bluuebunny/crossref_metadata_2025 huggingface dataset:
084 Effects of Fat Autografting on Porcine Skin Wound Healing after Injury
Authors: Fang Lijun , Fu Xiaobing , Wang Yuxin , Sun Tongzhu , Cheng Biao
Published: March 2007

It has been evidenced that the fat may have a potential to secret some growth factors or be a source of stem cells. So, we explore the effects of fat on healing of porcine skin wounds so as to provide a new method for clinical skin wound repair after injury.

Forty‐eight full‐thickness skin wounds were produced on both sides of the back in 6 male minipigs (8 wounds in each animal). Then these wounds were randomly divided into 4 groups, which were saline control group, fat autografting group, basic fibroblast growth factor (bFGF) treatment group and epidermal growth factor (EGF) treatment group. At day 3, 7, 14 and 21 after wounding, the area and the volume of wounds were measured and the histological examination was performed to evaluate the velocity and quality of wounds healing in different groups.

At day 3 and 7, the amount of granulation tissues and vessel density in fat treatment group were significantly more than that in other groups. Wound areas and volume in fat treatment wounds were markedly decreased in compared with those in other groups (P < 0.01). Regenerated epidermis in fat treatment group was thicker than that in other groups.

These results confirmed that the wound healing velocity and quality in wounds treated with fat autografting were enhanced. It indicated that fat has a potential to accelerate velocity and improve the quality of wound healing after skin injury.
085 Bone Marrow Mesenchymal Stem Cells as a Potential Source to Repair the Injury Skin
Authors: Fu Xiaobing , Fang Lijun , Li Xiaokun , Cheng Biao , Sheng Zhiyong
Published: March 2007

Adult stem cells are found in various tissues and organs and have potential to differentiate into different cell lineages, including bone, cartilage, fat, tendon, muscle, epithelial cells of the skin and gastrointestinal tract, etc. Here, we report that the expended and purified bone marrow MSCs might take on phenotypes and characteristics of vascular endothelial cells or epidermal cells after cultured and induced with different lineage‐specific culture conditions in vitro. Also, in vivo grafting experiments confirmed that those labeled MSCs could get the phenotypes of vascular endothelial cells in granulation tissue and sebaceous duct cells and epidermal cells in regenerated skin, which imply that these grafted MSCs might have transdifferentiated into vascular endothelial cells and sebaceous duct cells and epidermal cells. Our results indicate that locally delivered bone marrow MSCs may generate de novo intact skin and get perfect skin regeneration after full thickness injury.
086 Skin Wound Healing in Red Duroc X Yorkshire F1 Pigs: Effect of Wound Depth on Gene Expression
Authors: Gallant CL , Olson ME , Hart DA
Published: March 2007

Previous investigations have demonstrated that cutaneous healing in red Duroc pigs (RD) differs from healing in Yorkshire pigs (Y). Specifically, RD animals heal with the formation of hypercontracted, hyperpigmented scars, features which are not observed in Y animals. Further, this abnormal scarring may be genetically mediated, as demonstrated by the partial transmission of this phenotype to RD × Y offspring (F1). To further determine the degree of transmission of this phenotype, this study examined the effect of wound depth upon the healing response of F1 animals. Ten full thickness (FT) and ten deep dermal (DD, 1.8 mm) skin wounds (2 cm × 2 cm) were created on the backs of juvenile female F1 animals (N = 8) using previously published procedures. Biopsies (4 mm) were taken from FT and DD wounds on days 14, 28, 42, 56, and 70. Samples were used for histology and molecular analysis using RT‐PCR. There were no detectable differences between the FT and DD wounds on the gross or histologic level. However on a molecular level, there were numerous differences between the FT and DD wounds. Several genes investigated demonstrated increased expression levels in the DD wounds as compared to the FT wounds. Further, DD wounds demonstrated a unique pattern of expression for several other genes that differed from that observed in either the F1 FT wounds or in any RD or Y wounds. Given that previous investigations have shown that FT and DD wounds are nearly identical within each of the RD and Y strains, this represents a novel finding. These results indicate that the healing phenotype of the F1 animals may be regulated both by genetics and by the wound size/depth, suggesting that human wound healing may be similarly influenced by genetics, wound depth and potentially, environmental factors.

Funding provided by NSERC, CIHR.
087 Normal or Pathological Wound Healing: Apoptosis Sensitivity of Myofibroblasts
Authors: Moulin V. , Larochelle S. , Langlois C. , Thibault I. , Lopez‐Valle C. A. , Roy M.
Published: March 2007

During wound healing, myofibroblasts play a major role in wound contraction and matrix formation. At the end of healing, myofibroblasts disappear via apoptotic pathways. Hypertrophic scars are a fibroproliferative disorder that leads to considerable morbidity. Although no evidence exists, it has been postulated that a defect in myofibroblast apoptosis could be responsible for the pathological scar formation. We have isolated and cultured human normal wound (Wmyo) and hypertrophic scar (Hmyo) myofibroblasts and compared their basal apoptotic rates and their sensitivity to serum starvation and Fas antibody‐induced apoptosis to that obtained for dermal fibroblasts (Fb). A higher rate of apoptosis as evidenced by morphological criteria and a propidium iodide assay was observed for Wmyo in comparison to Fb and Hmyo. These results came along with a low level of the anti‐apoptotic proteins Bcl‐2 and BclxL in Wmyo, whereas there was an increase in the level of the pro‐apoptotic molecule Bax when compared to the results obtained for Fb and Hmyo. Hmyo showed a higher level of Bcl‐2 compared to Fb but no difference in the Bax or BclxL level. After serum starvation, Wmyo revealed an increased apoptotic rate whereas Hmyo and Fb did not show any difference. Anti‐Fas treatment did not modify the levels of apoptosis but strongly increased the cell growth of Hmyo as compared to Wmyo. This is the first study presenting a broad vision of the apoptotic sensitivity of normal and pathological myofibroblasts. These results confirmed the hypothesis of defects in apoptosis and growth during pathological scar formation impeding myofibroblast disappearance at the end of healing.
090 Effect of Cytokines and Heat Shock on Human β‐Defensin‐2 Levels in Cultured Keratinocytes
Authors: Bhat Satyanarayan , Bick Roger J. , Poindexter Brian J. , Gulati Salil , Buja Maximilian , Milner Stephen M.
Published: March 2007

Burns have been associated with high levels of circulating pro‐inflammatory cytokines which promote systemic inflammatory response syndrome (SIRS), immunosuppression and sepsis for which no effective treatment is currently available. Defensins, a family of cationic naturally occurring antimicrobial peptides are considered important components of the innate immune system and enhance adaptive immunity. We have examined the effects of pro‐inflammatory cytokines, interleukin 1β‐(IL‐1β), gamma‐interferon (IFNγ) and tumor necrosis factor‐α(TNFα) on human β‐defensin‐2 (HBD‐2) levels in cultured keratinocytes. We have also examined the effects of heat shock at 42 °C. Our results demonstrate that only TNFα shows significant induction of HBD‐2 but this induction was not sustained in the long term. In addition, endogenous levels of defensin were significantly reduced by exposure to heat shock. The keratinocytes also responded to IL‐1β by becoming hypertrophic. These results indicate that stress‐related, pro‐inflammatory cytokines can induce keratinocytes to synthesize HBD‐2, while heat shock appears to reduce its production. Understanding the roles cytokines play in the continued problems associated with severe wounding, and in particular, major burn injury, is important. This study provides further insight into the role of natural anti‐microbial peptides under conditions of stress.
091 Expression of Human β‐Defensin‐2 in the Skin Appendages of Burn Wounds
Authors: Gulati Salil , Bick Roger J , Bhat Satyanarayan , Pondexter Brian J. , Buja Maximilian , Milner Stephen M
Published: March 2007

Major burn wounds are often complicated by sepsis which currently accounts for over 54% of deaths in these patients. Defensins, a family of cationic naturally occurring antimicrobial peptides are considered important components of the innate immune system as they play a major role in body’s defence by inhibiting several bacteria, fungi and enveloped viruses. They also chemoattract immature dendritic cells and T and B‐lymphocytes, neutrophils and macrophages and act as an adjuvant and enhance adaptive immunity. Our prior studies using RT‐PCR suggest decreased expression of human β defensin‐2 (HBD‐2) in burn wounds. Furthermore we demonstrated remnants of HBD‐2 in the dermis. Our current study, using fluorescence deconvolution microscopy, has clarified that HBD‐2 is present in the surviving hair follicles. The peptide was also located in the eccrine and apocrine sweat gland acini but absent in the sweat ducts, in representative skin samples of deep partial and full thickness burns. HBD‐2 was also notably absent from the vascular endothelium and fat cells. The result of these studies will contribute to an understanding of the role of antimicrobial peptides in the pathophysiology of burn injury, associated immunosuppression and sepsis.
093 Prostaglandin E2 Inhibits Fibroblast Migration: Implications for Wound Healing
Authors: Sandulache V.C. , Li‐Korotky H.S. , Dohar J.E. , Hebda P.A.
Published: March 2007

Background: Wound healing is a complex process involving multiple cell types, extracellular matrix components and soluble mediators. Prostaglandin E2 is an important component of the inflammatory response to injury. PGE2 can regulate the fibroblast response to injury via the EP receptor family. Here, we examine PGE2 regulation of fibroblast migration. Our analysis extends to fibroblasts representing a spectrum of wound healing phenotypes.

Hypothesis: Prostaglandin E2 mediated inhibition of fibroblast migration is conserved across multiple fibroblast phenotypes.

Methods: Primary cultures of human fetal, adult and keloid fibroblasts were used. Analysis of the EP receptor profile for each fibroblast phenotype was conducted using real‐time PCR, Western blot and immunohistochemistry. Fibroblast migration was quantified using a well established in vitro scratch assay.

Results: Prostaglandin E2, via EP2/EP4 receptors, inhibits fibroblast migration in all fibroblast phenotypes. Fetal fibroblasts retain a more robust migratory phenotype when compared to normal adult and keloid fibroblasts. Normal adult fibroblasts exhibit a dramatic destabilization of the actin cytoskeleton which accompanies PGE2 inhibition of cell migration. This effect was not observed in fetal or keloid fibroblasts.

Conclusions: Fibroblast activity in the wound bed can be altered by inflammatory mediators. The effects of prostaglandin E2 appear to be partially conserved across various fibroblast phenotypes. Variability in the response of these cells, however, indicates that fibroblasts derived from fetal tissue may retain intrinsic altered response mechanisms to endogenous inflammatory mediators.
095 HSP70 is Proinflammatory in vivo. Implications for Chronic Wound Healing.
Authors: Perdrizet G , Enderle J. , Rewinski M , Kumar R. , Enderle G. , Berman M. , Hightower L.
Published: March 2007

Abstract Failure to downregulate inflammatory responses is often used to explain why chronic wounds fail to heal. The beneficial effects of surgical debridement are thought to be in part due to the transformation of a chronic wound to an acute wound, thereby allowing the inflammatory phase of acute wound healing to be reactivated. We tested the hypothesis that subcutaneous injection of the inducible isoform of the 70 kDa mammalian heat shock protein (iHSP70) will cause acute inflammatory swelling in an in vivo murine model. Comparisons between groups were performed using the Student’s t‐test and significance was accepted when p < 0.05. Subcutaneous injection of stress proteins iHSP70 was associated with significantly increased acute swelling in comparison to injections of saline, autologous serum (AS) or denatured iHSP70, *p < 0.05, see figure below. Histological analysis demonstrated increased inflammatory cell infiltrate in those tissues receiving iHSP70. Stress proteins, within the acute wound environment, are proinflammatory and may set the stage for persistent inflammation within the chronic wound bed. Stress proteins may be future targets for therapeutic manipulation wherever acute inflammation fails to be downregulated.

Exp. Group
N
Swelling(mm)‐24 hrs
Swelling(mm)‐ 48 hrs
p vs iHSP70

Saline
9
0.5 ± 0.25
0.6 ± 0.15
0.001

Serum
8
0.73 ± 0.18
0.72 ± 0.17
0.001

iHSP70
11
1.67 ± 0.36
1.55 ± 0.22
ns

Denatured iHSP70
10
1.48 ± 0.41
1.25 ± 0.24
0.05
096 Biochemical Analysis of Chronic Wounds Treated with the V.A.C.® System
Authors: Stechmiller J. K. , Childress B. B. , Blalock T. D. , Kilpadi D. V. , Nappo R. W. , Chin G. A. , Mozingo D. W. , Schultz G. S.
Published: March 2007

Introduction
: Proinflammatory cytokines TNF‐α, IL‐1β, and matrix metalloproteinases (MMPs) are elevated in chronic wounds and their levels decrease during healing. TNF‐α and IL‐1β stimulate the production of MMPs which cause degradation of growth factors. Wound fluid from the V.A.C.® is of interest when investigating the mechanisms by which V.A.C.® therapy aids in wound healing. We hypothesize that the clinical improvement in healing of chronic wounds by the V.A.C.® system occurs by a shift from a chronic cytotoxic environment to a more conducive acute healing wound environment. This study aims at understanding the molecular and mechanistic consequences of V.A.C.® therapy on chronic wound healing.

Methods
: Wound fluid collected from two patients with Stage IV pressure ulcers at baseline, 24hours, 72hours, and 7 days following V.A.C.® therapy. Concentrations of TNF‐α, IL‐1β, MMP‐2, ‐3, ‐9, TIMP‐2, and total protein were determined using ELISA.

Results
: TNF‐α levels in wound fluids decreased from baseline levels in two patients following 3 days of treatment. Similarly, levels of MMP‐3, MMP‐9 and TIMP‐2 decreased from baseline following 3 days of treatment. There were no consistent trends in IL‐1β & MMP‐2.

Conclusion
: The preliminary results from this study suggest that improved wound healing with V.A.C.® therapy is related to decreased levels of proinflammatory cytokines, MMPs and TIMP‐2 in wound fluid.
099 “Smart” Targeting of Anti‐Scarring Agents in an in vitro Model of Retinal Wound Healing
Authors: Dhawahir F E , Sheridan C , Kent D , Wong D , Grierson I , Roberts S
Published: March 2007

Scarring causes the irreversible loss of vision seen in macular degeneration and retinal detachment. Treatment of both conditions is ineffective. Cells within the retina, retinal pigment epithelial cells (RPE), are pivotal in the formation of these diseases. Modifying the behavior of these cells may help in controlling the scarring process. We have shown that RPE involved in scarring, unlike normal RPE, express a cell surface sugar called the Thomsen Friedenreich (TF) antigen. Binding by a naturally occurring substance from the common mushroom, called a lectin, can inhibit key RPE functions that are crucial to scar formation. The present study investigates the potential of conjugating this lectin and/or a monoclonal antibody to the TF antigen with known anti‐proliferative agents (e.g. Mitomycin) in order to evaluate if the anti‐scarring effects of the agents are additive.
101 VAC Therapy Versus Conventional Therapy in Acute and Chronic Wounds
Authors: Obdeijn M.C. , Braakenburg A. , Feitz R. , Klinkenbijl J.H.G.
Published: March 2007

Introduction: Vacuum therapy is a new concept in wound treatment. Animal studies have shown good results in chronic and acute wounds. In clinical practice we have used the system for many wounds with very promising results. However there are few randomized clinical trials that prove the efficacy of the system.

Patients and methods: In 2002 we have started a randomized prospective clinical trial to compare the results of Vacuum Assisted Closure versus our wound management protocol with mainly foam dressings and alginates. In this study we have included acute and chronic wounds. The wounds were assessed 3 times a week by 3 researchers (a medical doctor and 2 nurses). We looked at the wound healing, described in terms of color, smell, temperature and aspect of the wound. The size and depth of the wound was recorded and photographs were taken. Once a week we did a swab of the wound. Besides the effect on wound healing we also looked at the time that was needed for dressing changes, the benefits for the patient and the nurses and the costs of the therapy.

Results: At this moment we have treated 35 patients. The preliminary results will be presented at the meeting.

With this study as an example we will also illustrate some of the problems that can be encountered when designing a clinical trial in wound healing.
103 Autologous Thrombin: Continuing Studies
Authors: Jacobson May S. , Kevy Sherwin V.
Published: March 2007

Background: As many as 500,000 patients are exposed to bovine thrombin (BT) annually. This is increasing with the use of autologous platelet gel (PG) in surgery and in the treatment of chronic wounds (diabetic ulcers). The development of anti‐phospholipid antibodies after exposure to bovine thrombin is of concern. We compared the kinetics of growth factor release by autologous thrombin (AT) to BT.

Methods: Whole blood is incubated with 95% ethanol and then centrifuged in the SmartPReP™2 system (Harvest Technologies, Plymouth, MA) simultaneously with the preparation of a platelet concentrate (PC). The supernatant containing thrombin activity is collected. Clotting studies were done. The kinetics of growth factor release was determined by collecting the supernatant from the PG at 2 hours and daily thereafter for 7 days. The PC’s were prepared in two concentrations by adjusting the volumes to 10 mL and 7 mL. The activation of the PC was done at a 10:1 ratio (PC:BT) at 7 mL and 10 mL and 3:1 and 5:1 (PC:AT) at 7 mL.

Results: Following a 45 minute incubation period the mean clotting time of PC by AT at a 3:1 ratio was 14.3 sec and at a 5:1 ratio was 22 sec (n = 13). Thrombin activity remained stable for 6 hours. Baseline PDGF‐AB levels with AT was 50 ng/mL with a maximum of 106 ng/mL. BT using a 10 mL PC had a baseline level of 100 ng/mL with no increase over time. TGF‐B1 studies demonstrated an immediate release of 98 ng/mL with a maximum level of 168 ng/mL for AT compared to BT with an initial level of 107 ng/mL and a maximum of 152 ng/ml.

Conclusions: AT produces a sustained release of growth factors during a seven‐day period that is similar to BT at a 10:1 ratio. AT can be prepared simultaneously with the preparation of a PC.
105 Changes in Nitric Oxide Levels After Deep Dermal injury in the Female, Red Duroc Pig (FRDP)
Authors: Zhu KQ , Engrav LH , Muangman PM , Cole JK , Gibran NS
Published: March 2007

Introduction: Hypertrophic scar is a devastating sequel to burns and other tangential skin injuries. It follows deep dermal injuries and does not occur after superficial injuries. Nitric oxide (NO) plays many important roles in wound healing from inflammation to scar remodeling. Studies have shown that expression of nitric oxide synthase and nitric oxide production are decreased in human hypertrophic scar. However little is known about NO involvement in the early stages of hypertrophic scarring, because of the lack of an animal model. It was recently reported that the female red Duroc pig (FRDP) makes thick scar, which is similar to human hypertrophic scar. We hypothesized that NO production in wounds on the female, red Duroc pig is similar to that of human hypertrophic scar and that NO involvement in deep wounds is different from that in superficial wounds.

Methods: Superficial (0.015” to 0.030”) and deep (0.045” to 0.060”) wounds were created on the backs of four FRDPs. Biopsies were collected at weeks 1.5, 4, 8 and 21 post wounding including samples of uninjured skin. Nitric oxide levels were measured with the Griess reaction assay and normalized with tissue protein level.

Results: Superficial wounds healed with an invisible scar whereas the deep wounds healed with scar resembling mild hypertrophic scar. The thickness of the scars from the deep wounds was significantly greater than uninjured skin and healed superficial wounds (p < 0.01). NO levels were increased at 1.5 weeks in deep wounds compared to superficial wounds and uninjured skin (p < 0.05). At 8 weeks, NO levels in deep wounds had returned to the level of uninjured tissue and superficial wounds. By 21 weeks, NO levels had decreased significantly when compared to superficial wounds (p < 0.01). There were no differences in NO levels between uninjured skin and superficial wounds at any time point (p > 0.05).

Conclusions: NO production is similar in late, deep wounds on the female, red Duroc pig to that reported in the literature for human hypertrophic scar further validating this animal model. NO production is quite different after deep wounds as compared to superficial wounds in the FRDP. Early elevation in nitric oxide production might account for excessive inflammation in deep wounds that become thick scars in the FRDP. Nitric oxide regulators and effects at early stages of scar formation should be elucidated further and the FRDP appears to be a useful model.
106 Lentivirus and Adeno‐Associated Virus Mediated Targeted Gene Transfection in Low‐Oxygen Environment
Authors: Roy Nakshatra K. , Jia Sheng‐Xian , Mustoe Thomas A.
Published: March 2007

A critical limitation of using retroviral vectors for gene therapy is their inability to infect non‐dividing cells. Although, the adenoviral vectors have the advantage of being able to infect both dividing and non‐dividing cells, they elicit inflammatory response, thus making the interpretation of in vivo experiments harder. Adeno‐associated virus (AAV) and Lentiviral vectors do not have those limitations, however, scant information is available about their transfection efficiency under low‐oxygen tension. To determine if low‐oxygen microenvironment affects viral vector‐mediated gene transfection, we have used two other viral vectors, Adeno‐associated virus (AAV) and Lentiviral constructs in vitro and in vivo to express foreign genes in hypoxic cultured human dermal fibroblasts and ischemic rat wounds. Both cultured normoxic and hypoxic (1% O2) human dermal fibroblasts were identically transfected by the AAV vector. A lenti6‐LacZ construct was injected onto the periphery of rat ischemic and non‐ischemic wound (106 pfu/wound) at the time of wounding. Wounds were harvested at post‐operative day 7. Frozen sections of the wounds were fixed in cold acetone and stained with a in situ β‐gal staining kit. Intense expression of β‐gal was observed without any inflammatory response. No significant difference of transfection efficiency was observed between the ischemic and non‐ischemic wounds. Thus our data indicates that both AAV and Lentiviral vectors are suitable to use in gene‐therapy experiments in both ischemic and non‐ischemic cells and tissues in vitro and in vivo.
003 α1‐Antichymotrypsin – A Human Serpin with the Potential to Heal Diabetic Ulcers
Authors: Goppelt A. , Hans W. , Shi Y. , Bittner M. , Halle J.‐P. , Hof P. , Davidson J.M.
Published: March 2007

α1‐Antichymotrypsin (α1‐ACT) is a secreted serine proteinase inhibitor of the serpin family. It is strongly upregulated during the inflammatory phase of wound repair to control the undesirable destructive side effects of cathepsin G which is released from infiltrating neutrophils. We have shown that α1‐ACT and its mouse homologue spi2 exhibit a classic acute phase response after cutaneous injury in murine and human skin. The induction of spi2 gene expression following wounding is significantly less pronounced in diabetic mice. Transient overexpression of spi2 or α1‐ACT significantly increased wound tensile strength in two independent diabetic models: in genetically diabetic mice, gene gun mediated delivery of spi2 or α1‐ACT cDNA increased the average wound strength by 42%(P = 0.001) and 21%(P = 0.013) at d5 post‐wounding respectively. In a STZ induced diabetic rat model the breaking strength of adenovirally spi2‐ or α1‐ACT‐infected wounds increased by 20%(P = 0.049) and 23%(P = 0.004) at d7 after injection respectively. Moreover, the topical application of human α1‐ACT protein to wounds of diabetic mice had a significant and dose dependent effect on tensile strength at d5 post‐wounding (21% increase, P = 0.003). Histological analyses of these wounds indicated less infiltration of neutrophils in the treated wounds. α1‐ACT appears to be a key mediator between proteolysis and cytokine agonism and antagonism. Our data indicate that this balance is disturbed in diabetic wounds and that α1‐ACT might act as a switch to initiate wound healing in diabetic ulcers.
107 Examining Regulation Differences in TGFB1 with Age and Ischemia using the Rat Back Flap Model
Authors: Procaccini P. S. A. , Jia S. , Cross K. , Roy N. , Mogford J.E. , Mustoe T.A.
Published: March 2007

Chronic wounds are characterized by a continued inability to heal after an extended period of time (often defined as 3 weeks or longer) and more commonly found in the elderly over areas of compromised blood flow. Collagen is a gene vital to this healing process and Transforming Growth Factor beta 1 (TGFβ1) is an important signaling molecule for collagen induction. We chose to examine the effects of age and ischemia on TGFβ1 regulation using the rat backflap model, which demonstrates negative influences of age and ischemia on the wound healing. Four full‐thickness biopsy punches (7 mm) were made centered on the back of aged and young rats. The rostral wound pair was made ischemic by raising a transverse flap (1.8 cm wide × 8 cm length). The caudal wound pair served as a non‐ischemic control. Wound contraction was prevented by insertion of a sterilized polyethylene sheet under both the ischemic and nonischemic wounds. RNA was then extracted from wounds at post operation days 3, 7, 10 and 14. The RNA was then reverse transcribed and assayed by Real‐Time PCR to examine the relative expression of TGFβ1. TGFβ1 expression in the ischemic wounds of young rats was significantly increased versus nonischemic controls at post‐wounding days 3, 7 and 14 (p < 0.05, p < 0.05, p < 0.05, respectively). We also observed a significant increase in TGFβ1 expression in the ischemic of aged animals at day 14 (p = 0.01). The data suggest that there is either a loss of function in TGFβ1’s response to ischemia in the aged animals, or, at least, a significant delay. The results also demonstrate the usefulness of the rat backflap model for the study of age and ischemia on TGFβ1 function in a non‐contractile rat wound model.
110 A New Antimicrobial Alginate Dressing for Moderate to Heavily Exuding, Infected and Critically Colonised Wounds
Authors: Addison Deborah , Rennison Tracy Jane , Norris Sally‐Anne
Published: March 2007

Aim
: An antimicrobial dressing that combines high absorbency and potent antimicrobial properties. The unique composition of the dressing manages exudates in moderate to heavily exuding, infected or critically colonised wounds, which creates a favourable environment for effective wound management.

Methods
: Two test methods were used to evaluate the antimicrobial properties of the dressing: 1) A zone of inhibition sensitivity test that challenges the dressing to a seeded agar plate and 2) A log reduction test that exposes a small sample of dressing against a high bacterial loaded broth, measuring the log reduction of the bacteria over a specified time period. The absorbency of the dressing was evaluated using British Pharmacopoeia test methods.

Results
: The antimicrobial dressing has been shown to be highly effective against a wide range of microorganisms, including Pseudomonas aeruginosa, Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae and Candida albicans and also against resistant organisms MRSE, MRSA and VRE. The product is highly absorbent with absorbency > 16 g/g and 16 g/m2.
115 Carbohydrate‐based Wound Dressings with Elastase‐lowering Activity
Authors: Edwards Vincent , Yager Dorne , Cohen Kelman , Goheen Steven
Published: March 2007

The use of carbohydrate‐based wound dressings including cotton, xerogels, charcoal cloth, alginates, and hydrogels, for chronic wounds have afforded properties such as absorbency, ease of application and removal, bacterial protection, fluid balance, occlusion, and elasticity. An additional consideration is the use of the dressing to regulate proteolysis in the non‐healing wound. Elastase is a serine protease that has been associated with a variety of inflammatory diseases, and recently has been implicated as a destructive protease that impedes wound healing. The presence of elevated levels of elastase in non‐healing wounds has been associated with the degradation of important growth factors and fibronectin necessary for wound healing. Here we consider the design, preparation, and assessment of carbohydrate‐based wound dressings that either release protease inhibitors or act as sequestering agents to bind proteases such as elastase and thus reduce their high levels in the chronic wound. Carbohydrates ranging from small monosaccahrides up to large polysaccharides are crosslinked onto cotton wound dressings. The resulting carbohydrate conjugates of cotton cellulose possess unique properties advantageous for chronic wound treatment ranging from gelation and elasticity to elastase‐sequestering properties

Type in text here making sure it is in a single column format.
118 Dermagraft as an Adjunct in the Treatment of Venous Leg Ulcers
Authors: Snyder R.J.
Published: March 2007

Aim: To document successful healing of a recalcitrant venous ulcer with adjunctive use of Dermagraft

Materials and Methods: A 74‐year‐old Hispanic male presented with a chronic venous ulcer at the medial aspect of his right ankle. Biopsy failed to reveal malignancy and confirmed stasis changes. Treatment was ongoing including compression therapy, local debridements, and moist wound healing, off‐loading, and nutritional support. The wound remained free of infection. Due to the continued recalcitrant nature of the lesion multiple applications of Dermagraft were utilized to augment healing.

Results: The researcher observed dramatic improvement in wound dimensions, wound contracture, and granulation tissue.

Conclusions: Dermagraft appears to augment healing in patients with venous ulcers and may be useful as adjunctive therapy.

Acknowledgements: Smith & Nephew Wound Management, Largo, Fl.
120 Laser Doppler Perfusion Imaging for the Assessment of Healing in Pressure Ulcers
Authors: Kekan M. , Feldman D.
Published: March 2007

The standard clinical assessment parameter for skin wounds has been time to heal. There is a need for assessments that monitor the healing process and have been validated as indicators of clinical outcome. Although the Laser Doppler Perfusion Imager (LDPI) has been used to assess various wounds there is a need to validate it as a predictor of wound healing. Since this measure can have a high variability, previous studies were done to determine the key environmental and operational parameters as well to determine the correlation between blood perfusion and tissue oxygen levels. This helped determine the parameters to study as well the utility of using the change in blood perfusion after a provocation (e.g. heat) rather than the absolute blood perfusion level.

The objectives of this study were to further determine operational parameters, to develop clinical protocols, and to begin the process of correlating blood perfusion values to clinical outcome. The effect of parameters such as light intensity, distance of the laser head from the skin, and skin pigmentation on blood perfusion were examined. Further, the relationship between skin temperature and blood perfusion was studied as well as the best ways to deliver this provocation clinically. Preliminary studies have helped determine the appropriate ranges for each parameter to give the most consistent readings. In addition, the best way to use the heat provocation has also been determined. In ongoing studies similar experiments are being carried out on pressure ulcers to assure these protocols work for clinical wounds. The best clinical protocols will then be used to validate the prognostic capabilities of the LDPI in terms of predicting wound healing rates (overall healing rate, epithelialization rate, and contraction rate).
121 Efficient Sequestration of Neutrophil‐derived Proteases by a Novel Polymeric Hydrogel
Authors: Vachon D.J. , Yager D.R.
Published: March 2007

There is a growing interest in the development of wound dressings that possess functionality beyond providing physical protection and optimal moisture environment. To this end, a novel dressing material based on a sulfonated‐hydrocarbon backbone has been developed for the controlled release of therapeutic agents into chronic wounds. This versatile polymer possesses an ion‐exchange capability that makes it amenable for binding and releasing a variety of potential agents. Polymer backbone was coated onto polyester fabric and then modified by ion exchange to incorporate Na+, Ag+, or doxycycline onto the polymer. The ability of several formulations of this hydrocarbon backbone product to sequester elastase and neutrophil collagenase (MMP‐8) was then examined.

Wound fluids containing elastase and MMP‐8 were obtained from pooled wound fluids obtained from consented patients with pressure ulcers. Equivalent weights of product formulations were incubated for 2–4 hours at 25 °C with the wound fluids and then the remaining activities of elastase and MMP‐8 determined using specific substrates (methoxysuucinyl‐ala‐ala‐pro‐val‐p‐nitroanilide and collagen type I respectively). Untreated polyester fabric served as a control and weight equivalents of gauze and Promogran® were also included for the purposes of comparison. The average reduction in apparent elastase activity in the wound fluid was 4%, 20.4%, 14%, 29%, and 55% for gauze, Promogran®, doxycycline, Ag+, and Na+ formulations respectively. Only Promogran® and the doxycycline formulation affected a decrease in apparent collagenolytic activity.

These preliminary results provide evidence in support of the versatility of these new biomaterials for the controlled modulation of the chronic wound environment.
122 Microvascular Dressing for Burn Applications
Authors: Cabodi M. , Stroock A.D. , Staiano‐Coico L. , Yurt Roger
Published: March 2007

Vascular structures are a ubiquitous element of living tissues that allow for efficient mass transfer with the bulk of the tissue. Reasons for the vascularization of tissue include: 1) efficiency of transport over large distances (>1 mm) by convection, 2) spatial control of delivery and evacuation of solute from the tissues, and 3) centralization of the influx and efflux from the tissue; this centralization allows for temporal control and monitoring to be performed. Many of these characteristics would also be valuable in synthetic materials designed for interaction with biological systems. We will present the design and fabrication of a wound dressing that incorporates microvasculature in the form of embedded microchannels. As in living systems, the basic principle behind our design is that active convection is used to carry solute over large distances, while diffusion acts over smaller distances.

We will describe the microfabrication procedure, based on soft‐lithographic techniques, used to fabricate the microvascular dressing. We will also discuss the design parameters which are important for the optimization of mass transfer and a model of the system will be presented. We will report on the physical characterization of the system, with respect to the mass transport properties. Finally, we will discuss initial considerations about the use of these structures as wound dressings.
124 Venous Ulcer Healing Predicted by Urine Nitrate Assay: A Retrospective Study
Authors: Boykin J.V. , Baylis C. , Yager D. , Cohen I.K. , Sommer V. , Shawler L. , Watkins M. , Young J. , Crossland M.
Published: March 2007

Chronic venous stasis ulcerations (VSU) are associated with significant platelet and leukocyte activation with secondary superoxide anion and ROS production that may severely degrade nitric oxide (NO) production. This study was designed to document the possible association between NO production and the impaired healing of VSU patients. Twenty‐four subjects were used for the study. Group C (n = 8) the control group, consisted of healthy adults without history of VSU. Group HU (n = 8) the healed ulcer group, consisted of adults with documented VSU whose ulcers healed with routine wound care and compression therapy in 20 weeks or less. Group UU (n = 8) the unhealed ulcer group, consisted of adults with documented VSU without healing within 20 weeks. All groups had normal renal function and were hospitalized for 24 hours on bed rest with a low arginine and low nitrate diet. Fasting samples were obtained for plasma and urine nitrate (NOx) and plasma arginine, asymmetric dimethylarginine (ADMA) and isoprostane determinations. At 24‐hrs, group HU demonstrated the highest plasma NOx levels (33.25 ± 11.69 μM) as compared to group C (19.45 ± 2.63 μM) or group UU (27.17 ± 3.67 μM); urine NOx excretion of group UU (51.46 ± 11.77 μM) was significantly lower (p < 0.05; Kruskal‐Wallis) as compared to group HU (135 ± 38.29 μM) or group C (164.3 ± 38.58 μM). ADMA and arginine were not significantly different between groups. Ratios of NOx to isoprostane were disproportionate between groups. These results suggest, for the first time, a significant relationship between impaired VSU healing and deficient NO production. Furthermore, these findings establish the clinical value of measurements of NO production and bioavailability as effective predictivebiological markers for the healing of VSU.
125 “MIST Ultrasound Therapy for Recalcitrant Wounds, A new approach”
Authors: Ennis William J. , Valdes Wesley , Meneses Patricio
Published: March 2007

The use of adjunctive peri‐wound, ultrasound with either a 1 MgHz or 3 MgHz frequency has been reported on in the literature with variable results. MIST ultrasound therapy is a novel application of direct wound bed application of kilohertz ultrasound waves utilizing a normal saline mist as the coupling mechanism, allowing for no direct patient contact. The mist generated by the system is of relative uniform particle size and acts as a conduit of ultrasound energy. Unlike ultrasonic baths, which dissipate the vibrational energy over a large area, the transducer horn focuses the energy into a smaller area of application.

The MIST™ system consists of an ultrasonic power supply (generator), a transducer (or alternately referred to as the converter), and an applicator coupled to the transducer. The generator converts voltage to high frequency electrical energy. This electrical energy is transmitted to the piezoelectric transducer within the converter, where it is changed to mechanical vibrations. The generator is designed to operate the converter at 40 kHz with a distal displacement of 60 microns. Published reports have described various biological effects of low frequency ultrasound including VEGF and PDGF production, increased protein synthesis, improved bone and wound healing. Other authors have published abstracts demonstrating clinical efficacy of this device on a broad range of patients with recalcitrant wounds. This report describes the clinical results of a prospective, non‐randomized, efficacy trial, adding MIST ultrasound therapy to current treatment protocols in recalcitrant wounds. Wound healing trajectories before and after treatment will be evaluated and wound healing will be assessed with laser Doppler image analysis and trans‐cutaneous oximetry.
127 The Importance of Arm Dominance in Acute Wound Healing
Authors: Serena T.
Published: March 2007

Background: Physiological differences between dominant and non‐dominant arms may play an important role in wound healing of the upper extremities. The Wound Healing Cooperative Group (WHCG) studied this phenomenon in a human forearm model of acute wound healing.

Methods: With informed consent, sixteen normal healthy volunteers underwent four 6 mm biopsies on the flexor surface of both forearms: 2 biopsies on the dominant arm, and 2 on the non‐dominant arm. The acute wound sites were then treated with i) rhPDGF‐BB 0.01% gel topically at various dosing intervals (Q.D. versus Q.O.D.), ii) rhPDGF‐BB alone Q.D. × 7 days followed by bacitracin alone, or iii) bacitracin alone. Time‐to‐complete healing was measured as the primary endpoint.

Results: The average time‐to‐complete healing for the dominant arm was shorter than the time required to heal the biopsies on the non‐dominant arm, irregardless of the treatment applied.

Conclusion: In the forearm biopsy model of acute wound healing, arm dominance is an independent variable and must considered in study designs. We postulate that this effect may be due to variation in microvascular perfusion. These results provoke further investigation into the physiological mechanisms underlying increased rate of healing in the dominant extremity.

Acknowledgements: Funding from The Angiogenesis Foundation.
130 Development and Characterization of a Skin Organ Culture that Resembles Human Skin
Authors: Martins‐Green M. , Li QiJing , Yao Min
Published: March 2007

The inability to experiment in humans creates a need to develop culture systems that mimic human tissues/organs. Skin is arguably the simplest tissue hence provides an excellent prototype for tissue engineering. Moreover, skin is the body’s first line of defense. Currently available skin replacements have a number of drawbacks. Therefore, there is a need for skin replacements that: (a) are prepared with pertinent primary human cells but yet can be ready “off” the shelf; (b) can be prepared rapidly; (c) contain stable structures, in particular microvessels that can rapidly connect with the patient’s vasculature, thereby establishing circulation in the “graft” and increasing the chances of survival; (d) can be tailored for specific wound impairments (e) are long lasting. We have developed a generation human “skin” that can fulfill these requirements and can potentially be used as a “living bandage”. We start with three primary human cell types and a collagen matrix that self‐assemble into a connective tissue containing a network of mature microvessels, is covered with a stratified epidermis, expresses biochemical markers, matrix molecules, and cytokines characteristic of normal human skin, and matures in 10–15days. Moreover, two additional cell types, pericytes and monocytes, differentiate in situ adjacent to and within microvessels, respectively. The epidermis expresses keratins typical of mature skin and not characteristically produced in response to injury such as keratins 6, 16, 17. This tissue potentially can be developed into a skin replacement for patients with impaired healing. In addition, it responds normally to biological stimuli, providing a powerful vehicle to investigate mechanisms of skin development and regeneration, understand pathological processes, and test drugs and treatments for skin diseases.
131 Lateral Wicking, Good or Bad
Authors: Baldursson Baldur
Published: March 2007

The ability of polyurethane sponge dressings to absorb and contain wound fluid is often insufficient, resulting in maceration and eczema.

The term lateral wicking has been used to describe the fluid film between the peri‐ulcer skin and the dressing surface, responsible for the maceration. A “within dressing” lateral wicking is where the wound fluid is absorbed above the ulcer and transported laterally within the dressing without affecting the peri‐ulcer skin.

We wanted to test this phenomenon in a new type of dressing with a silicon surface towards the wound, a polyurethane sponge layer with enclosed absorbent particles and a vapour permeable outer layer.

A pump delivered 10 ml per hr of equine serum to a 1 sq cm surface at the centre of the dressings. The experiment went on for 2.5 hours. Seven dressings of each type were used in the experiment. The top and bottom aspects of the dressings were photographed at 30 min interval.

In the new ulcer dressing the serum was absorbed and distributed in a “within dressing” lateral wicking. In the established dressing an “under dressing” lateral wicking took place leading to erratic distribution of absorption often at the margin of the dressing instead of over the centre.

Conclusion

Enhancing lateral wicking within a chronic ulcer dressing is a realistic way of optimising its fluid handling characteristics. In this experimental set‐up the new ulcer dressing performed as intended while the conventional dressing did not.

Improved fluid handling characteristics are needed in today’s advanced dressings however, the importance of this phenomenon in the clinical situation must be tested in clinical trials.
133 Granulation Tissue Induction by Lassar Ointment vs. Collagen‐Polyvynilpyrrolidone in Venous Ulcers
Authors: Krötzsch Edgar , Suárez‐Colín Arturo , Salgado Rosa M. , Apis Ana M.Z.
Published: March 2007

Venous leg ulcers derived from tissue destruction is the consequence of a chronic inflammatory process that produces pain and physical disability, diminishing quality of life in patients. In this work, Lassar ointment and lyophilized collagen‐polyvinylpyrrolidone were administered separated each on one half in the same ulcer to 9 patients at the beginning and every 4 days. On day 16, all patients were auto‐grafted with partial thickness skin. Granulation tissue and graft integration were assessed clinically during 3 months. Inflammatory infiltrate, type I and III collagens, elastic fibers, alkaline phosphatase as well as blood vessels were evaluated histologically or histochemically in biopsies taken at the beginning and 16 days after the local treatment.

Clinically and morphologically, both treatments demonstrated appropriate granulation tissue promotion and optimal graft integration since the beginning. Nevertheless, in Lassar ointment treated group regionalization of alkaline phosphatase activity was observed, as well as the presence of granuloma in 2 of the 9 patients. In conclusion, Lassar ointment or lyophilized collagen‐polyvinylpyrrolidone are two different promoters of granulation tissue in venous leg ulcers, however Lassar ointment has the capability to produce granuloma and an exacerbated immune response; in consequence, ulcer recidivism could be present, may be due to mineral deposits in the wound.