Vascular grafts

Autogenous vein is the conduit of choice in the surgical creation of bypasses of small–to– medium–caliber vessels in patients with peripheral occlusive arterial disease and will remain so for the near future. The success rate of bypasses using conduits of diameters greater than 6 mm has been excellent, whereas the majority of bypasses using smaller conduits fail within 5 years. In addition, due to a steep increase in rates of diabetes and decreasing cardiovascular mortality rates, increasing challenges are presented by this population. These facts have motivated much of the research in the cardiovascular arena over the past four decades, with improved techniques and new materials. Strategies to improve outcomes include the use of alternative materials including autologous, nonautologous and prosthetic grafts, utilizing different methods for their harvesting and preservation; tissue engineering, using either polymer– or biological–based scaffolds for cell seeding; endovascular methodologies; and gene therapy. This report presents an overview of the several options currently available in the management of patients with peripheral arterial occlusive disease, as well as the ongoing research directed towards the creation of an artificial engineered vessel, discussing experimental work in which endothelial cells have been seeded on different scaffolds and finally the potential application of gene therapy in the field of vascular reconstruction.     

Revascularization of gingival autografts placed on different receptor beds

The revascularization of gingival autografts, placed either on fenestrated periosteum or on non-fenestrated periosteum, has been compared by means of 12 fluorescein angiographs, taken 8, 10 and 12 days postoperatively on 12 patients, 18-32 years of age. The grafts placed on periosteum (P-zone) showed a mean increase of fluorescence of 10.6% between the 8th and 10th day and of 19.4% between the 10th and 12th day. At that time the circulatory system in the graft seemed to be established for 97.7%. The grafts placed on fenestrated periosteum (B-zone) showed a mean increase of fluorescence of 13.2% between the 8th and the 10th day and of 13.5% between the 10th and 12th day. The revascularization reached 96.1% at that time. Between both groups no statistically significant difference has been found. It can be concluded that a periosteal receptor side is not a prerequisite for the formation of an even circulatory pattern in gingival autografts.     

Tops and flops using cultured epithelial autografts in children

The goal of this article is to review the status of cultured epithelial autografts in clinical practice with particular focus on the pediatric subset of patients. The current indications include massive deep burns (>60–70% total body surface area), resurfacing-type postburn scar revisions, and skin defect coverage following excision of large skin lesions like giant nevi. Although this method can be lifesaving for massively burned patients, and although excellent functional and cosmetic results may be obtained under ideal circumstances, formidable problems continue to exist. Take is inconsistent, cultured grafts are extremely susceptible to infection, and skin breakdown during the first months post grafting may occur due to mechanical instability of the regenerating skin. It may take one more decade of concerted research, jointly performed by clinicians and tissue culture technology experts in order to fabricate more skin-like grafts which are robust, reliable, and less expensive. Then, cultured skin will conquer the world and benefit countless patients.     

手腕部深度烧伤削切痂植大张自体皮疗效观察

目的通过手腕部深度烧伤不同治疗方法的比较,探讨手腕部深度烧伤的理想治疗方法。方法将60例共83只手腕部深度烧伤患者随机分成A、B2组,A组采用早期削切痂移植大张自体皮,B组采用肉芽创面移植邮票状自体皮,观察2组手部创面修复时间和功能恢复情况。结果A组一次植皮成功率与B组相比,无显著性差异（97．7％vs 100．0％,P〉0．05）;A组愈合时间与B组相比,有极显著性差异[（14．0±1．2）d vs （37．0±1．4）d,P〈0．01];A组优良率与B组相比,有极显著性差异（95．3％vs 30．0％,P〈0．01）。结论早期削切痂移植大张自体皮术治疗手腕部深度烧伤能有效保护手腕部的功能,疗效优于肉芽创面移植邮票状自体皮术。     

黑皮素受体-1在自体中厚移植皮片中的表达

目的　检测MC - 1R在自体移植皮片中的表达 ,并与自身正常皮肤作对照 ,初步认识MC - 1R在自体移植皮片过度色素沉着中的作用。方法　利用免疫组织化学方法检测自体中厚移植皮片与供区及受区周围自体正常对照皮肤中MC - 1R的表达 ,并行统计学分析。结果　MC - 1R的表达定位于表皮基底部黑素细胞、角朊细胞的胞浆及胞膜 ,在大部分自体中厚移植皮片中呈强阳性表达 ,其强阳性表达率为 6 7.7% ,与在自体正常对照皮肤中的表达差异有显著意义 (P <0 .0 1) ;MC - 1R在受区周围与供区正常对照皮肤中的表达差异无显著意义 (P >0 .0 1)。结论　MC - 1R在自体中厚移植皮片中的表达较在自体正常对照皮肤中显著增高 ,在自体移植皮片过度色素沉着中起重要调控作用。     

Preparation of autologous bone marrow grafts for cryopreservation using the AS104 cell separator

We evaluated the AS104 cell separator (Fresenius AG, Bad Homburg, Germany) for ex vivo processing of bone marrow (BM) grafts of 43 patients suffering from germ cell cancer (GCC, n = 22), acute lymphocytic leukemia (ALL, n = 13) and malignant lymphoma (ML, n = 8). Recoveries of total nucleated cells (TNC), mononuclear cells (MNC) and colony-forming units granulocyte-macrophage (CFU-GM) were determined in the BM concentrates prepared for cryopreservation. Hematopoietic reconstitution was analyzed in patients who underwent autologous transplantation following high-dose radio-/chemotherapy (HDRCT). Processing of the BM suspension with a median volume of 1,013 ml (range: 422–1,574) resulted in 156 ml (80–186) within 50–120 min (median: 90). In the BM concentrates, medians of 28.6% TNC (10.6–69.6), 37.9% MNC (22.3–86.4), and 52.4% CFU-GM (20.8–96.4) were recovered. Twenty-six patients underwent HDRCT with reinfusion of autologous BM and were evaluable for engraftment. They received a median of 0.8 × 10⁸ MNC/kg (0.3–1.6 × 10⁸) and 2.2 × 10⁴ CFU-GM/kg (0.6–12.8 × 10⁴) for hematopoietic rescue. Engraftment with neutrophils >500/μl occurred in a median time of 12 days (8–33) in all patients. We conclude that ex vivo processing of autologous BM with median recovery rates of 37.9% for MNC, and 52.4% for CFU-GM, results in a cell population that can rescue patients from HDRCT. The described technique is convenient, time-efficient, and provides reliable results in preparing BM autografts for cryopreservation. J. Clin. Apheresis 12:179–182, 1997. © 1997 Wiley-Liss, Inc.     

Anterior Cruciate Ligament Double-Bundle Reconstruction With Hamstring Tendon Autografts

The anterior cruciate ligament (ACL) surgical technique via a 5-strand hamstring tendon autograft is designed with a conventional single-bundle reconstruction that has shown favorable results and an additional posterolateral (PL) bundle reconstruction. The conventional single-tunnel technique is performed for the tibial tunnel, and the double-tunnel technique is performed for the femoral tunnel. The anteromedial (AM) femoral tunnel is prepared with 1 mm of the posterior femoral cortex being left over the top at the 11- to 1-o’clock position. The PL femoral tunnel is prepared with the outside-in technique by use of a 4.5-mm cannulated reamer. The AM bundle is fixed with a rigid fixation system on the femoral side, and the PL bundle is fixed to tie with the miniplate from the outside femur. A double-bundle reconstruction with 5-strand hamstring autografts, in conjunction with a conventional AM bundle and an additional PL bundle, seems to be a very effective method for the treatment of ACL instabilities. Although the long-term clinical outcome of the procedure is yet to be determined, complications including graft impingement, limitation in range of motion, and residual instability have not been observed to date in the first 38 patients who have undergone our technique.