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Biomedical subjects

J F Hansbrough

Publications and source records attributed to J F Hansbrough.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Success of immediate intragastric feeding of patients with burns.

We evaluated our attempts to aggressively feed 45 adult patients with burns with the use of intragastric tube feedings. Patients were divided into three burn sizes (20% to 30% total body surface area, 31% to 44% total body surface area, and > 44% total body surface area). No attempts were made to place feeding tubes across the pylorus. Patients were fed as early as possible after admission. Mean caloric intake met calculated nutritional goals beginning on the second day after burn injury, and in the severely burned group, mean caloric intake was 2500+ kcal by the second day. Initiation of intragastric feedings within hours of burn injury results in the provision of high daily levels of nutrition and may obviate the necessity of placing a transpyloric feeding tube in the majority of patients with burns.

Burns↗
PubMedDate not supplied

The use of biobrane II and specialty airflow beds (FluidAir Plus and Kinair for effective coverage of extensive posterior donor site wounds.

Posterior skin graft donor sites furnish large areas of skin for wound coverage, but the sites frequently are management problems. The wounds tend to become moist and to develop excessive drainage and fluid accumulation that may interfere with adherence of dressings, including our preferred donor site dressing, Biobrane II (red label, large pore). We studied the use of specialty airflow beds for improving the outcome of posterior donor sites. We evaluated 50 patients aged 1 to 69 years (mean 29.45 years) with posterior skin graft donor sites of the back, thigh, or buttocks that were covered with Biobrane II. Sites ranged in size from 3% to 13% body surface area (mean 8.34%). Forty patients were placed on a FluidAir Plus bed, and 10 were placed on air-filled pillow therapy beds (five on KinAir III, five on Therapulse) (Kinetic Concepts, Inc.) All patients were kept in the supine position. We evaluated six criteria: drainage, fluid accumulation under Biobrane, infection, days until Biobrane separated, days until epithelialization, and days of specialty bed usage. We related these criteria to nursing-care actions that interfere with airflow and prevent the drying action of the bed, such as use of a "linen saver" under the patient in the area of the donor site, a foam wedge under the back, and dressings applied over the Biobrane. Most donor sites had no complications. Donor site infections developed in six patients. Five of these patients had fluid accumulation under the Biobrane, necessitating early removal. Fluid accumulated under the Biobrane in 21 patients; nine of these incidences were related to a nursing-care action that impeded airflow.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Evaluation of Graftskin composite grafts on full-thickness wounds on athymic mice.

We used a living bilayered cultured skin replacement to close full-thickness wound defects on the dorsum of athymic mice. The skin replacement is composed of human fibroblasts that condense a bovine collagen lattice; the lattice is then seeded with cultured human keratinocytes. The collagen lattice with fibroblasts serves as a dermal template, and the overlying human keratinocytes form the epidermal component of this composite skin replacement. Twenty-four animals were grafted, and groups of six were killed and biopsied at 6, 15, 30, and 60 days after graft replacement. Twenty-four mice in the control group receiving grafts of fresh, split-thickness, human cadaver skin were biopsied at the same time points. "Take" of all grafts was excellent, with only one graft loss in the 48 mice (one Graftskin graft, at 15 days). Light microscopy revealed that vascular ingrowth into Graftskin occurred rapidly, and discrete dermal and epidermal layers were seen at all time points. Evidence of basement membrane formation was seen at 6 days after grafting by immunohistochemical staining for laminin and by electron microscopic visualization of lamina lucida and lamina densa zones at the dermal-epidermal junction. The results demonstrated that Graftskin formed a structurally complete skin replacement within 1 week of placement on full-thickness wounds on athymic mice, and effective skin coverage was provided for the 60-day observation period after grafting.

Animals↗
PubMedDate not supplied

Current trends in the use of allograft skin for patients with burns and reflections on the future of skin banking in the United States.

Cadaveric allograft skin can play a critical role in the care of patients with massive burns. It is difficult, however, to estimate current use and levels of enthusiasm for allograft skin in the United States. We report on a survey of 40 skin banks and 140 United States burn center medical directors as listed in the American Burn Association's Directory of Burn Care Resources for North America 1991-1992. Response rate was 45% for skin banks and 38% for burn directors. Overall, 12% of admitted patients were treated with allograft skin at the responding burn centers. Sixty-nine percent of burn center directors preferred to use fresh skin, although only 47% of skin banks were able to supply fresh cadaver skin. Tabulated survey results and a review and discussion of future directions in skin banking and replacement research are discussed in this paper and were presented to the Tissue Bank Special Interest group at the 1993 American Burn Association annual meeting.

Burn Units↗
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Wound healing in partial-thickness burn wounds treated with collagenase ointment versus silver sulfadiazine cream.

During burn care the wounds must be repeatedly debrided of adherent and loose debris until the decision is made to surgically excise and graft the wound or to await epithelialization. Though native proteolytic enzymes in the skin or those produced by colonizing bacteria can speed eschar separation, the use of exogenous enzymes for wound debridement may accelerate wound cleaning and healing. Collagenase digests native and denatured collagen in necrotic tissue. This multicenter trial of 79 patients with partial-thickness wounds compared the efficacy of collagenase ointment applied with polymyxin B sulfate/bacitracin powder with the efficacy of standard topical antimicrobial therapy (control) in which silver sulfadiazine cream (1%) was used to debride paired burn sites. Patients selected for the study had two noncontiguous, partial-thickness, comparably sized, and anatomically similar burn wounds. Ages of patients ranged from 5 to 60 years (mean 33 years). The total body surface area burned ranged from 2% to 30% (mean 13.6%). Mean burn sizes used for study treatment were 366 cm2 (26 to 2310 cm2) for collagenase sites and 355 cm2 (26 to 2394 cm2) for control sites. Sites on each patient were randomly assigned to treatment with either collagenase or control. Endpoints were time to clean wound bed (absence of retained debris) and time to healing (complete epithelialization). The sites treated with collagenase cleaned in less time (mean 9.3 days) than the control sites (mean 11.6 days). Similarly the collagenase sites healed faster than the control sites (mean 19 vs 22.1 days).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMedDate not supplied

Use of Biobrane for extensive posterior donor site wounds.

Optimal treatment of extensive donor sites in patients with major burn injuries can be frustrating for both physician and nursing staffs and can cause great discomfort for the patients. Slow healing or infections of donor site wounds may impede other aspects of burn care and delay further skin grafting. The posterior trunk is a particularly good site for donor site harvesting in patients who have incurred extensive burns. Posterior donor site wounds have been noted to heal with less hypertrophic scar compared with other donor sites, because the epidermis and dermis allow for thicker grafts and more rapid healing. The combination of Biobrane and airflow specialty beds can enable successful treatment of posterior donor site wounds.

Biocompatible Materials↗
PubMedDate not supplied

Accelerated healing and reduced need for grafting in pediatric patients with burns treated with arginine-glycine-aspartic acid peptide matrix. RGD Study Group.

Arginine-glycine-aspartic acid (RGD) peptide matrix is designed to promote dermal healing by providing a molecular scaffold that facilitates cell ingrowth and establishment of normal tissue architecture. This study investigated the effectiveness and safety of RGD peptide matrix in the treatment of partial-thickness scald burns in pediatric patients. Either topical RGD peptide matrix or control treatment with silver sulfadiazine was applied to matched burn sites daily for up to 21 days. With RGD peptide matrix application under synthetic occlusive dressing, the incidence of healing was nearly threefold higher, average time to healing 2.5 days shorter (regression estimation), extent burn closure at all treated sites 37% greater, and number of needed grafting procedures fourfold lower compared with control treatment. All these differences were statistically significant. RGD peptide matrix was well tolerated. RGD peptide matrix promoted and accelerated healing in this study and thus may be able to reduce morbidity and treatment costs of partial-thickness burns in pediatric patients.

Administration, Topical↗
PubMedDate not supplied

Effects of high-dose vitamin C administration on bacterial translocation and lung neutrophil sequestration in burned mice.

Severe burn injury produces shock and induces acute gastrointestinal derangements that may disrupt mucosal integrity and facilitate bacterial translocation (BT) to mesenteric lymph nodes, accompanied by endotoxemia. Antioxidant treatments may be beneficial after shock by acting as scavenger agents for highly reactive oxygen intermediates. We studied the effects of high dosages of vitamin C, a water-soluble antioxidant, on the incidence of BT and on levels of lung myeloperoxidase in burned mice. Myeloperoxidase is primarily found in neutrophils, and levels of myeloperoxidase in tissues reflect neutrophil sequestration. The doses of vitamin C used were equivalent on a weight basis to 1 gm/hr administered to humans over a 24-hour period, doses that have shown efficacy in improvement of resuscitation in other experimental burn models and currently are being used in clinical trials in patients with burns. Mice were anesthetized and received 32% total body surface area, full-thickness burn injury to the dorsum, followed by injection of 1 ml of Ringer's lactate (RL) for resuscitation. Mice were divided into three groups: (1) unburned, received anesthesia and RL injections; (2) burned, received vitamin C (14 mg/kg/hr) in 1 ml RL by intraperitoneal injection immediately after burn and via subcutaneous injection (0.5 ml) at 6 and 12 hours after burn; (3) burned, received identical injections of RL alone (control animals). Mesenteric lymph nodes were removed by use of sterile technique at 24 hours after burn and cultured; any growth was considered evidence of BT. The incidence of BT in burned mice was not altered by administration of vitamin C (normal, 10% BT; burn, 41.37% BT; burn+vitamin C, 45.83% BT). Similarly, burned animals that received vitamin C or RL alone did not differ in the levels of myeloperoxidase in the lungs (normal, 0.015 +/- 0.003 U/gm; burn, 0.2231 +/- 0.029 U/gm; burn+vitamin C, 0.281 +/- 0.041 U/gm).(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗
PubMedDate not supplied

Management of skin-grafted burn wounds with Xeroform and layers of dry coarse-mesh gauze dressing results in excellent graft take and minimal nursing time.

The goals of postoperative treatment for split-thickness skin grafts (STSGs) are to maintain graft integrity, prevent graft and wound desiccation, and minimize infections. As we documented in a telephone survey of 16 burn centers, dressings for skin grafts usually consist of multiple layers of coarse-mesh gauze; the dressings receive frequent applications of aqueous solutions that contain antimicrobial agents to control bacterial growth and to maintain a moist environment at the wound surface. We prospectively studied the efficacy of our standard dressing of one layer of Xeroform (Kendall Inc., Mansfield, Mass.), which consists of fine-mesh gauze impregnated with bismuth tribromophenate, applied to the STSG surface followed by layers of dry gauze dressings wrapped in Kerlix (Kendall Inc.); the entire dressings were left intact until postoperative day 5. We evaluated 142 STSGs on 100 patients, mean age 29.2 years (range 0.3 to 79 years), with burns of 0.5% to 60% total body surface area (mean 9.1%). Meshed or sheet STSGs of 0.5% to 18% total body surface area (mean 3.14%) were placed on deep partial- or full-thickness excised wounds. Xeroform, followed by coarse-mesh gauze dressing, was applied after skin grafts were completed. The entire dressing was left intact until the initial takedown-to-graft at 5 days. Patients' grafts were evaluated on postoperative day 5 for the percentage of "take" and subgraft fluid collected; this evaluation was then repeated every other day for 10 days. On postoperative day 5 evaluations, mean skin graft take in all patients was 98.54% +/- 0.72%. Xeroform and coarse-mesh gauze dressings used to cover STSGs and left intact for 5 days until the initial dressing change, resulted in highly successful graft outcomes, with minimal postoperative nursing care compared with other dressing methods for skin grafts.

Adolescent↗
PubMedDate not supplied

Burn injury results in decreased gastric acid production in the acute shock period.

Gastrointestinal complications including acute stress ulcerations occur after burn injury. The causes of acute gastric derangements are multiple, and tissue ischemia in the acute period of burn shock may promote breakdown of the gastric mucosal protective barrier. We compared gastric pH in mice after 25% total body surface area, full-thickness murine burn injury with that in unburned control animals. Animals were anesthetized with methoxyflurane and were resuscitated with 1 ml normal saline solution immediately after burn. Animals were killed at intervals up to 24 hours after burn injury, stomachs were removed and opened, and gastric mucosal pH was measured by use of a surface pH probe. In other animals mixed venous blood was obtained via direct inferior vena cava puncture, and blood gas analysis was performed at intervals up to 24 hours after burn injury. Unexpectedly, gastric mucosal pH increased in burned mice compared with that in controls. The peak difference, greater than one log pH unit, occurred at 3 hours after burn injury (pH 4.45 burn vs pH 3.34 control, p < 0.00001), and this difference was maintained through 12 hours (pH 4.88 burn vs pH 3.20 control, p < 0.005). In this model, shock was observed to begin as early as 1 hour after burn injury and reached its maximal period (base deficit, -27.8 mEq/L) at 12 hours after burn injury. In view of the higher gastric pH in burned mice with concomitant profound shock, gastric acid production appears to be impaired during this time, which suggests acute postburn gastrointestinal ulcerations may be primarily due to ischemia. Prevention of organ ischemia may play a key role in the prevention of acute gastric ulcerations after burn injury.

Acidosis↗
PubMedDate not supplied

The effect of an arginine-glycine-aspartic acid peptide and hyaluronate synthetic matrix on epithelialization of meshed skin graft interstices.

Keratinocytes and fibroblasts interact with proteins of the extracellular matrix such as fibronectin and vitronectin through RGD (arginine-glycine-aspartic acid) cell-attachment sequences. This study evaluated the ability of a provisional synthetic matrix composed of an RGD peptide and hyaluronic acid to accelerate the epithelialization of the interstices of meshed, human, split-thickness skin when placed on full-thickness wounds of athymic mice. Full-thickness skin defects, sparing the panniculus carnosus, were created on athymic mice and 3:1 meshed, human skin was placed on them. The grafts had four central, isolated interstices, which epithelialized by migration of human keratinocytes. Conditions were either the addition to the wound of the synthetic matrix or a matrix of hyaluronic acid alone. The time to closure of the graft interstices was decreased (p < 0.02) in the wounds treated with the RGD peptide-hyaluronic acid provisional matrix. The resultant epithelium of the closed interstices was significantly thicker 8 days after surgery for the RGD-treated wounds. Basement membrane proteins (laminin and type IV collagen) were also found to be present at the dermoepidermal junction earlier in the RGD-treated wounds. These results imply that use of the RGD peptide conjugate to effect cell-matrix interactions may have clinical significance in the field of wound healing.

Animals↗
PubMedDate not supplied

Integrin and matrix molecule expression in cultured skin replacements.

Current tissue culture techniques enable human keratinocytes (HK) from a small section of skin to be grown into sheets of epithelium for treating extensive wounds. The additional use of dermal replacements coupled with cultured skin substitutes may improve handling properties and effect ultimate healing results. Adhesion of cultured HK grafts to wounds, and final success rates of HK grafting, are variable and frequently unsatisfactory. To evaluate adhesion molecule (integrin) expression by cultured grafts, as well as matrix molecule distribution, we performed immunohistologic analysis of integrin expression on HK cultured on plastic and a polyurethane membrane, as well as on two dermal substitutes. Multilayered HK sheet grafts were prepared by culturing cells in plastic tissue culture dishes, and HK were cultured to single-layer confluence on polyurethane membranes (Hydroderm; Wilshire Medical Inc., Dallas, Texas). Composite grafts were prepared by seeding proliferating HK on Dermagraft, composed of human neonatal fibroblasts cultured in polyglactin mesh (Advanced Tissue Sciences, La Jolla, Calif.) and on AlloDerm, an acellular human dermis (LifeCell Inc., The Woodlands, Texas). Immunohistologic staining was performed for the integrin subunits alpha 5, alpha 6, and alpha v. Staining for matrix molecules included fibronectin, laminin-1, and laminin-5. HK in cultured epithelial sheets showed integrin alpha 6 expression on basal cells, and only faint alpha 5 and alpha v staining. HK cultured to confluence on Hydroderm reacted with monoclonal antibodies specific for alpha 5, alpha 6, and alpha v. Through HK adhered well to Dermagraft, there was reduced adhesion of HK on AlloDerm that was not accelerated by addition of fibronectin. HK in composite grafts showed distinct reactivity according to the time in culture. HK on Dermagraft lost alpha 5 reactivity by day 17 and only weak alpha v reactivity was seen. Basal keratinocytes on AlloDerm, however, remained alpha 5 and alpha v positive. In both composite grafts, integrin alpha 6 expression was limited to basal keratinocytes.

Biocompatible Materials↗
PubMedDate not supplied

Growth peptide release from biologic dressings: a comparison.

Biologic dressings are believed to stimulate wound healing in a variety of wound types. Cryopreserved allograft skin (CAS) is used as a biologic dressing for excised wounds, partial-thickness wounds, and meshed split-thickness skin grafts, and the use of allogenic or autologous cultured epithelial sheets (CES) has been reported to enhance healing of skin ulcers and deep partial-thickness wounds. However, limitations of allograft skin include bacteriologic and viral safety, limited availability, cost, and ease of handling. Previously we have reported the successful use of human keratinocytes cultured to single-layer confluence on Hydroderm polyurethane membranes (HD/HK) for grafting of full-thickness wounds. In this study we evaluated the release of five different growth peptides (transforming growth factors alpha and beta (TGF-alpha, TGF-beta), interleukin-6, interleukin-8, and melanoma growth stimulatory activity from CAS, CES, and HD/HK grafts. Highest levels of TGF-alpha were found for HD/HK (728 +/- 115 pg/10 cm2 of membrane) followed by CES (491 +/- 137 pg/10 cm2; NS). No TGF-alpha was detectable for CAS, and 3.7-fold, and 25-fold higher levels of interleukin-6 were found for CES (257 +/- 12.7 U/10 cm2) compared with HD/HK and CAS, respectively. Interleukin-8 had similar levels for CES (0.65 +/- 0.7 ng/10 cm2) and HD/HK (0.88 +/- 0.12 ng/10 cm2), whereas melanoma growth stimulatory activity was elevated in CES (2314 +/- 97 pg/10 cm2) compared with HD/HK (1071 +/- 55 pg/10 cm2). TGF-beta was barely detectable for CES and HD/HK. Cryopreserved allograft showed high levels of TGF-beta (5.2 +/- 1.6 ng/10 cm2). Overall mitogenic activity of the supernatants on keratinocyte cultures was assessed. Highest proliferation was seen for CES supernatants followed by HD/HK (NS). Supernatants from CAS had an antiproliferative effect on keratinocytes. We conclude that a single layer of keratinocytes cultured on a polyurethane membrane facilitates keratinocyte proliferation similar to CES, whereas cryopreserved allograft has no mitogenic effect on keratinocytes.

Analysis of Variance↗
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Clinical trials of a biosynthetic temporary skin replacement, Dermagraft-Transitional Covering, compared with cryopreserved human cadaver skin for temporary coverage of excised burn wounds.

Human cadaver allograft skin (HCAS) is widely used for covering excised burn wounds when limited available skin donor sites or the overall patient condition does not permit immediate grafting with autologous skin. However, recurring problems are associated with HCAS including limited supply, variable quality, ultimate immune rejection, and the potential for bacterial and viral disease transmission. These problems speak for the need for development of a dependable substitute for HCAS. We evaluated the ability of a biosynthetic analogue of human skin to temporarily close excised burn wounds in humans. Dermagraft-TC (Advanced Tissue Sciences, Inc.) (DG-TC) is composed of human neonatal fibroblasts cultured on a synthetic dressing (Biobrane; Dow Hickam, Inc.) that consists of nylon mesh fabric covered with a thin layer of silicone rubber membrane, which provides an epidermal "barrier." The material is stored frozen and thawed immediately before use. DG-TC is semitransparent, thus facilitating continuous observation of the underlying wound surface. Burn wounds in 10 patients (mean age 33.5 years, mean burn size 39.9% total body surface area) were surgically excised. Two variants of the DG-TC skin analogs were tested: a material that was cryopreserved to maintain fibroblast viability (DG-TC Red) and a material that was frozen without efforts to maintain fibroblast viability (DG-TC Blue). A control site on each patient received cryopreserved HCAS. Each study site was approximately 1% total body surface area. When clinically indicated, patients were returned to the operating room where the skin replacements were removed, the wound bed was evaluated and prepared for grafting, and the wounds were closed with meshed split-thickness autograft skin. The results showed that adherence to the wound and subsequent autograft "take" were excellent with both DG-TC variants and were at least equivalent to HCAS. No evidence of immune rejection of DG-TC was seen, whereas in four patients evidence of epidermal sloughing/rejection was noted in the HCAS control sites, which limited persistence of those grafts on the wound. Further clinical trials with this skin analogue are in progress.

Adolescent↗
PubMedDate not supplied

A multicenter clinical trial of a biosynthetic skin replacement, Dermagraft-TC, compared with cryopreserved human cadaver skin for temporary coverage of excised burn wounds.

This multicenter study compared the use of a biosynthetic human skin substitute with frozen human cadaver allograft for the temporary closure of excised burn wounds. Dermagraft-TC (Advanced Tissue Sciences, Inc.) (DG-TC) consists of a synthetic material onto which human neonatal fibroblasts are cultured. Burn wounds in 66 patients with a mean age of 36 years and a mean burn size of 44% total body surface area (28% total body surface area full-thickness) were surgically excised. Two comparable sites, each approximately 1% total body surface area in size, were randomized to receive either DG-TC or allograft. Both sites were then treated in the same manner. When clinically indicated (> 5 days after application) both skin replacements were removed, and the wound beds were evaluated and prepared for grafting. DG-TC was equivalent or superior to allograft with regard to autograft take at postautograft day 14. DG-TC was also easier to remove, had no epidermal slough, and resulted in less bleeding than did allograft while maintaining an adequate wound bed. Overall satisfaction was better with DG-TC.

Adult↗
PubMedDate not supplied

Acellular human dermis promotes cultured keratinocyte engraftment.

In full-thickness skin injury, loss of dermis may result in compromised wound repair, including contracture, hypertrophic scarring, and wound breakdown. This report examines the effect of an acellular dermal matrix on in vivo skin repair. Human keratinocytes cultured onto a synthetic hydrophilic dressing were applied with (N = 9) and without (N = 11) an acellular dermal matrix to full-thickness skin defects on athymic mice. Host cells progressively repopulated the acellular dermal component of the grafts. All animals with dermal matrix revealed fully differentiated epidermis by postoperative day 21. Human keratinocytes persisted in all animals grafted with dermal matrix, compared to only 63.6% of those animals without a dermal component. Planimetric analysis revealed significantly reduced wound contraction (p = 0.016) in animals receiving the dermal matrix. Histologic, immunohistochemical, and electron microscopic analyses also were performed. These studies suggest that an acellular dermal matrix can effectively direct regeneration of normal skin morphology.

Animals↗
PubMedDate not supplied

Safety and efficacy of TransCyte for the treatment of partial-thickness burns.

Standard treatment for extensive partial-thickness burns in the United States and in much of the world involves the application of topical antimicrobial agents and repetitive wound débridements and dressing changes. We evaluated a new biologic wound covering, TransCyte (Advanced Tissue Sciences, La Jolla, Calif, formerly marketed as Dermagraft-Transitional Covering), for the treatment of partial-thickness burns. This material is composed of human newborn fibroblasts which are then cultured on the nylon mesh of Biobrane (Dow B. Hickam, Inc, Sugarland, Tex); the thin silicone membrane bonded to the mesh provides a moisture vapor barrier for the wound. A prospective, randomized, comparison study of silver sulfadiazine and TransCyte was performed with the use of paired wound sites on 14 patients. Wounds treated with TransCyte healed more quickly (mean 11.14 days to 90% epithelialization vs 18.14 days, P = .002). A noncomparison evaluation was then done for an additional 18 patients, and it confirmed excellent wound healing and an absence of infections. There were no infections in the 32 wound sites treated with TransCyte. In the first study group, late wound evaluations (3, 6, and 12 months postburn) were performed with use of the Vancouver Scar Scale. The results indicated that wound sites treated with TransCyte healed with less hypertrophic scarring than sites treated with silver sulfadiazine (P < .001 at 3 and 6 months, P = .006 at 12 months).

Adolescent↗