Consensus statement on the relationship of breast implants to connective-tissue disorders.
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Biomedical subjects
Publications and source records attributed to M C Robson.
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To better define thrombin-receptor interactions, we synthesized human thrombin peptides and identified binding-domain peptides that bind thrombin receptors and activate mitogenic signals (Glenn, K.C., G.H. Frost, J.S. Bergmann, and D.H. Carney. 1988. Pept. Res. 1:65-73). Treatment of full dermal dorsal incisions with a single topical application of thrombin receptor-activating peptide (TRAP-508) or human alpha-thrombin in saline enhances 7-d incisional breaking strength in normal rats up to 82% or 55% over saline-treated controls, respectively. Control wounds require approximately 11.5 d to achieve breaking strength equivalent to TRAP-treated wounds at day 7. Thus, a single application of TRAP accelerates healing, shifting the time course forward by up to 4.5 d. Histological comparisons at day 7 show more type I collagen, less evidence of prolonged inflammation, and an increase in number and maturity of capillaries in TRAP- and thrombin-treated incisions. Angiograms also show 50-65% more functional vascularization going across thrombin- and TRAP-treated surgical incisions. Thus, alpha-thrombin and thrombin peptides, such as those released following injury, appear to initiate or enhance signals required for neovascularization and wound healing. The ability to accelerate normal wound healing events with synthetic peptides representing receptor binding domains of human thrombin may offer new options for management of wound healing in man.
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The goal of treatment of the burned hand is to make the hand functional at the conclusion of treatment. Function should ideally include both fine pinch and power grip but will ultimately be determined by the individual patient's needs. At no time, however, can the care of the burned hand be performed in a vacuum, losing sight of the patient as a whole. It must also be remembered that the hand functions as part of the upper extremity. Full hand motion is useless if significant contractures of the elbow or axilla prevent the patient from positioning the hand so that this motion can be utilized. Rehabilitation must render the entire extremity functional. Thus, it becomes obvious that a team effort is mandatory. This usually will include the following individuals: physician, nurse, occupational therapist, physical therapist, vocational rehabilitation counselor, and social worker. A functional upper extremity means that the goal must be to return patients to their preburn vocations and avocations. A clear understanding of job requirements and work habits will allow realistic goals to be established. However, when the goal of optimal function cannot be reached, early retraining will help to obtain optimal rehabilitation.
The role of angiogenesis in the delay phenomenon is unclear. In this study a potent angiogenic growth factor, basic fibroblast growth factor (bFGF) was used to ascertain the importance of angiogenesis in this phenomenon. bFGF (100 micrograms) was infiltrated beneath the panniculus carnosus on the dorsum of 50 rats. Another 50 rats received saline vehicle infiltration only. Ten days later a modified McFarlane flap (10 x 3 cm) was elevated and biopsies collected. Flap blood flow was determined by laser Doppler before and after elevation. The mean surviving length (Group I--71.3 +/- 4.6 mm and Group II--73.4 +/- 5.5 mm) and Doppler flow measurements were comparable between the two groups. Animals treated with bFGF showed marked perivascular changes and proliferation of fibroblasts, but no increase in the number or size of capillaries was seen. This lack of angiogenesis suggests pharmacologically mediated delay may require more than just an angiogenic stimulus.
Bacterial contamination of open wounds significantly inhibits wound contraction required in the healing process. Basic fibroblast growth factor (bFGF) has been shown to overcome contraction inhibition in wound-healing models impaired by diabetes or steroids. This study was designed to determine the effect of bFGF on wound contraction inhibition in an area contaminated with bacterial overgrowth. The topically applied bFGF reversed inhibition to wound contraction that normally occurs with bacterial contamination. This reversal does not appear to be due to increased collagen synthesis since bFGF has been shown to decrease collagen synthesis and the treated wounds showed no increase in breaking strength. The use of bFGF significantly decreased the number of days required for wound healing (P less than 0.01) despite active bacterial invasion and may be of value in the treatment of human contaminated wounds.
Wound healing can no longer be considered a generic term: it is the summation of a complex series of processes beginning with coagulation and ending in remodelling. This review, therefore, summarizes the past year's advances in growth factor research according to the roles of the individual growth factors in the specific processes of the wound healing scheme.
A rat model was created in which contaminated wounds were closed in either the presence or absence of autogenous bone graft. The recipients of bone graft were divided into two groups--one receiving autogenous cancellous bone, the other receiving nonviable autogenous autoclaved cortical bone. Quantitative bacterial cultures were collected both at the time of wound closure and 2 weeks after closure. A significantly increased level of soft-tissue contamination was associated with wound closure in the presence of either type of bone graft, indicating an overall adverse effect on soft tissues. A critical level existed such that at initial bacterial contamination levels greater than 10(4) organisms/g tissue, final contamination levels were significantly elevated. With initial contamination levels less than 10(4) organisms/g tissue, however, final bacterial contamination levels were not significantly different. These results may help explain the different rates of infection that have been reported when delayed primary closure of open fractures is done in conjunction with autogenous bone graft.
Class C fireworks are those which can be readily purchased by the public. Between July 1971 and August 1988, 23 patients were admitted to our institution with firework injuries. Fourteen patients (60.9%) sustained injuries related to Class C fireworks. All patients were males with a mean age of 9.0 +/- 3.6 years, with a total body surface area (TBSA) burn of 18 +/- 20% with 10 +/- 15% being full thickness. Thirteen of the 14 patients required hospitalization. Five patients were admitted acutely and eight patients were referred to our institution at least 3 days postinjury. All patients required operative intervention in order to obtain wound closure. Patients admitted acutely showed a decrease in length of hospital stay and patient morbidity when compared to referral patients. Our data suggest that class C firework injuries, although small in terms of TBSA burned, result in full-thickness wounds that warrant aggressive surgical management.
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Agents touted to benefit chronic non-healing wounds will become evermore prevalent. Examples, in addition to those cited, might include epictor (EGF) or platelet derived growth factor (PDGF). Although they may look promising in in vitro and experimental animal studies, they must be tested in humans. The pressure sore is a chronic three dimensional wound which lends itself to study of wound healing agents. It has been used for severe such trials and appears to be an excellent model for the continued study of peptide growth factors.
A new model of soft-tissue infection is used to investigate the effect of the local wound environment on the septic focus. Island pedicle flaps were raised on the buttock of 24 adult ewes and multiply inoculated with Staphylococcus aureus. Flaps with bacterial inoculation, without compromise of venous outflow, showed distal necrosis (mean +/- SEM percent of surface area, 25.8% +/- 8.6%) and developed septic foci with bacterial counts one log less than the amount injected. Flaps with inoculation and venous outflow obstruction underwent subtotal necrosis (mean percent of surface area, 73.3% +/- 11.2%) and had counts two logs higher than the nonobstructed flaps but without discrete septic foci. Flaps without inoculation, with or without venous obstruction, survived completely. Venous outflow obstruction is shown herein to potentiate tissue necrosis by raising bacterial counts in a septic focus and preventing defensive abscess formation by the host.
The etiology of fibrous capsular contractures in patients with silicone prostheses is unclear. However, cellular responses to the silicone polymers of the prostheses have not been examined. The exposure of human dermal fibroblasts to the components of the silicone gel prosthesis results in a significant change in cellular configuration and a progressive reduction in cell proliferation as determined by total matrix protein assays and hemocytometer cell counts. Transmission electron microscopy, however, documents a twofold increase in the rough endoplasmic reticulum when cells are exposed to the silicone gel. These findings suggest significant alterations in the behavior of human fibroblast subpopulations in response to silicone polymers.
This study investigated whether a cellular or a humoral-mediated immunologic response to silicone carpal prostheses could be detected in animals previously sensitized to silicone. Silicone carpal prostheses were emulsified in Freund's complete adjuvant (FCA). This emulsion was injected into guinea pigs weekly for 6 weeks. Controls received only FCA. Four weeks later a carpal prosthesis was implanted. Histology showed the implanted prosthesis encapsulated by fibrous tissue in sensitized animals, with a mononuclear infiltrate within the fibrous periprosthetic capsule consistent with a cellular immune response. Skin testing of the sensitized animals showed a true correlate response to the silicone antigen challenge, whereas no response was observed in the control group. The passive cutaneous anaphylaxis reaction in sensitized animals was positive, emphasizing that the antigen-antibody response was passively transferred. Tissue adjacent to the silicone implant in sensitized animals revealed an IgG deposition around the silicone particles by the fluorescent antibody technique. Control animals showed none of these reactions. These results indicate that microparticulate matter from carpal implants can possibly initiate both a cellular immunologic response and the production of a circulating antibody.
If frostbite is to be treated successfully, direct and indirect effects of injury must be understood. Rapid rewarming helps to preserve tissue by limiting the amount of direct cellular injury. Selective management of blisters helps protect the subdermal plexus, and application of Aloe vera cream (eg, Dermaide Aloe Cream) combats the local vasoconstrictive effects of thromboxane. Oral administration of ibuprofen decreases systemic levels of thromboxane.
Correction of burn alopecia using tissue expansion has recently gained acceptance. Yet, the technical approach to correction of this problem remains one of trial and error. Between January 1985 and December 1988, 102 children underwent placement of tissue expanders for correction of burn alopecia. Two hundred twenty-two expanders were placed during the 178 operative settings. Mean age was 9.1 +/- 4.3 years (range, 3-17 years). Forty-two patients previously underwent partial excisions or rotation of flaps to reduce or camouflage the initial burn alopecia. A review of our experience has dictated that proper classification of burn alopecia can influence operative planning and is essential for establishing guidelines for the correction of this problem. We have developed a classification scheme that addresses this problem. Patients are classified as type I, uniform alopecia; type II, segmental alopecia; type III, patchy alopecia; and type IV, total alopecia. The role of tissue expansion is reviewed in each group.
The scalp cannot be used as skin graft donor site with impunity. A review of 2,620 charts identified 194 pediatric patients whose scalps served as donor sites for split-thickness skin grafts for the treatment of acute burns. The overall incidence of alopecia was 32%. However, the incidence of alopecia in unburned scalps was 13%. The occurrence of alopecia in this group was associated with larger burn area requiring more frequent use of the scalp and shorter intervals between graft harvests (p less than 0.05). Among this group of patients (n = 15), nine had mild spotty alopecia, four had surgically correctable alopecia, and two had global patchy alopecia not amenable to surgical correction. In the patients with concomitant burns to their scalps, the incidence of alopecia was 61%. Whether the burn or the graft harvest caused alopecia could not be established. Meticulous donor site care is mandatory in this latter group when the scalp donor site is indicated.