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Biomedical subjects

U Bosch

Publications and source records attributed to U Bosch.

At least 91 records · Page 5Linked to original sources
PubMed1991

Influence of immobilization on autograft healing in the knee joint. A preliminary study in a sheep knee PCL model.

The influence of immobilization on patellar tendon autograft healing was investigated in 12 sheep with replaced posterior cruciate ligaments of the knee (PCLs). In one group achillotomy immobilized the operated knee joint. In another group initial reduced weight-bearing was obtained by hanging the sheep in a special trapeze. In the third group no protection at all was given to the operated knee. The sheep in this group went within 8 weeks from partial use of the operated leg to unrestricted weightbearing and mobility. Biomechanical testing 16 weeks after the operation demonstrated a considerable decrease in the maximum force, ligament stiffness, and strain values in the achillotomy group, as well as an increase in posterior laxity. The best data were observed in the no-protection group. This study demonstrates the negative effect of immobilization on autograft healing in a sheep PCL model. Even early in the healing process tissue may be extremely sensitive to stress and strain.

Animals↗
PubMed1991

[Compartment syndrome of the pelvis].

In the pelvic region three major compartments (gluteus medius-minimus, gluteus maximus and iliopsoas) can be distinguished from the smaller compartment of the tensor fasciae latae muscle. Pelvic compartment syndromes are rare. A clear history of trauma is often lacking. Association with drug and alcohol abuse is common as well as an association with the widespread use of anticoagulant therapy. From 1982 to 1988 six acute buttock compartment syndromes were treated in the Trauma Department of Hannover Medical School. In five patients fasciotomy of the gluteal compartment was performed. Two patients with a compartment syndrome secondary to necrotising fasciitis died of septic multiple organ failure. The mean follow-up of the four other patients was 29 months (7-48 months). Three of these four patients revealed a decrease of gluteal muscle volume. Ergometric tests showed a decrease in gluteal muscle strength in all patients.

Adolescent↗
PubMed1991

[Age, activity and strength of knee ligaments].

The cruciate ligaments of older persons are thought to have diminished biomechanical properties. On the other hand, joint immobilization also leads to similar functional losses in ligaments. It can be difficult to differentiate between these factors in older and immobile persons. The anterior and posterior cruciate ligaments of six younger (average age 30 years) and six older (average age 64.7 years) donors with similar levels of activity were subjected to biomechanical testing. Each sample had to meet the following conditions: appropriate age, no chronic vascular and cardiopulmonary disease found on autopsy, no signs of osteoarthrosis and no knee injuries. The material properties of maximum stress (e.g. ACL: young/old 24/21N/mm2), elastic modulus (e.g. ACL: young/old 144/129 MPa), and strain (e.g. ACL: young/old 25/28%), did not differ significantly (p less than 0.05). This indicates that older persons who are active do not necessarily show functional losses in the cruciate ligaments. Other data found in the literature can be ascribed to immobilization influences. In this data many of the older test persons had chronic vascular insufficiency, cardiopulmonary disease or malignancies.

Aged↗
PubMed1991

Ultrastructural changes of the patellar tendon as a cruciate ligament substitute (one year and two year results).

In four black-faced sheep, the posterior cruciate ligament was replaced with a free autogenous patellar tendon transplant. Tissue samples from the transplants were investigated by light and electron microscopy 1 year and 2 years after surgery. The normal contralateral posterior cruciate ligament and the normal contralateral patellar tendon were used as controls. The structural differences concerned cells, collagen fibrils, elastic tissue and proteoglycans. Most of the cells of the contralateral patellar tendon were spindle-shaped, whereas those of the transplant were frequently chondroid. In the central region of the transplant as well as in the area far from the bone, cell degenerations, and occasionally hypo- or even acellular zones were found. Measurements of the diameter of collagen fibrils in both contralateral patellar tendon and posterior cruciate ligament showed a more or less pronounced bimodal distribution. A unimodal distribution with mainly thin fibrils (20-60 nm) was demonstrated in the transplant tissue which also revealed some morphological alterations of the collagen fibrils. Thin elastic fibers (microfibrils and amorphous material) were randomly scattered among the collagen fibrils of the control samples, bundles of microfibrils (without amorphous material) characterized the transplant. Staining with Alcian blue in the presence of 0.3 M MgCl2 demonstrated a close relationship between proteoglycans and collagen fibrils as well as elastic components in patellar tendon. This arrangement was lost in the transplant where abundant proteoglycans were revealed which, however, composed a tight irregular network between the collagen fibrils. The results serve as a baseline for understanding the impaired biochemical properties of a free autogenous patellar tendon transplant.

Animals↗
PubMed1990

[The pedestrian-automobile accident at lower velocity. Experimental studies of biomechanical and clinico-prognostic topics].

The influence of bumper configuration on injury patterns resulting from car/pedestrian collisions were analyzed. 18 experimental settings were carried out on the deceleration device of the Institute of Forensic Medicine of the Medizinische Hochschule Hannover using a middle class passenger car at collision speed of 32 km/h. Three modifications of the standard bumper design did not reduce the severity of injuries induced by collision. Comparatively promising results were given by another bumper construction consisting of an additional bumper relatively easy to deform attached to the standard variant at a level of 12 cm below. Authors discuss findings regarding injury patterns, injury mechanisms and subsequent implications. Based on trauma surgeons' experience it is suggested not only to aim on reduction of bone injuries. Major attention has to be paid on improving rehabilitation prognosis and on reducing medical treatment expenses. According to data available soft tissue damage is of major importance and needs to be quantified before taking one particular bumper construction as pedestrian friendly design.

Accidents, Traffic↗
PubMed1990

[Healing phases in autogenous posterior cruciate ligament replacement. A decision aid for after-care. A biomechanical and histologic study].

In a sheep model for reconstruction of the posterior cruciate ligament using the central one-third of the autogenous patellar tendon and immediate mobilization, the incorporation course was studied biomechanically, histomorphometrically and radiographically at eight different points in time up to 1 year after surgery. Four different phases of autograft healing were demonstrated on the basis of the histological events. The biomechanical data were correlated with the morphological findings. Phase 1--necrosis--was characterized by a maximum of necrotic autograft tissue 2 weeks postoperatively. Initially, graft strength was determined by the surgical fixation strength. During phase 2--revitalization--the autograft showed cellular proliferation and revascularization, starting from the periphery. The autograft was determined to be weakest during this phase. Phase 3--collagen formation--revealed a marked increase in newly formed collagen tissue between weeks 12 and 16. A significant increase in maximum load and stress was measured. In phase 4--remodeling--the longest phase, the collagen tissue appeared more compact and less cellular. The fiber bundles were arranged more longitudinally. However, the biomechanical properties remained clearly below that of a normal posterior cruciate ligament.

Animals↗
PubMed1989

Toxicity and toxin production by Fusarium isolates from New Zealand.

Sixty-two isolates of Fusarium were obtained from pasture grass and soil from various areas of New Zealand and identified as F. anthophilum, F. avenaceum, F. crookwellense, F. culmorum, F. graminearum, F. nivale, F. oxysporum, F. sambucinum, F. semitectum, F. tricinctum and an unidentified Fusarium spp. These isolates were grown on autoclaved rice and tested for toxicity to rats in feeding tests. Eighty two percent of the isolates were toxic, of which twenty-four percent were severely toxic and caused hemorrhages of stomach and intestine, hematuria, and finally death. Cultures of the most toxic isolates contained 0.1 to 104 ppm of deoxynivalenol, 0.7 and 7 ppm of 15- and 3-acetyldeoxynivalenol respectively, 0.2 to 4 ppm of fusarenon-X, 11 to 1021 ppm zearalenone, 40 to 272 ppm of the hemorrhagic factor (wortmannin), 2,100 to 7,200 ppm of moniliformin, 565 ppm of the cytotoxic factor (HM-8) and enniatin in substantial concentrations. F. sambucinum is reported as a moniliformin producer for the first time.

Animals↗
PubMed1989

Biological aspects of long-term failure of autografts after cruciate ligament replacement.

The alterations of the ultrastructure of the posterior cruciate ligament autograft of patellar tendon origin were examined in a sheep model 1 year after surgery. The ultrastructure was also compared with that of the normal contralateral posterior cruciate ligament and patellar tendon. The most striking finding was the unimodal distribution of the collagen fibrils, with a predominance of loosely packed thin fibrils in the central portion of the autograft. The results suggested that the remodeled autograft tissue became highly organized but never exhibited the ultrastructural features of a ligament. This could be responsible for the decreased biomechanical properties and the long-term failure of a patellar tendon autograft.

Animals↗
PubMed1989

Healing at graft fixation site under functional conditions in posterior cruciate ligament reconstruction. A morphological study in sheep.

The incorporation course at the fixation sites of a free patellar tendon graft used in posterior cruciate ligament reconstruction was examined in eight adult sheep. After surgery the sheep were functionally treated without any protection of the operated legs. Two, 6, 12, 16, and 26 weeks after surgery the sheep were killed and the character of biological attachment to bone at fixation sites was evaluated using macroradiography, high-resolution radiography, and routine histology. After 6 weeks good osseous incorporation of the bone pegs of free patellar tendon grafts could be demonstrated at the desired position.

Animals↗
PubMed1988

[Risk of lung embolism following preventive intravenous use of heparin in polytraumatized patients].

The risk of thrombo-embolic complications in multiple injured patients is increased due to several pathophysiological factors. The purpose of this study was to analyse the effect of a continuous IV heparin prophylaxis (10000IE/24h) in polytraumatized patients. A post-mortem evaluation of 72 decreased patients out of 373 multiple trauma patients treated during 1984-1985 was performed. In one patient multiple major pulmonary emboli were found to contribute to his death. No deep vein thrombosis as well as no fulminant pulmonary embolism were found in any case.

Adolescent↗
PubMed1988

[Prevention of thromboembolism in surgery].

Thromboembolic complications are one of the most common complications in patients undergoing major surgery or conservative treatment in cast. The incidence of thromboembolic complications is the highest in orthopedic and trauma surgery. Stasis in the deep veins of the lower extremity, intimal damage and disorders in blood coagulation are important factors in the pathogenesis of deep vein thrombosis. The most important predisposing risk factors are age, previous thrombosis, varices and the combination of oral contraceptives and smoking. 50% of thrombosis begins intraoperatively and 80-90% in the first 3-4 days after operation. The incidence of thromboembolic complications was significantly reduced after introduction of low-dose heparin and heparin with dihydroergotamine in the perioperative regimen. Recently various investigations demonstrated that low-molecular-weight heparin (LMWH) is equally as effective as a low-dose heparin regimen in preventing postoperative thromboembolic complications. Our own management of prophylaxis of thromboembolic complications is presented. In a prospective pilot study 100 trauma patients were evaluated. 84 patients received LMWH plus dihydroergotamine (DHE), 12 patients heparin alone because of contraindications for DHE and 4 patients received a low dose continuous intravenous heparin prophylaxis because of high risk. Two deep vein thrombosis occurred, one in a patient with high risk prophylaxis and one in a patient with a subcutaneously heparin prophylaxis. No thromboembolic complications occurred in patients with LMWH + DHE prophylaxis.

Heparin, Low-Molecular-Weight↗
PubMed1988

[Significance of lung contusion in mortality following polytrauma. Possibilities for therapeutic influence].

Multiple trauma is often associated with blunt thoracic injuries. Especially lung contusion can result in respiratory insufficiency and therefore a higher mortality rate. In our prospective study comparing 8 multiple trauma patients with and without associated lung contusion, we found that respiratory function was already significantly disturbed (decrease of paO2/FiO2 and increase of AaDO2, a rise in extravascular lung water (EVLW) both early after trauma and also with a second peak following the 4th day. This group (LK) developed significantly more cases of respiratory distress (ARDS). The disturbance of respiratory function seen initially was interpreted as a consequence of the direct mechanical impact, leading to the formation of interstitial fluid and hematoma. The frequent development of ARDS in the LK-group probably results from a pronounced activation of cellular and humoral mechanisms and therefore an enforced injury of the pulmonary capillary bed. A significant increase of pulmonary infections or the development of sepsis was not seen in the LK-group and is probably not responsible for the higher ARDS-rate in this group.

Adolescent↗
PubMed1988

[Wounds and wound treatment, prevention of tetanus].

The care principles of injuries base on founded knowledge about the phases of wound healing, the causes of wound healing disturbances and the development of wound infections. The wound care includes the judgement of injuries, the surgical wound treatment and the aftercare. The wound evaluation with four categories makes a different therapeutic approach possible. The primary union is aspired to all non-infected wounds by direct wound closure. Suspicious infected and infected wounds are treated open after adequate wound excision. A secondary suture with a delayed primary wound closure is possible when the inflammation symptoms are recurrent. Other important aspects of wound care are a correct wound dressing, wound control and the checking for tetanus prophylaxis.

Humans↗
PubMed1988

[The infected wound].

The therapy of infected wounds is based on the knowledge of the pathophysiology of infection and on early diagnosis. The development of an infection depends on the general condition of the patient, local factors like foreign body contamination and tissue necrosis and the pathogenicity of the bacteria. The diagnosis of a wound infection is made upon the classical symptoms dolor, rubor, calor, tumor and functio laesa and depends on continuous wound care and repeated clinical judgement. The differentiation between an abscess as encapsulated infection and a diffuse non localized phlegmonous inflammation has different therapeutic consequences as the surgical treatment of an abscess consists of incision and drainage whereas the excision of infected tissue is necessary in phlegmones. The wound revision is a special form of excision. The surgical debridement is the most effective part of the therapy. Excision of infected and necrotic tissue help the phagocytic cells in infection fighting and remove the ideal culture medium for bacteria. The use of antibiotics can be very helpful if stringent indications are applied. Additional therapeutic approaches like improvement of local oxygen supply and enhancement of phagocytic function of macrophages could support the surgical therapy of the infected wound.

Abscess↗