Background A chronic wound is tissue with an impaired ability to heal. This is often a consequence of one of the following etiologies: diabetes, venous reflux, arterial insufficiency sickle cell ...disease, steroids, and/or pressure. Healing requires granulation tissue depending on epithelialization and angiogenesis. Currently no growth factor is available to treat patients with impaired healing that stimulates both epithelialization and angiogenesis. The objective is to review is the multiple mechanisms of vascular endothelial growth factor (VEGF) in wound healing. Materials and Methods The authors reviewed the literature on the structure and function of VEGF, including its use for therapeutic angiogenesis. Particular attention is given to the specific role of VEGF in the angiogenesis cascade, its relationship to other growth factors and cells in a healing wound. Results VEGF is released by a variety of cells and stimulates multiple components of the angiogenic cascade. It is up-regulated during the early days of healing, when capillary growth is maximal. Studies have shown the efficacy of VEGF in peripheral and cardiac ischemic vascular disease with minimal adverse effects. Experimental data supports the hypothesis that VEGF stimulates epithelialization and collagen deposition in a wound. Conclusion VEGF stimulates wound healing through angiogenesis, but likely promotes collagen deposition and epithelialization as well. Further study of the molecule by utilizing the protein itself, or novel forms of delivery such as gene therapy, will increase its therapeutic possibilities to accelerate closure of a chronic wound.
Background
Analysis of surgical instrument motion is applicable in surgical skill assessment and monitoring of the learning progress in laparoscopy. Current commercial instrument tracking technology ...(optical or electromagnetic) has specific limitations and is expensive. Therefore, in this study, we apply inexpensive, off-the-shelf inertial sensors to track laparoscopic instruments in a training scenario.
Methods
We calibrated two laparoscopic instruments to the inertial sensor and investigated its accuracy on a 3D-printed phantom. In a user study during a one-week laparoscopy training course with medical students and physicians, we then documented and compared the training effect in laparoscopic tasks on a commercially available laparoscopy trainer (Laparo Analytic, Laparo Medical Simulators, Wilcza, Poland) and the newly developed tracking setup.
Results
Eighteen participants (twelve medical students and six physicians) participated in the study. The student subgroup showed significantly poorer results for the count of swings (CS) and count of rotations (CR) at the beginning of the training compared to the physician subgroup (
p
= 0.012 and
p
= 0.042). After training, the student subgroup showed significant improvements in the rotatory angle sum, CS, and CR (
p
= 0.025,
p
= 0.004 and
p
= 0.024). After training, there were no significant differences between medical students and physicians. There was a strong correlation between the measured learning success (LS) from the data of our inertial measurement unit system (LS
IMU
) and the Laparo Analytic (LS
Lap
) (Pearson’s
r
= 0.79).
Conclusion
In the current study, we observed a good and valid performance of inertial measurement units as a possible tool for instrument tracking and surgical skill assessment. Moreover, we conclude that the sensor can meaningfully examine the learning progress of medical students in an ex-vivo setting.
Chitin (CT), the well-known natural biopolymer and chitosan (CS) (bio-based or “artificial polymer”) are non-toxic, biodegradable and biocompatible in nature. The advantages of these biomaterials are ...such that, they can be easily processed into different forms such as membranes, sponges, gels, scaffolds, microparticles, nanoparticles and nanofibers for a variety of biomedical applications such as drug delivery, gene therapy, tissue engineering and wound healing. Present review focuses on the diverse applications of CT and CS membranes and scaffolds for drug delivery, tissue engineering and targeted regenerative medicine. The chitinous scaffolds of marine sponges’ origin are discussed here for the first time. These CT based scaffolds obtained from Porifera possess remarkable and unique properties such as hydration, interconnected channels and diverse structural architecture. This review will provide a brief overview of CT and CS membranes and scaffolds toward different kinds of delivery applications such as anticancer drug delivery, osteogenic drug delivery, and growth factor delivery, because of their inimitable release behavior, degradation profile, mucoadhesive nature, etc. The review also provides an overview of the key features of CT and CS membranes and scaffolds such as their biodegradability, cytocompatibility and mechanical properties toward applications in tissue engineering and wound healing.
ABSTRACT
Bell's introduction of the fibroblast‐populated collagen lattice (FPCL) has facilitated the study of collagen–cell interactions. As a result of the numerous modifications of the casting of ...FPCLs, the in vivo applications of these in vitro findings have been confusing. Here experimental FPCL contraction findings are viewed in regard to three proposed mechanisms responsible for lattice contraction. The cellular mechanisms responsible for generating FPCL contraction are cell contraction, cell tractional forces related to cell locomotion, and initial cell elongation and spreading.
For the first time, the adsorption of 4-aminopyridine (4-AP) drug onto four X12Y12 fullerene-like nanocages (Al12N12, Al12P12, B12N12, and B12P12) was investigated using density functional theory ...(DFT) calculations at the M06-2X /6-311 g(d,p) theoretical level. We tried to study the relaxed structures of the adsorbed 4-AP drug on each cages by considering the calculations of bond distance, adsorption energy, charge analysis, frontier orbital analysis, dipole moment, and density of states. For each system, we found the transfer of charge from drug to nanocage that points to the p-type semiconducting property of nanocages. The bond formation of the drug with nanocages is resulted from the connection of nucleophilic part of 4-AP drug (as an electron-donating substance) with the electrophilic part of these nanocages. The adsorption energy of 4-AP was calculated to be − 1.36, − 1.09, − 1.35, and − 1.09 eV upon interaction with Al12N12, Al12P12, B12N12, and B12P12, respectively. The results reveal that, in all cases, the 4-AP is bonded covalently through the nitrogen. The bandgap of each nanocage (except Al12N12) is significantly reduced upon adsorption of 4-AP. Finally, it can be concluded that Boron- containing nanocages are better sensors for the 4-AP molecule than aluminum-containing owing to the higher changes in their bandgap.
Environmental problems have contributed to numerous collapses of civilizations in the past. Now, for the first time, a global collapse appears likely. Overpopulation, overconsumption by the rich and ...poor choices of technologies are major drivers; dramatic cultural change provides the main hope of averting calamity.
Transformational change McAlpine, Clive A.; Seabrook, Leonie M.; Ryan, Justin G. ...
Ecology and society,
01/2015, Letnik:
20, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Many ecologists and environmental scientists witnessing the scale of current environmental change are becoming increasingly alarmed about how humanity is pushing the boundaries of the Earth’s systems ...beyond sustainable levels. The world urgently needs global society to redirect itself toward a more sustainable future: one that moves intergenerational equity and environmental sustainability to the top of the political agenda, and to the core of personal and societal belief systems. Scientific and technological innovations are not enough: the global community, individuals, civil society, corporations, and governments, need to adjust their values and beliefs to one in which sustainability becomes the new global paradigm society. We argue that the solution requires transformational change, driven by a realignment of societal values, where individuals act ethically as an integral part of an interconnected society and biosphere. Transition management provides a framework for achieving transformational change, by giving special attention to reflective learning, interaction, integration, and experimentation at the level of society, thereby identifying the system conditions and type of changes necessary for enabling sustainable transformation.
In this study, we hypothesize that local sustained release of vascular endothelial growth factor (VEGF), using adenovirus vector (ADV)-mediated gene transfer, accelerates experimental wound healing. ...This hypothesis was tested by determining the specific effects of VEGF165 application on multiple aspects of the wound healing process, that is, time to complete wound closure and skin biomechanical properties. After showing accelerated wound healing in vivo, we studied the mechanism to explain the findings on multiple aspects of the wound healing cascade, including epithelialization, collagen deposition, and cell migration. Intradermal treatment of wounds in non-obese diabetic and db/db mice with ADV/VEGF165 improves healing by enhancing tensile stiffness and/or increasing epithelialization and collagen deposition, as well as by decreasing time to wound closure. VEGF165, in vitro, stimulates the migration of cultured human keratinocytes and fibroblasts, thus revealing a non-angiogenic effect of VEGF on wound closure. In conclusion, ADV/VEGF is effective in accelerating wound closure by stimulating angiogenesis, epithelialization, and collagen deposition. In the future, local administration and sustained, controlled release of VEGF165 may decrease amputations in patients with diabetic foot ulcers and possibly accelerate closure of venous ulcers and pressure ulcers.
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Abstract
The investigation of unique carbonate substituted bioapatite of
Champsocephalus gunnari
icefish jaw and skull bones was carried out using NEXAFS spectroscopy. It has been established that ...these bones contain the B-type carbonate substituted hydroxyapatit with a content CO
3
2-
anion of about 0.79-3.07 wt.%.
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