Biomedical subjects
Publications and source records attributed to M Schütz.
The human endothelial membrane antigens HECMA 112 and VE-cadherin were immunochemically compared. The antibodies 1.3.1 against HECMA 112 and 7B4 against VE-cadherin recognized the same protein in extracts of tissue as well as of cells. The antigen HECMA 112 was immunoprecipitated by anti-VE-Cadherin antibody 7B4.
Operative treatment of subtrochanteric femur fractures is demanding. The implants available follow different biomechanical and surgical principles. Extramedullary implants like the condylar blade plate and the dynamic condylar screw require subtle surgical and indirect reduction techniques. Intramedullary implants like intramedullary hip screws and interlocking nails are biomechanically advantageous. In contrast to the extramedullary implants these fixations can stand postoperative weight-bearing. The different operative techniques for the fixation of subtrochanteric fractures are presented and evaluated. Current trends in treatment rationales are outlined.
The emergency stabilization of unstable pelvic injuries, in particular, injuries to the posterior pelvic ring, can be achieved following reduction by application of the pelvic C-clamp. This and other procedures contribute to controlling what is almost always a life-threatening blood loss. The pelvic C-clamp is a temporary measure preceding definitive treatment of the injury. If this procedure is to have an optimal and lasting effect, the clamp must be applied correctly, provide adequate compression and stability, and be easy to handle. In one year, we applied the AO and ACE pelvic clamps in 9 clinical cases. Satisfactory primary compression and stability were achieved for unstable injuries with both clamps. It was more difficult to achieve good rotational stability as required for subsequent treatment with the ACE clamp due to its construction design.
Endothelial cells were isolated from human full-term placenta by perfusion with trypsin solution via the umbilical cord vein. Human placental endothelial cells (HPEC) were successfully grown and kept in culture. HPEC exhibited endothelial characteristics as judged by morphology of confluent monolayers, staining with low density lipoprotein, binding of Ulex europaeus I lectin, and immunostaining against von Willebrand factor, alpha-thrombomodulin, VE-cadherin and a series of integrins. Different growth requirements and particular morphological characteristics indicated the different vascular origin of HUVEC and HPEC.
Fractures of the femoral shaft are combined in 2-5% of all cases with an ipsilateral fracture of the proximal femur. These double fractures are mostly caused by high energy trauma. An analysis of 9 selected papers points to the problem. In more than 10% the proximal fracture is not diagnosed initially. In the literature nearly 30 different operative treatments are described and underline the demands on proper operative techniques and implants for ipsilateral femoral shaft and hip fractures. In this publication the new unreamed femoral nail system (UFN) with a special proximal interlocking option for double fractures will be presented. This system provides a good possibility to stabilize femoral double fractures in an easy and safe manner.
The advantages of the unreamed nailing technique compared to the reamed procedure are less damage to bone vascularity, lower intramedullary pressure during the operation and a fast operation time. These new solid nails with high mechanical stiffness and no central dead space have extended the nail indications for tibial as well as for femoral fractures, particularly in tibial shaft fractures with severe soft tissue damage and in polytraumatized patients with a femoral shaft fracture. Besides these advantages the new AO unreamed femur nail has a modular proximal interlocking system, which increases significantly the range of indications for nailing. Not only very high subtrochanteric femur fractures can be stabilized with greater stability, but also combined ipsilateral fractures of the shaft and the proximal femur can be treated with this new nail. The first clinical results of the AO unreamed nails for the tibia as well as for the femur are very encouraging. The unreamed nails prove to be excellent implants in the treatment of long bone fractures of the lower extremity.
One serious disadvantage of conventional fixator systems is the need to open the medullary space, hence creating a direct communication with the exterior. The new pinless external fixator does not have this major disadvantage, because the fixator clamps simply rest on the cortical bone without penetrating it. Clinically, this easily managed system is intended for fractures of the tibia in cases in which primary internal fixation is precluded either by precarious local or general conditions or by infrastructural problems. In such situations the new pinless fixator is an excellent device with which to achieve good stabilization of the fracture rapidly, while leaving open all options for subsequent alteration of treatment. If the surgeon decides to convert to locked intramedullary nailing, the pinless fixator facilitates the new approach, because it can be used as a distractor and makes it unnecessary to transfer the patient to a fracture table.
In the period from 1. January to 31. December 1992, the new pinless external fixator was applied in eight European and North American clinics as part of a prospective multicentric study run by the AO/ASIF Documentation Centre. The aim of this study was to determine the indications, handling, and clinical results with the new fixator. The new pinless fixator was used 77 times on a total of 75 patients. The main indications were fresh tibial shaft fractures for which immediate definitive treatment was impossible. The majority of cases were secondarily stabilized with an unreamed tibial nail once the local and/or general condition of the patient had improved. In the remaining cases the pinless fixator was used for calcaneal and tibial head traction, segment transport and temporary stabilization in cases of tibial infection. Only after long-term application of the fixator was local infection at the pin site observed. There were no other complications. The new pinless fixator is a valuable addition in the treatment of fresh tibial fractures, in particular, in those cases which cannot be primarily treated due to contributing factors whether local or general.
Calcaneus traction with a Steinmann-pin or K-wire inserted into the dorsal aspect of the calcaneus is a common temporary procedure in fractures of the lower leg when internal fixation has to be delayed. Infection due to this simple manoeuvre is rare, but is a very serious complication. In 1991, a so-called pinless external fixator was introduced in clinical trials, based on the idea of external fixation without transosseus pins, thus preserving local blood supply and lowering the risk of pin track infection. This pinless clamp also represents a handy tool for calcaneus traction. We have used this pinless clamp for calcaneus traction in 39 patients without any major problems or complications. Of these, 29 patients were scheduled for delayed internal fixation, and in 10 patients this clamp was used intraoperatively in closed tibial nailing for traction on the fracture table. Tips and tricks for the use of this pinless clamp, and its advantages and disadvantages are discussed.
The unreamed femoral nail system (UFN) features highly versatile proximal interlocking options for the treatment of a wide range of femoral fracture patterns and combinations. Besides standard interlocking modes for diaphyseal fractures, special interlocking options for subtrochanteric fractures and ipsilateral neck/shaft fractures are available. Two aiming arms can be attached to the insertion handle of the nail in a modular fashion. The standard aiming arm is designed for transverse static or dynamic locking. The special aiming arm permits spiral blade, 130 degrees, and miss-a-nail interlocking. From August 1992 to July 1994, in 10 out of 55 UFN implantations the special interlocking options were used. In 9 subtrochanteric fractures the spiral blade interlocking and in one ipsilateral neck/shaft fracture the miss-a-nail cancellous screw interlocking was applied. ASIF type A fractures with closed soft tissue damage prevailed. Fracture healing was uneventful and no implant complications or loss of reduction have been observed.
A serious disadvantage of conventional external fixators is the opening of the medullary canal. This creates a direct communication between the canal and the exterior. The new pinless external fixator does not have this disadvantage. The clamps of the new fixator system do not penetrate cortical bone, they simply rest on the cortical surface. The clinical indications of this easily managed system are fractures of the tibial shaft in cases in which primary internal fixation is precluded either by precarious local or general conditions, or even by a lack of infrastructure. In such situations the pinless external fixator is an excellent device to achieve a good fracture stabilisation rapidly, while leaving open all subsequent alteration of treatment. In case of secondary change to an intramedullary nail the pinless fixator facilitates the procedure, because this fixator can be also used as an distractor during nailing. Furthermore this fixator can be combined with any intramedullary nail to increase the stability in case of very proximal or distal as well as highly instable shaft fractures. The clamps of the pinless external fixator set are used in combination with the standard AO fixator system.
From the beginning of 1988 to July 1991, ten Swiss and German clinics undertook to document all cases of internal fixation using the titanium LC-DCP as part of a prospective multicenter study. The follow-up period was 14.2 months on average. The clinical results of 504 fixations were convincing. The follow-up rate was 72%. Of these, 95% healed without complication. The most frequent complication was delayed healing which occurred in 2.5% of cases. The infection rate was low (1.1%). A separate comparison of DCP fixations on the tibial shaft in 1984-1988 demonstrated the obvious biological compatibility of the new plate and shows that excellent results can be obtained using plate fixation.
During the period from the beginning of 1988 until July 1991 all LC-DCP plate osteosynthesis at the hospital of Davos have been documented in a prospective multicenter study and were followed up after a meantime of 17.6 months. The clinical results of the 57 implantations at the hospital of Davos were excellent as the results of the overall study. 98% of all reexaminated patients (follow up rate 81%) had an uneventful clinical course. The results demonstrate the good biological tolerance of the new plate and underline, that in combination with a careful soft tissue handling excellent clinical outcomes can be reached with this plate osteosynthesis.
Calcaneus traction is a common temporary procedure in fractures of the lower leg, when an internal fixation is not permitted for soft tissue reasons. Usually a Steinmann-pin or a K-wire is driven across the calcaneus, which is a simple manoeuvre performed in local anaesthesia. Infection due to this perforation of the calcaneus are rare, but signify for the patient a catastrophic complication. With the introduction of the pinless external fixateur in 1991 in clinical trials a very handy pinless-clamp exists, which can safely be anchored in the heel and thus permits safe calcaneus traction without any transosseous fixation. We have used this pinless clamp in 39 patients for various reasons and haven't stated any major complications. The clamp has proved to be very useful for temporary traction as well as for the fixation of the leg during closed intramedullary nailing using the fracture table.
Based on the AO Classification of Fractures, the classification of fractures of the proximal femur will be explained. Especially the sub- and pertrochanteric fractures, as well as the fractures of the femoral neck will be considered. During the period from 1980-1989 26,126 fractures of the proximal femur were documented in the AO/ASIF Documentation Center. These fractures will be discussed regarding following aspects: dispersion of age and fractures, pre-existing systemic illnesses, general and local postoperative complications, choice of implant.
From the cell walls of various Phytophthora species (Oomycetes) different water-soluble beta-1,3/1,6-glucans were isolated and characterized. The glucans with relative molecular masses between 13 and 50 kd exhibited varying degrees of branching in the beta-1,3-linked glucan backbone ranging from 14 to 50%. The dose-dependent antitumor activity of the glucans against allogeneic sarcoma-180 was investigated. It could be demonstrated that beta-1,3/1,6-glucans with relative molecular masses below 50 kd can exhibit a prominent antitumor activity (inhibition rate up to 99%), being comparable to that of the high relative molecular mass (450 kd) beta-1,3/1,6-glucans. Biological activity of the glucans could be shown to be correlated with a low degree of branching. The most potent glucan with a degree of branching of 14% also was active against the syngeneic DBA/2-MC.SC-1 fibrosarcoma (inhibition rate up to 90%) and in combination with a suboptimum dose of diethylstilbestrol against Nobel-Nb prostate carcinoma (inhibition rate up to 90%).
Ganglioneuroma is an uncommon benign tumor of the sympathetic nervous system. In most cases it originates from the thoracic or lumbar portion of the gangliated cord or from the medulla of the suprarenal glands. It is the differentiated form of malignant neuroblastoma. The tumor often manifests itself in young adults by displacement of the surrounding structures. In the case presented the special diagnostic problems of locating the tumor in the pelvis in early pregnancy are discussed.