ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Monocyte/T-cell interactions play a critical role in the systemic response to infection. Distinct patterns of cytokines are produced by two different types of T-helper cells (Th). Th1cells secrete interleukin-2 (IL-2) and interferon-γ (IFN-γ ), whereas Th2 cells produce IL-4, IL-5, IL-6, IL-10, and IL-13. In volunteers systemic endotoxin administration initiates many features of gram-negative sepsis including cytokine release, but the patterns (i.e., Th1/Th2 patterns) have not yet been studied. In this institutional review board-approved study we investigated the effect of an intravenous bolus of endotoxin fromEscherichia coli(4 ng/kg body weight) on the Th1/Th2 response in four female and four male volunteers (mean age 27.1 ± 0.8 years). Plasma cytokine levels for IL-2, IL-4, IL-10, IL-12, and IFN-γ and heart rate, mean arterial pressure, temperature, white blood cell, and differential blood count were determined before and hourly for 5 hours after endotoxin administration. All volunteers had tachycardia, decreased mean arterial pressure, fever, and leukocytosis. IL-10 was significantly (p< 0.05) elevated (9.4 ± 3.9 pg/ml vs 60.9 ± 19.3 pg/ml) 3 hours after endotoxin was administered, whereas IL-2 levels were decreased (69 ± 26 U/ml vs 30.6 ± 14.9 U/ml). IL-4 and IFN-7 were not detectable in plasma. No changes were seen in the plasma levels of IL-12. Systemic responses did not correlate with changes in cytokine levels. Cytokine patterns found in this study suggest that after low-dose endotoxin administration the T-cell immune response is shifted towards the Th2 cell type response. This early shift towards a Th2 cell response may contribute to the depressed cell-mediated immune response associated with sepsis.

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Fibroblast cytomorphology is tightly coupled to phenotypic expression, particularly as it relates to extracellular matrix protein synthesis and degradation. We have observed that calcium antagonists, such as verapamil and trifluoperazine, depolymerize actin filaments and alter fibroblast cell shape from bipolar to spherical. Characteristically, die depolymerization of actin filaments, which mediates the cell shape change, turns on procollagenase gene expression in normal human skin fibroblasts. We have.found the same effects of calcium antagonists on cell shape, cytoskeletal components, and induction of procollagenase in the keloid fibroblasts of three cell lines, CB792, CW792, and WT949. Rounded cells were seen in 74.8% of verapamil-treated and 86.7% of trifluoperazine-treated cells, whereas only 1.1% of the control cells were spherical. The percentage of cells that synthesized collagcnase in the control, verapamil-treated, and trifluoperazine-treated groups was 3.8%, 42.8%, and 53.4%, respectively. Approximately 60% of rounded cells exhibited increased collagenase synthesis when the cells were treated with a calcium antagonist. These results indicate considerable heterogeneity in the phenotypic response to morphologic change. The amount of procollagenase synthesized in a cell was estimated by the fluorescence intensity of the fluorescein-labeled antibody. The normalized fluorescence intensity of procollagenase in the control cells was about 2 to 2.6 times that of background. In contrast, the normalized fluorescence intensity of procollagenase in the calcium antagonist-treated cells was about 2.4 to 12 times diat of background. This high intensity level indicates an increase in procollagenase production in the calcium antagonist-treated cells. Calcium green dye used to study cytosolic calcium revealed that after cells were treated with verapamil, the cytosolic calcium ion concentration first increased and then decreased. The change of cytosolic calcium ion concentration may be related to the depolymerization of actin filaments and the alteration of cell shape.

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The evaluation of wound outcome after burn injury is a challenging problem in the performance of clinical trials evaluating potential impact on wound healing and scar formation. The purpose of this study was to determine whether an ocular tonometer could be adapted to provide an objective measurement of scar compliance. A pneumatonometer was used to perform measurements of cutaneous compliance at 8 anatomic areas (14 separate sites) on each of 17 normal volunteers and on 59 burn scars. Comparison of different anatomic sites showed there to be significant differences in the cutaneous compliance of different areas. The aggregate compliance of the burn scars in all sites was less than that of the control sites. These results indicate that the pneumatonometer can discern differences in the compliance of normal skin and differences between normal skin and scar and suggest that it may be a useful tool in the objective assessment of scar formation.

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

To determine the role of immobilization in the pathogenesis of burn-associated bone disease, we selected die sheep as a model to study the effects of burn injury compared with a sham-burned control group. Seven of the sheep were subjected to controlled 40% flame burn, and seven underwent anesthesia with arterial and venous cannulation but without burn. After labeling newly formed bone with tetracycline and calcein, die sheep were killed 2 weeks after burn or sham burn, and die iliac crest and lumbar vertebrae were analyzed for histomorphometry. Analysis failed to demonstrate a significant reduction of bone formation rate in the burned sheep. Osteoid area and surface and osteoblast surface, which correlated significant reduction of bone formation rate (r=0.49,p< 0.025), were reduced in the burned sheep. Results suggest that immobilization may play a primary role in die pathogenesis of burn-associated bone disease, but die presence of differences in other histomorphometric features indicates the bone disease is multifactorial.

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

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 α and β (TGF-α, TGF-β), interleukin-6, interleukin-8, and melanoma growth stimulatory activity from CAS, CES, and HD/HK grafts. Highest levels of TGF-α were found for HD/HK (728 ± 115 pg/10 cm2of membrane) followed by CES (491 ± 137 pg/10 cm2; NS). No TGF-a 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-β was barely detectable for CES and HD/HK. Cryopreserved allograft showed high levels of TGF-β (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.

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Electromagnetic fields are now being used in many diseases such as osseous, ligamental, cartilaginous, or nervous reparation, diabetes, and myocardial or cerebral ischemia. Although many publications show the usefulness of magneto-therapy, discrepancies exist about the utility of electromagnetic fields in skin wound healing. The objective of this work was to study the effect of pulsed electromagnetic fields on wound healing in rats. Twenty-two male Wistar rats were used; a circular lesion was made in the back of each animal. They were divided into three groups: group C (control) with sham treatment («=8), group NF, treated with topical nitrofurazone solution (n=7), and group PEMF, treated with pulsed electromagnetic fields of 20 mT (n=7). The treatments were 35 minutes twice a day. The absolute and relative values of the area and perimeter of the wounds showed significantly lower values in the PEMF group at days 7, 14, and 21 compared with those in group C (p< 0.01, analysis of variance), whereas the PEMF group showed significantly lower values at day 21 only compared with the NF group (p< 0.01, analysis of variance). The results suggest a significant beneficial stimulation in the wound healing process in rats treated with PEMF, which could lead to the development of a practical tool for research and clinical use.

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The objective of this study was to characterize the association between drug and alcohol. intoxication at the time of injury and subsequent complications and mortality in hospitalized patients with burns. A computerized burn database was used to analyze data on 3047 consecutive adult (21 to 75 years) hospitalized patients with burns admitted between January 1982 and August 1994. Data for intoxicated (by history, blood alcohol content, or positive drug screen) and nonintoxicated patients were compared. The same analysis was also conducted on 429 consecutive adolescent patients with burns (ages 14 to 20 years) admitted during the same time period. The incidence of intoxication at the time of burn was 6.9%. No significant differences in age, sex, race, or burn size were noted. Intoxicated patients had a higher incidence of associated injuries. Skin graft loss, cellulitis, donor site conversion, hypotension, and pneumonia were more common in the intoxicated group. They also had more intensive care unit admissions, ventilator days, operations, transfusions, and total hospital days. Intoxicated patients had a lower mortality (7.1%) than patients in the control group (10.9%). Intoxication at the time of burn injury is an important predictor of complications in adult patients with burns.

ISSN:0273-8481    

出版商:OVID    

年代:1996

数据来源: OVID