bluuebunny/crossref_metadata_2025_split huggingface dataset:
049 Lactate Controls Vascular Development in Wound Healing
Authors: Aslam R. S. , Scheuenstuhl H. , Beckert S. , Hopf H. , Hussain Z. , Hunt T. K. 
Published: March 2007

INTRODUCTION: High concentrations of lactate approx. 10 mM are characteristic of wound healing. We have previously shown that lactate instigates release of VEGF from macrophages and endothelial cells. Our present study uses an in vivo murine Matrigel model to study how lactate enhances vascular development and repair.METHODS: Matrigel is a reconstituted basement membrane complex, a liquid at 4 degree C. When injected subcutaneously, it reconstitutes as a gel. 30 mgs of finely divided polylactate polymer (DL‐lactide‐co‐glycolide) was mixed with 1cc of Matrigel, and 2 injections were made into the dorsum of each of 60 (average 7/group), 6‐month‐old Swiss Webster mice. The gel implants were harvested at 3, 6, 9, 11 and 16 days post injection, and were fixed in buffered formalin or frozen. Cell migration and vascular development were assessed using H&E, anti‐CD31 and anti‐MAC3 antibody stainings for leukocytes, fibroblasts, endothelial cells, and macrophages. Cells and vessels were quantified microscopically.RESULTS: Control implants (without polylactate) developed little or no inflammation or angiogenesis. Polylactated implants developed highly significant number of endothelial cells and recognizable vessels at 6 and 9 days. At 11 and 16 days, sizeable vessels with surrounding connective tissue were found. Though a moderate inflammation occurred in the lactate groups, no foreign body reaction was seen. Larger implants of high molecular weight instigated little inflammation and few vessels.CONCLUSION: Slowly released lactate leads to the formation of new vessels. Our results provide support for further clinical applications of lactate polymer in wounds.NIH/NIGMS Trauma Training Grant
050 The Angiogenesis Inhibitor Endostatin Impairs Wound Healing at Tumor‐inhibiting Doses
Authors: Michaels J , Dobryansky M , Galiano RD , Bhatt KA , Ashinoff R , Ceradini DJ , Levine JP , Gurnter GC 
Published: March 2007

Introduction: Angiogenesis is thought to be important for granulation tissue formation and for the delivery oxygen and other nutrients to the healing wound bed. We examined whether angiogenesis inhibitors (AI) such as endostatin decrease neovascularization in full‐thickness wounds leading to impaired granulation tissue formation and delayed wound closure. Methods: Endostatin at tumor‐inhibiting doses (20 mg/kg/BID) was injected daily starting three days prior to surgery. Two full‐thickness wounds were created on the mouse dorsum using a novel wound healing model developed in our lab. A second experimental group had topical VEGF (10 μg/QD) applied to these wounds. Both groups were compared to PBS‐treated controls. Wounds were analyzed for closure time, granulation tissue formation, and wound vascularity using CD31. Results: Endostatin‐treatment delayed wound closure compared to control mice (17.4d ± 1.51 vs. 12.8 ± 0.89, P < 0.05), resulted in decreased granulation tissue formation at all time points (P < 0.05), and significantly reduced wound vascularity as measured by CD31+ vessel counts (P < 0.05). VEGF application to the wound bed of endostatin‐treated mice normalized wound closure despite endostatin treatment (13.8d ± 1.1 vs. 17.44d ± 1.51, P < 0.05). Conclusion: Endostatin impairs wound angiogenesis, granulation tissue formation and delays full‐thickness wound closure. Topical VEGF was able to reverse this effect and may represent a novel approach to improve wound healing in patients receiving AI. These findings may have serious implications for patients undergoing AI treatment that require surgery or who have wound healing complications. Acknowledgements: This project received no outside funding.
052 Redox Control of Dermal Wound Healing
Authors: Sen Chandan K. , Pendyala Srikanth , Khanna Savita , Hunt Thomas K. , Roy Sashwati 
Published: March 2007

Reactive oxygen species (ROS) are generally thought to be deleterious to biologic systems. The phagocyte NADPH oxidase provides a classical example of deliberate ROS generation. High amounts of ROS are generated in transient bursts to kill pathogens. The recent discovery of another family of NADPH oxidases, the Nox/Duox family, provides additional examples of deliberate generation of ROS by non‐phagocytic cells present at the wound site. Our working hypothesis is that ROS generated by wound‐related cells (low‐ROS by Nox; and residual ROS in the aftermath of phagocyte respiratory burst) support early‐phase acute wound healing by inducing redox‐sensitive signal transduction pathways especially those related to wound angiogenesis.We have observed that ROS‐sensitive redox signaling pathways drive wound angiogenesis. Genetic as well as pharmacological approaches to deliver low concentrations of ROS promote dermal wound angiogenesis, contraction and closure. While at such low levels ROS do not serve as a potent disinfectant, they may act as modulators of cellular response facilitating the healing process. Strategies to decompose ROS at the wound site impaired healing. Congenital defect in human NADPH oxidase results in impaired wound healing as well as increased susceptibility to infection. We have observed that NADPH oxidase deficient transgenic mice suffer from impaired healing even under super sterile conditions; the impairment is corrected by low‐dose ROS delivery. Dermal wound healing is subject to tight redox control. The state of wound tissue oxygenation is a key factor that enables such control.
056 In Vitro Evaluation of Biofilm Development on Tissue Engineered Skin
Authors: Charles CA. , Ricotti CA , Davis SC , Kirsner RS 
Published: March 2007

Bacteria reside in various forms, including planktonic, or free‐floating, or as biofilms, which are a tightly adherent, potentially more treatment‐resistant form. Biofilms, composed in part as polysaccharide matrices, can act as protection for bacteria by shielding them from antimicrobials and the innate immune system. It is estimated that bacterial biofilm are responsible for 65–80% of all chronic infections and may be responsible in part for non‐healing of chronic wounds.An advance in the treatment of non‐healing wounds has lead to the development of human skin equivalents (HSE), which can successfully treat many non‐healing wounds. Better understanding the interaction between bacteria and HSE might improve patient outcomes. Studies involving planktonic E. coli and HSE have demonstrated the growth of bacterial colonies only on the dermal surface. Growth was not seen on the epidermal layer of the HSE, possibly due in part to the expression of innate antimicrobial peptides called human β defensin‐2 (hBD‐2), which are expressed by HSE keratinocytes. The objective of this study was to determine if biofilm formation could occur on a bioengineered HSE.We used a commercially available HSE. Three (3) mm full‐thickness incisions were made in a triangular section of HSE. Each section was inoculated on the epidermal aspect with 1.0 × 105CFU per gram of Pseudomonas aeruginosa at 35 degrees Celsius for specified time points. Sections of HSE were sampled in areas of injury at various time points. Biopsy sections were processed for histologic analysis with H&E and epifluorescent microscopy to visualize Pseudomonas aeruginosa. We found that biofilm formation occurred at multiple time points on HSE. Colonies of adherent bacteria were visualized within the injured area of the epidermal layer of HSE by H & E staining. Eplifluoresecnt microscopy using calcofluor white staining revealed the characteristic exopolysaccharide (EPS) matrix of biofilm.Visualization of the expression of human β defensin‐2 (hBD‐2) with HSE after biofilm formation is underway. This knowledge will help to understand the role of bacterial biofilms within HSE and their effect on subsequent healing.
057 Epifluorescent and light microscopic visualization of bacterial microcolonies in acute wound infections – Are these biofilms?
Authors: Ricotti Carlos , Cazzaniga Alex , Chen Halland , Mertz Patricia M. , Davis Stephen 
Published: March 2007

A biofilm is a formation of surface‐associated microbial cells that are enclosed in a self produced extracellular polymeric substance matrix. This definition is acceptable for in‐vitro research but a clear definition for biofilm‐associated diseases has yet to be elucidated. A structural/morphological definition is currently used to define biofilms; additionally, physiological or molecular criteria will allow us to define biofilms in disease infection accurately. Our objective over the past several years has been to characterize and observe bacterial biofilms in wound infections using different wound models. To broaden our current understanding of biofilm morphology in wounds for this study we used epifluorescent and light microscopy to visualize wound pathogenic pseudomonas aeruginosa bacteria in a porcine partial thickness infection model.Three experimental animals were used for this study. After animal preparation, partial thickness wounds were created on the backs of 3 animals. Wounds were then inoculated with 106 colony forming units/ml (CFU/ml) of Pseudomonas aeruginosa and covered for 48 hours to allow bacteria to colonize and infect the wound. Biopsies were obtained from normal skin, wounds before inoculation, wounds at 48 hours and wounds 48 hours after inoculation. Biopsies were processed and stained with Hematoxylin and Eosin for light microscopy and Calcofluor White and Ethidium Bromide for epifluorescence microscopy.Images obtained using epifluorescent and light microscopy demonstrate that bacteria form aggregates of microcolonies. These structures are representative of bacterial biofilms and support the hypothesis that bacteria live as biofilms in wound infection. Although currently there is no established and accepted definition for biofilm associated diseases, we anticipate that more studies looking into physiological changes of these structures will clarify our current understanding of wound infection and treatment.
058 Silver Dressings: Effective Antimicrobial Therapies?
Authors: Davis SC , Ricotti C , Cazzaniga AL , Mertz PM 
Published: March 2007

Many silver‐dressings have been recently developed to prevent infection of burn and chronic wounds. Antimicrobial therapies are usually studied in in‐vitro assays, which evaluate the antimicrobial efficacy against free‐floating bacteria. In a wound environment bacteria attach to tissues and establish bacterial biofilms. Biofilms are communities of colonies of bacteria and other microorganisms encased in a self produced exopolymeric substance. Biofilms help protect the bacteria from the environment and limit the effectiveness of antimicrobials. In this study we evaluated the efficacy of two silver dressings to eradicate biofilm‐associated and planktonic Pseudomonas aeruginosa cells using our biofilm burn wound animal model.Three pigs were used in this study. Second‐degree burn wounds were made on one‐half of the animal’s back and inoculated with a burn wound isolate of P. aeruginosa. These wounds were then covered for 72 hours with a polyurethane dressing to allow biofilm formation. After 72 hours, additional burn wounds were made on the unwounded half of the animal. The new burns were then inoculated with the same P. aeruginosa strain. At this 72 hour point we had established two bacterial groups, one side of the animal had burns with planktonic bacteria and the other half with biofilm bacteria.Both sides of the animal were treated 20 minutes after inoculation of the planktonic group with the following dressings: 1) Nanocrystalline Silver, 2) Hydrocolloid Silver, or 3) untreated. Wounds were cultured from all treatment groups at 24, 48 and 72 hours post treatment. Sites were cultured quantitatively using a novel flush‐scrub technique to obtain both planktonic and biofilm bacterial counts. The baseline biofilm bacterial count was 7.56 LogCFU/ml (prior to treatment).The hydrocolloid dressing significantly reduced planktonic bacteria counts as compared to untreated and nanocrystalline silver dressing at 24, 48 and 72 hours. However, biofilm bacteria counts for both dressings were similar to untreated control at all sample points. Our study demonstrates that both silver dressings showed limited effect against P. aeruginosa biofilm‐associated cells when compared to untreated wounds.Based on our results we question the effectiveness of silver dressings for infected wounds that are colonized with biofilm associated‐cells. We conclude that anti‐biofilm susceptibility models may improve on current antimicrobial sensitivity assays.
061 Predictors of Poor Outcome in S. Aureus Wound Infection
Authors: Tibor L. , Cramton S.E. , Hopf H.W. , Götz F. , Hunt T.K. 
Published: March 2007

Objectives: Staphylococcus aureus is the most common bacterium cultured from infected wounds. We hypothesized that diabetes mellitus (DM) and/or peripheral arterial disease would be patient predictors of severe outcomes, defined as amputation, sepsis, or death, and infections caused by resistant strains would be bacterial predictors of severe outcomes. Methods: With IRB approval, 50 S. aureus strains (45 wound, 5 central line) were isolated during routine clinical care. Investigations included antibiotic resistance (>5 mcg/ml), and PCR for STAR elements. Chart review included wound type, location, relevant comorbidities, antibiotic resistance, and outcome. Results:

Outcome n(%of outcome total)

Severe
All others
Total

Diabetic
7 (70)
6 (17)
13 (29)

Non‐diabetic
3 (30)
29 (83)
32 (71)

MRSA STAR groups
2 (20)
8 (23)
10 (22)

All other STAR
8 (80)
27 (77)
35 (78)

MRSA
4 (40)
8 (23)
12 (27)

MSSA
6 (60)
27 (77)
33 (73)

Total patients
10 (22)
35 (78)
45

No non‐DM patient with arterial disease (n = 6) had a poor outcome.

Conclusions: The strongest predictor of outcome was the presence of DM. Patients with severe outcomes were slightly more likely to have MRSA infection, although only 33% of patients with MRSA had severe outcomes. Although STAR/arsRBC groups have been shown previously to predict antibiotic resistance, in this collection there was no correlation between these molecular markers and outcome. This study shows that the strongest predictor of clinical outcome in wound infection is patient‐dependent, while bacterial factors appear to play a lesser role.
062 The Impact of Nosocomial Resistant Pseudomonas Infections in a Burn Unit
Authors: Tredget Edward E. , Shankowsky Heather A. , Lee Jonathan P. , Swanson Todd 
Published: March 2007

Introduction: Pseudomonas aeruginosa, remains a serious cause of nosocomial infection and septic mortality in burn patients particularly when nosocomially acquired. Our purpose is to investigate the morbidity and mortality associated with nosocomial infection with an aminoglycoside resistant Pseudomonas and associated costs compared to a group of patients with similar severity of burn injury that did not acquire resistant Pseudomonas during hospitalization. Methods: Using a TRACS burn database, patients treated at our institution with Pseudomonas resistant to gentamicin were identified and case‐matched to controls for age (±5 years), TBSA(±5%), admission year (±5 years) and presence of inhalation injury. Patients who died <48 hours after injury were excluded. Data examined included demographics, number of days to onset of positive Pseudomonas culture and gentamicin resistance, as well as antibiotic use and cost. Results: 42 patients admitted to our unit between 1980 and 2001 were identified with gentamicin resistant Pseudomonas. Patients in the resistant Pseudomonas(Ps) group were similar in age (39.2 ± 3.2 vs 40.4 ± 3.3 years), TBSA (47.5 ± 3.7 vs 48.9 ± 3.7%), extent of full thickness injury (37.0 ± 3.9 vs 30.3 ± 3.2%) and presence of inhalation injury (62.8% vs 55.0%) compared to controls. There was a significant increase in the mortality rate in the Ps group (39.5 vs 5.0%, p < 0.001)(paired t test) compared to controls and the morbidity in terms of length of stay, increased in the Ps group (73.1 ± 13.2 vs 55.8 ± 8.1 days). Ventilatory days (22.6 ± 5.1 vs 8.2 ± 2.4, p < 0.05), number of surgical procedures (4.5 ± 0.6 vs 2.9 ± 2.5, p < 0.05), and amount of blood products used (packed cells 47.9 ± 7.8 vs 18.6 ± 3.3, p < 0.01)(platelets 10.5 ± 2.9 vs 0.5 ± 0.3, p < 0.01) were all significantly higher in the Ps group compared to control. Costs associated with antibiotic requirements were also significantly higher in the Ps group ($3,191.90 ± 848.00 vs $613.60 ± 145.50, p < 0.01). Conclusions: Our data demonstrate that nosocomial infection in burn patients with aminoglycoside‐resistant Pseudomonas is associated with significantly higher morbidity and mortality and cost of care. Increased resource consumption in terms of length of stay, number of surgical procedures, amount of blood products, and antibiotic costs did not prevent significantly higher mortality rates when compared to control patients who avoided infection with the resistant organism. Thus, prevention, identification and eradication of nosocomial Pseudomonas infection are critical for cost‐effective, successful burn care.
065 Improving Integra™“Take” with Negatively Charged Methacrlylic Acid Beads
Authors: Eckhaus AA , Fish JS , Sefton MV 
Published: March 2007

Introduction: Integra™ has gained acceptance as a dermal replacement for large burns with limited donor sites. Integra™ vascularization takes between 14 and 21 days. Accelerating the vascularization of Integra™ could improve “take” rates and potentially decrease the obligatory waiting period between application and autografting. Hypothesis: Application of negatively charged methacrylic acid (MAA) beads will enhance vascularization of Integra™ Methods Male Wistar rats (n = 11) had two 2 × 3 cm contra lateral dorsal full thickness wounds excised and grafted using Integra™. The MAA beads were applied under the Integra™ topically on the wound bed. Three experimental treatments were compared: Group 1‐ high‐dose MAA beads, Group 2‐ low‐dose MAA beads, Group 3‐ Integra only. Laser Doppler Imaging (LDI) to assess perfusion, as well as digital photography was done on days 7,10 and 14. Tissue samples for H + E and Factor VIII histological staining were collected on day 14. Results: The average “take” was 99%(p < 0.05) for high‐dose MAA beads, 98%(p < 0.05) for low‐dose MAA beads and 82% in the Integra™ only group at day 7. At day 7 (p < 0.01) and day 10 (p < 0.05), the low‐dose MAA group had significantly greater perfusion than the Integra™ only group. There were no statistically significant differences at day 14. Microvessel density (MVD) counts revealed a >40% increase in the number of vessels in both the low‐dose MAA (p < 0.05) and high‐dose MAA (p < 0.05) groups when compared to the Integra™ only group. There was no difference in LDI perfusion or MVD counts between low and high‐dose MAA groups. Conclusion: Factor VIII staining revealed enhanced angiogenesis in Integra™ treated with low and high‐dose negatively charged MAA beads. Low‐dose negatively charged MAA beads improved and accelerated the vascularization of Integra™ in this rodent model.
069 Scar Reduction by Adhesive Patches: Efficacy and Potential Mode of Action
Authors: Meyer‐Ingold W. , Achterberg V. 
Published: March 2007

There is a wide spectrum of treatment modalities to manage hypertrophic scars, techniques like surgical excision, intralesional application of corticosteroids, pressure therapy or laser therapy are extensively used.From a cosmetic and physiological point of view scars are predominantly a concern of the patients, the cosmetic relevance for doctors is often of less importance. Therefore a treatment that can be performed by the patient her‐/himself might be advantageous if it is efficacious and safe. Since the early 1980s so‐called “silicone gel sheeting” has been a widely used safe clinical management option for hypertrophic scars and keloids.The principle of the latter treatment has now been adapted and optimised towards a specific easily applicable adhesive polyurethane patch. This breathable, hypoallergenic patch is very well tolerated and avoids – in contrast to silicone sheets – moisture accumulation on the skin. Several clinical studies on both mature scars and on scar formation after surgical incisions show a reduction in visibility, redness, and roughness of the scars. The recommended eight weeks treatment might even be interrupted daily for twelve hours; the scar reducing effect is achieved as well.Extensive investigations on the polyurethane patch in vivo and in vitro propose an improved remodelling process of the scar tissue due to thermal and pressure effects of the patch but not by stratum corneum hydration. In vivo a better microcirculation can be observed in the scar tissue after treatment and in vitro an activation of enzymes involved in the remodelling process can be measured.In summary, physical effects are likely to be responsible for the successful results in clinical studies and individual applications of the new polyurethane patch for the reduction of hypertrophic scars.
074 Wound Healing Enhancement by Pulsed Electromagnetic Fields
Authors: Callaghan M.J. , Kinnuncan E.R. , Michaels J. , Simon B.J. , Gurtner G.C. 
Published: March 2007

The effects of pulsed electromagnetic fields (PEMF) on soft tissue are not well characterized. This study utilized a diabetic wound model to examine the effects of PEMF effects on soft tissue healing. Methods: Wounds were created on the dorsum of db/db and wild type C57BL6 mice. Mice were exposed to PEMF (4.5 ms pulse/15 hz) for 8 hrs/day for 14 days. Gross closure was assessed with digital analysis of area changes over time. Histological examination assessed granulation and epithelial gap, cell proliferation (BrdU), and endothelial cell density (CD31). Human umbilical vein endothelial cells (HUVECs) were incubated in the presence or absence of PEMF for 8 hrs and VEGF/FGF2 was measured in culture supernatants by ELISA. Results: Mice exposed to PEMF had accelerated wound closure at day 7 (wound area as % of original, db/db: 60%(PEMF) vs. 78%(control), C57BL6: 15% vs. 42%, p < 0.05) and day 14 (db/db: 21% vs. 55%, C57BL6: 8% vs. 28%, p < 0.05), with increased granulation and cell proliferation (db/db day 7: 52 ± 8 vs. 31 ± 5 cells/HPF (200x)). Immunohistochemical analysis revealed significantly higher CD31 density in wounds exposed to PEMF at day 7 (vessels/HPF, db/db: 28 ± 4 vs. 17 ± 4, C57BL6: 41 ± 7 vs. 28 ± 6) and day 14 (db/db: 32 ± 6 vs. 21 ± 5, C57BL6: 48 ± 5 vs. 40 ± 5). HUVECs in PEMF exhibited 5‐fold higher levels of FGF2 compared to controls after 30 min (20.50 pg/ml ± 6.75 vs. 4.25 pg/ml ± 0.75), with no change in VEGF through 8 hrs. Conclusions: PEMF accelerates closure time and endothelial cell proliferation in wound healing. Upregulation of FGF2 in HUVECs exposed to PEMF suggests that release of angiogenic growth factors may explain increased vascular density and accelerated wound closure. Clinical uses include treatment for diabetic ulcers and other non‐healing wounds.This work is supported in part by the Alumni Fund, Alumni Association of SUNY Downstate College of Medicine (MJC).