Fluid and mononuclear cells from healing wounds inhibit thymocyte immune responsiveness

It has been shown previously that fluid obtained from 7-day-old wounds noncytotoxically inhibits normal thymic lymphocyte blastogenesis and that mononuclear cells (MNC) from the same wounds lack mitogenic responsiveness. The present series of experiments studies whether wound MNC are the source of the wound inhibitory factor(s) and the effect of adult thymectomy (ATDX) on their generation. Adult male Sprague-Dawley rats (300-350 g), intact or ATDX (performed at 8-10 weeks of age), underwent dorsal wounding (7 cm) and subcutaneous implantation of sterile Ivalon sponges. Seven days later sponges were harvested, wound fluid was obtained, and the cell pellet was purified to 90% MNC. Normal rat thymocyte blastogenesis (stimulation index) to Con A and PHA evaluated in a microculture system (10 separate experiments) was 169.9 +/- 10.0 and 30.1 +/- 3.7. Addition of 10% wound fluid markedly inhibited thymocyte mitogenesis--6.3 +/- 1.0 and 2.7 +/- 0.6, respectively (P less than 0.001). Heat-inactivated wound fluid (56 degrees C, 30 min) had similar inhibitory activity--3.4 +/- 0.9 and 2.7 +/- 0.6 (P less than 0.001). Normal thymic blastogenesis could also be inhibited by the addition of 5 X 10(4) wound MNC to the microculture system--4.4 +/- 1.1 and 1.9 +/- 0.3 (P less than 0.001). Wound fluid from ATDX rats had much less inhibitory activity (77.1 +/- 22.4 and 7.2 +/- 2.1, P less than 0.01) vs control wound fluid. In addition wound MNC from ADTX animals were also less immune suppressive (30.7 +/- 4.9 and 13.5 +/- 3.7, P less than 0.001) than control MNC. Forty-eight-hour supernatants of wound MNC from intact rats, added in 25% concentration to normal thymocyte cultures, demonstrated inhibition similar to that of the wound fluid from the same animals: 4.4 +/- 0.7 and 3.9 +/- 0.6, while ATDX MNC supernatants had minimal inhibitory activity (110.1 +/- 18.2 and 25.7 +/- 6.5, P less than 0.005). No cytotoxicity could be demonstrated in any of these experiments by trypan blue exclusion. It is concluded that 7-day-old wound fluid noncytotoxically inhibits thymocyte blastogenesis; this effect is also demonstrated by wound MNC and their supernatants, suggesting immune "suppressor" lymphocytes are present in wounds; ATDX, which abrogates suppressor cell induction, leads to marked diminution of wound inhibitory activity. The data suggest that important immune events occur at the wound site; their relation to normal wound healing remains to be elucidated.     

Inhibition of host immunity by fluid and mononuclear cells from healing wounds

Severe trauma impairs host immunity, which in turn renders the host susceptible to infection often terminating in death. This impairment occurs 7 to 14 days after injury, a time when wound healing is at its maximum. We examined the interactions of wound healing to host immunity by studying the in vitro and in vivo immune effects of wound components (i.e., wound fluid [WF] and wound mononuclear cells [WMNC]). Lewis male rats (RT-1(1] weighing 300 to 350 gm underwent 7 cm dorsal skin incisions and subcutaneous placement of polyvinyl alcohol sponges. At 7 and 10 days after wounding, sponges were removed and WF was separated from the cellular elements. The cell suspension was purified to contain 80% to 90% WMNC. Ten percent WF from 7- and 10-day-old wounds inhibits normal thymic lymphocyte blastogenesis to concanavalin A and phytohemagglutinin. Addition of 5 X 10(4) WMNC leads to similar inhibition. WF and WMNC from 10-day-old wounds also inhibit in vitro allogeneic responses tested in one way MLR of Lewis splenocytes with inactivated ACI (RT-1a) spleen cells by 75% to 96% and 85% to 98%, respectively. The inhibitory action of WF is heat resistant (56 degrees C for 30 minutes) and noncytotoxic. In vivo allogeneic responses, tested by grafting ACI skin onto Lewis recipients, were inhibited by intraperitoneal administration of 10-day-old WF (p less than 0.01). We conclude that WF contains factor(s) that inhibit in vitro and in vivo immune responses. WMNC exhibits the same action, suggesting that they may be the source of the WF inhibitory factor(s). These findings may explain host immunosuppression after severe trauma.     

Lymphocyte participation in wound healing. Morphologic assessment using monoclonal antibodies.

To investigate lymphocyte participation in wound healing, the migration of T lymphocyte subsets into healing wounds and subcutaneously implanted polyvinyl alcohol sponges was studied. Frozen sections of 5-, 7-, and 10-day-old incisional wounds and sponges from Lewis rats were stained with mouse anti-rat monoclonal antibodies. Cellular staining to OX1 (all leucocyte), W3/25 (helper/effector T lymphocytes), and OX8 (suppressor/cytotoxic T lymphocytes) was quantitated in two arbitrarily defined areas based on maximal cellular infiltration: the superficial wound, down to and including the papillary dermis, and the deep wound, the reticular dermis. Five-day wounds were significantly more cellular than 10-day wounds in the deep portion (p less than 0.05) and somewhat more cellular in the superficial section (p less than 0.10). Approximately 2:1 W3/25 to OX8 ratios were noted for wound strips on all days. At 5 and 10 days there are twice as many W3/25 and OX8 labeled cells in the deep wound as in the superficial portion. At 7 days there is a peak in surface W3/25 and OX8 lymphocytes, whereas the deep population remains constant. Seven- and 10-day sponge granulomas demonstrate ratios similar to the wound strips (5-day sponge lymphocytic infiltration was insufficient to count). The data demonstrate that lymphocyte subpopulation participation in wound healing is a dynamic and distinctive process.     

Generation of an anti-interleukin 2 factor in healing wounds

Previously we have noted that fluid obtained from ten-day-old healing wounds noncytotoxically inhibits the blastogenesis of lymphocytes in response to mitogens or antigens. Since these lymphocytic responses are interleukin 2 (IL-2)-mediated, we looked for a specific IL-2 inhibitor in wound fluid. We have found that wound fluid blocks the response of thymic lymphocytes and of two cloned T-helper cell lines (D10 and HT2) to exogenous human recombinant IL-2. The wound fluid enhances fibroblast proliferation, thus demonstrating that its proliferative inhibitory activity is specific for lymphocytes. The findings suggest that wound fluid contains a factor that impairs lymphocyte response to IL-2, probably at the receptor or postreceptor level.     

Cyclosporine A impairs wound healing in rats

Cellular immune responses may play an important role in the early inflammatory and cellular phases of wound healing. Cyclosporine A (CSA), a new immunosuppressive agent, impairs cellular immunity and T-cell-dependent humoral immunity. Therefore, the effect of CSA-induced immunosuppression in a rat wound-healing model was studied. Sprague-Dawley rats underwent a standardized skin incision and subcutaneous implantation of sterile polyvinyl alcohol sponges. CSA was dissolved in olive oil and given by gavage to one group of animals at a total dose of 125 mg/kg/10 days. The control group received an equivalent volume of olive oil. Ten-day-old wounds were weaker in CSA-treated animals, both in the fresh state (282 +/- 19 g vs 380 +/- 27 g, P less than 0.01), and after formalin fixation (1111 +/- 74 g vs 1419 +/- 57 g, P less than 0.01). In addition, CSA-treated rats accumulated significantly less hydroxyproline in the wound sponge granuloma, an index of reparative collagen deposition. The impairment in wound healing occurred without differences in body weight gain or organ weights. There was a profound immunosuppression in the animals receiving CSA as determined by thymic lymphocyte blastogenesis in response to Con A and PHA. These findings suggest that immunosuppression in otherwise healthy animals impairs wound healing.     

The wound is a possible source of posttraumatic immunosuppression

Wound fluid from 10-day-old healing wounds in rats inhibits lymphocyte immune responses. Since severe injury is frequently complicated by immunosuppression as manifested by sepsis, we hypothesized that the wound may be a source of factors that impair host immune responses. Therefore, we studied the effect of systemic wound fluid administration on the survival of rats subjected to an acute peritonitis model. Male Sprague-Dawley rats, fitted with internal jugular catheters 48 hours previously, underwent cecal ligation and puncture with a 23-gauge needle. Immediately after the operation, rats were treated intravenously every 12 hours with either wound fluid obtained from 10-day-old healing wounds and adjusted to 10 mg of protein per milliliter or rat serum. In vitro testing of the wound fluid showed it to be highly inhibitory of thymic lymphocyte mitogenesis. Rats treated with wound fluid had significantly higher mortality after peritonitis than did control rats. The data show that the wound contains factors that can impair host immune responses to sepsis. This suggests that the wound may be the source of posttraumatic host immunosuppression.     

The effect of surgical excision and grafting procedures on postburn lymphocyte suppression

Previous reports have stressed the immunosuppressive effects of major surgical procedures. In this study, 30 adult patients with a mean burn size of 42.8% TBSA and a mean age of 31.9 years underwent 78 surgical excision and grafting (E/G) procedures. The mean surface area excised was 2,373 cm2, with a mean blood transfusion requirement per E/G of 3,355 cc or 1.4 cc/cm2. The suppressive effect of burn serum was assayed in mixed lymphocyte cultures. Before E/G, burn serum caused a mean 42.2 +/- 3.3% suppression of normal lymphocyte blastogenesis; serum suppressive activity following E/G was reduced to 29.1 +/- 2.9% (p less than 0.005). The mean duration of improvement in lymphocyte function was 5.0 days. E/G procedures which achieved complete burn wound closure were more effective in restoring lymphocyte immunocompetence. E/G has a significant beneficial effect on restoring lymphocyte responsiveness in burn patients. Preliminary evidence suggests that this effect is related to blood transfusions.     

Intravenous hyperalimentation with high arginine levels improves wound healing and immune function

The purpose of this study was to evaluate the effect of increased arginine levels in intravenous hyperalimentation (IVH) therapy on wound healing and thymic immune function. Groups of SD rats, 275-325 g, underwent placement of internal jugular catheter, 7-cm dorsal skin wounding, insertion of polyvinyl alcohol sponges subcutaneously, and closure of wounds with stainless-steel sutures. Twenty-four hours later, rats were started on IVH at a rate of 0.8-1 ml/100 g body wt/hr. All IVH solutions contained 20% dextrose, adequate amounts of minerals and vitamins, and two different amino acid mixtures: (A) Fre III (4.05 g ARG/liter) (n = 13); (B) experimental (7.50 g ARG/liter) (n = 11). Solutions were isonitrogenous, and contained similar amounts of essential amino acids. After 7 days of IVH, weight gain did not differ between the two groups; however, cumulative N balance was superior in group A. Wound healing was improved in group B as assessed by fresh wound strip breaking strength, fixed breaking strength, and the amount of reparative collagen deposition as assessed by the hydroxyproline content of the implanted sponges. Group B animals also had improved thymic function as assessed by thymic weight, the total number of thymic lymphocytes/gland and mitogenic reactivity of thymic lymphocytes to PHA and Con A. The experiments indicate that high arginine levels in IVH solutions improve wound healing and thymic immune function following injury.     

Effect of a diode laser on wound healing by using diabetic and nondiabetic mice

The purpose of this study was to evaluate a 980-nm gallium-aluminum-arsenide diode laser for wound healing. Using genetically diabetic and nondiabetic mice, two 6-mm wounds were created on the back of each mouse by using a punch biopsy. The mice were assigned to 1 of 4 subgroups for laser treatment at different fluence and frequency of treatment: 5 W (18 J/cm2) every 2 days, 5 W (18 J/cm2) every 4 days, 10 W (36 J/cm2) every 2 days, and 10 W (36 J/cm2) every 4 days. In addition, control mice were used and the wounds were allowed to heal naturally. Wound healing was evaluated on days 5, 12, and 19 by percentage of wounds healed and percent wound closure. A maximum of 5 mice per subgroup were killed at days 7, 14, and 21, and histology was conducted on the wound sites. For diabetic mice receiving 5 W every 2 days, the percentage of wounds healed after 19 days was 100% versus 40% in the control group. Only 20% of wounds in the 10-W diabetic subgroups achieved healing during the same period. For the subgroups whose wounds did not completely heal, all but the 10 W every 2 days subgroup had average closure of >90%. The 100% closure for the 5 W every 2 days subgroup was significantly greater than the other subgroups. For nondiabetic mice, 100% of the wounds in the 5 W every 4 days and control subgroups were completely healed, whereas 90% of the wounds from the 5 W every 2 days and the 10 W every 4 days subgroups were completely healed. In the latter 2 subgroups, wound closure was 99.4% and 98.8%, respectively. These differences were not significant. The histologic results confirmed these findings. In conclusion, treatment at 18 J/cm2 shows a beneficial effect on wound healing in diabetic mice and does not have a detrimental effect in nondiabetic mice.     

Plasma ultrafiltration as cancer therapy

Studies of cancer-related immunosuppression reveal the presence of low-molecular-weight (less than 10 kilodaltons) serum factors capable of in vitro lymphocyte suppression. Removal of suppressor factors by ultrafiltration (UF) prolongs survival in tumor-bearing rabbits. This study determined the prevalence of low-molecular-weight suppressor factors in patients with cancer and normal volunteers and evaluated safety and feasibility of UF in patients with cancer. Intact serum and serum ultrafiltrate from 32 patients with cancer and 24 normal volunteers was examined with mitogen-induced lymphocyte blastogenesis. Eleven (34%) of serum samples from patients with cancer suppressed blastogenesis, while ultrafiltrate was suppressive in 25 (78%). None of the ultrafiltrate from normal volunteers was suppressive. Six patients with cancer underwent UF in a phase I trial, completing 82 sessions. There were no therapy-related complications, and high-performance liquid chromatography showed significant (greater than 90%) posttreatment reduction in serum suppressor factors.     

应用表皮生长因子治疗深Ⅱ度烧伤创面的远期临床疗效观察

目的　观察重组人表皮生长因子 (rhEGF)用于深Ⅱ度烧伤创面治疗的远期疗效及安全性。　方法　对 37例烧伤患者进行随机、双盲、同体对照实验 ,每例患者选择一块深Ⅱ度烧伤创面 ,并将其分为面积相近的两部分 ,于伤后第 1天开始分别用单纯等渗盐水 (对照组 )和含rhEGF的等渗盐水 (治疗组 )进行换药治疗。创面愈合后 1、4年时 ,对各患者进行院外随访 ,采用改良温哥华瘢痕测量法 ,评价上述受试创面愈合后的瘢痕指数 (SI)。　结果　 1年后随访时 ,治疗组SI为 7.19± 1.6 7,明显小于对照组 8.92± 1.78(P <0 .0 1) ;4年后随访时 ,治疗组SI为 6 .12± 1.5 4 ,明显小于对照组 8.0 9± 1.81(P <0 .0 1)。所有受试创面均无肿瘤形成、癌变等并发症发生。　结论　外用rhEGF治疗深Ⅱ度烧伤创面 ,能明显减少后期瘢痕的形成 ,远期疗效和安全性较好。     

硝酸银软膏对Ⅱ度烧伤创面治疗作用的多中心临床研究

目的观察硝酸银(AgNO3)软膏对浅Ⅱ、深Ⅱ度烧伤创面的治疗效果,并评价其药物不良反应。方法选择80例浅Ⅱ度和40例深Ⅱ度烧伤患者,进行多中心、随机、阳性药物平行对照和同体试验研究(共4个中心,每个中心30例)。将患者创面按用药不同分为AgNO3组和磺胺嘧啶银(SD-Ag)组,观察各组创面完全愈合时间、指定时相点下创面愈合率、创面细菌培养情况、药物疗效和安全性、药物对创面的刺激性等。结果浅Ⅱ度创面:AgNO3组完全愈合时间为(9．5±2．7)d, SD-Ag组为(10．8±3．4)d,用药后7 d创面愈合率分别为(77．9±20．5)％及(67．3±22．6)％;深Ⅱ度创面:AgNO3组完全愈合时间为(21．5±4．8)d,SD-Ag组为(23．3±6,4)d,用药后20 d创面愈合率分别为(86．6±15．9)％及(78．5±17．7)％。同等深度烧伤创面上述各项数据两组间比较,差异均有统计学意义(P<0．01)。同等深度烧伤创面AgNO3组与SD-Ag组比较,具有同样明显的杀菌作用,但前者对创面的刺激性更小。结论AgNO3软膏是一种可用于浅Ⅱ、深Ⅱ度烧伤创面的有效、安全的外用药。     

Simple biochemical markers to assess chronic wounds

We investigated the potential for the biochemical analysis of chronic wound fluid to predict healing using simple and widely available analytes in an out-patient clinic setting. Wound fluid was collected from 12 patients attending a leg ulcer clinic and analyzed for a variety of analytes, including lactate, total protein, and albumin. Twelve weeks after collection the wound was assessed for healing (defined as complete healing or greater than 50% reduction in wound size). The median total protein (44.3 +/- 8.8 g/l) and albumin (25.0 +/- 2.3 g/l) concentrations in exudate collected from four healing wounds were significantly higher (p < 0.05) than in exudate from eight nonhealing wounds (median total protein 29.7 +/- 7.6 g/l, median albumin 17.0 +/- 4.3 g/l). No significant difference was observed for lactate. A second specimen of wound fluid was collected from four of the patients (three nonhealing and one healing). The protein analysis confirmed the pattern observed for the first collection: nonhealing wounds had total protein and albumin which remained low compared to healing wounds. No wound with an exudate albumin of less than 20 g/l healed. Both total protein and albumin are stable analytes which can be easily measured in any laboratory and may offer a simple biomarker of healing in chronic wounds.     

Healing of partial thickness porcine skin wounds in a liquid environment.

This study employs a liquid-tight vinyl chamber for the topical fluid-phase treatment of experimental wounds in pigs. Continuous treatment with normal saline significantly reduced the early progression of tissue destruction in partial thickness burns. Uncovered burns formed a deep layer of necrosis (0.49 +/- 0.004 mm, mean +/- SD) although burn wounds covered with empty chambers demonstrated less necrosis (0.14 +/- 0.01 mm), fluid-treated wounds formed no eschar, and little tissue necrosis could be detected (less than 0.005 mm). Topical treatment with hypertonic dextran increased water flux across burn wounds by 0.24 ml/cm2/24 hr (mean, n = 95) over saline-treated wounds during the first 5 days after wounding. When partial thickness burn and excisional wounds were immersed in isotonic saline until healed, the daily efflux of water, protein, electrolytes, and glucose across the wound surface declined during healing to baseline values found in controls (saline-covered unwounded skin). The declining protein permeability was used as a reproducible, noninvasive, endogenous marker for the return of epithelial barrier function. Saline-treated excisional wounds healed within 8.6 +/- 0.6 days (mean +/- SD, n = 27) and burn wounds within 12.1 +/- 1.4 days (mean +/- SD, n = 15). Healing of fluid-treated wounds occurred without tissue maceration and showed less inflammation and less scar formation than healing of air exposed wounds (no attempt was made to compare rates of healing between air- and fluid-exposed wounds). We consider the fluid-filled chamber a potentially very useful diagnostic, monitoring, and delivery system for wound-healing research and for human wound therapy.     

Healing of full-thickness wounds treated with lyophilized cultured keratinocyte cell lysate in genetically diabetic mice

The effect of a lyophilized cell lysate prepared from cultured human keratinocytes on the healing of full-thickness wounds was evaluated in an impaired healing model. Full-thickness wounds (8 mm in diameter) were made on the dorsal areas of female genetically diabetic mice C57 BL/KsJ (db/db) and their normal (db/+) littermates. Wounds were covered with an occlusive polyurethane film dressing and were treated for 5 days either with the lyophilized cell lysate from cultured human keratinocytes prepared in phosphate-buffered saline solution or with phosphate-buffered saline solution. In normal (db/+) mice, all wounds were closed 16 days after wounding, and more than 90% of the wound closure was due to wound contraction. Wound contraction accounted for a similar extent of wound closure in both lyophilized cell lysate-treated and phosphate-buffered saline solution-treated wounds. In contrast, in the diabetic (db/db) mice, after histologic examination of the wounds 32 days after wounding, four of ten lyophilized cell lysate-treated wounds and four of seven phosphate-buffered saline-treated wounds were found to be closed. Moreover, applications of lyophilized cell lysate from cultured human keratinocytes to full-thickness wounds in diabetic db/db mice significantly decreased the contribution of contraction to wound closure. Day 32 after wounding, contraction contribution to wound closure amounted to 57.7%+/- 4.7% and 80.4%+/- 3.2% (mean +/- standard error of the mean, p < 0.005) of the initial wound areas, respectively, for lyophilized cell lysate-treated and phosphate-buffered saline solution-treated wounds. At this time of wound healing, the thickness of the dermis was increased 1.7-fold by the keratinocyte cell lysate treatment, but neither epithelial migration from the wound edges nor the thickness of the regenerated epithelium were significantly affected. In conclusion, in diabetic (db/db) mice the application of lyophilized cell lysate from cultured human keratinocytes influenced the healing of the dermis and wound contraction, but had no effect on reepithelialization.     

Molecular and mechanistic validation of delayed healing rat wounds as a model for human chronic wounds

The purpose of this study was to provide molecular and mechanistic evaluation of an ischemic wound model in rats to determine if it is a valid model for human chronic wounds. Compared to acute wounds, human chronic wounds contain markedly elevated levels of proinflammatory cytokines and matrix metalloproteinases, while matrix metalloproteinase inhibitors and growth factor activity are diminished. Accordingly, tissue from ischemic and normal rat wounds were analyzed for cytokine, proteases and growth factor levels. Dorsal full thickness punch wounds were created in rats using a reproducible template. The ischemic wound group (n = 10) had six uniformly placed wounds within a bipedicled dorsal flap. The control group (n = 10) had the same wounds created without elevation of a flap. On postwound days 3, 6 and 13 wounds were excised and analyzed. Protein levels for tumor necrosis factor-alpha were determined with a rat-specific enzyme-linked immunosorbent assay, while mRNA was determined by RNase protection assay. Matrix metalloproteinases and serine protease detection was done using gelatin and casein zymography, respectively. Significant delay in healing was achieved in the ischemic group: 50% healing for control wounds was at 7 days and 11 days for ischemic wounds (p < 0.001). No significant differences between wound groups were found for interleukin-1beta, and mRNA for tumor necrosis factor-alpha and interleukin-1beta. However, at day 13 ischemic wounds contained significantly more tumor necrosis factor-alpha than controls and normal skin (586 +/- 106 pg/biopsy vs. 79 +/- 7 pg/biopsy vs. 52 +/- 2 pg/biopsy; p < 0. 001). Zymography showed substantially greater quantities of matrix metalloproteinase-2, matrix metalloproteinase-9, and serine proteases in ischemic wounds. This model of delayed healing in rats shares many of the key biochemical, molecular and mechanistic characteristics found in human chronic wounds, namely elevated tumor necrosis factor-alpha and protease levels. As such, this model will likely prove to be useful in chronic wound research, particularly in developing novel therapeutics.     

The effect of in vivo T helper and T suppressor lymphocyte depletion on wound healing.

The role of T lymphocytes in wound healing is still not well-defined. Because it had been previously shown that in vivo depletion of T cells leads to impaired wound healing, the effect of depleting T cell subsets on subsequent fibroplasia was studied. T helper/effector cells were depleted by the use of the monoclonal antibody GK1.5, reactive against the L3T4 antigen (CD4). T suppressor/cytotoxic lymphocytes were depleted by using the 2.43 monoclonal antibody reactive against the Lyt 2 antigen (CD8). In the first experiment, Balb/c mice were treated with the antibodies starting at 24 hours before wounding was performed, and weekly thereafter. Depletion of the T helper/effector cells had no effect on wound-breaking strength or hydroxyproline deposition in sponge granulomas, whereas depletion of T suppressor/cytotoxic cells significantly enhanced both of these healing parameters. In a second experiment, T cell subset depletion was started on Days 0, 3, 7, 10, and 14 postwounding, and treatments were continued weekly thereafter. Once again, depletion of T helper/effector cells had no effect on wound healing, whereas depletion of T suppressor/cytotoxic cells markedly increased both wound-breaking strength and collagen synthesis. In conclusion, the data show that T suppressor/cytotoxic cells have a counter-regulatory role in wound healing, whereas the T cell subset responsible for up-regulating wound healing remains to be identified.     

Postburn immunosuppression in an animal model. III. Maintenance of normal splenic helper and suppressor lymphocyte subpopulations by immunomodulating drugs

Delineation of lymphocyte subpopulations by labeling cells with specific monoclonal antibody now appears to be a reliable means of measuring cellular immunity in various disease states. We determined splenic helper/inducer and suppressor/cytotoxic lymphocyte populations in mice given a 20% to 25% body surface area steam burn injury. The lymphocyte helper: suppressor ratio fell from 3.13 +/- 0.06 in control mice to 1.77 +/- 0.04 in burned animals (p less than 0.0005) 14 days after burn. Immediate postburn eschar removal resulted in improvement in the ratio 14 days later (2.66 +/- 0.14) although not in restoration to normal levels. Postburn treatment of burned mice with intraperitoneal cimetidine, ibuprofen, indomethacin, cyclophosphamide, and topically applied cerium nitrate resulted in substantial restoration of the lymphocyte ratio toward normal values; in animals treated with cimetidine and ibuprofen the resultant lymphocyte ratio was not statistically different from that in control (unburned) mice. These drugs probably inhibit suppressor cell populations or suppress the immunosuppressive effect of toxic materials in the burn wound. Specific pharmacologic therapy improves immune function in burned mice and may result in increased resistance to infection.     

重组人表皮细胞生长因子治疗烧伤创面研究

目的　探讨外用重组人表皮细胞生长因子 (rh EGF)治疗 度烧伤创面最佳用药方式。　方法　 2 0 0 0年6月～ 2 0 0 1年 12月对 6 0例浅 度和深 度烧伤患者共 180个创面进行随机双盲实验 ,每例患者设 A、B、C 3个治疗区。A区为 SD- Ag对照治疗区 ,1% SD- Ag霜涂创面 ,每日 1次 ;B区为 rh EGF治疗区 ,rh EGF4 0 U/ cm2 直接喷在创面上 ,每日 1次 ;C区为 rh EGF和速愈平混合治疗区 ,rh EGF4 0 U/ cm2和速愈平 5 g混合涂在创面上 ,每日 1次 ;每日观察记录 3个治疗区变化 ,直至创面愈合停止用药 ;愈合 1周后检查创面外观、皮肤弹性 ,并行统计学处理。　结果　浅 度创面 A区愈合时间为 (13.2 0± 2 .4 0 )天 ,B区为 (10 .2 0± 2 .2 0 )天 ,C区为 (8.72± 2 .31)天 ,组间比较有统计学意义 (P<0 .0 1) ;深 度创面 A区愈合时间为 (2 0 .10± 3.4 0 )天 ,B区为 (17.2 0± 3.12 )天 ,C区为 (15 .10± 3.81)天 ,组间比较有统计学意义 (P<0 .0 1和 P<0 .0 5 )。治疗期中 A区渗出液、创缘炎性反应均较 B、C区显著。深 度创面愈合后 B、C区无充血 ,有弹性和韧性 ;A区充血 ,无弹性和韧性。　结论　rh EGF对烧伤创面有明显促愈合作用 ,可改善愈合质量。rh EGF和速愈平联合使用对缩短创面愈合时间及提高愈合质量作用     

Differential regulation of activation-associated receptor expression on CD4- and CD8-positive T lymphocytes by allosensitized suppressor T cells

We have demonstrated by two-color flow cytometry that allosensitized human suppressor T cells thwart progression of alloactivated T cells into the G1B stage of the cell cycle, and consequently prevent the expression of transferrin receptors on the majority of alloreactive MLR responder cells (P less than 0.005). Suppressor cells inhibit transferrin as well as interleukin-2 receptor expression on both CD4- and CD8-positive responder cells. The addition of 20 U/ml of recombinant interleukin-2 at the initiation of suppressor coculture bioassays completely neutralizes the suppressive effect of suppressor T cells exerted on CD8-positive responder T cells, but does not restore expression of transferrin and interleukin-2 receptors on CD4-positive T cells. Hence, CD4-positive T cells are the direct target of the suppressor cells, while inhibition of transferrin and interleukin-2 receptor expression on CD8-positive T cells results from reduced levels of interleukin-2 in suppressor cell-regulated cultures. In suppressor cell modified mixed lymphocyte reactions supplemented with exogenous interleukin-2 CD8+/CD28- responder cells proliferate preferentially. It is apparent that mixed lymphocyte reactions supplemented with allosensitized suppressor cells cultured in an interleukin-2-rich environment create a milieu that permits the preferential expansion of T cells with suppressor effector phenotype. This in vitro system provides a convenient model in which to cultivate activated CD8+/CD28- T cells.