Extracellular matrix preparation of expanded polytetrafluoroethylene grafts seeded with endothelial cells: influence on early platelet deposition, cellular growth, and luminal prostacyclin release.

The importance of blood and extracellular matrix precoating of expanded polytetrafluoroethylene (ePTFE) grafts on the effectiveness of endothelial cell (EC) seeding was assessed in a canine experimental model. Part I of the study documented ex vivo platelet deposition in 256 ePTFE grafts, 6 cm x 4 mm internal diameter, after implantation as femoral artery-femoral vein or carotid artery-jugular vein arteriovenous shunts. These conduits were precoated with blood, fibronectin, laminin, or collagen type IV with laminin, after which they were seeded with enzymatically derived and cultivated venous canine endothelium at a density of 30,000 to 40,000 EC/cm2 of graft surface. Luminal deposition of Indium 111-labeled platelets, expressed as 10(8) platelets/cm2, at 30 minutes (n = 176) and 24 hours (n = 80), respectively, was 2.29 and 0.30 for blood, 2.83 and 0.37 for fibronectin, 0.99 and 0.08 for laminin, and 0.98 and 0.11 for collagen type IV with laminin. Part II of the study documented in vivo luminal EC coverage at 14 days of 6 cm x 4 mm internal diameter ePTFE femoral or carotid arterial grafts (n = 8) prepared in the same manner as part I ex vivo shunt grafts. EC coverage with blood, fibronectin, laminin, and collagen type IV with laminin preparation was 42%, 49%, 44%, and 52%, respectively. The graft:carotid artery ratio of luminal 6-keto-PGF1 alpha release at 14 days with these same four preparations was 0.38, 0.31, 0.35, and 0.32, respectively. Precoatings of ePTFE prostheses with fibronectin, laminin, and collagen type IV are known to enhance the initial attachment of seeded EC. Fibronectin caused an insignificant increase in early platelet accumulation; laminin or laminin with collagen type IV preparations were associated with significantly less (p less than 0.005) deposition of platelets when compared to whole blood preparations. Most importantly, none of the four preparation techniques resulted in different in vivo rates of EC growth or luminal release of prostacyclin from conduits studied 14 days after implantation.

[The color-coded duplex sonography and contrast-enhanced magnetic resonance tomography of scintigraphically cold thyroid nodules]. / Farbkodierte Duplexsonographie und kontrastverstärkte Magnetresonanztomographie szintigraphisch kalter Schilddrüsenknoten.

In order to establish diagnostic criteria, colour-coded duplex sonography was performed on 40 patients who had a total of 43 operatively confirmed thyroid lesions which were scintigraphically "cold" (28 adenomas, 8 carcinomas, 4 cases of thyroiditis and 3 cysts). 32 of these patients also had MRT with T2- and T1-weighted images before and after injection of Gd-DTPA (0.1 mmol/kg). Adenomatous nodules and adenomas showed a peripheral vascular halo on colour-coded duplex sonography with a sensitivity of 96% and a specificity of 93%. Malignant lesions showed marked central vascularisation and on B-images irregular marginal structures. Adenomas and adenomatous nodules showed hyperintense areas on T1-weighted unenhanced MR images and/or homogeneous uptake in the lesion (sensitivity 100%, specificity 77%). Malignant lesions typically showed an irregular margin with increased contrast uptake on MRT. If sonography and colour-coded duplex sonography is unable to classify a lesion with any degree of assurance then MRT with Gd-DTPA enhancement should be performed.

Experimental improvement of microvascular allografts with the new material polyurethane and microvessel endothelial cell seeding.

The major aim of this experimental study was the improvement of hemo- and biocompatibility of microvascular allografts. Comparison of polyurethane and ePTFE (expanded polytetrafluoroethene) micrografts did not show a significant advantage of the new material polyurethane. When the endothelial cell seeding method was applied, endothelial cell harvesting from rat fat proved to be very difficult. Therefore, further research on microvessel endothelial cell seeding is planned.

[Hereditary thrombophilia as a cause of recurrent transplant thromboses]. / Hereditäre Thrombophilie als Ursache rezidivierender Transplantatthrombosen.

We report a case of hereditary protein S and protein C deficiency which are a rare defects of the anti-coagulation-system. Protein S is a vitamin K dependent glycoprotein that functions as a cofactor to activated Protein C in the inactivation of coagulation factors V and VIIIa. A deficiency of these proteins caused by a genetic defect increase the risk of recurrent thrombosis at a younger age. Acquired decreases in protein S and C concentration have been reported in connection with age, sex, pregnancy and with oral anticonception. The higher risk for thrombotic diseases of patients with thrombophilia requires a sufficient treatment and prophylaxis, e.g. with fresh frozen plasma or a protein C concentrate.

[Network of surgical wound centers using a new electronic data processing documentation system]. / Die Vernetzung chirurgischer Wundzentren mit Hilfe eines neuen EDV-Dokumentationssystems.

UNLABELLED: Care of chronic wounds is of enormous medical, social and economic importance. Nevertheless there is a lack of epidemiological and economical data. A network of ten wound care centers was created and data were documented in a new computerized wound documentation system. METHODS: Treatment was performed according to a comprehensive and standardized wound care protocol. The new documentation system is a network-capable solution. Digital images and planimetry as well as patient and wound related data are recorded. RESULTS: During the first year the ten centers treated and documented already 3281 wounds. There is a wide spectrum of different chronic wounds treated in the participating centers. Despite of long wound duration of several wounds with a median of 5 weeks (range 0-62 years), the healing rate was 80% within 455 days. CONCLUSION: Large amounts of data can be collected and scientifically evaluated in the wound net. This is realized by a new computerized documentation system, which was integrated into the clinical routine and enables clear and standardized documentation. Therefore even large multicenter therapy studies may be performed easily in the wound net and economical data could be collected.

[Standardized combined pancreas and liver explantation]. / Standardisierung der kombinierten Pankreas- und Leberexplantation.

Maximum use of organs from a single donor is mandatory as a result of the current organ shortage. In combined liver and pancreas allograft retrieval, it is vital that one remember the variability in the anatomy of vessels. Based on our experience, we describe a new technique of dividing the celiac trunk horizontally with subsequent arterial reconstruction, depending on the anatomical situation. Vascular division of the grafts can be performed either in situ or in an ex situ fashion in cases where cardiovascular function has deteriorated.

[The wound care center in surgery: an interdisciplinary concept for diagnostic and treatment of chronic wounds]. / Die chirurgische Wundsprechstunde. Ein interdisziplinäres, diagnostisches und therapeutisches Konzept für chronische Wunden.

In Germany there is no standardized wound care for patients with chronic wounds in specialized centers. We have established a wound care unit for the past 6 years. The principal concept of therapy was characterized by standardized local surgery, moist wound dressings and concomitant treatment of the underlying disease. We performed local therapy, coordinated the interdisciplinary treatment and developed a new wound documentation system for quality control. We established a close network, integrating general practitioners and home care organizations to realize a mainly outpatient treatment supported by short hospital therapy. Exclusive outpatient treatment was performed in 42% of all patients. According to our prospective data, we achieved an improvement in wound care: 69% of the wounds resistant to therapy for a mean of 30 months healed within 12 months after therapy according to our protocol. Our data strongly supported the importance of local surgery: neither wound depth nor wound infection had any influence on the healing rate, presumably due to radical excisional debridement of necrotic tissue. The presented data justify on medical and economic grounds the establishment of such wound care centers in Germany.

[Drying with hexamethyldisilizane--a time-saving alternative to the "critical point" method]. / HMDS-Trocknung--eine zeitsparende Alternative zur "Critical-Point"-Methode.

The capability of Hexamethyldisilizane (HMDS) as a solute for the last step in the dehydration of biological material for scanning electron microscopy was tested in the renal vessels of the rat. The HMDS-drying-method proved to be an economical alternative to the critical-point method.

[Stimulation of wound healing with thrombocyte growth factors in treatment of chronic unhealed wounds]. / Stimulation der Wundheilung mit thrombozytären Wachstumsfaktoren bei der Behandlung chronisch nicht-heilender Wunden.

The management of chronic wounds remains a challenge for various medical and surgical specialties. General strategies include local wound care, surgery, skin grafting, debridement, and vascular reconstruction. However, many wounds remain resistant to conventional therapies. Because platelet factors are important in the normal mechanism of wound healing, we report on the topical application of platelet-derived growth factor. Our initial results suggest that the topical application may stimulate and promote healing of chronic wounds.

Clinical application of fibrin glue in cardiovascular surgery.

Since 1978, fibrin glue has been applied in 268 patients. The indications were: (1) sealing of woven Dacron, (2) sealing of knitted Dacron, (3) control of various bleeding sites. The "blood preclotting" and "fibrin sealing" methods were compared in 32 patients with an aortoventriculoplasty operation using Dacron patches. In the fibrin glue group there was a significant reduction in postoperative blood loss as well as a shortening of the operation time (period of protamin administration to skin closure). From the data it can be concluded that sealing woven Dacron prostheses with fibrin glue is superior to conventional blood preclotting.

Growth factors in clinical practice.

Wound repair consists of a complex interaction of cellular and biochemical events. Several growth factors have been identified as regulatory polypeptides co-ordinating the healing process. Although it is not known precisely why chronic wounds do not follow the normal pattern of healing, diminished growth factor content and accelerated growth factor degradation may contribute to poor healing. Topical application of different factors exert stimulatory effects on wounds in animal models. Human data are limited but the most investigated compound is recombinant human platelet-derived growth factor-BB (rhPDGF-BB). PDGF-BB enhances granulation tissue formation and facilitates epithelialisation. Clinical trials in patients with 'hard to heal' diabetic foot ulcers demonstrated significant improvement in the 'healing rate' and the 'time to healing' compared with controls. Refinement of therapeutic strategies with growth factors will take place in the future.

[Recurrent hematemesis and hemobilia in ruptured hepatic artery aneurysm--differential diagnostic aspects of acute, upper gastrointestinal hemorrhage]. / Rezidivierende Hämatemesis und Hämobilie bei perforiertem Leberarterien-aneurysma--ein differentialdiagnostischer Aspekt der akuten, oberen GIB.

Aneurysms of the hepatic artery are mostly localized extra hepatic (80%). Today atherosclerosis is the most prevalent etiology (32%), followed by trauma (22%) and inflammatory lesions (10%). Rupture or perforation of the aneurysm is the initial clinical manifestation (60-80%), and occurs with nearly equal frequency into the peritoneal cavity and into the hepatobiliary tract. Rupture into bile ducts is often responsible for characteristic findings of upper gastrointestinal bleedings with hematemesis. The case of a 38 year-old man is presented and the clinical manifestation, the diagnostic and therapeutic procedures are demonstrated.

[Incidence of recurrence following surgery of perforating and non-perforating complications in Crohn disease]. / Rezidivhäufigkeit nach Eingriffen wegen "perforierenden" und "nichtperforierenden" Komplikationen bei Morbus Crohn.

From 1980-1987 131 patients were operated for Crohn's disease. Among these 73 patients had perforated (PC) free perforation, abscess, fistula, and 47 had nonperforating complications (NC). Ileums, bleeding, stenosis reoperations (58 pts, 44%) were seen more often in the PC-group (57%) compared to 31% in the NC-group. Furthermore there was a high concordance in the indication for the initial and subsequent operations.

[Ulcus cruris venosum: surgical debridement, antibiotic therapy and stimulation with thrombocytic growth factors]. / Ulcus Cruris Venosum: Chirurgisches Debridement, antibiotische Therapie und Stimulation mit thrombozytären Wachstumsfaktoren.

Despite the availability of various topical agents and of new technics for surgical correction, venous stasis ulcers are still characterized by high recurrent rates. Experimental data from wound healing studies demonstrate stimulation of wound healing after topical application of various growth factors (TGF beta, PDGF, EGF). The results of clinical studies suggest that topical use of an autologous platelet releasate (PDWHF) containing various growth factors accelerates healing. In this prospective study the stimulating effect of autologous PDWHF on epithelialization of small ulcers (group A, < 5000 mm2) and granulation of large ulcers before mesh grafting (> 5000 mm2) will be demonstrated. Inclusion criteria were the venous aetiology of the ulcer and the failure of conventional therapy for 6 month. Exclusion criteria were arterial occlusive disease, diabetes mellitus, acute wound infection, thrombocytopenia and pregnancy. There were 24 patients with 36 ulcers, caused by postthrombotic syndrome in one-third of cases and in two-thirds by severe insufficiency of the perforating veins. The ulcer had been present for more than in 10 years in 38% of cases, while there were 6 circumferential ulcers. The overall ulcer healing rate was 77% after a mean of 14 weeks. In group A 78% of the patients were healed after a mean of 16 weeks. In group B the mesh graft procedure was successful in 90% of the patients after a mean of 13 weeks. Compared with other conventional therapy studies, we achieved a higher healing rate. PDWHF seems to create ideal granulation tissue for mesh graft, indicated by a high uptake of the skin grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

[Lichtenstein alloplastic repair of inguinal hernia]. / Die alloplastische Reparatur des Leistenbruchs nach Lichtenstein.

Tension-free repair, a prerequisite for long-term stability, cannot always be achieved with conventional techniques established for groin reconstruction. Lichtenstein gathered substantial experience simply by closing the hernia in a tension-free fashion using prosthetic material. However, most surgeons fearing graft infection are reluctant to further evaluate this technique. In a feasibility study we entered 70 patients (29 patients with recurrent hernia) receiving a polypropylene mesh (Marlex) to bridge the defect from the inguinal ligament to the internal oblique muscle. Only 1 wound infection and 1 local hematoma requiring reoperation were observed. Nearly 2 years follow-up data revealed no case of recurrence. The Lichtenstein procedure deserves more attention from surgical community and might be a reliable technique esp. in large hernias and redos.

Clinical experience with fibrin glue in cardiac surgery.

Cardiac surgery is often associated with hemostatic abnormalities leading to severe bleeding. Special problems are to be expected, if prosthetic material has to be implanted. Preclotting of Dacron prostheses with blood is well established but failures are sometimes encountered. Several years ago a new hemostatic sealing system (fibrin glue) was introduced into therapy. Since 1978 fibrin glue has been applied in 176 patients. The indications were: 1. sealing of woven Dacron prostheses, 2. bleeding from suture-holes (Gore-Tex), 3. diffuse myocardial bleeding and 4. prevention of kinking of coronary artery grafts. In 32 patients with an aortoventriculoplasty operation using Dacron the "blood preclotting" and "fibrin sealing" methods were compared. In the fibrin glue group there was a significant reduction in postoperative blood loss as well as a shortening of the operation time (period of protamin administration to skin closure). No fibrinolytic dissolution of the fibrin layer on the prostheses was observed.

[Prognostic factors in treatment of diabetic foot ulcers]. / Prognosefaktoren in der Behandlung diabetischer Fussulzera.

138 patients with nonhealing diabetic foot ulcers were treated between 1994 and 1996. Sixty-nine percent of these foot ulcers healed within 17 weeks. Heel ulcers had a significantly lower healing rate, probably because of the difficulty of taking weight-bearing off this zone. Ischemia also correlated well with low healing rates, underlining the importance of vascular diagnosis and surgery. Since compliance is the most significant factor for success, it is mandatory to educate the patient about his disease and prevent further complications.

[Results of therapy of acute mesenteric vascular occlusion]. / Ergebnisse der Therapie des akuten Mesenterialgefässverschlusses.

From 1979 to 1984 39 patients were operated on for acute mesenteric ischemia. The purpose of this retrospective study was the documentation of the therapeutic results and discussion of the value of a second-look operation and postoperative angiography. Proximal occlusion of SMA in 33 patients (85%) resulted in extended bowel infarction, whereas segmental infarction due to peripheral occlusion was found in 15%. The hospital mortality was 85%. Operative procedure consisted of revascularisation (18%), bowel resection (18%), revascularisation and resection (10%) and explorative laparotomy (18%). The second-look operation as a routine procedure has been replaced by a postoperative angiogram. Laparotomy was performed in case of reocclusion of SMA or clinical signs.

Growth factors in distraction osteogenesis. Immuno-histological pattern of TGF-beta1 and IGF-I in human callus induced by distraction osteogenesis.

Although growth factors have been demonstrated during bone healing, their presence has not yet been confirmed in callus distraction. Therefore, in 3 patients we searched for cytokines during callus distraction. Bone biopsies were immuno-histochemically stained for TGF-beta1, IGF-I, TGF-beta type II receptor, IGF receptor, and proliferating cell nuclear antigen (PCNA). Histologically we found immature woven bone in the middle of the callus zone and increasing calcification and lamellar bone in the re-modelling zone. Osteoblasts and fibroblast-like cells in the middle zone, and osteoblasts in all zones stained for TGF-beta and its receptor. The number of positive staining cells related to proliferous activity as assessed both by PCNA, and by bone density in radiographs. IGF-I could be detected everywhere. In conclusion, growth factors are present in bone formation and in areas of re-modelling during callotasis. Their relation to proliferous activity and radiographic density supports their involvement in osteogenesis.