Design Characteristics for the Tissue Engineering of Cartilaginous Tissues

Tissues like the temporomandibular joint (TMJ) disc and the knee meniscus are often mistakenly viewed as a tantamount to hyaline cartilage, largely due to the absence of a comprehensive understanding of the distinguishing properties of cartilaginous tissues. Because of this confusion, fibrocartilaginous tissue engineering attempts may not be based on suitable experimental designs. Fibrocartilaginous tissues are markedly different than hyaline cartilage; however, the dearth of knowledge related to their cellular and biochemical composition, as well as their biomechanical characteristics, is stunning. Hyaline articular cartilage is exclusively composed of chondrocytes that produce primarily type II collagen, whereas the TMJ disc and the knee meniscus have a mixed cell population of fibroblasts and cells similar to chondrocytes, which predominantly secrete type I collagen. Additionally, fibrocartilaginous tissues have a low glycosaminoglycan content, a low compressive modulus, and a high tensile modulus when compared to hyaline cartilage. Therefore, it is crucial for fibrocartilaginous tissue engineering attempts to be tissue-specific, utilizing the knowledge of the distinct and unique properties of these tissues. At the same time, advances and insights related to the science and engineering aspect of hyaline cartilage regeneration must be carefully considered for the in vitro engineering of fibrocartilaginous tissues.     

多普勒组织显像评价高血压病心房内传导间期变化与房性心律失常的关系

目的　应用多普勒组织显像评价高血压病心房内传导间期变化与房性心律失常的关系 ;方法　利用超声多普勒组织显像法测量了 2 0例高血压病心房内传导间期与正常人对比分析 ;结果　高血压病心房内传导间期存在异常 ,心房内传导间期与左房内径大小无相关 (r =0 1,P >0 2 5 ) ,与左室舒张功能指标E A比值中度相关 (r=0 5 7,0 0 1

0 2 5 ) ;结论　高血压病房性心律失常与心房内传导异常及左室舒张功能有关 ,多普勒组织显像法是一种较好的测量高血压病心房内传导间期的方法     

Slicer and tissue retrieval system for excisional endoscopic surgery

Extraction of large specimens risks detachment of malignant cells within the peritoneal cavity and contamination of the parieties with resultant seedling implantation at the access wounds. Therefore, extraction is best conducted through a rip-proof sleeve-retrieval system which creates a third space in which the specimen can be sliced under visual control. Slicing of tissue is preferable to morcellation or disintegration since it preserves the structural integrity of the tissue and thereby does not jeopardize histopathological examination and staging of excised tumors. Of the two types of tissue-slicing mechanisms investigated, the compression-moving blade system (CMB) was found to be superior to wire-cutting devices. A prototype CMB slicer has been developed which has been tested experimentally and is currently undergoing clinical evaluation.     

Biological activity of tissue flaps in the treatment of complicated irradiation wounds

Within the last ten years, 79 patients were treated for 114 chronically contaminated, intractable irradiation wounds using various methods of the modern plastic surgery. Radical excision of the devitalised contaminated tissue has been impracticable in 25 cases due to the risk of life-threatening complications or significant functional loss. Different types of flaps such as cutaneous, fasciocutaneous, musculocutaneous, split muscle, isolated vascularised fascia and greater omentum have been used. Despite the incomplete excision, 84% of wounds healed primarily. The essential factor for good wound healing seems to be the biologic activity (BA) of the flap's deep tissue layer that directly contacts the wound bed. BA includes density of the vascular net, ability of neovascularisation, plasticity and specific immunological capacities. It seems to be possible to classify the flaps according to the BA level. Tissue defects in which the chances for radical debridement are poor need the highest BA level in the flap reconstruction.Presented to the European Congress on Wound Healing and Skin Physiology, Bochum, Germany, 1992     

Effects of interleukin-1, tumor necrosis factor-β, and forskolin on tissue plasminogen activator activity in human osteoblastic osteosarcoma cells

Summary The effects of interleukin-1 (IL-1), forskolin, and tumor necrosis factor (TNF-) on tissue plasminogen activator (t-PA) activity were studied in the human osteoblastic osteosarcoma cell line, G292. t-PA activity was measured in the cell media using the chromogenic substrate, S-2251. After a 24 hour incubation period, IL-1 increased t-PA in a dose-dependent manner. The effect of IL-1 at 10.0 U/ml was partially inhibited in the presence of indomethacin. Forskolin (1.0 M) increased t-PA activity after 24 hours with the effects of combined treatment of IL-1 (1.0 U/ml, 10.0 U/ml) and forskolin being apparently additive in nature. TNF- (10^-8–10^-7 M) also produced increased t-PA activity in the cell medial after a 24 hour incubation period. These results suggest that the cytokines, IL-1 and TNF-, can increase t-PA activity in G292 cells and that there is both a cAMP-dependent as well as a cAMP-independent pathway involved in the regulation of this osteoblastic cell function.     

First experiences with HLA-matched corneal grafts in high risk cases

In highly vascularized corneas the number of graft failures caused by irreversible rejections is higher than in non- or slightly vascularized corneas. The importance of antigen compatibility is demonstrated, especially in these high risk cases.Ten highly vascularized corneas were grafted with HLA-matched donor material; only one reversible rejection was seen in this group.Nine non- or slightly vascularized corneas were grafted with donor material chosen at random. Retrospective HLA matching was performed. Three irreversible rejections were seen in this group. The number of HLA incompatibilities was high.     

Staged TRAM Breast Reconstruction: Combining the Advantages of Tissue Expansion with Surgical Delay

The TRAM flap has become the gold standard in breast reconstruction but suffers from the disadvantages of poor color match, different texture, and impaired sensation compared to the normal breast. This study reports on a two-stage procedure to address these problems. The first stage consists of insertion of a tissue expander and surgical delay of the TRAM flap. The second stage consists of removal of the tissue expander and transposition of a deepithelized TRAM flap into the tissue expanded cavity. (The capsule is excised.) Four cases of breast reconstruction are reported. The advantage of this procedure is that it offers the benefits of tissue expansion, viz., normal color match, texture, and sensation, and in addition, reconstruction is achieved with autologous tissue by a pedicled TRAM flap. The vascularity of the TRAM is enhanced by a surgical delay procedure.     

皮瓣和肌皮瓣修复头颈组织缺损30例报告

目的：探讨皮瓣、肌皮瓣移植修复耳鼻咽喉科组织缺损的作用。方法：采用前臂皮瓣、胸大肌皮瓣、额正中皮瓣、鼻唇沟皮瓣、脐旁腹直肌皮瓣修复或重建耳鼻咽喉科组织缺损30例。结果：29例皮瓣存活，1例额正中皮瓣失败。结论：皮瓣、肌皮瓣应用于耳鼻咽喉科较大组织缺损的移植修复，安全可靠、成功率高，但应掌握一定的原则，预防并发症的发生。     

Use of N-butyl-2-cyanoacrylate in oral surgery: biological and clinical evaluation

N-butyl-2-cyanoacrylate based tissue adhesive, Tisuacryl, was employed as a nonsuture method for closing wounds in oral surgery. One hundred thirty patients were treated with the adhesive and 30 with suture. The surgical procedures were apicectomy, extraction of molars, and mucogingival grafting. The studied product was well tolerated by the tissue and permitted immediate hemostasis and normal healing of incisions. When Tisuacryl was used as dressing material for donor sites and mucosal ulcerations, pain relief was observed.     

Pulmonary thrombo-embolism in nephrotic syndrome treated with tissue plasminogen activator

We describe the case of a boy with steroid sensitive nephrotic syndrome and left pulmonary artery thrombo-embolism. Clinical presentation initially suggested sepsis and respiratory signs were minor. Treatment with tissue plasminogen activator infused into the pulmonary artery was successful. Conclusion Pulmonary thrombo-embolism should be considered in unwell children with nephrotic syndrome. Received: 6 September 1996 / Accepted: 17 December 1996