Biomedical subjects

G Bauer

Publications and source records attributed to G Bauer.

At least 235 records · Page 13Linked to original sources

PubMed1996

Early, full weightbearing with flexible fixation delays fracture healing.

Secondary fracture healing is known to be accelerated by the process of periosteal callus formation that can be induced by flexible fracture fixation in connection with loading of the injured extremity. The purpose of this study was to compare the healing of experimental fractures of long bones in sheep under early weightbearing with that of fractures under delayed, steadily increasing weightbearing. Differences in the quality of fracture healing were described by biomechanical (rigidity of fracture, indentation stiffness of callus) and histologic methods. Prevention from early, full weightbearing resulted in a higher flexural rigidity of the fracture, an increased mechanical stiffness of the callus tissue, and an enhanced bone formation at the healing front. Although early loading of a fresh fracture initiated an enormous amount of periosteal callus, the healing of the osteotomy was significantly delayed, and the quality of the newly formed tissue was reduced as compared with fractures with a reduced loading situation. A reduction of load transfer by delaying full weightbearing is advantageous for the healing of fractures stabilized with flexible fixation systems.

Animals↗

PubMed1996

Magnetic resonance volumetry of the cerebellum in epileptic patients after phenytoin overdosages.

The aim of this study was to evaluate the relationship between phenytoin medication and cerebellar atrophy in patients who had experienced clinical intoxication. Five females and 6 males, 21-59 years of age, were examined with a 1.5-T whole-body system using a circular polarized head coil. Conventional spin echo images were acquired in the sagittal and transverse orientation. In addition, we performed a high-resolution 3D gradient echo, T1-weighted sequences at a 1-mm slice thickness. The images were subsequently processed to obtain volumetric data for the cerebellum. Cerebellar volume for the patient group ranged between 67.66 and 131.08 ml (mean 108.9 ml). In addition 3D gradient echo data sets from 10 healthy male and 10 healthy female age-matched volunteers were used to compare cerebellar volumes. Using linear regression we found that no correlation exists between seizure duration, elevation of phenytoin serum levels and cerebellar volume. However, multiple regression for the daily dosage, duration of phenytoin treatment and cerebellar volume revealed a correlation of these parameters. We conclude that phenytoin overdosage does not necessarily result in cerebellar atrophy and it is unlikely that phenytoin medication was the only cause of cerebellar atrophy in the remaining patients. Quantitative morphometric studies of the cerebellum provide valuable insights into the pathogenesis of cerebellar disorders.

Adult↗

PubMed1996

[Foot stress simulator for biomechanical in vitro studies of lower leg segments].

In this paper we describe a foot-loading simulator that permits in vitro studies on human lower leg and foot specimens. The specimens are fixed in a jig and loaded axially with the aid of a pneumatic cylinder. The resulting transfer of forces through the ankle joint complex and Chopart's articulation (line) can be demonstrated on a pressure-sensitive film. Plantar pressure measurements obtained in patients or normal subjects can be used to ensure the comparability of in vivo and in vitro measurements. The supporting platform can be tilted in such a manner as to provide a range of foot positions up to 20 degrees in plantar- or dorsiflexion, eversion or inversion. The system is used for investigating the effects on the intra-articular pressures and plantar pressure patterns of physiological muscle activity and pathological conditions following fracture of the calcaneum or damage to the lateral ligament. By way of an example, the effects of muscle forces on plantar pressure distribution are presented.

Ankle Joint↗

PubMed1996

[Arthrodesis of the ankle joint].

Arthrodesis of the ankle joint is still an important operation in the treatment of painful arthrosis, chronic infection, and malalignment instability when these cases have been treated unsuccessfully with other therapeutic procedures. To date, prosthetic replacement of the ankle joint has been an alternative only in rheumatoid patients. Concerning the long-term results, ankle arthrodesis is much better than alloarthroplasty. Because of the good functional results achievable by arthrodesis when done in the right position, there is less often a need for prosthetic replacement than in the hip or knee joint. A patient with a fused ankle joint is only limited when running. Compression arthrodesis is possible at present with various operative techniques utilizing external fixators, ring fixators and open reduction internal fixation with plates and screws. The last procedure can be carried out arthroscopically. With these techniques, fusion of the ankle joint in the correct position is possible in nearly all situations, e.g., infection, malalignment, osteoporosis, soft tissue damage. The main complication of ankle arthrodesis is pseudarthrosis (up to 35%) and postoperative infection (3%-25%). An important late sequela is arthrosis in the joints adjacent to the fused ankle joint (10-60%).

Ankle Joint↗

PubMed1996

Elimination of transformed cells by normal cells: a novel concept for the control of carcinogenesis.

Control of transformed cells by neighbouring normal cells is known since the beginning of transformation studies in vitro. The classical explanation for this phenomenon is based on proliferation inhibition of transformed cells by normal cells. We extend this model by presenting data that show that TGF-beta-treated normal cells can eliminate transformed cells by induction of apoptosis. Both the TGF-beta-induced signal pathway in normal cells, leading to the production of a short-lived apoptosis-inducing factor, as well as the specific interaction of this factor with transformed cells depend on the action of reactive oxygen species. Sensitivity to induction of apoptosis seems to be a common feature associated with the transformed state, independent of the originally transforming principle. Therefore, tumor development should require either interference with the process of elimination or acquisition of resistance against it. We discuss experimental evidence for interfering substances, such as antioxidants, as well as for genetic systems that protect transformed cells from the negative effects of their cellular environment, such as Bcl-2 or papilloma viruses. These findings, as well as the general resistance of exvivo tumor cells against induction of apoptosis are in line with the novel model of control of tumor progression presented by us in this review.

Animals↗

PubMed1996

[Quality control after pelvic injuries with a scoring system].

Quality control after treatment of pelvic injuries is often poor because many criteria of assessment lack objectivity. In order to attain improved comparability of results, we present a scoring system including subjective as well as functional and radiological criteria. The assessment is based on a calculation according to the importance of the criteria. The total score supplies the final result with a breakdown into excellent, good, fair and poor. 33 patients with type B and C injuries (Tile) underwent evaluation with this scoring system. We found 15 excellent, 10 good, 2 fair and 6 poor results. The score showed that patients' most frequent handicap was pain (median 60% of maximum score). Hip mobility was hardly affected, and from the radiological point of view it appeared that alterations of pelvic symmetry and symphysis were most common. Our proposal is to apply this scoring system on a wide basis, because only with a great number of patients can the effectiveness of the score be tested and different ways of treatment assessed with regard to early and late results. Our system could be a useful contribution to sufficient quality control, particularly after such complex and severe injuries.

Activities of Daily Living↗

PubMed1996

Suicidal chloroquine poisoning: clinical course, autopsy findings, and chemical analysis.

Suicidal overdose of chloroquine is rare. We present a 14-year-old girl who was admitted to our Emergency Department after intentional ingestion of 7.5 g of chloroquine base followed by cardiac and respiratory arrest. Despite early mechanical ventilation, cardiac support, and treatment with high doses of diazepam, the patient died. Laboratory investigation indicated disseminated intravascular coagulation confirmed by petechial hemorrhages in the leptomeninges at autopsy, a finding that has not previously been described. Postmortem tissue analysis demonstrated early drug distribution to the medulla oblongata and cerebellum.

Adolescent↗

PubMed1995