Chitosan and Xyloglucan-Based Hydrogels: An Overview of Synthetic and Functional Utility

The development of new strategies for wound healing has resulted in the design of biomedical devices using polymers of natural origin. Hydrogels are biomaterials formed by three-dimensional polymeric networks that can retain large amounts of water or biological fluids, and smooth texture similar to living tissue. Chitosan is a linear polysaccharide, (1-4)-2-amino-2deoxy-ß-D-glucan, which has desirable features such as biocompatibility, non-toxicity, hemostasis and antibacterial character. Xyloglucans have different applications in tissue engineering for their physicochemical properties, biocompatibility and control of cell expansion. Hydrogels had been made of homogeneous mixtures prepared of chitosan and purified xyloglucan, followed by a freeze-drying process to develop a flexible and porous structure. Additionally, their mechanical properties such as porosity, solubility, biodegradation, and the antibacterial activity of the hydrogels are studied. The results suggest that the incorporation of xyloglucan favors the characteristics from chitosan-based hydrogels, providing a promising alternative for application in biomaterials with antimicrobial activity

Executive functions and functional impairment in Latin seniors suffering from depression

Functional impairment (FI) relates to the condition of executive functions (EFs). While EFs become affected by age and educational level (EL). Seniors suffering from depression (SSDs) on the other hand show EF-related deficiencies; however, there is hardly any literature available regarding their relationship with FI in Latin SSDs, who usually have low ELs. Objective: To verify the relationship between EFs and FI in SSDs of Latin origins, by controlling the effects associated with age and educational level. Methodology: Cross-sectional study, of cases and controls, conducted on a nonprobability sample, made up of 102 self-sufficient SSDs and 142 control subjects over age 50, monolinguals of Latin origin (Chileans), all assessed by means of a battery of assessments such as: Geriatric Depression Scale, Addenbrook's Cognitive Assessment III, Trail making Tests A and B, STROOP word-color test, and semantic and phonological verbal fluency tests. A domain of composite EFs was established with standardized Chilean population scores, where age and educational levels were controlled. A simple linear regression analysis was conducted to determine the relationship between EFs and FI in SSDs. Results: Upon controlling age and educational levels, EFs explained an FI variance of 3.9% in SSDs; depression explained an EF variance of 3.2%, and 3.7% of FI. Conclusion: The results of the present study highlight the importance of a timely intervention when it comes to geriatric depression, considering the negative effect it has over the executive functions and the functionality of seniors

Sugar-lowering drugs for type 2 diabetes mellitus and metabolic syndromestrategies for in vivo administration: Part-II

Diabetes is a complex disease characterized by hyperglycemia, together with polyuria, polydipsia, and polyphagia. While Type 1 diabetes mellitus (T1DM) results from genetic, environmental, or immune dysfunction factors leading to pancreatic ß-cell destruction depriving the organism from endogenous insulin, Type 2 diabetes mellitus (T2DM) is characterized by peripheral insulin resistance. Depending on the type of diabetes mellitus and drug mechanism to study, the animal model should be carefully selected among the wide variety of the currently available ones. This review discusses the most common animal models currently employed to study T1DM and T2DM. Moreover, an overview on the administration routes that could be used is also discussed.The authors acknowledge the financial support received from Portuguese Science and TechnologyFoundation (FCT/MCT) and from European Funds (PRODER/COMPETE) under the project referenceM-ERA-NET/0004/2015-PAIRED, co-financed by FEDER, under the Partnership Agreement PT2020. The authors also acknowledge the support of the Institute of Nanoscience and Nanotechnology under the project ART (2018).info:eu-repo/semantics/publishedVersio

Inhibition of gastric acid secretion by H2 receptor antagonists associates a definite risk of enteric peritonitis and infectious mortality in patients treated with peritoneal dialysis

[Abstract] Background. Evidences linking treatment with inhibitors of gastric acid secretion (IGAS) and an increased risk of serious infections are inconclusive, both in the population at large and in the particular case of patients with chronic kidney disease. We have undertaken an investigation to disclose associations between treatment with IGAS and infectious outcomes, in patients undergoing chronic Peritoneal Dialysis (PD). Method. Observational, historic cohort, single center design. Six hundred and ninety-one patients incident on PD were scrutinized for an association among treatment with IGAS (H2 antagonists H2A or proton pump inhibitors PPI) (main study variable), on one side, and the risks of enteric peritoneal infection (main outcome), overall peritoneal infection, and general and infectious mortality (secondary outcomes). We applied a three-step multivariate approach, based on classic Cox models (baseline variables), time-dependent analyses and, when appropriate, competing risk analyses. Main results. The clinical characteristics of patients treated with H2A, PPI or none of these were significantly different. Multivariate analyses disclosed a consistently increased risk of enteric peritonitis in patients treated with IGAS (RR 1.65, 95% CI 1.08–2.55, p = 0.018, Cox). Stratified analysis indicated that patients treated with H2A, rather than those on PPI, supported the burden of this risk. Similar findings applied for the risk of infectious mortality. On the contrary, we were not able to detect any association among the study variables, on one side, and the general risks of peritonitis or mortality, on the other. Conclusions. Treatment with IGAS associates increased incidences of enteric peritonitis and infectious mortality, among patients on chronic PD. The association is clear in the case of H2A but less consistent in the case of PPI. Our results support the convenience of preferring PPI to H2A, for gastric acid inhibition in PD patients

Analysis of ultrafiltration failure diagnosed at the initiation of peritoneal dialysis with the help of peritoneal equilibration tests with complete drainage at sixty minutes: a longitudinal study

[Abstract] Background: Ultrafiltration failure (UFF) diagnosed at the initiation of peritoneal dialysis (PD) has been insufficiently characterized. In particular, few longitudinal studies have analyzed the time course of water transport in patients with this complication. ♦ Objective: To investigate the time course of peritoneal water transport during the first year on PD in patients presenting UFF since the initiation of this therapy (study group). ♦ Method: Prospective, observational, single-center design. We analyzed, at baseline and after 1 year of follow-up, peritoneal water transport in 19 patients incident on PD with UFF. We used incident patients without UFF as a control group. Water transport was characterized with the help of 3.86/4.25% dextrose-based peritoneal equilibration tests (PETs) with complete drainage at 60 minutes. ♦ Results: The study group revealed a disorder of water transport affecting both small-pore ultrafiltration (SPUF) (p = 0.054 vs incident without UFF) and free water transport (FWT) (p = 0.001). After 1 year of follow-up, FWT displayed a general increasing trend in the study group (mean variation 48.9 mL, 95% confidence interval [CI] 15.5, 82.2, p = 0.012), while the behavior of SPUF was less predictable (-4.8 mL, 95% CI -61.4, 71.1, p = 0.85). These changes were not observed in incident patients without UFF. Neither initial clinical characteristics, baseline PET-derived parameters, or suffering peritoneal infections during the first year predicted the time course of the capacity of UF in the study group. Recovery from incident UFF was apparently linked to improvement of SPUF. ♦ Conclusions: Patients with UFF at the start of PD suffer a disorder of peritoneal water transport affecting both FWT and SPUF. Free water transport increases systematically in these patients after 1 year of follow-up. The evolution of SPUF is less predictable, and improvement of this parameter marks reversibility of this complication

Sugar-lowering drugs for type 2 diabetes mellitus and metabolic syndrome - review of classical and new compounds: Part-I

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia together with disturbances in the metabolism of carbohydrates, proteins and fat, which in general results from an insulin availability and need imbalance. In a great number of patients, marketed anti-glycemic agents have shown poor effectiveness in maintaining a long-term glycemic control, thus being associated with severe adverse effects and leading to an emerging interest in natural compounds (e.g., essential oils and other secondary plant metabolites, namely, flavonoid-rich compounds) as a novel approach for prevention, management and/or treatment of either non-insulin-dependent diabetes mellitus (T2DM, type 2 DM) and/or Metabolic Syndrome (MS). In this review, some of these promising glucose-lowering agents will be comprehensively discussed.This work was financially supported by the Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) under the project reference M-ERANET/0004/2015-PAIRED and UID/AGR/04033/2019 (CITAB), co-financed by FEDER, under the Partnership Agreement PT2020, and also by the Institute of Nanoscience and Nanotechnology under the project ART(2018).info:eu-repo/semantics/publishedVersio

Performance of surveillance case definitions for respiratory syncytial virus infections through the sentinel influenza surveillance system, Portugal, 2010 to 2018

Background: Well-established influenza surveillance systems (ISS) can be used for respiratory syncytial virus (RSV) surveillance. In Portugal, RSV cases are detected through the ISS using the European Union (EU) influenza-like illness (ILI) case definition. Aim: To investigate clinical predictors for RSV infection and how three case definitions (EU ILI, a modified EU acute respiratory infection, and one respiratory symptom) performed in detecting RSV infections in Portugal. Methods: This observational retrospective study used epidemiological and laboratory surveillance data (October 2010–May 2018). Associations between clinical characteristics and RSV detection were analysed using logistic regression. Accuracy of case definitions was assessed through sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). A 0.05 significance level was accepted. Results: The study involved 6,523 persons, including 190 (2.9%) RSV cases. Among 183 cases with age information, RSV infection was significantly more frequent among individuals < 5 years (n = 23; 12.6%) and ≥ 65 years (n = 45; 24.6%) compared with other age groups (p < 0.0001). Cough (odds ratio (OR): 2.4; 95% confidence interval (CI): 1.2–6.5) was the best RSV-infection predictor considering all age groups, while shortness of breath was particularly associated with RSV-positivity among ≤ 14 year olds (OR: 6.7; 95% CI: 2.6–17.4 for 0–4 year olds and OR: 6.7; 95% CI: 1.5–28.8 for 5–14 year olds). Systemic symptoms were significantly associated with RSV-negative and influenza-positive cases. None of the case definitions were suitable to detect RSV infections (AUC = 0.51). Conclusion: To avoid underestimating the RSV disease burden, RSV surveillance within the Portuguese sentinel ISS would require a more sensitive case definition than ILI and, even a different case definition according to age.info:eu-repo/semantics/publishedVersio

State-of-the-art polymeric nanoparticles as promising therapeutic tools against human bacterial infections

Infectious diseases kill over 17 million people a year, among which bacterial infections stand out. From all the bacterial infections, tuberculosis, diarrhoea, meningitis, pneumonia, sexual transmission diseases and nosocomial infections are the most severe bacterial infections, which affect millions of people worldwide. Moreover, the indiscriminate use of antibiotic drugs in the last decades has triggered an increasing multiple resistance towards these drugs, which represent a serious global socioeconomic and public health risk. It is estimated that 33,000 and 35,000 people die yearly in Europe and the United States, respectively, as a direct result of antimicrobial resistance. For all these reasons, there is an emerging need to find novel alternatives to overcome these issues and reduced the morbidity and mortality associated to bacterial infectious diseases. In that sense, nanotechnological approaches, especially smart polymeric nanoparticles, has wrought a revolution in this field, providing an innovative therapeutic alternative able to improve the limitations encountered in available treatments and capable to be effective by theirselves. In this review, we examine the current status of most dangerous human infections, together with an in-depth discussion of the role of nanomedicine to overcome the current disadvantages, and specifically the most recent and innovative studies involving polymeric nanoparticles against most common bacterial infections of the human body.Authors acknowledge the support of the Spanish Ministry of Economy and Competitiveness (SAF2017-84283-R and RTI2018-098641-B-I00), Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED, CB06/05/0024), Scientifc Project Marató TV3 (ref 201829-10) and European Regional Development Founds. Authors also acknowledge the Portuguese Science and Technology Foundation (FCT) for the strategic fund (UIDB/04469/2020).info:eu-repo/semantics/publishedVersio

Antimicrobial Activity of Chitosan Membranes Against Staphylococcus Aureus of Clinical Origin

Healthy human skin has beneficial microflora and many pathogens causing infections. Staphylococcus aureus is the most prevalent and can have multiresistance to antibiotics. Chitosan is a polysaccharide composed of glucosamine and N-acetyl-D-glucosamine, which is biodegradable and has antimicrobial activity. As part of a national scientific research project for the development and application of biomaterials, we decided to study the effect of different membranes based on chitosan against strains of S. aureus isolated from infected ulcers. The study found that seven of nine strains of S. aureus are sensitive to rifampin and the least eight of nine strains were multiresistant to more than ten antibiotics. All chitosan-based membranes confirm its antimicrobial effect on direct contact with an increase in its diameter. The contact area of the membranes is increased according to the concentration of chitosan. The highest average area increase was the chitosan membranes with honey and glycerin, 88.32%. Chitosan membranes have shown their effectiveness against S. aureus strains of clinical origin. Thus, these materials can be applied for the treatment of chronic ulcers without toxic hazards and resistance caused by antibiotics