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Interest is growing in entrapping natural antimicrobial compounds (NACs) within polyhydroxyalkanoates (PHAs) to produce active food-biopackaging systems. PHAs are versatile polymeric macromolecules that can protect NAC activity by entrapment. This work reviews 75 original papers and 18 patents published in the last 11 years concerning PHAs as matrices for NACs to summarize the physicochemical properties, release, and antimicrobial activities of systems fabricated from PHAs and NACs (PHA/NAC systems). PHA/NAC systems have recently been used as active food biopackaging systems to inactivate foodborne pathogens and prolong food shelf life. PHAs protect NACs by increasing the degradation temperature of some NACs and decreasing their loss of mass when heated. Some NACs also transform the PHA/NAC systems into more thermostable, flexible, and resistant when interacting with PHAs while also improving the barrier properties of the systems. NAC release and activity are also prolonged when NACs are trapped within PHAs. PHA/NAC systems, therefore, represent ecologically friendly materials with promising applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Every year, new organisms that survive and colonize adverse environments are discovered and isolated. Those organisms, called extremophiles, are distributed throughout the world, both in aquatic and terrestrial environments, such as sulfurous marsh waters, hydrothermal springs, deep waters, volcanos, terrestrial hot springs, marine saltern, salt lakes, among others. According to the ecosystem inhabiting, extremophiles are categorized as thermophiles, psychrophiles, halophiles, acidophiles, alkalophilic, piezophiles, saccharophiles, metallophiles and polyextremophiles. They have developed chemical adaptation strategies that allow them to maintain their cellular integrity, altering physiology or improving repair capabilities; one of them is the biosynthesis of extracellular polysaccharides (EPS), which constitute a slime and hydrated matrix that keep the cells embedded, protecting from environmental stress (desiccation, salinity, temperature, radiation). EPS have gained interest; they are explored by their unique properties such as structural complexity, biodegradability, biological activities, and biocompatibility. Here, we present a review concerning the biosynthesis, characterization, and potential EPS applications produced by extremophile microorganisms, namely, thermophiles, halophiles, and psychrophiles. A bibliometric analysis was conducted, considering research articles published within the last two decades. Besides, an overview of the culture conditions used for extremophiles, the main properties and multiple potential applications of their EPS is also presented., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The physicochemical characterization and emulsifying functional properties of a novel exopolysaccharide (EPS) produced by haloarchaea Haloferax mucosum (DSM 27191) were investigated. This biopolymer has a high molecular weight of 152 kDa and important protein content of 10%. Different culture media compositions were investigated taking the ATCC 2185 medium as a base and supplementing with varying concentrations of yeast extract and glucose or sucrose as carbon sources to produce the EPS in a liquid medium. The highest EPS production (7.15 ± 0.44 g/L) was obtained at 96 h. EPS aqueous dispersions showed a non-Newtonian rheological behavior which was well fitted to the Cross equation. The EPS (at 0.32% w/w) was capable of stabilizing water-in-oil emulsions with different nonpolar solvents, including n-hexane, kerosene, chloroform, castor oil and mineral oil. EPS retained its emulsifying activity after to be incubated for one hour in a wide range of temperatures (25, 40, 70 and 100 °C), pH (4, 6.5, 7 and 12) and NaCl concentrations (0, 2.0 and 4.0 M). The viscoelastic behavior and stability of hexane-in-water emulsion were examined through oscillatory shear measurements., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Increased acetataemia during haemodialysis sessions has been associated with a number of abnormalities, including increased oxidative stress, pro-inflammatory cytokines and nitric oxide synthesis. However, citric acid may play an alternative role to acetate as a dialysate stabiliser given that the effect of citrate on complement and leukocyte activation is different to that of acetate. The purpose of this study was to compare the inflammatory effect in immunocompetent blood cells of acetate dialysate and citrate dialysate., Material and Methods: The effect of acetate and/or citrate was investigated in the whole blood of uraemic patients and in healthy in vitro samples. Four types of dialysate were tested: dialysate 1, acetate-free with 1mmol/L of citrate; dialysate 2, with 0.8mmol/L of citrate and 0.3mmol/L of acetate; dialysate 3, citrate-free with 3mmol/L of acetate; and dialysate 4, citrate-free with 4mmol/L of acetate. The cell types used were: human monocyte culture (THP-1); and peripheral blood mononuclear cells (PBMCs) from healthy subjects and uraemic patients on haemodialysis. ICAM-1 was determined and levels of reactive oxygen species and total microvesicles were quantified., Results: Unlike the citrate dialysates, the dialysates with acetate (dialysate 3 and dialysate 4) induced increased ICAM-1 expression density in THP-1 cells; an increase in ICAM-1 expression was observed in the immunocompetent cells of healthy subjects with acetate dialysate (dialysate 3 and dialysate 4) but not with citrate dialysate (dialysate 1 and dialysate 2). No significant ICAM-1 differences were found between the different dialysates in the cells of haemodialysed patients. Reactive oxygen species expression and the number of microvesicles increased significantly with acetate dialysate but not with citrate dialysate in the cells of both healthy subjects and haemodialysed patients., Conclusions: At the concentrations in which it is generally used in clinical practice, acetate-based dialysate increases oxidative stress and the total number of microvesicles and may induce other pro-inflammatory stimuli typical of uraemic patients on haemodialysis. Citrate dialysates do not induce this activation, which could make them a suitable alternative in clinical practice., (Copyright © 2017 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

The addition of phosphorus (P) to the dialysate (LD) in the form of enema Casen® is common practice in patients with hypophosphatemia. The estimation of the amount to be used and the identification of the problems that may can occur are not well defined. As a result of our work we propose a practical approach of how to proceed to increase phosphate concentration in the hemodialysate. We present a reasoned formula to calculate how much enema has to be added and the problems that may arise., (Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Background: The daily pill burden in hemodialysis patients is one of the highest reported to date in any chronic disease. The adherence to prescribed treatment has implications on the quality of life, the survival of patients, and the economic cost of their treatment, this being a priority public health issue., Objective: To evaluate the adherence to pharmacological treatment examining, among the possible causes of non-adherence, psychosocial factors such as depression, anxiety, cognitive impairment and social support., Method: Transversal-observational study of thirty five patients that suffer from chronic renal disease and who are on manteinance hemodialysis, evaluated by self-reported measures., Results: Non-adherent patients have significant higher depression index than adherent patients. Anxiety, cognitive impairment and social support do not show a significant relation with the degree of adherence or compliance with farmacological treatment., Conclusions: These results suggest that psychological intervention in chronic haemodialysis patients with a severe depression index could increase the degree of fulfillment and general well-being of renal patients.

Introduction: Haemodiafiltration (HDF) with high reinfusion volumes is the most effective technique for clearing uraemic toxins. There are various modalities depending on the location where the replacement volume is administered in the extracorporeal circuit: pre-dilution, mixed or mid-dilution and post-dilution, in which the infusion is carried out pre-dilution, pre- and post-dilution simultaneously and post-dilution, respectively., Objective: Compare the clearance of small, medium-sized and protein-bound molecules and the convective volume administered in online HDF (OL-HDF) in post-dilution and mixed (pre-post-dilution) infusion., Material and Method: A prospective, randomised, crossover study comparing post-dilution and mixed OL-HDF. Patients (n=8) were randomly assigned to receive 6 sessions in each technique. We conducted 89 sessions, of which 68 were at a scheduled time (ST) and 21 at an effective time (ET). We determined the reduction rate (RR) percentages for various substances and the infusion volumes. The RR study was performed using ET., Results: The KT value obtained was greater with post-dilution OL-HDF [68 (8.1) compared to 64.9 (8.8) litres] (P=.009) when patients were dialysed at ST. This difference disappeared when dialysis was performed at ET. The difference between ST and ET was greater in mixed HDF than in post-dilution HDF [10.3 (7.4) compared to 6.5 (3.1) minutes, P=.02]. We found no differences in the RR of the substances analysed., Conclusion: Mixed OL-HDF is not inferior to post-dilution OL-HDF either in the clearance of small and medium-sized molecules or in the clearance of protein-bound molecules at the same ET.

Introduction: Peritonitis is one of the most common and severe complications associated with peritoneal dialysis (PD), constituting the primary cause of catheter loss and exit from the dialysis technique. The incidence and aetiology of peritonitis episodes vary based on geographical region, and change over time. For this reason, it is vital to maintain an updated understanding of the current risk factors and prognostic factors associated with peritonitis., Method: We performed an observational, multi-centre, prospective cohort study with a maximum follow-up period of 7 years (2003-2010), which included 1177 patients and a total of 476 first episodes of peritonitis (total: 1091 cases of peritonitis)., Results: We describe the characteristics of the first episode of peritonitis from a large and current study sample. The factors associated with a shorter interval until the first episode of peritonitis as selected by the multivariate analysis included prior cardiovascular comorbidity (Hazard Ratio [HR]: 1.25 [1.04-1.58]), having previously received haemodialysis (HR: 1.39 [1.10-1.76]) or a kidney transplant (HR: 1.38 [1.10-1.93]), having started PD on a manual modality (HR: 1.39 [1.13-1.73]), and initial age >70 years (HR: 1.53 [1.23-1.90]). The first episode of peritonitis was associated with a 7.8% rate of recurrence, an 11.7% rate of catheter removal, and a mortality rate within one month of the episode of 1.3%. The progression of peritonitis infections depended on the type of causal microorganism. We calculated a greater risk for gram-negative bacterial infections (Odds Ratio [OR]: 5.31 [2.26-12.48]) and the aggregate group of infections caused by multiple microorganisms, fungal infections, and mycobacterial infections (OR: 38.24 [13.84-105.63]), as compared to gram-positive bacterial infections., Conclusion: The development of a first case of peritonitis depends on the characteristics of the patient upon starting dialysis, comorbidities present, and the technique used. Patients at a greater risk for peritonitis must receive special care during training and follow-up.

Introduction: 25-hydroxy vitamin D (25-OH-vit D) levels in the blood are associated with multiple pathologies. "Normal" values have been defined based on cardiovascular risk, and under this framework, patients with chronic kidney disease often have a deficit. 25-OH-vit D replacement in patients on haemodialysis (HD), in which dosage has not yet been clearly established, is becoming a constant in our daily practice., Objective: To assess whether dialysis technique influences the baseline concentration of 25-OH-vitamin D and the response to supplements., Method: Prospective observational study of two cohorts of patients, those patients treated with calcifediol and those untreated (controls). Blood levels of Ca, P, PTH, and 25-OH-vit D were measured in 59 prevalent patients on HD (35 male; mean age: 65.2 (15.7) years) in November 2010. Thirty-six patients with 25-OH-vit D<10 ng/ml were treated with weekly calcifediol (Hidroferol®, 1 ampoule: 266 μg) since January 2011, which was administered after HD by a nurse. They received 6 doses, and blood levels were measured again in March 2011. We compared the response based on the technique of HD (online haemodiafiltration [OL-HDF] vs HD)., Results: Mean baseline values (n=59): 25-OH-vit D: 9.8 (7.0)ng/ml, Ca: 9.3 (0.5)mg/dl, P: 4.5 (1.4)mg/dl, and iPTH: 299 (224)pg/ml. There were no differences by age, sex, or dialysis technique (HD vs OL-HDF). Treated patients (n=36): 25-OH-vit D levels rose from 6.2 (3.4)ng/ml to 51 (22.9)ng/ml (P<.0001), without significant changes in Ca. Serum phosphate increased an average of 0.6 (1.4)mg/dl, from 4.4 mg/dl to 5mg/dl, (P=.015). PTH decreased an average of 85 (208)pg/ml (P=.023). In these patients, the indication for phosphate binders increased by an average dose equivalent of 0.47 (0.82)mg/dl (P<.001). The 13 patients under treatment with OL-HDF reached 25-OH-vit D levels significantly higher than the 23 treated on HD: 63 (21)ng/ml vs 43 (21)ng/ml (P=.011). Dual treatment with native and active Vit D was associated with significantly increased levels of P (P=.043). Untreated patients (n=23): 25-OH-vit D levels decreased from 15.3 (7.5)ng/ml in November to 11.1 (6.8)ng/ml in March (P<.01), without significant changes in P or PTH and without differences according to age. 25-OH-vit D levels declined in patients on HD (15) but not in patients on OL-HDF., Conclusion: The patients on haemodialysis have low or very low baseline values for 25-OH-vit D. The response to treatment with calcifediol is good, with the most marked improvement occurring in patients on OL-HDF. Furthermore, 25-OH-vit D levels decreased in untreated patients, which was probably correlated with the lower sun exposure in winter. Some patients experienced an increase in phosphataemia despite increasing the dosage of phosphate binders, mainly in those receiving treatment with active vitamin D.