Human Platelet-Rich Plasma- and Extracellular Matrix-Derived Peptides Promote Impaired Cutaneous Wound Healing In Vivo

Previous work in our laboratory has described several pro-angiogenic short peptides derived from endothelial extracellular matrices degraded by bacterial collagenase. Here we tested whether these peptides could stimulate wound healing in vivo. Our experiments demonstrated that a peptide created as combination of fragments of tenascin X and fibrillin 1 (comb1) applied into cranial dermal wounds created in mice treated with cyclophosphamide to impair wound healing, can improve the rate of wound closure. Furthermore, we identify and characterize a novel peptide (UN3) created and modified from two naturally-occurring peptides, which are present in human platelet-rich plasma. In vitro testing of UN3 demonstrates that it causes a 50% increase in endothelial proliferation, 250% increase in angiogenic response and a tripling of epithelial cell migration in response to injury. Results of in vivo experiments where comb1 and UN3 peptides were added together to cranial wounds in cyclophosphamide-treated mice leads to improvement of wound vascularization as shown by an increase of the number of blood vessels present in the wound beds. Application of the peptides markedly promotes cellular responses to injury and essentially restores wound healing dynamics to those of normal, acute wounds in the absence of cyclophosphamide impairment. Our current work is aimed at understanding the mechanisms underlying the stimulatory effects of these peptides as well as identification of the cellular receptors mediating these effects.National Institutes of Health (U.S.) (Grant EY15125)National Institutes of Health (U.S.) (Grant EY19533)Wound Care Partners, LL

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

When alkanethiolate self-assembled monolayers on Au{111} are exchanged with alkaneselenols from solution, replacement of thiolates by selenols is rapid and complete, and is well described by perimeter-dependent island growth kinetics. The monolayer structures change as selenolate coverage increases, from being epitaxial and consistent with the initial thiolate structure to being characteristic of selenolate monolayer structures. At room temperature and at positive sample bias in scanning tunneling microscopy, the selenolate-gold attachment is labile, and molecules exchange positions with neighboring thiolates. The scanning tunneling microscope probe can be used to induce these place-exchange reactions

Pollutant Cycling and Removal Processes within a subsurface Flow Constructed Wetland.

peer reviewe

Removal processes and their distribution inside a subsurface horizontal flow constructed wetland.

peer reviewe

Optimisation de la fertilisation azotée de cultures industrielles légumières sous irrigation

Optimisation of fertilisation for irrigated vegetables. Experiments were performed over four years, testing five cultivations to optimise mineral nitrogen fertilisation when irrigation with wastewater occurs. The experimental site was located inside an irrigated perimeter around the agro-food industry Hesbaye Frost, producing frozen vegetables, in Belgium. Depending on the crop rotation adopted by the farmer, four vegetable cultivations (spinach, bean, carrot and broad bean) and one cereal (winter wheat) were tested. Because of the time required for implementation of the experiment and meteorological conditions, the irrigation factor was not tested for spinach (1999) and wheat (2000) cultivations. The two experimental factors were three fertilisation levels, with comparison to a reference without any mineral nitrogen supply, and irrigation with or without wastewater. These factors were assessed for their impacts on crop yields and mineral nitrogen residues in the soil after harvest. The three vegetable cultivations of bean, carrot and broad bean were irrigated and systematically presented statistically higher yields with wastewater irrigation supply than without. The fertilisation factor also significantly improved all the yields, or protein rate for cereal cultivation, except for carrot and broad bean where differences were not significant, even for the zero fertilisation rate. The nitrogen residues in the soil after harvest were acceptable and regular as long as the fertilisation advice was not exceeded; the maximum fertilisation level tested, 50% higher than the recommendation, systematically left unacceptable nitrogen residues in the soil, harmful for the environment. Mainly located on the top surface horizon layers, thenitrogen residues could be held back by a catch crop classified as a nitrogen trap, with the condition to be set on late summer, with fall being considered as too late to have any influence to avoid nitrogen leaching. For all fertilisation levels, nitrogen residues were too high for the broad beans cultivation because of the phenomenon of surface mineral nitrogen release, due to meteorological conditions and the wastewater high nitrogen load brought by irrigation. The nitrogen residues under conditions of no irrigation were higher than under irrigation. Irrigation allowed better nitrogen solubility, easier for uptake by the plants and thus left fewer residues in the soil