Role of Wounds

A tremendous variety of agents wound trees. Trees are immobile so they are usually wounded by external moving agents. However, spontaneous wounds occurring naturally at branch stubs are very common they form a bridge of dead tissue from the external environment to the heartwood, which can be an avenue for infection by decay fungi. 

Trees are frequently wounded, but only rarely develop decay. Their second line of defense against decay fungi is the response of the injured tissue in such a manner as to restrict the entry of invading microorganisms. Most wounds are either 

The response strategy of the tree is twofold first, to close the wound with new callus tissue, thus re-establishing that unbroken layer of living tissue and, second, to develop a reaction layer in the uninjured sapwood tissue adjacent to the damaged cells. The rate of wound closure and the production of the reaction zone are dependent not only upon the size of the wound but also upon the growth rate or vigor of the host. 

Death of the parenchyma in the sapwood of woody plants normally results in a marked increase in susceptibility of that tissue to decay. However, certain types of wounds apparently stimulate in adjacent cells the synthesis and accumulation of compounds such as lignans, stilbenes, resin acids, or tannins. The reaction zones surrounding wounds in some species show an accumulation of compounds inhibitory to decay fungi in other species the discolored wood surrounding the wounds is no more decay-resistant than the sapwood of that particular species. The ability of the sapwood to form discolored wood containing toxic components may be linked with an ability to produce heartwood resistant to decay fungi. 

The best documented evidence for an extractive (pinosylvins) functioning as a phytoalexin (an antimicrobial compound produced as an active response of the plant to the pathogen) is the reaction zones produced in pine in response to invasion by Heterobasidion annosum, the Sirex-Amylostereum complex, and the Den-droctonus- idin fungi complex (20). As with other phytoalexins, the accumulation of sitilbenes in pine sapwood is a nonspecific response to injury. In some cases the wounding agent causes rapid death of the invaded tissue and no stilbene 

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Tkinter F H, French D W 1971 The role of wound periderm in the resistance of eastern larch and jack pine to dwarf mistletoe. Can J Bot 49 501-504... 

Spotnitz, W.D., Falstrom, J.K. and Rodeheaver, G.T., The role of sutures and fibrin sealant in wound healing. In Barbul, A. (Ed.), Surgical Clinics of North America — Wound Healing. W.B. Saunders, London, 1997, pp. 1-19. 

Elson ML (1998) The role of retinoids in wound healing. J Am Acad Dermatol Suppl 39 79-81... 

Halpin (1) and Tsai (2) have presented treatises that address the effects of fiber content, orientation and properties on the composite s mechanical performance. A numerically controlled filament winding machine is capable of placing fiber in precise, three dimensional, engineered patterns. Future research addressing the molecular role of the resin s infrastructure on mechanical performance, will couple filament wound composite... 

Miyasaki KT, Wilson ME, Brunetti AJ, Genco RJ (1986) Oxidative and nonoxidative killing of actinobacillus actinomycetemcomitans by human neutrophils. Infect Immun 53(1) 154—160 Moore K (1999) CeU biology of chronic wounds the role of inflammation. J Wound Care 8(7) 345-348 Moses MA (1997) The regulation of neovascularization of matrix metaUoproteinases and their inhibitors. Stem Cells 15(3) 180-189... 

Pacifici R, Di Carlo S, Bacosi A, Zuccaro P (1993) Macrophage functions in drugs of abuse-treated mice. Int J Immunopharmacol 15(6) 711-716 Park JE, Barbul A (2004) Understanding the role of immune regulation in wound healing. Am J Surg 187(5A) 11S-16S... 

Demling, R.H., Katz, A., Lalonde, C., Ryan, P. and Jin, L-J. (1987). The immediate effect of burn wound excision on pulmonary function in sheep. The role of prostanoids, oxygen radicals and chemoattractants. Surgery 101, 44-55. 

Epidermal growth factor suppresses nitric oxide and hydrogen peroxide production by keratinocytes. Potential role for nitric oxide in the regulation of wound healing. J. Biol. Chem. 267, 21277-21280. 

While the role of PHD inhibitors in the treatment of anemia is now validated, therapeutic validation is less certain in other HIF-associated pathologies such as wound healing, ulcerative colitis, therapeutic angiogenesis, and treatment of acute ischemic events such as myocardial ischemia and stroke. All of these indications are supported by a compelling array of in vitro and in vivo preclinical studies but their utility in the clinical setting remains to be evaluated and represents exciting possibilities for the future of small-molecule inhibitors of PHD enzymes. 

The role of antimicrobials for noninfected dog bite wounds remains controversial because only 20% of wounds become infected. Antibiotic recommendations for empiric treatment include a 3- to 5-day course of therapy. Amoxicillin-clavulanic acid is commonly recommended for oral outpatient therapy. Alternative agents include doxycycline, or the combination of penicillin VK and dicloxaciHin. 

The synthesis of arginine from citrulline. The latter is produced from other amino acids in the small intestine and then released into the blood. The kidney takes up citrulline and converts it to arginine, which is then released into the blood for use by other tissues (Figure 8.18). Since arginine is a precursor for a number of important compounds, and aids wound healing, this is a significant biochemical role of the kidney. 

Madhyastha R, Madhyastha H, Nakajima Y et al (2011) MicroRNA signature in diabetic wound healing promotive role of miR-21 in fibroblast migration. Int Wound J 9 355-361... 

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