Genetic variability profiling of the p53 signaling pathway in chronic lymphocytic leukemia. Individual and combined analysis of TP53, MDM2 and NQO1 gene variants.

TP53 gene disruption, including 17p13 deletion [del(17p)] and/or TP53 mutations, is a negative prognostic biomarker in chronic lymphocytic leukemia (CLL) associated with disease progression, treatment failure and shorter survival. Germline variants in p53 signaling pathway genes could also lead to p53 dysfunction, but their involvement in CLL has not been thoroughly evaluated. The aim of this study was to determine the association of TP53, MDM2 and NQO1 gene variability with clinical and genetic data of CLL patients. Individual genotype and haplotype data of CLL patients were compared with clinical prognostic factors, cytogenetic and molecular cytogenetic findings as well as IGHV and TP53 mutational status. The study included 116 CLL patients and 161 healthy blood donors. TP53 (rs1042522, rs59758982, rs1625895), NQO1 (rs1800566) and MDM2 (rs2279744, rs150550023) variants were genotyped using different PCR approaches. Analysis of genotype frequencies revealed no association with the risk of CLL. TP53 rs1042522, rs1625895 and MDM2 rs2279744 variants were significantly associated with abnormal karyotype and the presence of del(17p). Similarly, these two TP53 variants were associated with TP53 disruption. Moreover, TP53 C-A-nondel and G-A-del haplotypes (rs1042522-rs1625895-rs59758982) were associated with an increased likelihood of carrying del(17p) and TP53 disruptions. MDM2 T-nondel haplotype (rs2279744-rs150550023) was found to be a low risk factor for del(17p) (OR = 0.32; CI: 0.12-0.82; p = 0.02) and TP53 disruptions (OR = 0.41; CI: 0.18-0.95; p = 0.04). Our findings suggest that TP53 and MDM2 variants may modulate the risk to have chromosome alterations and TP53 disruptions, particularly del(17p). To our knowledge this is the first study of several germline variants in p53 pathway genes in Argentine patients with CLL.

Exploring the relationship between nanoscale dynamics and macroscopic rheology in natural polymer gums.

We report a study connecting the nanoscale and macroscale structure and dynamics of Acacia mearnsii gum as probed by small-angle X-ray scattering (SAXS), X-ray photon correlation spectroscopy (XPCS) and rheology. Acacia gum, in general, is a complex polysaccharide used extensively in industry. Over the analyzed concentration range (15 to 30 wt%) the A. mearnsii gum is found to have a gel-like linear rheology and to exhibit shear thinning flow behavior under steady shear. The gum solutions exhibited a steadily increasing elastic modulus with increasing time after they were prepared and also the emergence of shear thickening events within the shear thinning behavior, characteristic of associative polymers. XPCS measurements using gold nanoparticles as tracers were used to explore the microscopic dynamics within the biopolymer gels and revealed a two-step relaxation process with a partial decay at inaccessibly short times, suggesting caged motion of the nanoparticles, followed by a slow decay at later delay times. Non-diffusive motion evidenced by a compressed exponential line shape and an inverse relationship between relaxation time and wave vector characterizes the slow dynamics of A. mearnsii gum gels. Surprisingly, we have determined that the nanometer-scale mean square displacement of the nanoparticles showed a close relationship to the values predicted from the macroscopic elastic properties of the material, obtained through the rheology experiments. Our results demonstrate the potential applicability of the XPCS technique in the natural polymers field to connect their macroscale properties with their nanoscale structure and dynamics.

Complex coacervation between lysozyme and pectin: Effect of pH, salt, and biopolymer ratio.

The complexation between lysozyme and pectin was studied by acidification using zeta potential, turbidity measurements and calorimetry titration. The complexes were analyzed in various NaCl concentrations with different ratios. At ratio 1:1 with 0.01M NaCl, is worth mentioning that the insoluble complexes were formed between pH 2.0 and 7.0, which represents a great range to apply this complex to different food matrices. When the ratio was increased from 1:1 to 3:1, the pH range between the pHφ1 and pHφ2 increased even more. When the NaCl concentration was increased from 0.01M to 0.2M, a progressive reduction of turbidity was observed. At 0.4M NaCl, there was total suppression of complex formation at ratio ≤ 3:1. The process of complex coacervate formation occurred in two different steps, presenting favorable enthalpic as well as entropic contributions. The positive entropy change is a strong indication that water molecules have been released from the complex surface, however the positive sign of TΔS suggests that hydrophobic interactions were involved in the interaction between lysozyme and pectin. Microscopy images of the samples revealed that the complexes presented a spheroid-like appearance which may contribute to possible future applications.

Complicaciones en accesos venosos vasculares: estudio descriptivo de catéteres venosos centrales y catéteres de línea media / Complications in vascular venous access: descriptive study of central venous catheters and midline catheters

[RESUMEN]. Los accesos vasculares venosos son dispositivos elementales para el tratamiento hospitalario de diversas condiciones. Está bien documentada la tasa de complicaciones para catéteres venosos centrales (CVC) y catéteres de línea media (MD), pero existe un solo trabajo que los compara directamente. Por ello realizamos el presente trabajo con el objetivo de establecer las tasas generales y comparativas de complicaciones en ambos tipos de catéteres. Se realizo un estudio descriptivo retrospectivo donde se reclutaron 168 pacientes, los cuales recibieron 268 catéteres (120 accesos venosos centrales y 148 midline), con una media de edad de 45 años, con leve predominio del sexo femenino (51,2%). De estos, la principal comorbilidad fue neoplasia (57,1%). En el 29,8% el principal motivo de colocación fue la infusión de quimioterapia. Como resultados, la prevalencia de complicaciones fue del 19%: infecciosas en el 7,5% de los casos (con una tasa de infecciones asociadas a catéter de 4.9/1000 días catéter), 1,9% trombóticas y 9,7% mecánicas. La tasa de complicaciones fue mayor para los catéteres venosos centrales, no alcanzando una diferencia estadísticamente significativa: infecciosas (10.8% vs. 4,7%; p: 0,059; OD: 2.47; IC 95%: 0.94 - 6.34) y mecánicas (5.8% vs. 12,8%; p: 0,054; OD: 0.42; IC 95%: 0.17 ­ 1.03) para CVC y MD, respectivamente. Las complicaciones trombóticas fueron similares en ambos (1,6% en CVC y 2% en MD, p: 0,82).

[ABSTRACT]. Venous vascular accesses are fundamental devices for in hospital treatment of various conditions. Complication rates for central venous catheters (CVC) and midline catheters (MD) are well-documented, but there is only one study in wich both devices were compared. Therefore, we conducted the present study with the aim of establishing the overall and comparative complication rates of both types of catheters. We conducted a retrospective descriptive study recruiting 168 patients who received 268 catheters (120 central venous accesses and 148 midlines). The mean age was 45 years, with a slight predominance of females (51.2%). Among these, the main comorbidity was neoplasia (57.1%). In 29.8% of cases, the main reason for catheter placement was chemotherapy infusion. As a result, the prevalence of complications was 19%: infectious complications in 7.5% of cases (with a catheter-associated infection rate of 4.9/1000 catheter days), thrombotic 1,9%, and mechanical 9,7%. Complication rate were higher for central venous accesses, although the difference did not reach statistical significance: infectious (10.8% vs. 4.7%; p: 0.059; OR: 2.47; 95% CI: 0.94 - 6.34) and mechanical (5.8% vs. 12.8%; p: 0.054; OR: 0.42; 95% CI: 0.17 ­ 1.03) for CVC and MD, respectively.Thrombotic complications were similar in both (1.6% in CVC and 2% in MD, p: 0.82).

A peptidogalactomannan isolated from Cladosporium herbarum induces defense-related genes in BY-2 tobacco cells.

Cladosporium herbarum is a plant pathogen associated with passion fruit scab and mild diseases in pea and soybean. In this study, a peptidogalactomannan (pGM) of C. herbarum mycelium was isolated and structurally characterized, and its role in plant-fungus interactions was evaluated. C. herbarum pGM is composed of carbohydrates (76%) and contains mannose, galactose and glucose as its main monosaccharides (molar ratio, 52:36:12). Methylation and 13C-nuclear magnetic resonance (13C-NMR) spectroscopy analysis have shown the presence of a main chain containing (1 → 6)-linked α-D-Manp residues, and ß-D-Galf residues are present as (1 → 5)-interlinked side chains. ß-Galactofuranose containing similar structures were characterized by our group in A. fumigatus, A. versicolor, A. flavus and C. resinae. Tobacco BY-2 cells were used as a model system to address the question of the role of C. herbarum pGM in cell viability and induction of the expression of plant defense-related genes. Native and partially acid hydrolyzed pGMs (lacking galactofuranosyl side-chain residues) were incubated with BY-2 cell suspensions at different concentrations. Cell viability drastically decreased after exposure to more than 400 µg ml-1 pGM; however no cell viability effect was observed after exposure to a partially acid hydrolyzed pGM. BY-2 cell contact with pGM strongly induce the expression of plant defense-related genes, such as phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX), as well as the pathogen-related PR-1a, PR-2 and PR-3 genes, suggesting that pGM activates defense responses in tobacco cells. Interestingly, contact with partially hydrolyzed pGM also induced defense-related gene expression at earlier times than native pGM. These results show that the side chains of the (1 → 5)-linked ß-D-galactofuranosyl units from pGM play an important role in the first line fungus-plant interactions mediating plant responses against C. herbarum. In addition, it was observed that pGM and/or C. herbarum conidia are able to induced HR when in contact with tobacco leaves and in vitro plantlets roots, producing necrotic lesions and peroxidase and NO burst, respectively.

Structural characterization and rheological properties of a gel-like ß-d-glucan from Pholiota nameko.

A crude fraction (SCW) was extracted with cold water from Pholiota nameko and showed mannose (24.1%), galactose (44.9%) and glucose (31%). Purification procedures resulted in a polysaccharide fraction (bG-PN), that showed only glucose. NMR and methylation analyses of bG-PN indicated a ß-d-glucan-(1→3)-linked, substituted at O-6 by ß-d-Glcp or (1→6)-linked ß-d-Glcp side chains. Rheological studies of crude and purified fractions at the same concentration showed similar shear-thinning behavior and gel-like structure which indicates no need to isolate the polymer to achieve some desirable rheological properties. SCW (at 1% and 2%) and bG-PN (at 2%) presented thermal stability during heating and cooling, suggesting that the physical structure of gels (SCW and bG-PN at 2%) and viscoelastic fluid (SCW at 1%) formed were not altered in the tested temperature range. Our results suggest that P. nameko ß-d-glucans can be applied in different food preparations as thickener or gelling agents modifying their rheological properties.

Effect of low and high methoxyl citrus pectin on the properties of polypyrrole based electroactive hydrogels.

Electroactive hydrogels were prepared using commercial citric pectin, either raw (PC) or purified through dialysis (dPC), and chemically synthesized polypyrrole (PPy). 1H NMR analyses showed that PC is a low methoxyl pectin (degree of methoxylation, DM=46%) and dPC is a high methoxyl pectin (DM=77%). The pyrrole polymerization was monitored through UV-vis spectroscopy and both samples were observed to be good stabilizers for PPy in aqueous medium. The dispersions were used to prepare the hydrogels h-PC-PPy and h-dPC-PPy. The hydrogel h-dPC-PPy has a higher swelling index (SI≈25%) at pH 1.2 than the hydrogel h-PC-PPy (SI≈7%). Contrastingly, at pH 6.8 both hydrogels lost their mechanical integrity. Raman spectroscopy revealed that PPy is more oxidized in h-PC-PPy. Nevertheless, both hydrogels are electroactive and therefore can be considered for applications in which the control of the degree of swelling is desired.

Rheological behavior of high methoxyl pectin from the pulp of tamarillo fruit (Solanum betaceum).

Rheological behavior of a high methyl-esterified pectic fraction (STW-A) from tamarillo was evaluated at different concentrations in water and with sucrose (50% w/w, pH 3). STW-A dispersions at 3, 5, and 8% (w/w) showed low apparent viscosities, shear-thinning and liquid-like behaviors. They were well fitted using the Ostwald-de Waele model and obey the Cox-Merz rule. The viscosity and the viscoelastic behavior were greatly modified by the presence of sucrose. STW-A at 1% (+ sucrose) showed shear-thinning and concentrated solution behavior. Pronounced shear-thinning and gel-like behaviors were obtained with STW-A at 2 and 3% (+ sucrose). Their flow curves profiles were better fitted using the Hershel-Bulkley model and not followed the Cox and Merz rule. Temperature sweeps (5-80°C) showed that STW-A formed thermostable gels. Altogether, our results suggested tamarillo can be a new source of pectin with potential applications as thickeners/gelling agents depending on solvent or applied processes.

Antioxidant dietary fibre recovery from Brazilian Pinot noir grape pomace.

Brazilian grape pomace was extracted in hot water, and a factorial experiment was used to evaluate polysaccharide recovery. The dependent variables were the temperature, particle size and solute:solvent ratio. Polysaccharide yields varied from 3% to 10%, and the highest sugar content was observed when extraction was carried out at 100 °C from finely sized particles (⩽249 µm) in a 1:12 solute:solvent ratio. The monosaccharide composition of extracts obtained from flours were, on average, Rha:Ara:Xyl:Man:Gal:Glc:GalA in a 3:32:2:13:11:20:19 M ratio, with varying Glc:GalA ratios. (13)C NMR and HSQC spectra confirmed the presence of pectic- and glucose-based polysaccharides in the extracts. Phenolic compounds were found after pomace extraction, and catechin, gallic acid and epicatechin were the principal compounds identified. The extracts also had ABTS radical scavenging capacity (from 8.00 to 46.60 mMol Trolox/100 g pomace). These findings indicate that these grape pomace flours are rich in antioxidant dietary fibre and have a potential use as food ingredients.

A tailored biocatalyst achieved by the rational anchoring of imidazole groups on a natural polymer: furnishing a potential artificial nuclease by sustainable materials engineering.

Foreseeing the development of artificial enzymes by sustainable materials engineering, we rationally anchored reactive imidazole groups on gum arabic, a natural biocompatible polymer. The tailored biocatalyst GAIMZ demonstrated catalytic activity (>10(5)-fold) in dephosphorylation reactions with recyclable features and was effective in cleaving plasmid DNA, comprising a potential artificial nuclease.

Anticoagulant activity of native and partially degraded glycoglucuronomannan after chemical sulfation.

Heparin has great clinical importance as anticoagulant and antithrombotic agent. However, because of its risks of causing bleeding and contamination by animal pathogens, several studies aim to obtain alternatives to heparin. In the search for anticoagulant and antithrombotic agents from a non-animal source, a glycoglucuronomannan from the gum exudate of the plant Vochysia thyrsoidea was partially hydrolyzed, and both native and partially degraded polysaccharides were chemically sulfated, yielding VThS and Ph-VThS respectively. Methylation analysis indicated that sulfation occurred preferentially at the O-5 position of arabinose units in the VThS and at the O-6 position of mannose units in Ph-VThS. In vitro aPTT assay showed that VThS and Ph-VThS have anticoagulant activity, which could be controlled by protamine, and ex vivo aPTT assay demonstrated that Ph-VThS is absorbed by subcutaneous route. Like heparin, they were able to inhibit α-thrombin and factor Xa by a serpin-dependent mechanism. In vivo, VThS and Ph-VThS reduced thrombus formation by approximately 50% at a dose of 40 IU/kg, similarly to heparin. The results demonstrated that the chemically sulfated polysaccharides are promising anticoagulant and antithrombotic agents.

Native and structurally modified gum arabic: exploring the effect of the gum's microstructure in obtaining electroactive nanoparticles.

Electroactive nanoparticles combining gum arabic (GA) and polyaniline (PANI) were prepared by chemical synthesis. The gum consists of highly branched anionic polysaccharides with some protein content. GA was structurally modified by Smith controlled degradation, in order to reduce its degree of branching (GAD), aiming the elucidation of the relationship between the structure and the properties of complex polysaccharides. The modification was studied by SEC, GC-MS, (13)C NMR and colorimetric methods. GAD has lower molecular mass, lower degree of branching and lower uronic acid content. Besides it is enriched in galactose and protein when compared with GA. The obtained composites (GA-PANI and GAD-PANI) were thoroughly characterized. Although the use of both polysaccharides (GA and GAD) produced highly stable electroactive nanoparticles, the best combination of properties was achieved for GA-PANI. The sample GAD was not able to prevent the occurrence of crosslinking between PANI chains, possibly due to its lower microstructural complexity which diminishes the occurrence of hydrogen bonds between the polymers.

Monosaccharide composition of glycans based on Q-HSQC NMR.

Glycans have essential functions related to structural architecture and specific cell surface phenomena, such as differentiation, biosignalling, recognition and cell-cell interaction, with the carbohydrate structure determining main function in the cell. Due to the importance of the primary structure, the monosaccharide composition is crucial to show the glycan structure. We now present a method for complex carbohydrates based on NMR spectroscopy, which has shown to give similar results to those obtained by the classic GC-MS-carboxy-reduction/deuterium labeling approach. Quantitative HSQC, through JCH dependence showed 155 Hz as the best value for (1)H/(13)C anomeric aldoses, allowing milli-microM detection using conventional inverse probe heads. Combining the quantification of native monosaccharide units of the glycan and those from the hydrolyzed product, a strong correlation occurs between the molecular mobility of the monosaccharide units, giving rise to some insights on the dynamic properties of the parent glycan.

Glucuronoarabinoxylan from coconut palm gum exudate: chemical structure and gastroprotective effect.

A glucuronoarabinoxylan (CNAL) was extracted with 1% aq. KOH (25°C) from Cocos nucifera gum exudate. It had a homogeneous profile on HPSEC-MALLS-RI (Mw 4.6 × 10(4)g/mol) and was composed of Fuc, Ara, Xyl, GlcpA (and 4-O-GlcpA) in a 7:28:62:3 molar ratio. Methylation data showed a branched structure with 39% of non-reducing end units, 3-O-substituted Araf (8%), 3,4-di-O- (15%), 2,4-di-O- (5%) and 2,3,4-tri-O-substituted Xylp units (17%). The anomeric region of CNAL (13)C NMR spectrum contained 9 signals, indicating a complex structure. The main chain of CNAL was characterized by analysis of a Smith-degraded polysaccharide. Its (13)C NMR spectrum showed 5 main signals at δ 101.6, δ 75.5, δ 73.9, δ 72.5, and δ 63.1 that were attributed to C-1, C-4, C-3, C-2 and C-5 of (1→4)-linked ß-Xylp-main chain units, respectively. CNAL exhibited gastroprotective effect, by reducing gastric hemorrhagic lesions, when orally administered (1 and 3mg/kg) to rats prior to ethanol administration.

Structural characterization of a glucuronoarabinoxylan from pineapple (Ananas comosus (L.) Merrill) gum exudate.

Native polysaccharide from pineapple gum (PANP) was obtained following alkaline extraction of gum and fractionation with cetylpyridinium chloride. It was characterized as a glucuronoarabinoxylan using NMR, methylation data, controlled Smith degradation, carboxy-reduction, and ESI-MS of oligosaccharides produced on mild acid hydrolysis of PANP. HSPEC-MALLS-RI of carboxy-reduced fraction showed homogeneous profile (Mw 1.943×10(5) g/mol). PANP was composed of Ara, Xyl, Gal, and GlcpA (40:23:7:30 molar ratio). Its main chain presented (1→4)-linked ß-xylan, highly substituted at O-2 and O-3 by side chains of 3-O- and 3,5-di-O-linked α-Araf, 2-O- and 4-O-linked α-GlcpA, and nonreducing end-units of α-Araf, ß-Arap, ß-Galp, and α-GlcpA. ESI-MS of a mixture of oligosaccharides formed on the mild acid hydrolysis of PANP was consistent with repetitive structures of α-GlcpA O-3 linked at ß-Xylp units, whereas in others glucuronoarabinoxylan-type gum exudates, α-GlcpA units had been previously found to be linked at O-2.

Structural characterization and emulsifying properties of polysaccharides of Acacia mearnsii de Wild gum.

Polysaccharides (GNF) from Acacia mearnsii de Wild gum exudates, collected from trees growing in the south of Brazil, were characterized ((13)C and HSQC NMR, GC-MS, colorimetric assays). A commercial gum arabic (GAC) was analyzed similarly and compared with GNF. There were differences, consistent with distinct behavior in tensiometry tests and as emulsion stabilizer. GNF had a higher protein content than GAC, with small differences in the monosaccharide composition, the greater one being the lower uronic acid content of GNF (4%), compared with GAC (17%). GNF had a much broader molecular mass distribution, M(w)/M(n), and a lower M(w). GNF was more efficient in lowering the surface tension of water and saline solutions and was more efficient in emulsifying castor oil droplets. Results were discussed taking into account structural and molecular differences between the studied gums. It was concluded that polysaccharides from A. mearnsii de Wild are candidates as substitutes of currently commercialized arabic gums (Acacia senegal and Acacia seyal) having, depending on their application, improved properties.

Isolation of a gastroprotective arabinoxylan from sugarcane bagasse.

After industrial processing, one-third of sugarcane culms is converted into residual bagasse. The xylan-rich hemicellulose components of the bagasse were extracted with hot aqueous alkali (AX-CRUDE). Approximately 82% of the extracted hemicelluloses was precipitated with ethanol (AX-PET). Both AX-CRUDE and AX-PET contained an arabinoxylan as confirmed by 13C NMR and methylation analysis. Fraction AX-PET was fed to female Wistar rats with ethanol-induced gastric lesions. Oral administrations of 30, 100, and 300 mg/kg reduced the gastric lesion area by over 50%, and replenished ethanol-induced depletion of glutathione. The polysaccharide also increased mucus production by over 70%, indicating its cytoprotective action on experimentally induced gastric ulcers. These findings are significant, since a biologically active compound can be extracted in high yields from an abundant, readily available residue.