Natural Film Based on Pectin and Allantoin for Wound Healing: Obtaining, Characterization, and Rat Model.

INTRODUCTION: In our days, several approaches reported the use of natural compounds in medical applications. Among them, pectin and allantoin are nontoxic, biocompatible, and biodegradable; however, its use for possible wound healing therapeutics is still limited. Pectin and allantoin have been applied in pharmaceutical industry and beauty cosmetic and could be also applied as scaffolds for tissue regeneration, wound healing, and so on. The aim of this study was to combine by the first time two natural ingredients to develop a new biomaterial to treat skin injuries in a rat model. METHODS: For the hydrogel development, new synthesis parameters were established for the obtaining of the film such as temperature, mixing velocity and time, and drying temperatures as well. To enrich the film, the allantoin concentrations were set at 90 wt% and 100 wt% of pectin used. By in vivo assay, films were tested in wound healing in female Wistar rats, 190 ± 10 g in weight and 2 months aged. RESULTS: The obtained films comprise 2 well-differentiated layers, one layer rich in allantoin, which will be the regenerative layer, and one rich in pectin, which will work as an antimicrobial and protective layer to the wound. These were characterized by swelling kinetics, Fourier transform of the infrared spectrum of absorption (FTIR) spectroscopy, and contact angle. The morphology and topography were determined by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). In vivo assay showed remarkable reduce in a time period in a wound healing process when the film was used. The results show that the use of PA (Pectin-Allantoin) hydrogel reduces the total healing time by 25% approximately. CONCLUSIONS: Pectin-Allantoin (PA) film has potential use in medical applications as wound healing material promoting healthy tissue renewal.

Synthesis, Characterization, and In Vitro and In Vivo Evaluations of Cellulose Hydrogels Enriched with Larrea tridentata for Regenerative Applications.

INTRODUCTION: Tissue engineering is an elementary necessity for several applications in the biomedical field through the use of several biopolymers derived from plants. Larrea tridentata (LT) is a very used plant for various medicinal applications with interesting properties; however, its use into cellulose hydrogels for possible regenerative therapeutics is still limited. Cellulose films could be applied in medical field as wound healing, scaffold for connective tissue for periodontal applications, and so on. The aim of this study was to evaluate the mechanical properties and in vivo and in vitro biocompatibility of cellulose hydrogels that have been enriched with LT in a rat model. METHODS: By in vivo and in vitro assays, the concentration of LT was varied from 1 to 5 wt%, respectively. Hydrogel films were implanted intramuscularly into female Wistar rats, 250 g in weight and aged 2 months, to analyze their cytocompatibility and biocompatibility. RESULTS: No case showed any evidence of inflammation or toxicity. Regarding cell morphology and adhesion, the prepared LT cellulose films had better cytocompatibility values than when polystyrene (PS) dishes were used as the control. In all cases, the results suggest that the addition of LT to the hydrogel films did not affect their cytocompatibility or biocompatibility properties and increases their clinical application due to the reported uses of LT. CONCLUSIONS: Cellulose hydrogel films enriched with LT have the potential to be used in the biomedical field acting as regenerative scaffolds.

Rotifers from selected inland saline waters in the Chihuahuan Desert of México.

BACKGROUND: In spite of considerable efforts over past decades we still know relatively little regarding the biogeography of rotifers of inland waters in México. To help rectify this we undertook an extensive survey of the rotifer fauna of 48 water bodies in the Chihuahuan Desert of México. RESULTS: Of the sites surveyed, 21 had salinities >or= 2000 microS cm-1 and in these we found 57 species of monogonont rotifers and several bdelloids. Species richness in the saline sites varied widely, with a range in species richness of 1 to 27 and a mean (+/- 1SD) = 8.8 (+/- 6.2). Collectively all sites possess relatively high percent single- and doubletons, 33.3 and 21.7%, respectively. Simpson's Asymmetric Index indicated that similarity in rotifer species composition varied widely among a set of 10 sites. These were selected because they were sampled more frequently or represent unusual habitats. These SAI values ranged from 0.00 (complete dissimilarity) to 1.00 (complete similarity). The Jaccard Index varied between 0.00 and 0.35. This observation probably reflects similarities and differences in water chemistry among these sites. Inland saline systems differed in their chemical composition by region. Conductivity was related to hardness and alkalinity. In addition, hardness was positively associated with chloride and sulfate. RDA showed that several species were positively associated with chloride concentration. Other factors that were significantly associated with rotifer species included the presence of macrophytes, nitrate content, oxygen concentration, TDS, latitude and whether the habitat was a large lake or reservoir. CONCLUSION: This study illustrates the diversity of the rotiferan fauna of inland saline systems and the uniqueness among waterbodies. Conservation of these systems is needed to preserve these unique sources of biodiversity that include rotifers and the other endemic species found in association with them.

Interaction effects of multi-metal solutions (As, Cr, Cu, Ni, Pb and Zn) on life history traits in the rotifer Plationus patulus.

While many studies have determined toxicity of single heavy metals, few have addressed the combined effects of multiple elements at different concentrations. In order to estimate how metal mixtures affect population dynamics of freshwater rotifers, we exposed Plationus patulus to environmentally relevant concentrations and combinations of arsenic and five heavy metals (Cr, Cu, Ni, Pb and Zn) for 8 days. The life-history parameters, intrinsic rate of increase (r), relative cumulative reproduction (RCR), mortality ratio, mictic ratio, fertilization ratio, and number of deformed offspring were used as endpoints. Exposures were repeated 4 times and considered as blocks in the experimental design. Differences between treatments were evaluated through ANOVA and LSD mean analysis. The combined presence of As, Cu, Ni, Pb, and Zn in different concentrations produced a variety of changes in the population dynamics of P. patulus. However, only Cr produced a significant element*environment interaction. The presence of Cr leads to significant decreases in the intrinsic rate of increase and increased mortality ratio in multi-metal environments. The population growth (as r) decreased from 0.25 to -0.16 due to Cr (10 microg/L) interaction with the remaining elements, and values 0.16-0.12 were observed in treatments containing high levels (50 microg/L) of Cr. Mortality ratio increased from 0.066 to 0.822 due to Cr (10 and 50 microg/L) interactions with the remaining elements at high concentrations. Responses of this basal consumer to metal mixtures will provide insights into how aquatic food webs and their constituent organisms can be altered by anthropogenic inputs like heavy metal contamination.