls: median 1315.0 (mean 1265.2 ± SD 391.3) in AVD with AAD, 1240.0 (1327.8 ± 352.5) in AVD without AAD versus 902.5 (872.3 ± 166.2) ng/ml in the healthy controls, in both cases P < 0.001. The serum levels of MMP-9 were significantly higher in AVD with AAD patients [107.0 (202.3 ± 313.0)] and in AVD without AAD patients [107.0 (185.8 ± 264.3)] compared to the healthy controls [14.5 (21.2 ± 24.8) ng/ml], in both cases P < 0.001. No significant correlation was observed between plasma MMP-2 and MMP-9 and ascending aorta diameter. Genetic screening did not reveal any variation in the TGFBR2 gene in the patients. Measurement of MMP levels is a simple and relatively rapid laboratory test that could be used as a biochemical indicator when evaluated in combination with imaging techniques.

Growth and anatomical parameters of adventitious roots formed on mung bean hypocotyls are correlated with galactoglucomannan oligosaccharides structure.

The effect of galactoglucomannan oligosaccharides (GGMOs) compared with chemically modified oligosaccharides, GGMOs-g (with reduced number of D-galactose side chains) and GGMOs-r (with reduced reducing ends) on mung bean (Vigna radiata (L.) Wilczek) adventitious roots formation, elongation, and anatomical structure have been studied. All types of oligosaccharides influenced adventitious root formation in the same way: stimulation in the absence of exogenous auxin and inhibition in the presence of exogenous auxin. Both reactions are probably related with the presence/content of endogenous auxin in plant cuttings. However, the adventitious root length was inhibited by GGMOs both in the absence as well as in the presence of auxin (IBA or NAA), while GGMOs-g inhibition was significantly weaker compared with GGMOs. GGMOs-r were without significant difference on both processes, compared with GGMOs. GGMOs affected not only the adventitious root length but also their anatomy in dependence on the combination with certain type of auxin. The oligosaccharides influenced cortical cells division, which was reflected in the cortex area and in the root diameter. All processes followed were dependent on oligosaccharides chemical structure. The results suggest also that GGM-derived oligosaccharides may play an important role in adventitious roots elongation but not in their formation.

Antitussive activity of Althaea officinalis L. polysaccharide rhamnogalacturonan and its changes in guinea pigs with ovalbumine-induced airways inflammation.

AIM: The presented studies were aimed on experimental confirmation of Althaea officinalis polysaccharide rhamnogalacturonan antitussive effect and its changes in conditions of allergic inflammation. METHODS: We have tested whether rhamnogalacturonan inhibits cough reflex and modulates airways reactivity of guinea pigs in vivo. The cough in guinea pigs was induced by 0.3 M citric acid (CA) aerosol for 3 min interval, in which total number of cough efforts (sudden enhancement of expiratory flow accompanied by cough movement and sound) was counted. Specific airway resistance and its changes induced by citric acid aerosol were considered as an indicator of the in vivo reactivity changes. RESULTS: 1) Althaea officinalis polysaccharide rhamnogalacturonan dose- dependently inhibits cough reflex in unsensitized guinea pigs. Simultaneously, plant polysaccharide shortened the duration of antitussive effect when it was been tested in inflammatory conditions. 2) Rhamnogalacturonan did not influence airways reactivity in vivo conditions expressed as specific resistance values neither sensitized nor unsensitized groups of animals. 3) The antitussive activity of codeine (dose 10 mg.kg(-1) b.w. orally) tested under the same condition was comparable to higher dose of rhamnogalacturonan in unsensitized animals. 4) The characteristic cellular pattern of allergic airways inflammation was confirmed by histopathological investigations. CONCLUSION: Rhamnogalacturonan isolated from Althaea officinalis mucilage possesses very high cough suppressive effect in guinea pigs test system, which is shortened in conditions of experimentally induced airways allergic inflammation (Tab. 1, Fig. 4, Ref. 25). Full Text in free PDF www.bmj.sk.

Dietary fibre degradation and fermentation by two xylanolytic bacteria Bacteroides xylanisolvens XB1A and Roseburia intestinalis XB6B4 from the human intestine.

AIMS: To characterize fibre degradation, colonization and fermentation, and xylanase activity of two xylanolytic bacteria Bacteroides xylanisolvens XB1A(T) and Roseburia intestinalis XB6B4 from the human colon. METHODS AND RESULTS: The bacteria grew well on all the substrates chosen to represent dietary fibres: wheat and corn bran, pea, cabbage and leek fibres, and also on purified xylans. Roseburia intestinalis colonized the substrates more efficiently than Bact. xylanisolvens. For the two bacteria, 80-99% of the total xylanase activity was associated with the cells whatever the substrate and time of growth. Optimal specific activities of cells were obtained on oat spelt xylan; they were higher than those previously measured for xylanolytic bacteria from the human gut. Roseburia intestinalis produced high molecular mass xylanases (100-70 kDa), while Bact. xylanisolvens produced lower molecular mass enzymes, including a cell-associated xylanase of 37 kDa. CONCLUSIONS: The two bacteria display very high xylanolytic activity on the different substrates. Differences were observed on substrate attachment and enzyme systems, suggesting that the two species occupy different niches within the gut microbiota. SIGNIFICANCE AND IMPACT OF THE STUDY: This study characterizes xylan degradation by two major species of the human intestine.

Axonal transport of dopamine- -hydroxylase by human sural nerves in vitro.

Dopamine-beta-hydroxylase activity accumulated above a ligature on biopsy samples of normal human sural nerves incubated in vitro. The rate of accumulation indicated that this enzyme was transported distally at a velocity of 2 millimeters per hour. Axoplasmic transport of dopamine-beta-hydroxylase was greatly reduced in sural nerves from a few patients with peripheral neuropathies.

The effect of rosiglitazone on the expression of thrombogenic markers on leukocytes in type 2 diabetes mellitus.

Diabetes mellitus is associated with a number of prothrombotic abnormalities, and correction of these abnormalities might translate into the reduction of cardiovascular risk. Glitazones improve endothelial function and reduce inflammation, but much less is known about their effect on thrombogenic factors. We have therefore studied the effect of rosiglitazone on leukocyte and soluble thrombogenic markers in patients with type 2 diabetes mellitus. Thirty-three subjects with type 2 diabetes and 32 normal controls were included; patients were examined at baseline and after 5 months of rosiglitazone treatment (4 mg/day). We measured leukocyte-platelet aggregates and leukocyte expression of either P-selectin glycoprotein ligand 1 (PSGL-1) or receptor for urokinase-type plasminogen activator (uPAR) using flow cytometry, as well as several circulating soluble thrombogenic markers by ELISA method. Leukocyte expression of uPAR and PSGL-1 was significantly higher in patients than in controls. Leukocyte-platelet aggregates and leukocyte expression of uPAR and PSGL-1 significantly decreased after rosiglitazone. There was also significant decrease in CRP and fibrinogen levels, but there was no effect of diabetes and/or rosiglitazone on other circulating molecules. In conclusions, we observed a substantial improvement in the expression of thrombogenic markers on leukocytes after rosiglitazone treatment, suggesting the novel antithrombotic effects of rosiglitazone.

Scavenging and antioxidant activities of immunomodulating polysaccharides isolated from Salvia officinalis L.

Crude polysaccharides, isolated from the aerial parts of sage (Salvia officinalis L.) by sequential extraction with water (A), hot ammonium oxalate (B), dimethyl sulfoxide (C), 1M (D) and 4M (E) potassium hydroxide solutions, and six ion-exchange fractions of A were examined for their ability to inhibit peroxidation of liposome lipid by hydroxyl radicals and to reduced DPPH radical content. The highest inhibition of liposome lipid peroxidation was found with crude polysaccharides A, B and D, antioxidant activities reached approximately 37%. The purified fractions A1 and A2 inhibited the liposome peroxidation to approximately 35%. However, the radical scavenging abilities of the most active crude polysaccharides A, B and C on DPPH radicals were found in the range 80-90%, while the most active purified fractions A3-A6 in three or fourfold doses achieved 75-92%. The least effective tested polysaccharides succeeded 20% inhibition using both methods.

The extracellular proteoglycan produced by Rhodella grisea.

Highly viscous extracellular proteoglycan (EPG) has been isolated from culture medium of the unicellular red alga Rhodella grisea (Rhodophyceae) by ethanol precipitation. EPG was composed of xylose (29.3%), 3-O-methyl-xylose (26.0%), uronic acids (17.1%), rhamnose (14.4%), galactose (7.5%), glucose (3.9%), arabinose (1.4%) and mannose (0.4%), and traces of fucose, 4-O-methyl-xylose and 2,3-di-O-methyl-rhamnose or fucose. In addition, the polymer contained proteins (13.1%), sulphates and 13C-CP MAS spectra indicated the presence of acetyl and succinyl groups. The molecular mass was estimated to be 136,000. Ion-exchange chromatography afforded five fractions differing in composition of neutral sugars, uronic acids, and protein content indicating thus the complex structure of the EPG.

An extracellular galactoxylomannan of acapsular Cryptococcus laurentii mutant.

An extracellular galactoxylomannan (GalXM) composed of D-Gal (34.0%), D-Xyl (26.6%) and D-Man (31.0%), and a small amount of L-Ara (4.0%) and D-Glc (4.4%) has been isolated from culture medium of acapsulated mutant of Cryptococcus laurentii by ethanol precipitation and gel filtration. Phosphorylated polymer of Mw approximately 75,000 contained 90% carbohydrates, 3.9% phosphorus and 5.3% proteins. Results of chemical and spectroscopic studies showed a highly branched structure of GalXM with a 1,6-linked mannopyranosyl-galactopyranosyl backbone (approximately 44%) branched predominantly at C-2 and C-3 of mannosyl, and C-3 of galactosyl residues by side chains terminated mainly by xylosyl and mannosyl residues, and to a less extent by arabinosyl and glucosyl ones.

Hypertrophic cardiomyopathy--molecular genetic analysis of exons 9 and 11 of the TNNT2 gene in Czech patients.

OBJECTIVES: Our research is a pilot study that specializes in the molecular genetic investigation of the TNNT2 gene in Czech patients with HCM/FHC disease. This study was initiated with exons 9 and 11 of TNNT2 because of their crucial role in the binding ability of cardiac troponin T to alpha-tropomyosin, and continued with analyses in other regions of the gene. METHODS: Hundred and eighty-one Czech probands with HCM/FHC were enrolled in this study. The study group consisted of 24 families with FHC and probands without FHC history but with HCM diagnosis. The clinical diagnosis was based on echocardiography. DNA was isolated from peripheral blood lymphocytes and subsequently analyzed by the polymerase chain reaction (PCR), followed by DNA sequencing analyses, which were cross-sequenced. RESULTS: The DeltaGlu160 mutation was observed in a sequence of the TNNT2 gene in a patient with the severe form of hypertrophic cardiomyopathy. No sequence alteration was found in exons 9 and 11 of the TNNT2 gene found in the rest of the DNA samples. CONCLUSION: The DeltaGlu160 mutation was observed in patients with severe forms of hypertrophic cardiomyopathy. This region is responsible for binding troponin T to alpha-tropomyosin. This mutation may lead to functional and structural effects on the troponin T protein. Mutations in this region are reported relatively rarely and therefore it was unique to observe the DeltaGlu160 mutation in our study.

Hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy is a multigenetic cardiac disease with autosomal dominant pattern of inheritance and incomplete penetrance, with the exclusion of those cases caused by mutations in the mitochondrial genome. The disease is usually caused by mutations in several sarcomeric contractile protein genes. Mutations have been found in four genes that encode components of the thick filament: beta myosin heavy chain (5), essential myosin light chains (6), regulatory myosin light chains (6), and cardiac myosin binding protein -C (7), (8); in five genes that encode thin filament proteins: cardiac actin (9), cardiac troponin T (10), cardiac troponin C (11), cardiac troponin I (12), and alpha-tropomyosin (10); and in the sarcomeric cytoskeletal protein titin (13). In addition to mutations in contractile sarcomeric proteins, mutations in other genes encoding for non-sarcomeric proteins also have been identified in patients with-non pure form of hypertrophic cardiomyopathy. As a complex cardiac disease, hypertrophic cardiomyopathy has unique pathophysiological characteristics and a various morphological, functional, and clinical features.

The antiviral potency of Fagus sylvatica 4OMe-glucuronoxylan sulfates.

Herpes simplex virus belongs to Herpesviridae family and causes infection of humans from ancient times. 4OMe-glucuronoxylans as the renewable biopolymers can be promising glycomaterials for various applications in pharmacy. Control enzymatic degradation of the native 4OMe-glucuronoxylan (GX1) followed by targeted sulfation procedure afforded a range of 4OMe-glucuronoxylan sulfates differed in the degree of sulfation (10-16%) and molecular mass (21,000-5000g/mol; GXS1>GXS2>GXS3>GXS4). Antiviral activity tests on GXS1-4 against herpes simplex virus (HSV) types 1 and 2 revealed the positive effect of all compounds against strains of herpes virus. Of them, the compounds GXS1 and GXS4 were shown to be the most active for both HSV serotypes. The antiviral activity of GXS1 and GXS4 was similar to those of heparin or dextran sulfate, used as reference compounds. It was found that GXS1 and GXS4 were active as well against Polio and dengue viruses, however, on a smaller scale. The mode of antiviral action of 4OMe-glucuronoxylan sulfates is due to inhibition of the virus binding to the cell receptors.

Improved left ventricular function after chronic left ventricular unloading.

BACKGROUND: This study assessed the effect of prolonged left ventricular unloading on native ventricular function. METHODS: We reviewed data from 31 patients (30 men, 1 woman) supported more than 30 days (mean, 137 days; range, 31 to 505 days) with the HeartMate left ventricular assist system. The patients' mean age was 46 years (range, 22 to 64 years); 17 had idiopathic and 14 had ischemic cardiomyopathy. Data (anatomic, physiologic, hemodynamic, histologic, and biochemical) were collected at the time of HeartMate implantation, during support with the device temporarily off, and at the time of device explantation. RESULTS: Routine chest roentgenogram showed improvement in cardiothoracic ratio (0.62 +/- 0.04 to 0.55 +/- 0.03; p < 0.0001). Echocardiography performed with the pump off showed a significant decrease in left ventricular end-diastolic dimension (6.81 +/- 0.87 cm to 5.39 +/- 1.08 cm; p < 0.0005) and a significant improvement in ejection fraction (0.11 +/- 0.05 to 0.22 +/- 0.17; p < 0.02). Cardiac index increased (1.96 +/- 0.52 L.min-1.m-2 to 2.93 +/- 0.73 L.min-1.m-2; p < 0.0001), mean aortic pressure increased (71.40 +/- 10.63 mm Hg to 76.33 +/- 16.84 mm Hg; p = 0.48), pulmonary capillary wedge pressure decreased (24.18 +/- 6.27 mm Hg to 14.48 +/- 3.01 mm Hg; p < 0.0001), and pulmonary vascular resistance decreased (3.34 +/- 2.00 Wood units to 2.51 +/- 0.88 Wood units; p < 0.05). Comparisons of tissue samples taken at the time of implantation and at the time of transplantation showed a marked reduction in myocytolysis. Calcium uptake, calcium-binding rates, and lipid levels normalized in patients studied. Plasma norepinephrine levels decreased to near normal levels. CONCLUSION: Prospective studies are now indicated to determine whether device removal without transplantation may be beneficial in selected patients.

Base-catalyzed degradation of permethylated 3-O-glycosyl- glycopyranosid-2-uloses.

In a modification of the Svensson degradation, otherwise permethylated glycopyranosid-2-uloses bearing 4-O-glycosyl substituents are formed by the Swern oxidation. Base-catalyzed elimination on treatment with triethylamine then gives 4-deoxy-3-O-methylglyc-3-enopyranosid-2-ulose-terminat ed oligosaccharides with liberation of glycosyl substituents as reducing sugars but without further degradation. Mild acid hydrolysis results in removal of the unsaturated sugar residues so that the overall depolymerization occurs with net loss only of the initially oxidized sugar residue.

A novel L-fuco-4-O-methyl-D-glucurono-D-xylan from Hyptis suaveolens.

The acidic polysaccharide from the seed-coat mucilage of Hyptis suaveolens is a highly branched L-fuco-4-O-methyl-D-glucurono-D-xylan for which a structure is proposed having a 4-linked beta-D-xylan backbone carrying side chains of single 4-O-methyl-alpha-D-glucuronic acid residues at O-2 and 2-O-L-fucopyranosyl-D-xylopyranose units at O-3. The structural analysis involves base-catalyzed beta-elimination of uronic acid residues from the methylated glycan followed by degradation using a modified Svensson oxidation-elimination sequence.

Galactoglucomannan from the secondary cell wall of Picea abies L. Karst.

The fine structural features of alkali-extracted galactoglucomannan composed of D-galactose, D-glucose and D-mannose in a 1:8:33 mole proportion from the secondary cell walls of Picea abies L. Karst have been determined. Compositional and methylation analyses of the polymer, partial acid hydrolysis, as well as 1H and 13C NMR measurements of the polymer and products of partial acid hydrolysis confirmed a beta-(1-->4)-linked backbone of galactoglucomannan containing the segments of mannosyl residues (Man2, Man3, Man4, etc.) interrupted with the segments having both mannose and glucose residues, as well as the segments in which D-Glcp units can be adjacent to each other (Glc2). Further, the low content of branching points (approximately 3%) at the positions of 0-6, 0-3 and 0-2 of mannosyl and 0-6 and 0-3 of glucosyl residues, but preferably of mannosyl ones, indicates the presence of short side-chains terminated at position 0-6 predominantly by D-galactose units as single stubs.

Enzymatic degradation of cell walls of apples and characterization of solubilized products.

Partially depectinated apple cell walls were digested by pectin lyase or endoglucanase or a combination. By combining these commercial enzymes, a higher yield of 22.2% of carbohydrate material was obtained compared with only 13.9% and 5.7%, respectively, when using them singly. Only small amounts of carbohydrates were extracted by buffer (0.8%). The solubilized extracts were fractionated using a combination of ion-exchange chromatography and gel filtration. The individual subfractions were analysed for neutral sugar and uronic acid content. The results indicated the existence of a synergistic effect between pectin lyase and endoglucanase based on the percentage of material extracted.

Characterization of immunomodulatory polysaccharides from Salvia officinalis L.

Crude polysaccharide fractions, rich mainly in arabinogalactans (A), pectin (B) and glucuronoxylan-related polymers (D), have been obtained from aerial parts of sage (Salvia officinalis L.) by sequential extraction with various reagents. Arabinogalactans displayed on HPLC a dominance of lower molecular-mass polymers (MW < 10,000), while pectin and glucuronoxylan-related polysaccharides showed predominance of polymers with MW > 50,000. Individual polysaccharide fractions were examined for their immunomodulatory activity in the in vitro comitogenic thymocyte test. The polysaccharide fractions tested possessed the capacity to induce rat thymocyte proliferation in the order D>B>A. Besides, fraction D possessed a significant comitogenic effect, and the SIcomit/SImit ratio 3-4 indicates potential adjuvant properties of this glucuronoxylan-rich material.

The effect of prolonged left ventricular support on myocardial histopathology in patients with end-stage cardiomyopathy.

To determine the histopathologic effect of prolonged (> 30 days) left ventricular unloading on the myocardium, the authors studied myocardial tissue specimens from eight men (mean age, 40.8 years) with end-stage cardiomyopathy (six idiopathic, two ischemic) who were supported with the HeartMate (Thermo Cardiosystems, Inc., Woburn, MA) left ventricular assist device (LVAD) as a bridge to cardiac transplantation. The average length of support was 79.6 days (range, 31-136 days). Before left ventricular support was instituted, transthoracic echocardiography revealed that all patients had significantly dilated left ventricular cavities (average left ventricular diastolic dimension, 7.2 cm). Tissue specimens from the core of the left ventricular apex, which is removed at the time of LVAD implantation, were compared through pathologic examination with specimens from the explanted hearts at the time of cardiac transplantation. Apical core specimens from all patients exhibited extensive areas of attenuated myocardial fibers, combined with wavy patterns in some areas. In these regions, the nuclei of the cardiac myocytes from idiopathic cardiomyopathy specimens were neither pyknotic nor disappearing, as was noted in an infarcted area of a specimen from one patient with ischemic cardiomyopathy. At the time of heart transplantation, myocardial tissue specimens from the explanted hearts had a significant decrease or disappearance of stretched fibers. There was also a slight increase in interstitial replacement fibrosis, as well as an increase in the diameter of the myocardial fibers. These findings appear to correlate with the clinical impression of improved native ventricular function and with radiographic findings and decreased chamber size during prolonged ventricular support.