Experimental study of new polymer dressings in the treatment of burn wounds

Data on the experimental study of a new polymer coverage for treatment of burn wounds are presented in the article. Application of this coverage, which has a tanning and absorbing affect promotes formation of a dry eschar over a burn wound within the first two days after the accident. This allows to perform early chemical necrectomy on the 6-7th day after the accident. Microbiological investigations show that wound dissemination after application of the coverage remains low and is 3.5 +/- 0.1 per. 1.0 g of the tissue.     

Studies towards the potential of poliovirus as a vector for the expression of HPV 16 virus-like-particles

In this study we tested the hypothesis that after administration of a single intraperitoneal dose of concanavalin A (Con-A) to mice, the proportion of neutrophils and macrophages in the peritoneal exudate and their phagocytic and candidacidal activities should change with time. The number of neutrophils in the peritoneal exudate was greatly increased 6 h after administration of Con-A, and those cells were able to kill both intracellular and extracellular yeast and germ tube forms of Candida albicans. Addition of catalase to the culture medium reduced the killing of C. albicans, suggesting that the candidacidal activity depended on the myeloperoxidase system. The survival of mice pretreated with Con-A and submitted to an inoculum of C. albicans 6 h afterwards was twice higher than that of controls, which suggests that neutrophils were able to clear the experimental infection. One day after the treatment, the population of neutrophils in the exudate was about 45%, but after 2 days it was reduced to only 5% and the candidacidal activity was also reduced. After 4 days the exudate contained over 95% of macrophages, the candidacidal activity reached a maximum, and the phagocytosis mediated by both complement receptors and mannose receptors was increased. Uptake of FITC-mannose-BSA by macrophages was maximal on about the 4th day and was inhibited by mannan, suggesting that treatment with Con-A increased the activity of mannose receptors. These results support the hypothesis that activation of cellular immunity by Con-A occurred in two phases, one dominated by neutrophils, and the other by macrophages expressing increased activity of mannose receptors.     

烧烫伤创面感染的小鼠模型构建

目的探讨一种简单、稳定的烧烫伤创面感染的小鼠模型构建方法,以便进行相关烧烫伤创面修复研究。方法取30只BALB/c小鼠,采用自制木质烫伤板,沸水浴法烫取直径8 mm的圆形创面,烫伤时间分别为5 s、10 s、15 s。伤后48 h,取创面组织进行HE染色观察,筛选最佳创面烫伤时间。另取72只小鼠制成深Ⅱ度烫伤创面,采用擦刮法分别接种20μL菌浓度为1×106、l×107、1×108CFU/mL金黄色葡萄球菌标准菌株ATCC 25923的菌液。接种细菌后72 h,取创面组织HE染色观察创面炎症反应情况,并测定3、7、14 d的皮肤菌负荷,筛选最佳的细菌接种浓度。最后,按最佳条件建模后,观察创面的完全愈合时间以及创面愈中、愈后的组织学变化,以确定此创面感染模型是否建立成功。结果组织学结果表明,10 s为深Ⅱ度创面的理想致伤时间,最佳接种菌浓度为l×108CFU/mL,此时期,14 d内菌负荷均高于l×105CFU/g。该模型的创面愈合时间(21±0.95 d)较正常创面愈合时间(15.92±0.34 d)明显延长(P<0.01),炎性反应明显,愈后不佳。结论烧烫伤创面感染的小鼠模型构建成功,可作为感染创面防治研究的实验动物模型。     

Effect of Alternanthera brasiliana (L) Kuntze on healing of dermal burn wound

Wound healing activity of methanol extract of Alternanthera brasiliana [5% (w/w) ointment] was evaluated in experimental burn wound model in rats. Healing potential was assessed by the rate of wound contraction, estimation of anti-oxidants like catalase, superoxide dismutase, reduced glutathione, protein, vitamin C and hydroxyproline, along with histopathological examination on 8th day post wounding. The statistical data indicated that there was significant increase in wound contraction along with augmented level of antioxidants in granulation tissues in A. brasiliana treated group. Histopathological assessment of the granulation tissue revealed formation of epidermis with keratin layer and deposition of collagen fibers after treatment with the plant extract.     

Prophylactic treatment with fms-like tyrosine kinase-3 ligand after burn injury enhances global immune responses to infection

Severely burned patients are susceptible to infections with opportunistic organisms due to altered immune responses and frequent wound contamination. Immunomodulation to enhance systemic and local responses to wound infections may be protective after burn injury. We previously demonstrated that pretreatments with fms-like tyrosine kinase-3 (Flt3) ligand (Flt3L), a dendritic cell growth factor, increase the resistance of mice to a subsequent burn injury and wound infection by a dendritic cell-dependent mechanism. This study was designed to test the hypothesis that Flt3L administration after burn injury decreases susceptibility to wound infections by enhancing global immune cell activation. Mice were treated with Flt3L after burn injury and examined for survival, wound and systemic bacterial clearance, and immune cell activation after wound inoculation with Pseudomonas aeruginosa. To gain insight into the local effects of Flt3L at the burn wound, localization of Langerhans cells was examined. Mice treated with Flt3L had significantly greater numbers of CD25-expressing T cells and CD69-expressing T and B cells, neutrophils, and macrophages after, but not before, infection. Overall leukocyte apoptosis in response to infection was decreased with Flt3L treatment. Survival and local and systemic bacterial clearance were enhanced by Flt3L. Langerhans cells appeared in the dermis of skin bordering the burn wound, and further increased in response to wound infection. Flt3L augmented the appearance of Langerhans cells in response to both injury and infection. These data suggest that dendritic cell enhancement by Flt3L treatments after burn injury protects against opportunistic infections through promotion of local and systemic immune responses to infection.     

新型抗菌凝胶敷料治疗深II度烧伤创面的疗效评价

目的:评价新型抗菌凝胶敷料普朗特联合磺胺嘧啶银霜治疗深Ⅱ度烧伤创面的临床疗效和安全性。方法:采用前瞻性随机对照的方法将2015年3月至2016年5月来我科初次就诊的深Ⅱ度烧伤患者74例分为两组:试验组38例采用新型抗菌凝胶敷料普朗特联合磺胺嘧啶银霜治疗,对照组36例采用磺胺嘧啶银霜治疗。两组均采用规定的标准化创面处理方式,其余治疗均按常规进行。分别统计和比较两组的创面愈合时间、愈合率、创面细菌培养阳性率、换药时的疼痛程度,同时定期监测患者在用药期间有无实验室指标异常及不良反应的发生。结果:试验组创面愈合时间(21.11 3.13)d,明显短于对照组(25.28 4.50)d(P0.01)。治疗后7 d、14 d、21 d,试验组创面愈合率分别为(26.63 5.21)%、(63.32 5.32)%、(92.66 4.19)%,均显著高于对照组(P0.05)。治疗后7 d、14 d,试验组分别有5例(13.16%)和1例(2.63%)创面细菌培养阳性,明显低于对照组的12例(33.33%)和8例(22.22%)(P0.05)。治疗后7 d、14 d、21 d,试验组换药时的疼痛评分均明显低于对照组(P0.05)。两组治疗期间实验室检查指标均无异常波动,均未见明显不良反应。结论:新型抗菌凝胶敷料普朗特联合磺胺嘧啶银霜治疗深Ⅱ度烧伤创面能缩短愈合时间,提高愈合率,减少创面感染发生,减轻患者痛苦。     

Effects of burn wound excision on bacterial colonization and invasion

Rates of survival after thermal injury have improved in the past two decades, and rates of wound infections and sepsis have decreased during the same period. Early excision has been advocated as one of the major factors, but its safety and efficacy and the exact timing of burn excision are still under debate. It was hypothesized that acute burn wound excision (in the first 24 hours after burning) would be superior to conservative treatment and delayed excision in preventing bacterial colonization and invasion. Twenty consecutive patients with thermal injuries were studied. Twelve patients underwent acute burn wound excision, and eight patients underwent conservative treatment and delayed excision. The second group of patients received topical treatments in another facility and underwent delayed excision after transfer to our service, on postburn day 6. Quantitative bacteriological assessments of the excised wound and biopsy samples of the wound bed, obtained before autografting and/or homografting, were performed. The effects of time on bacterial counts, differences between superficial and deep biopsy samples, and the effects of early versus late debridement were studied. Patients admitted early exhibited bacterial counts of less than 10 bacteria per gram of tissue. Patients in this group did not experience infection or graft loss. Patients admitted late exhibited counts of more than 10 bacteria (p = 0.001, compared with early admission). Three patients in the late excision group experienced infection and graft loss (p < 0.05, compared with the early excision group). Burn wound excision significantly decreased bacterial colonization for all patients (p < 0.001). Greater bacterial colonization and higher rates of infection were correlated with topical treatment and late excision (p < 0.001). It is concluded that burn wound excision significantly reduces bacterial colonization. Patients who undergo topical treatment and delayed burn wound excision exhibit greater bacterial colonization and increased rates of infection. Acute burn wound excision should be considered for all full-thickness burns.     

The effects of topical treatment with curcumin on burn wound healing in rats

The present study was designed to determine the role of topical treatment with curcumin (Cur) on burn wound healing in rats. The Wistar-albino rats were randomly allotted into one of three experimental groups: 4th, 8th and 12th day (post burn) and all groups include subgroups which Burn and Burn + Cur. Each group contains 12 animals. Burn wounds were made on the back of rat and Cur was administered topically. At the end of the study, all animals were sacrificed and the wound tissues removed for analyse to biochemical and histopathological changes. There was a significant increase in the hydroxyproline levels in the skin of the Cur groups. Cur treated wounds were found to heal much faster as indicated by improved rates of inflammatory cells, collagen deposition, angiogenesis, granulation tissue formation and epithelialization which were also confirmed by histopathological and biochemical examinations. Our data also indicate that there is a rise in the expression of proliferating cell nuclear antigen in skin tissues of Cur-treated rats in the Burn group. The results clearly substantiate the beneficial effects of the topical application of Cur in the acceleration of wound healing.     

Dynamic study of the development of edema in the organs in experimental burn trauma

Proton magnetic relaxation with measuring the time of spin-screen relaxation (T1) was used to study the time course of derangement of organ and tissue flooding after stage IIIB experimental burn of 15% body area. To examine the structures of the microcirculatory vessels, use was made of electron microscopy of the organs. The internal organs under study demonstrated a significant long-term (up to 49 days) increase in flooding: in the liver and kidneys, it occurred since the first day after burn, while in the lungs, myocardium and brain, since the 7th day. The results indicate the parallelism of the changes in the T1 and electron microscopic alterations in the histohematic barriers. Proton magnetic relaxation enables a more rapid and more convenient assay of the changes in tissue flooding as compared to the method of drying at high temperature. Therefore, it may be applied to the assessment of the efficacy of different therapeutic means.     

Wound fluid bacterial levels exceed tissue bacterial counts in controlled porcine partial-thickness burn infections

In the present study, an established controlled burn wound model was used to test the hypothesis that controlled surface contamination with is capable of generating a noninvasive method for the creation of a reproducible deep tissue burn wound infection. Using a liquid tight-wound chamber in Yorkshire pigs, partial-thickness burns were inoculated with saline-immersed for 24 hours. Noninoculated burns and unwounded skin immersed in normal saline served as controls. Bacterial cultures of wound fluid were performed daily, and tissue biopsies for bacteriological and histological evaluations were performed on days 1, 3, and 5. was only recovered from -inoculated wounds (tissue and fluid), whereas all controls contained endogenous only. The number of colony-forming units per gram of wound tissue did not correlate with the bacterial counts found in the overlying wound fluid for any wounds. Fluid counts were consistently higher than tissue counts by two logs. -inoculated wounds showed three times deeper tissue destruction than control wounds. Obtaining consistently deep tissue colonization without cross-contamination among wounds, this study introduces a noninvasive model for controlled burn wound infection suitable for future investigations regarding the efficacy of topical antibiotic wound treatment in experimental burns.     

Cultured epidermal allografts: Quantitative evaluation of their healing effect in deep dermal burns

This study summarizes the Brno Burn Centre experience with the application of cultured epidermal allografts (CEAl) in the treatment of deep dermal burns. In a prospective randomised trial on 30 patients with deep dermal burns CEAl obtained from young healthy and examined donors and fixed on tulle grass carrier (Grasolind) were compared with empty Grasolind as the lowest layer of dressing. All the other layers were identical. Both kinds of dressing were applied simultaneously on the same deep dermal burn wound between 6th and 10th day after burn. Six days later the non-healed wound areas were recorded through painting on cellophane membrane and scanned in the computer. The percentage of wound reduction was calculated and statistically evaluated. The reduction of the non-epithelialized wound area was 86.5% when covered through CEAl and only 71.2% when covered with tulle grass (Grasolind) only. This difference is statistically significant. In conclusion it can be stated that cultured epidermal allografts strongly stimulate reepithelialisation in deep dermal burns. This revised version was published online in July 2006 with corrections to the Cover Date.     

The role of endogenous porphyrins in laser therapy of experimental skin wounds

The role of endogenous porphyrins in the effect of laser irradiation on the superoxide dismutase (SOD) activity of wound exudate and rat leukocyte activity has been studied on models of aseptic incised skin wounds. Wounds were irradiated with a He-Ne laser (632.8 nm, 1.5 J/cm²) on the 2nd, 3rd, and 4th days after the beginning of the experiment. Irradiation effects were evaluated by the SOD activity (NBT test) and the activity of leukocytes of the wound exudate (as a chemiluminescent response to opsonized zymosan). It was found that in animals subjected to laser irradiation, the SOD activity sharply increased. This effect depended on endogenous porphyrin concentration and was retained throughout the experiment. The SOD activity in unirradiated animals decreased from the 2nd to the 5th day of experiment. The evaluation of the activity of wound exudate leukocytes did not reveal any distinct dependence of the effect on the concentration of endogenous porphyrins.     

封闭负压引流对兔糖尿病溃疡创面组织愈合影响的观察

目的:探讨封闭负压引流(VAC)对兔糖尿病溃疡创面组织愈合的影响及其可能机制。方法:采用四氧嘧啶法建立兔糖尿病溃疡模型,设空白对照组和实验组(对照组创面采用常规包扎治疗处理,实验组创面则采用VAC处理),观察和比较两组动物的创面肉眼观、愈合时间,在致伤前、致伤后3 d、7 d、14 d取创面软组织,检测和比较两组动物的创面组织含水量、血流量以及血浆ET-1和NO含量。结果:与对照组比较,实验组动物的创面肿胀及分泌物得到明显控制,创面坏死组织的清除与肉芽组织的生长明显加快,平均愈合时间明显缩短(P0.05);致伤后3 d、7 d和14 d,创面组织含水量与血浆ET-1含量明显下降(P0.05),创面组织血流量与血浆NO含量明显增加(P0.05)。结论:VAC对兔糖尿病溃疡创面组织的愈合可起到积极的促进作用,这可能与其增加血浆NO含量及降低ET-1的含量有关,其具体机制尚有待于进一步的研究。     

Rapid preparation of a noncultured skin cell suspension that promotes wound healing

Autologous skin cell suspensions have been used for wound healing in patients with burns and against normal pigmentation in vitiligo. To separate cells and the extracellular matrix from skin tissue, most researchers use enzymatic digestion. Therefore, this process is difficult to perform during a routine surgical procedure. We aimed to prepare a suspension of noncultured autologous skin cells (NCSCs) using a tissue homogenizer as a new method instead of harsh biochemical reagents. The potential clinical applicability of NCSCs was analyzed using a nude-rat model of burn healing. After optimization of the homogenizer settings, cell viability ranged from 52 to 89%. Scanning electron microscopy showed evidence of keratinocyte-like cell morphology, and several growth factors, including epidermal growth factor and basic fibroblast growth factor, were present in the NCSCs. The rat model revealed that NCSCs accelerated skin regeneration. NCSCs could be generated using a tissue homogenizer for enhancement of wound healing in vivo. In the NCSC group of wounds, on day 7 of epithelialization, granulation was observed, whereas on day 14, there was a significant increase in skin adnexa regeneration as compared to the control group (PBS treatment; p < 0.05). This study suggests that the proposed process is rapid and does not require the use of biochemical agents. Thus, we recommend a combination of surgical treatment with the new therapy for a burn as an effective method.     

Changes in human burn fluid biological activity during normal burn healing

The main goal of this work was monitoring the changes occurring in human burn fluid biological activity during normal burn healing. The fluid available in the burn until healing makes a good material for controlling biochemical microenvironment of burn cells. This environment involves factors, such as extracellular matrix proteins and matrix metalloproteinases. In this work our previous studies of the influence of wound and burn fluids on the functional activity of cells were extended to include the effect of burn fluid on fibroblasts and keratinocytes, i. e. human skin cells present in the wound and involved in wound healing. It was shown that human burn fluid biological activity depends on the time that passed after burning, and on the correctness of healing. Migration of human fibroblasts becomes more intensive under the influence of such a fluid independently on the time of fluid sampling. Unlike, keratinocyte migration was inhibited by burn fluid sampled 1-3 days after burning but was enhanced by fluids sampled 6 days following burning. The obtained data are to be necessarily taken into consideration at burn treatment and also at transplantation of cells for healing of wounds of different nature.     

Oxalosis associated with an Aspergillus niger fungus ball. Report of a case

During a seventeen day period an A. niger fungus ball evolved within a healed tuberculous cavity of a patient. Symptoms were a cough with a chocolate brown expectoration and dyspnea. The patient died and necropsy was performed. Crystals of calcium oxalate were deposited in the cavity lining and in the adjacent tissue of the lung. Fibrosis, mononuclear infiltration and intraalveolar purulent exudate were seen in these tissues. Some small vessels presented recent thrombosis and deposition of calcium oxalate. The bronchus connected with the cavity presented a disrupted epithelial layer, edema, polymorphonuclear infiltration and birefringent crystals. Scattered areas of tubular atrophy, glomerular sclerosis and lymphoid infiltration were seen in the cortex of the kidney. Oxalate crystals were also seen within the renal tubuli.Bolsistas do CNPq (Brazil).     

Wound‐healing evaluation of entrapped active agents into protein microspheres over cellulosic gauzes

The use of active ingredients in wound management have evolved alongside the pharmaceutical agents and dressings used to deliver them. However, the development of gauzes, dressings with specific properties, still remains a challenge for several medical applications. A new methodology for the controlled release of active components for the healing of burn wounds is proposed herein. Cotton and non‐woven bandages have been cationised to promote the attachment of protein microspheres. The active agents, piroxicam and vegetable oil, were entrapped into the microspheres using ultrasound energy. Active agents were released from the microspheres by a change in pH. Wound healing was assessed through the use of standardised burn wounds induced by a cautery in human full‐thickness skin equivalents (EpidermFT). The best re‐epithelialisation and fastest wound closure was observed in wounds treated with proteinaceous microspheres attached to gauzes, after six days of healing, in comparison with commercial collagen dressing and other controls. Furthermore, the ability of these materials to reduce the inflammation process, together with healing improvement, makes these biomaterials suitable for wound‐dressing applications.     

马桑水提取物对大鼠深Ⅱ度烧伤创面微循环和氧化应激的影响

目的：探索马桑水提取物（CSME）对大鼠深Ⅱ度烧伤创面微循环和氧化应激的影响。方法：随机将180只SD大鼠分成6组（n=30）：对照组（生理盐水组,NS）、凡士林组（WPL）、磺胺嘧啶银组（SSD）、马桑提取物组（低剂量组（CSME-L）、中剂量组（CSME-M）和高剂量组（CSME-H）。麻醉后用烫伤仪烫伤脱毛区（病理结果证实深Ⅱ度烫伤）,伤后创面分别涂擦NS、WPL、SSD和不同浓度的CSME烧伤软膏。于伤后48 h、7 d、14 d、21 d计算创面愈合率（HR）,检测创面微血管（MVD）、创面组织含水量（TM）、血管内皮生长因子（VEGF）、丙二醛（MDA）、超氧化物歧化酶（SOD）、羟脯氨酸（HYP）,进行创面组织学观察。结果：CSME各组的HR呈剂量依赖性大于NS和WPL （P<0.05）;在21 d,其创面组织血管管径、数量、分布及TM呈剂量依赖性少于其他各组（P<0.05）,伤后7 d、14 d,CSME各组呈现剂量依赖性高于NS、WPL和SSD （P<0.05）,而伤后21 d呈剂量依赖性低于NS、WPL和SSD （P<0.05）;CSME的SOD活性、HYP、NO和ET含量呈剂量依赖性高于其他各组（P<0.05）,而MDA活性呈剂量依赖性弱于其他各组（P<0.05）,CSME呈剂量依赖性缩短创面修复时间,瘢痕少于其他各组。结论：CSME具有早期减轻烧伤创面组织水肿、促进创面收缩、加快创面结痂以及促进肉芽组织增生,有利于创面愈合;后期则抑制创面肉芽组织增生,防止瘢痕过度增生。其机制与创面微循环、氧化应激、NO和VEGF的调控有关。     

Glycerol treatment as recovery procedure for cryopreserved human skin allografts positive for bacteria and fungi

Human donor skin allografts are suitable and much used temporary biological (burn) wound dressings. They prepare the excised wound bed for final autografting and form an excellent substrate for revascularisation and for the formation of granulation tissue. Two preservation methods, glycerol preservation and cryopreservation, are commonly used by tissue banks for the long-term storage of skin grafts. The burn surgeons of the Queen Astrid Military Hospital preferentially use partly viable cryopreserved skin allografts. After mandatory 14-day bacterial and mycological culture, however, approximately 15% of the cryopreserved skin allografts cannot be released from quarantine because of positive culture. To maximize the use of our scarce and precious donor skin, we developed a glycerolisation-based recovery method for these culture positive cryopreserved allografts. The inactivation and preservation method, described in this paper, allowed for an efficient inactivation of the colonising bacteria and fungi, with the exception of spore-formers, and did not influence the structural and functional aspects of the skin allografts.     

Acute alcohol intoxication increases interleukin-18-mediated neutrophil infiltration and lung inflammation following burn injury in rats

In this study, we examined whether IL-18 plays a role in lung inflammation following alcohol (EtOH) and burn injury. Male rats ( approximately 250 g) were gavaged with EtOH to achieve a blood EtOH level of approximately 100 mg/dl before burn or sham injury ( approximately 12.5% total body surface area). Immediately after injury, rats were treated with vehicle, caspase-1 inhibitor AC-YVAD-CHO to block IL-18 production or with IL-18 neutralizing anti-IL-18 antibodies. In another group, rats were treated with anti-neutrophil antiserum approximately 16 h before injury to deplete neutrophils. On day 1 after injury, lung tissue IL-18, neutrophil chemokines (CINC-1/CINC-3), ICAM-1, neutrophil infiltration, MPO activity, and water content (i.e., edema) were significantly increased in rats receiving a combined insult of EtOH and burn injury compared with rats receiving either EtOH intoxication or burn injury alone. Treatment of rats with caspase-1 inhibitor prevented the increase in lung tissue IL-18, CINC-1, CINC-3, ICAM-1, MPO activity, and edema following EtOH and burn injury. The increase in lung IL-18, MPO, and edema was also prevented in rats treated with anti-IL-18 antibodies. Furthermore, administration of anti-neutrophil antiserum also attenuated the increase in lung MPO activity and edema, but did not prevent the increase in IL-18 levels following EtOH and burn injury. These findings suggest that acute EtOH intoxication before burn injury upregulates IL-18, which in turn contributes to increased neutrophil infiltration. Furthermore, the presence of neutrophils appears to be critical for IL-18-meditaed increased lung tissue edema following a combined insult of EtOH and burn injury.