Thermo-responsive copolymers grafted with N-isopropylacrylamide (NIPAm) are excellent candidates for drug release. Dextran sulfate (DS) acts as a specific ligand in inflamed regions, turning it ...highly useful as a target for drug delivery. DS was associated with NIPAm to produce amphiphilic graft copolymers prepared via free radicals. The molar ratio of feed reagents NIPAm/DS varied from 1 (DS-g-PNIPAm) to 4 (DS-g-4PNIPAm). The synthesis was confirmed by spectroscopic techniques (Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR)). All copolymers showed self-organization capacity in an aqueous medium in temperatures higher than 34 °C, and sizes less than 300 nm. DS-g-3PNIPAm exhibited stability in water and in phosphate buffer at pH 7.4. Scanning electron microscopy confirmed their spherical shape. This copolymer showed specificity to leukemic cells, and normal cells’ proliferation. Methotrexate (MTX) is a very low water-soluble drug used for rheumatoid arthritis and cancer. Unfortunately, MTX have severe collateral effects. MTX-loaded nanoparticles can overcome such issues as well as enhance bioactivity and stability. The MTX was encapsulated and delivered from the DS-g-3PNIPAm with potential target delivery due to the presence of DS. Comparison with MTX encapsulated in other nanoparticles reveals that the DS-g-PNIPam presents the best performance among the thermoresponsive and the second among the target MTX nanocarriers.
Chitosan (CH) and angico gum (AG) nanoparticles were loaded with essential oil, Lippia sidoides (Ls), being characterized according to their composition, size distribution, Ls:polymer ratio, thermal ...stability and in vitro and in vivo controlled release. Nanoparticles prepared using Ls:AG ratios of 1:2 to 1:20 had loading values of 3.3 to 7.7%, with encapsulation efficiencies in the range of 16.0 to 77.8%. Particle sizes were in the range of 10-60 nm and size distributions were independent of Ls content, for different Ls:AG ratios. Infrared spectroscopy revealed the presence of thymol in the nanoparticles. TGA and DSC revealed that the degradation temperature of AG-CH nanoparticles decreased with an increase in Ls content. Controlled-release data showed a slower release profile for samples with Ls:AG = 1:10 than for the other samples. Bioassays showed that sample Ls:AG = 1:10 has a greater larvicidal effect, with 85 ± 3% mortality.
This cohort profile aims to describe the ongoing follow-up of children in the Microcephaly Epidemic Research Group Paediatric Cohort (MERG-PC). The profile details the context and aims of the study, ...study population, methodology including assessments, and key results and publications to date. The children that make up MERG-PC were born in Recife or within 120 km of the city, in Pernambuco/Brazil, the epicentre of the microcephaly epidemic. MERG-PC includes children from four groups recruited at different stages of the ZIKV microcephaly epidemic in Pernambuco, i.e., the Outpatient Group (OG/
= 195), the Microcephaly Case-Control Study (MCCS/
= 80), the MERG Pregnant Women Cohort (MERG-PWC/
= 336), and the Control Group (CG/
= 100). We developed a comprehensive array of clinical, laboratory, and imaging assessments that were undertaken by a 'task force' of clinical specialists in a single day at 3, 6, 12, 18 months of age, and annually from 24 months. Children from MCCS and CG had their baseline assessment at birth and children from the other groups, at the first evaluation by the task force. The baseline cohort includes 711 children born between February 2015 and February 2019. Children's characteristics at baseline, excluding CG, were as follows: 32.6% (184/565) had microcephaly, 47% (263/559) had at least one physical abnormality, 29.5% (160/543) had at least one neurological abnormality, and 46.2% (257/556) had at least one ophthalmological abnormality. This ongoing cohort has contributed to the understanding of the congenital Zika syndrome (CZS) spectrum. The cohort has provided descriptions of paediatric neurodevelopment and early epilepsy, including EEG patterns and treatment response, and information on the frequency and characteristics of oropharyngeal dysphagia; cryptorchidism and its surgical findings; endocrine dysfunction; and adenoid hypertrophy in children with Zika-related microcephaly. The study protocols and questionnaires were shared across Brazilian states to enable harmonization across the different studies investigating microcephaly and CZS, providing the opportunity for the Zika Brazilian Cohorts Consortium to be formed, uniting all the ZIKV clinical cohorts in Brazil.
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•Oxidized and carboxymethylated cashew gum (CG) were successfully prepared.•The CG functionalization increased the polyelectrolyte net charge.•Multilayered films were successfully ...produced using chitosan, CG, and its derivatives.•CG functionalizations increased the film thickness compared with native CG.•The roughest surface was obtained for the CG with the high oxidation degree due Schiff bases.
Cashew gum (CG), an exudate polysaccharide from Anacardium occidentale trees, was carboxymethylated (CGCm) and oxidized (CGO). These derivatives were characterized by FTIR and zeta potential measurements confirming the success of carboxymethylation and oxidation reactions. Nanostructured multilayered films were then produced through layer-by-layer (LbL) assembly in conjugation with chitosan via electrostatic interactions or Schiff bases covalent bonds. The films were analyzed by QCM-D and AFM. CG functionalization increased the film thickness, with the highest thickness being achieved for the lowest oxidation degree. The roughest surface was obtained for the CGO with the highest oxidation degree due to the predominance of covalent Schiff bases. This work shows that nanostructured films can be assembled and stabilized by covalent bonds in alternative to the conventional electrostatic ones. Moreover, the functionalization of CG can increase its feasibility in multilayers films, widening its potential in biomedical, food industry, or environmental applications.
Purification of guar gum for biological applications Cunha, Pablyana L.R.; Paula, Regina C.M. de; Feitosa, Judith P.A.
International journal of biological macromolecules,
08/2007, Letnik:
41, Številka:
3
Journal Article
Recenzirano
Commercial guar gum (GG) was purified by four different methods and characterized by gel permeation chromatography (GPC), thermogravimetric analysis and the determination of monosaccharides ...composition, protein and copper content, turbidity, intrinsic viscosity and rheological parameters. The first method was based on enzymatic hydrolysis with porcine pancreatin. In the second method successive gum dissolution, centrifugation and precipitation with acetone and ethanol were carried out. Precipitation with Fehling solution was employed in the third method. In the fourth method, the gum was purified by method 2 and then by method 3. All methods led to a reduction in protein content, arabinose and glucose residues, considered as sugar contaminants, and also in intrinsic viscosity and molar mass. Total elimination of protein was only achieved by method 4. Using methods 3 and 4, the gum was contaminated with small amounts of Cu(II) from the Fehling solution. Methods 2 and 4 apparently provided purer guar gum. If the amount of protein is a crucial parameter in the biological application and the guar will be taken in low amounts, method 4 is recommended. Taking into account the purity, thermal stability, rheological parameters of the purified gum and also the cost and simplicity of the procedure, method 2 has wider biological application.
Interviews were conducted with the owners of three organic lettuce farms in the state of Rio Grande do Sul in southern Brazil using a standardized self-assessment questionnaire to ascertain the ...status of implementation of good agricultural practices and management systems in place. In addition, on each farm 132 samples (manure, field soil, water, workers' hands and equipment, lettuce seedlings, and crops) were collected during four visits throughout the lettuce crop production cycle and subjected to analysis for hygiene indicators (Escherichia coli, coliforms) and presence of Salmonella and E. coli O157. E. coli O157 was detected twice (in irrigation water and in rinse water) out of 27 analyzed water samples. Salmonella spp. was detected in one out of nine manure samples applied as organic fertilizer. In addition, generic E. coli was frequently present in numbers exceeding 10 cfu/g in manure, manured soil, and lettuce samples or more than 1 cfu/100 ml in water. No E. coli O157 was detected in any of the lettuce samples (n = 36), but Salmonella spp. was detected once in lettuce taken during the crop cycle 2 weeks before harvest. It was demonstrated that the combination of the self-assessment questionnaire and microbiological sampling and analysis could identify weak points in current organic farming practices in this region of southern Brazil. It was noted that manure composting was not adequately controlled and appropriate waiting times before application as an organic fertilizer to crop were not respected. Also the selection of the water source and the sanitary quality of the water used for irrigation were not under control. The washing step (with sanitizer) of lettuce crops at harvest, generally considered a potential reduction step for microbial contamination, was often not verified for its efficiency. This may detract from the sanitary quality of the produce and are risk factors for the introduction of pathogens in the lettuce sent to market. The study, combining interviews, sampling, and analysis, contributed to increasing the farmers' awareness of enteric pathogens as a food safety issue in leafy greens. Further communication and training on good agricultural practices are recommended to remediate the weak points identified in the current management system.
•The microbial contamination in organic lettuce production was followed in three organic farms.•Escherichia coli O157:H7 was detected in irrigation and wash waters.•The food safety management systems were evaluated to gain insights affecting microbiological contaminations.
•Tdap maternal vaccination results in significantly higher anti-PT IgG in newborn infants.•Vaccination early in the third trimester may be more effective than later in pregnancy.•Our findings support ...the current recommendation of the Brazilian Immunization Program.
Pertussis remains an important global public health concern, despite the presence of extensive immunization programs. Incidence and severity of pertussis are typically higher in neonates and young infants. As a strategy to protect these young infants, maternal vaccination with Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) has been recommended in Brazil. The objective of this study was to evaluate the effects of Tdap vaccination during pregnancy on the anti-pertussis toxin (PT) IgG response in mothers and their infants at birth.
Maternal and cord blood samples were collected from vaccinated (n = 243) and unvaccinated (n = 75) pregnant women, at the time of delivery, from July 2015 to August 2016 in São Paulo, Brazil. Anti-PT IgG antibodies were quantified by Enzyme-Linked Immunosorbent Assay (ELISA) and geometric mean concentrations (GMC) were calculated. Relationship between timing of vaccination and antibody concentrations were evaluated.
Maternal and cord blood GMCs among the vaccinated group were 5.4 and 5.6 fold higher 66.5 International Units (IU)/mL and 89.8 IU/mL compared to the unvaccinated group (12.4 IU/mL and 16.1 IU/mL), respectively (p < 0.001). Higher anti-PT IgG GMCs were observed when vaccination occurred ≥60 days before delivery compared to <60 days, suggesting that vaccination early in the third trimester may be more effective than later in pregnancy.
Tdap maternal vaccination results in significantly higher anti-PT IgG in newborn infants and supports the current recommendation of the Brazilian Immunization Program.
Mutations in the SARS-CoV-2 genome can alter the virus' fitness, leading to the emergence of variants of concern (VOC). In Brazil, the Gamma variant dominated the pandemic in the first half of 2021, ...and from June onwards, the first cases of Delta infection were documented. Here, we investigate the introduction and dispersal of the Delta variant in the RS state by sequencing 1077 SARS-CoV-2-positive samples from June to October 2021. Of these samples, 34.7% were identified as Gamma and 65.3% as Delta. Notably, 99.2% of Delta sequences were clustered within the 21J lineage, forming a significant Brazilian clade. The estimated clock rate was 5.97 × 10
substitutions per site per year. The Delta variant was first reported on 17 June in the Vinhedos Basalto microregion and rapidly spread, accounting for over 70% of cases within nine weeks. Despite this, the number of cases and deaths remained stable, possibly due to vaccination, prior infections, and the continued mandatory mask use. In conclusion, our study provides insights into the Delta variant circulating in the RS state, highlighting the importance of genomic surveillance for monitoring viral evolution, even when the impact of new variants may be less severe in a given region.
•The main constituent of sulfated polysaccharide fraction (PLS) was the ι carrageenan.•The monosaccharide composition of the sulfated polysaccharide fraction was galactose and its derivates.•The PLS ...(30mgkg−1) significantly reduced the inflammatory response.
The sulfated polysaccharide (PLS) fraction of Agardhiella ramosissima was characterized by microanalysis, infrared spectroscopy, NMR and gas–liquid-chromatography–mass-spectrometry. The main constituent of PLS was the ι carrageenan. The monosaccharide composition of the PLS showed galactose, 3,6-anhydrogalactose and 6-O-methylgalactose. The PLS (30mgkg−1) significantly reduced the paw oedema induced by carrageenan, dextran, histamine and serotonin and also was able to significantly inhibit leucocyte migration into the peritoneal cavity and decrease the concentration of myeloperoxidase (MPO) in paw tissue. In the antinociceptive tests, the pre-treatment with PLS reduced the number of writhes, the licking time but did not increase the latency time of response. This study demonstrates for the first time the anti-inflammatory and anti-nociceptive effects of PLS from A. ramosissima. Thus, we concluded that PLS could be a new natural tool in pain and acute inflammatory conditions.
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