Influence of tissue nitration on tissue damage with thermal injury

A gas mediator, nitric oxide, is converted into peroxynitrite in the presence of superoxide anion. Peroxynitrite is a potent oxidant, which injures various tissues and organs by nitration of tyrosine residue in protein and enhances the inflammatory response in the prolonged phase. In this study, the authors investigated the relationship between peroxynitrite-mediated tissue nitration and tissue damage with thermal injury using an experimental burn model. The content of nitrotyrosine in the burned tissue significantly increased 1 to 6 h after injury. The nitrotyrosine content in the burned ear significantly decreased with 100 mg/kg of LNAME administration. Vascular hyperpermeability was also significantly suppressed in the iNOS antibody immunoneutralized mice 6 h after injury. There was a positive correlation between the severity of tissue damage, an indicator of which is the increase in the weight of the burned ear along with the development of edema after injury, and the concentration of nitrotyrosine in the wound tissues. Nitrotyrosine-like immune reactants were also diffusely detected in the burned region and the surrounding areas. These results indicate that peroxynitrite is produced in the surrounding burned region and a reaction of nitration of tissue tyrosine is involved with tissue damage at the burn wound. Therefore, to prevent the systemic vascular hyperpermeability and tissue damage in a large area burn or severe burn patients, the administration of NOS inhibitors or radical erasers may be easy to manage generally by inhibition of peroxynitrite formation.     

Experimental studies on tissue injury by microwave tissue coagulator]

The tissue injury caused by Microwave Tissue Coagulator (MTC) was assessed clinically and experimentally with dogs. Following hepatic transection using MTC on condition that the output was 60 watts and radiation lasted for 60 seconds at one time, GOT, GPT, lactic acid, FDP and endotoxin concentration increased and coagulation parameters such as hepaplastin test were deteriorated transiently. Of tissue injury, following results were obtained. 1) The mechanism of tissue injury by MTC consists of direct heat injury and infarct by circulatory disturbance. The extent of injury from the needle electrode is approximately 10 mm in the former mechanism and 20mm in the latter. 2) Injury of vessels in Glisson's sheath was confirmed up to 50mm apart from the needle electrode by labelling index of bromodeoxyuridine in bile duct epithelial cells. 3) The granulation formation at the site of necrosis was considerably retarded by wound infection. Accordingly, when MTC is utilized on hepatectomy, followings should be noted: 1) To prevent the large intrahepatic vessels from heat injury, MTC may be utilized at the surface of the liver and the needle electrode must be punctured more than 10mm apart from them. 2) Bile leakage at the resected stump should be eliminated to prevent infection at the stump.     

肝脏组织工程的研究进展

目前,肝移植是公认的各种原因所致的急慢性肝功能衰竭等终末期肝病的唯一可治愈手段,但是肝脏供体来源有限、费用昂贵、终生服用免疫抑制剂及术后并发症等缺点限制了其临床应用.20世纪90年代以来,随着细胞生物学、分子生物学、免疫学、遗传学等基础学科的产生和迅猛发展,组织工程学也得到了进一步的发展.由于肝脏细胞的强大再生能力,肝脏组织工程学的发展尤其迅速.@@肝脏组织工程学的核心是建立细胞与生物材料的三维空间复合体,即具有生命力的活体组织,用以对病损组织进行形态、结构和功能的重建,并达到永久性替代.目前肝脏组织工程学研究主要围绕种子细胞的选择、生物材料及血管化等几个方面进行.本文就这几个方面的相关进展作一综述.     

Effect of tanning agent on tissue reaction to tissue implanted collagen sponge

Pure collagen, isolated from bovine skin, was reconstituted into the form of a sponge in the presence of either glutaraldehyde (GTA) or hexamethylene diisocyanate (DIC). Extensively washed sponges were implanted subcutaneously in rats and harvested 5 and 17 days later. Histology showed that at 5 days, the GTA-crosslinked sponge induced more cellular reaction at the outer layer of the sponge than the DIC-tanned sponge. After 17 days, the cellular infiltration of the GTA-tanned sponge remained at the periphery of the implant while the DIC-tanned sponge was completely infiltrated by inflammatory cells, including fibroblasts. Quantitative morphometry and determination of cellular DNA in sponges harvested at 17 days support the morphological finding. We conclude that GTA-tanned sponges are cytotoxic as evidenced by more pronounced tissue reaction soon after tissue implantation, and no cellular infiltration at later stages into the implant. Hexamethylene diisocyanate seems to be a more adequate tanning agent for sponges designed as a tissue substitute.     

血管组织工程研究进展

组织工程的概念是美国科学基金会于1987年提出的,是综合应用生命科学和工程学的原理,研制并开发出组织、器官的替代物以解决组织缺损和器官损伤的修复和重建问题.血管组织工程是指利用血管壁的正常细胞和生物可降解材料来制备、重建和再生血管替代材料的科学.目前国内外已经进行了较多的研究以期研制出无免疫原性、抗血栓形成、组织和细胞相容性高、具有一定强度和生长性并能广泛应用于临床的血管替代物,以解决临床上治疗血管狭窄或闭塞导致的缺血性疾病自体血管移植中血管来源有限的问题[1].     

组织工程气管研究进展

气管切除超过原长度的一半时便需要一个人工气管以进行安全的重建.本文就组织工程化气管构建的研究进展进行了综述,并指出组织工程化气管研究领域所面临的问题和今后的研究方向.     

Imaging update on soft tissue sarcoma

Soft tissue sarcomas (STS) are rare tumours presenting as soft tissue lumps. Ultrasound is often the primary modality for the initial assessment, with MRI the mainstay for lesion characterisation. PET/CT along with other emerging MRI sequences are used in certain situations as an adjunct and problem solving tool in STS staging and assessment of disease recurrence. Recent advances include the promise of whole body MRI, hybrid PET/MRI, diffusion weighted imaging, dynamic contrast enhanced MRI and advances in artificial intelligence. This article discusses current concepts in extremity STS imaging and highlights recent advances.     

Comparison of antigen expression on normal urothelial cells in tissue section and tissue culture

Antigenic characterization of urothelial cells cultured from normal adult ureter was performed. These cells were cultured using a simplified isolation and culture technique and a commercially available serum-free medium. The cells growing in these cultures had epithelioid morphology and normal quantities of DNA. The antigen expression on these cultured normal urothelial cells was evaluated using a panel of monoclonal antibodies: 5G6.4, AN43, URO-5, anti-keratin and anti-blood group antibodies, and 425 (anti-epidermal growth factor receptor). Lower levels of anti-A and AN43 binding on cultured cells were observed than are seen on urothelial cells in sections of normal ureter, while the binding of anti-blood group H, 5G6.4, and URO-5 was unchanged. Binding of anti-epidermal growth factor receptor antibody 425 was improved if the cells were grown in medium lacking epidermal growth factor. These results confirm the urothelial origin of these cultured urothelial cells but indicate that some antigenic differences between cultured normal urothelial cells and urothelial cells in situ in the normal ureter exist.     

Reflections on tissue engineering and trauma therapy

Although all of Trauma Care has remarkably improved during the latter half of the last century the treatment of burn injury has substantially out paced other areas and serves as an excellent example illustrating the improvements taking place in the treatment of injured patients. Although Trauma treatment lagged behind the rest of medicine in mid-century today it rests solidly on the cutting edge of advancing therapeutic knowledge and practice in areas of metabolism, immunology, infection control, critical care, tissue engineering and the delivery of clinical care. It is important to understand what has happened to allow the treatment of injury to be so effective. The bench mark therapeutic moves that have had major effects allowing the present highly effective treatment are: immediate tailored fluid resuscitation, preventive (prophylactic) and topical antibiotics, metabolically designed nutritional therapy and most important early definitive repair of the injury. All must be delivered early after trauma if they are to be optimally effective in preventing the complications of injury that are devastating if encountered. Unfortunately, all problems are not solved by todays treatment of injury, improved as it is. These problems are largely related to an inexact understanding: of the physiologic changes of aging, of the exact pathophysiologic events in inhalation injury and multisystem organ failure and of the technology required to replace those body parts damaged by the injury itself that lead to death or to healing with loss of function. There will be major improvements in the understanding and ability to effectively deal with the problems of aging and inhalation injury through basic and clinical research but perhaps the major improvement in injury treatment will come through the ability to replace worn out, defective or damaged body parts through technologies that resemble regeneration. Here the concepts of Tissue Engineering have much to contribute and it is worth exploring the donation of Tissue Engineering to dermal replacement following burn injury to serve as an example of what types of additions to treatment Tissue Engineering can make.     

The effects of radiotherapy on maxillofacial tissue

Radiation therapy for the treatment of maxillofacial tumours can lead to delayed complications. One of the most severe complications is osteoradionecrosis (ORN), which can cause orocutaneous fistulae, exposed mandible and considerable pain. The condition can occur years after radiotherapy and requires aggressive prevention and treatment. Hyperbaric oxygen therapy has been found beneficial for patients with maxillofacial ORN, leading to pain relief, fistula closure and bone coverage.     

结肠黏膜相关淋巴组织淋巴瘤12例报告

目的探讨结肠黏膜相关淋巴组织淋巴瘤误诊的原因。方法回顾性分析我院1996年10月至2002年11月间收治的12例结肠黏膜相关淋巴组织淋巴瘤的临床资料。结果全部12例中发生误诊的有9例,误诊率为75．0％;X线钡剂灌肠检查的误诊率为66．7％;内镜及病理检查的误诊率为57．0％。结论误诊的原因与本病认识不足,发病率低,缺乏特异的临床表现,X线钡剂灌肠及结肠镜征象与结肠癌或溃疡性结肠炎酷似有关。     

组织工程皮肤修复皮肤缺损的初步实验研究

目的:探讨组织工程皮肤移植的手术方法、注意事项及临床效果。方法:2.5～3月龄约克猪6只,制备全厚皮肤缺损创面48个,随机分为三组,每组16例。A组:组织工程全层皮肤移植组;B组:组织工程真皮和自体表皮复合移植组;C组(对照组):自体全厚皮片移植组。观察实验组与对照组间的治愈率。结果:A组治愈率75.00%,B组治愈率87.50%,C组治愈率93.75%,三组比较无显著性差异(χ2=2.34,P>0.05)。结论:组织工程皮肤修复皮肤缺损是可行的。     

泌尿生殖道组织工程学研究进展

目的目前泌尿生殖道缺损的临床修复包括异体移植、自体移植及人工合成组织替代物,都存在一定的缺陷和普遍应用的限制,因而寻求一种新的方法和材料十分必要,组织工程技术是一种新的可能解决途径。深入了解国内外泌尿生殖道组织工程学进展情况,为进一步研究打下基础。方法应用计算机检索PubMed和Medscape数据库1994-01至2005-06的相关文章,检索词为“tissue en-gineering,genitourinarytract(bladder,ureter,urethra,penis),surgery”,并限定文章语言种类为英文。同时检索中国期刊全文数据库1999-01至2005-06的相关文章,检索词为“组织工程,泌尿生殖道(膀胱、输尿管、尿道、阴茎),外科修复”,并限定文章语言种类为中文。对资料进行初审,并查看每篇文献后的引文。与泌尿生殖道组织工程相关的内容纳入,重复文章或Meta分析类文章排除。结果共收集到78篇相关文献,纳入30篇,排除48篇。综合纳入的30篇文献,对组织工程细胞支架作了简单介绍,对组织工程技术在膀胱、输尿管、尿道、阴茎等方面的研究现状进行了综述。结论虽然种子细胞与支架等仍存在一些尚待解决的问题,但组织工程的发展给泌尿生殖道组织缺损的修复,提供了更广泛的临床应用及最为崭新的思路。继续研究以组织工程的方法修复泌尿生殖道组织缺损是极为必要的。