Chronic ischemic wounds presenting at wound clinics are heterogeneous with respect to etiology, age of the wound, and other factors complicating wound healing. In addition, there are ethical challenges associated with collecting repeated biopsies from a patient to develop an understanding of the temporal dynamics of the mechanisms underlying chronic wounds. The need for a preclinical model of ischemic wound is therefore compelling. The porcine model is widely accepted as an excellent preclinical model for human wounds. A full-thickness bipedicle flap approach was adopted to cause skin ischemia. Closure of excisional wounds placed on ischemic tissue was severely impaired resulting in chronic wounds. Histologically, ischemic wounds suffered from impaired re-epithelialization, delayed macrophage recruitment and poorer endothelial cell abundance and organization. Compared with the pair-matched nonischemic wound, unique aspects of the ischemic wound biology were examined on days 3, 7, 14, and 28 by systematic screening of the wound tissue transcriptome using high-density porcine GeneChips. Ischemia markedly potentiated the expression of arginase-1, a cytosolic enzyme that metabolizes the precursor of nitric oxide l-arginine. Ischemia also induced the SOD2 in the wound tissue perhaps as survival response of the challenged tissue. Human chronic wounds also demonstrated elevated expression of SOD2 and arginase-1. This study provides a thorough database that may serve as a valuable reference tool to develop novel hypotheses aiming to elucidate the biology of ischemic chronic wounds in a preclinical setting.

This updated edition of Care Practice Paper #3 presents the evidence for the benefits of continuous support in labor. The role of the doula is explained. Women are encouraged to plan for continuous support during labor and to consider including a woman experienced with childbirth among their labor support team.

All women should be allowed and encouraged to bring a loved one, friend, or doula to their birth without financial or cultural barriers. Continuous labor support offers benefits to mothers and their babies with no known harm. This article is an updated evidence-based review of the "Lamaze International Care Practices that Promote Normal Birth, Care Practice #3: Continuous Labor Support," published in The Journal of Perinatal Education, 16(3), 2007.

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