Summary
Wound healing studies are intricate, mainly because of the multifaceted nature of the wound environment and the complexity of the healing process, which integrates a variety of cells and ...repair phases, including inflammation, proliferation, reepithelialization and remodelling. There are a variety of possible preclinical models, such as in mice, rabbits and pigs, which can be used to mimic acute or impaired for example, diabetic and nutrition‐related wounds. These can be induced by many different techniques, with excision or incision being the most common. After determining a suitable model for a study, investigators need to select appropriate and reproducible methods that will allow the monitoring of the wound progression over time. The assessment can be performed by non‐invasive protocols such as wound tracing, photographic documentation (including image analysis), biophysical techniques and/or by invasive protocols that will require wound biopsies. In this article, we provide an overview of some of the most often needed and used: (a) preclinical/animal models including incisional, excisional, burn and impaired wounds; (b) methods to evaluate the healing progression such as wound healing rate, wound analysis by image, biophysical assessment, histopathological, immunological and biochemical assays. The aim is to help researchers during the design and execution of their wound healing studies.
Context: The quantification of total collagen is of major importance in a wide range of research areas, including the study of cutaneous wound healing and new drugs trials.
Objective: The total ...collagen content in skin biopsies was compared by biochemical hydroxyproline assay and by two computer-aided histomorphometric analyses of histological sections.
Materials and methods: Two methods were used to evaluate collagen formation: the hydroxyproline assay, as the gold standard and histomorphometric image analysis of the filled areas by corresponding stained collagen fibres, using picrosirius and Gomori's trichrome staining. The image analyses were determined by digital densitometry recognition using computer-aided ImageJ software. One-way ANOVA, simple linear regression and ANCOVA were applied for the statistical analysis and correlation.
Results: In a simple linear regression analysis carried out on the 14th day period after the induction of skin injury, three techniques, picrosirius red (F = 33.57, p = 0.00), Gomori's trichrome (F = 81.61, p = 0.00) and hydroxyproline content (F = 16.85, p = 0.00) were able to detect collagen production. After scale adjustment, there were no significant differences among either the slopes (F = 1.17, p = 0.32) or the intercepts (F = 0.69, p = 0.51) of the estimated regression lines. It seems that a highly significant correlation exists between the histomorphometrical analysis and hydroxyproline assay.
Discussion and conclusion: The morphometric analysis proved to be adequate and can be used as a simple, rapid, low-cost technology for evaluating total collagen in cutaneous wound specimens, compared with the gold standard hydroxyproline assay.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Hyaluronidases are enzymes that degrade hyaluronan an important constituent of the extracellular matrix. They have been used as a spreading agent, improving the absorption of drugs and facilitating ...the subcutaneous infusion of fluids. Here, we investigated the influence of bovine testes hyaluronidase (HYAL) during cutaneous wound healing in in vitro and in vivo assays. We demonstrated in the wound scratch assay that HYAL increased the migration and proliferation of fibroblasts in vitro at low concentration, e.g. 0.1 U HYAL enhanced the cell number by 20%. HYAL presented faster and higher reepithelialization in in vivo full-thickness excisional wounds generated on adult Wistar rats back skin already in the early phase at 2nd day post operatory compared to vehicle-control group. Wound closured area observed in the 16 U and 32 U HYAL treated rats reached 38% and 46% compared to 19% in the controls, respectively. Histological and biochemical analyses supported the clinical observations and showed that HYAL treated wounds exhibited increased granulation tissue, diminished edema formation and regulated the inflammatory response by modulating the release of pro and anti-inflammatory cytokines, growth factor and eicosanoids mediators. Moreover, HYAL increased gene expression of peroxisome proliferator-activated receptors (PPAR) γ and PPAR β/δ, the collagen content in the early stages of healing processes as well as angiogenesis. Altogether these data revealed that HYAL accelerates wound healing processes and might be beneficial for treating wound disorders.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The objective of this work was to develop new NR‐based biocomposite containing BioS and/or BL0 particles, which exhibit better tensile response, biocompatibility, and bioactivity for biomedical ...applications. Morphological, tensile, thermal, and biological tests were performed on the biocomposites to evaluate the influence of BioS and BL0 particles on the properties of the NR matrix. According to TG/DTG tests, the decomposition profiles of the NR/BioS and NR/BL0 biocomposites were similar to those of NR, whose main event could be seen in the 290–450°C temperature range, indicative of NR's structural degradation. Tensile analysis demonstrated that the addition of BioS or BL0 to the NR‐based biocomposite improved the elastic modulus and the tensile strength at break (σat break) in comparison to NR. The σat break value of the NR matrix increased from 0.99 ± 0.06 MPa to 1.84 ± 0.09 and 2.29 ± 0.04 MPa for the NR/BioS and NR/BL0 specimens with 30 wt%. Indirect cytotoxicity testing revealed that NR, NR/BL0, and NR/BioS biocomposite specimens promote the attachment of MSCs cell, that is, greater than 70% viability as defined in ISO 10993‐5:2009. The results indicate that BioS and BL0 particles have improved the tensile response and biological properties of the NR matrix, resulting in a range of potential biomedical applications.
An illustration of the production process and properties of biocomposite specimens.
The bacterial cellulose membrane (CM) is a promising biomaterial due to its easy applicability and moist environment. Moreover, nanoscale silver compounds (AgNO3) are synthesized and incorporated ...into CMs to provide these biomaterials with antimicrobial activity for wound healing. This study aimed to evaluate the cell viability of CM incorporated with nanoscale silver compounds, determine the minimum inhibitory concentration (MIC) for Escherichia coli and Staphylococcus aureus, and its use on in vivo skin lesions. Wistar rats were divided according to treatment: untreated, CM (cellulose membrane), and AgCM (CM incorporated with silver nanoparticles). The euthanasia was performed on the 2nd, 7th, 14th, and 21st days to assess inflammation (myeloperoxidase-neutrophils, N-acetylglucosaminidase-macrophage, IL-1β, IL-10), oxidative stress (NO-nitric oxide, DCF-H2O2), oxidative damage (carbonyl: membrane's damage; sulfhydryl: membrane's integrity), antioxidants (superoxide dismutase; glutathione), angiogenesis, tissue formation (collagen, TGF-β1, smooth muscle α-actin, small decorin, and biglycan proteoglycans). The use of AgCM did not show toxicity, but antibacterial effect in vitro. Moreover, in vivo, AgCM provided balanced oxidative action, modulated the inflammatory profile due to the reduction of IL-1β level and increase in IL-10 level, in addition to increased angiogenesis and collagen formation. The results suggest the use of silver nanoparticles (AgCM) enhanced the CM properties by providing antibacterial properties, modulation the inflammatory phase, and consequently promotes the healing of skin lesions, which can be used clinically to treat injuries.
•Silver nanoparticles (around 15-nm in size) were successfully incorporated into bacterial cellulose membranes.•Bacterial cellulose membrane (BCM) with silver nanoparticles: bacteriostatic property; no cytotoxicity for animal cells.•BCM with silver nanoparticles modulated the inflammatory process and stimulated angiogenesis and collagen formation.•Balanced oxidative stress and antioxidant markers by treating wounds with BCM incorporated with silver nanoparticles.
This study aimed to investigate the application of low‐intensity electrostimulation (ES) and electromagnetic stimulation (EM) associated with bioactive glass (BG) or allogeneic grafts (BB) in bone ...regeneration. A cell viability test on osteoblasts (UMR‐106) was performed in the presence of BB and BG grafts associated with ES (10 μA/5 min) and EM (500 Hz/2 min). Critical defects (25 mm2) in calvaria were generated in male Wistar rats, and bone regeneration was evaluated on the 30th, 60th, and 120th days after surgery. Cell proliferation increased with the application of ES in both grafts and after EM with BG. Bone remodeling was more effective using the allogeneic graft in both therapies, with increased angiogenesis, osteoblast proliferation, and OPN expression in the BB + EM group. A higher number of osteoblasts and osteoclasts, and an increase in bone sialoprotein, Runx‐2, and Opn gene expression were found in the BB + ES group. The BG graft associated with EM therapy had an increased proliferation of osteoblasts and increased expression of Runx‐2 and Opn. Groups that had BG and ES therapy had increased numbers of osteoblasts, osteoclasts, and increased OPN expression. The expression of voltage‐gated calcium channels increased in groups with ES, while calmodulin expression increased in therapies without grafting. ES and EM therapies favored the repair of bone defects upon grafting by improving angiogenesis, osteogenic gene expression, and tissue reorganization. Despite activating different pathways, both therapies increased the intracellular concentrations of calmodulin, leading to cell proliferation and bone regeneration.
Critical bone defects are considered one of the major clinical challenges in reconstructive bone surgery. The combination of 3D printed conductive scaffolds and exogenous electrical stimulation (ES) ...is a potential favorable approach for bone tissue repair. In this study, 3D conductive scaffolds made with biocompatible and biodegradable polycaprolactone (PCL) and multi-walled carbon nanotubes (MWCNTs) were produced using the extrusion-based additive manufacturing to treat large calvary bone defects in rats. Histology results show that the use of PCL/MWCNTs scaffolds and ES contributes to thicker and increased bone tissue formation within the bone defect. Angiogenesis and mineralization are also significantly promoted using high concentration of MWCNTs (3 wt%) and ES. Moreover, scaffolds favor the tartrate-resistant acid phosphatase (TRAP) positive cell formation, while the addition of MWCNTs seems to inhibit the osteoclastogenesis but present limited effects on the osteoclast functionalities (receptor activator of nuclear factor
κβ
ligand (RANKL) and osteoprotegerin (OPG) expressions). The use of ES promotes the osteoclastogenesis and RANKL expressions, showing a dominant effect in the bone remodeling process. These results indicate that the combination of 3D printed conductive PCL/MWCNTs scaffold and ES is a promising strategy to treat critical bone defects and provide a cue to establish an optimal protocol to use conductive scaffolds and ES for bone tissue engineering.
This study aimed to investigate the application of low-intensity electrostimulation (ES) and electromagnetic stimulation (EM) associated with bioactive glass (BG) or allogeneic grafts (BB) in bone ...regeneration. A cell viability test on osteoblasts (UMR-106) was performed in the presence of BB and BG grafts associated with ES (10 μA/5 min) and EM (500 Hz/2 min). Critical defects (25 mm
) in calvaria were generated in male Wistar rats, and bone regeneration was evaluated on the 30th, 60th, and 120th days after surgery. Cell proliferation increased with the application of ES in both grafts and after EM with BG. Bone remodeling was more effective using the allogeneic graft in both therapies, with increased angiogenesis, osteoblast proliferation, and OPN expression in the BB + EM group. A higher number of osteoblasts and osteoclasts, and an increase in bone sialoprotein, Runx-2, and Opn gene expression were found in the BB + ES group. The BG graft associated with EM therapy had an increased proliferation of osteoblasts and increased expression of Runx-2 and Opn. Groups that had BG and ES therapy had increased numbers of osteoblasts, osteoclasts, and increased OPN expression. The expression of voltage-gated calcium channels increased in groups with ES, while calmodulin expression increased in therapies without grafting. ES and EM therapies favored the repair of bone defects upon grafting by improving angiogenesis, osteogenic gene expression, and tissue reorganization. Despite activating different pathways, both therapies increased the intracellular concentrations of calmodulin, leading to cell proliferation and bone regeneration.
•Developed a front-end platform to link dynamic programming, water simulation and cost minimization.•Application for Southern Brazil in a system characterized by large system losses.•A portfolio ...approach for developing surface or groundwater sources.•Consider costs of expansions, economic value of money, interest rates.•Consider timing on investment in reduction of systemwide water losses.
The expansion and operation of water supply systems under growing demands, hydrologic variability, and water scarcity requires strategic decisions on supply sources for reducing and improving reliability and flexibility. The design and operation of such supply portfolio merits decisions of what and when to expand, and how much of each source to use considering interest rates, economies of scale and hydrologic variability. This paper provides an integrated framework to optimize water supply system expansions using dynamic programming and combining short and long term water supply source optimization using quadratic programming. The approach represents water supply infrastructure features and hydrologic conditions under increasing water demands. Results allow (a) identification of tradeoffs between cost and reliability of various expansion paths and supply source decisions, and (b) evaluation of potential gains from water system loss reductions, an often neglected supply augmenting alternative in developing countries. Results show the need for supply infrastructure expansions can be dampened by investments in reduction of systemwide losses. A losses reduction program cutting losses in half will cost R$ 532 million annually with a minimum system reliability of 60 percent. This program would yield net savings of 2.7 percent with respect to the status quo annual costs. Decreasing system losses from fifty to five percent, will cost R$ 547 million per year with a minimum system reliability of 87 percent. Earlier investments in system loss reduction programs will greatly improve reliability and system expansion costs. The framework proves its usefulness for planning its transferability to similarly urbanized systems.
The large amount of medical exams generated by hospitals has a great potential to boost the support for physicians on decision making tasks. This requires efficient and reliable computational systems ...to retrieve relevant information in real-time. Existing Content-Based Image Retrieval (CBIR) systems rely on Metric Access Methods (MAMs) to speed-up the retrieval task. In this context, images are represented by Feature Extraction Methods (FEMs), according to information such as color or texture. However, MAMs usually index images based on a single FEM. Whenever physicians want to search for similar images using multiple FEMs simultaneously, they need to perform separated queries. In this work, we propose UCORM, an access method capable of indexing images using multiple FEMs by overlapping different metric spaces. UCORM selects the best FEMs to generate a concise yet accurate indexing space. It relies on an interesting use of Pearson correlation, that we named PCMS, to compute the correlation between different FEMs. PCMS allows UCORM to improve the retrieval task by minimizing the overlapping between metric spaces, resulting on fewer intermediary images when performing a query. Experimental analysis shows that UCORM prunes well the data distribution regions with low correlation between FEMs. Also, two medical application scenarios support our claim that UCORM is well-fitted for clinical environments.
PDF
