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Biomedical subjects

G Bauer

Publications and source records attributed to G Bauer.

At least 217 records · Page 12Linked to original sources

Risk of dying after a free fall from height.

Falls from height are predominantly an urban phenomenon and represent an important form of blunt trauma. Disagreement predominates regarding the height at which death results. The aim of this study was to investigate the risk of dying after a free fall from height in relation to the distance fallen. Therefore, medical records of victims of a fall from height treated in 1989 at Viennese emergency units were analysed. In addition, post-mortem reports of deaths due to falls from height, examined in the same year at the Institute of Forensic Medicine in Vienna, were studied. For the purpose of an homogenous investigation sample in regard to physical condition, only people aged from 20 to 50 years were taken into account. A total of 11 females and 30 males suffered an accidental fall from buildings, seven men from scaffolding and two men from a tree. A total of 18 females and 18 males jumped from residential buildings. One woman and nine men intentionally fell from other buildings. All victims landed on concrete or pavement. Suicidal jumps occurred from significantly higher places than accidental falls. The results of this analysis suggest that death usually occurs when distance is more than five storeys.

Accidental Falls↗

Common subtypes of idiopathic generalized epilepsies: lack of linkage to D20S19 close to candidate loci (EBN1, EEGV1) on chromosome 20.

Hereditary factors play a major role in the etiology of idiopathic generalized epilepsies (IGEs). A trait locus (EBN1) for a rare subtype of IGEs, the benign neonatal familial convulsions, and a susceptibility gene (EEGV1) for the common human low-voltage electroencephalogram have been mapped close together with D20S19 to the chromosomal region 20q13.2. Both loci are potential candidates for the susceptibility to IGE spectra with age-related onset beyond the neonatal period. The present study tested the hypothesis that a putative susceptibility locus linked to D20S19 predisposes to spectra of IGEs with age-related onset from childhood to adolescence. Linkage analyses were conducted in 60 families ascertained through IGE patients with juvenile myoclonic epilepsy, juvenile absence epilepsy or childhood absence epilepsy. Our results provide evidence against linkage of a putative susceptibility gene for four hierarchically broadened IGE spectra with D20S19 assuming tentative single-locus genetic models. The extent of an "exclusion region" (lod scores below-2) varied from 0.5 cM up to 22 cM on either side of D20S19 depending on the trait assumed. These results are contrary to the expectation that a susceptibility gene in vicinity to D20S19 confers a common major gene effect to the expression of IGE spectra with age-related onset from childhood to adolescence.

Chromosome Mapping↗

Reactive oxygen species act at both TGF-beta-dependent and -independent steps during induction of apoptosis of transformed cells by normal cells.

We have recently shown that TGF-beta-treated normal fibroblasts can induce apoptosis of transformed cells. The overall process was inhibited by antioxidants and radical scavengers, pointing to a role of reactive oxygen species (ROS). To define the ROS-dependent steps precisely, our experimental system was dissected into three phases. During phase I, TGF-beta 1 induced production and release of apoptosis-inducing signal molecules by normal cells. In phase II, these signal molecules were transferred between normal and transformed cells. During phase III, transformed cells went into apoptosis. The use of antibody directed against TGF-beta revealed that TGF-beta was required only during phase I. Application of radical scavengers and antioxidants at defined phases revealed that reactive oxygen species are involved specifically with biochemical processes induced by TGF-beta in normal cells and early in signal transfer between normal cells and transformed cells. These data therefore point to a functional role of reactive oxygen species both for the TGF-beta 1-induced signal pathway in normal cells and for the induction of apoptosis in transformed cells.

Acetylcysteine↗

[The "low contact plate" for stabilizing the dislocated intra-articular calcaneus fractures].

Open reduction and internal fixation of intraarticular calcaneus fractures have been increasingly emphasized in recent years. Operation of most of these fractures is via an extended lateral approach. Different implants are used to stabilize the often complex fractures. We have developed a low contact plate that is specially designed for calcaneal fractures. Because the design is based on the anatomy of the calcaneus, all types of fractures can be treated. The plate has a large number of holes to accommodate screw fixation. Our results in 36 cases were comparable to those of other series using open reduction and internal fixation with plates and the demands on the plate were fulfilled.

Adolescent↗

Calcaneal fractures cause a lateral load shift in Chopart joint contact stress and plantar pressure pattern in vitro.

In order to evaluate the effects of the anatomical changes after calcaneal fractures on joint loading characteristics we investigated the effects of simulated calcaneal fractures on intra-articular loading in the Chopart joint and on plantar pressure patterns in vitro. Five fresh-frozen lower leg specimens were axially loaded with 500 N in three positions: neutral, 10 degrees plantarflexion and 10 degrees dorsiflexion. The loading characteristics were determined before and after creating a tongue-type fracture by osteotomy. Plantar loading patterns were measured with a capacitive pressure distribution platform. Intra-articular contact areas and pressures were recorded on pressure sensitive film introduced into the talonavicular and calcaneocuboid joint. Increased loading in the calcaneocuboid joint (+25%,p = 0.005) and decreased loading in the talonavicular joint (-16%,p = 0.01) corresponded to increased loading of the lateral aspects of the plantar surface. These findings were independent of the foot position. The results suggest that the effects of increased lateral foot loading which have been observed in calcaneal fracture patients (Rosenbaum et al., Clin. Biomech. 10, 345-351, 1995) are caused by changes in joint kinematics and do not appear to result from a protective gait pattern established after the injury.

Adult↗

Brain lipid peroxidation and hydroxy radical attack following the intravenous infusion of hydrogen peroxide in an infant.

Death following peroxide administration in humans has been reported repeatedly. Hydrogen peroxide, an odorless and clear solution is considered a harmless liquid and is in use for cleaning of superficial wounds. We describe the fatal infusion of this compound by mistake leading to oxygen embolism and, subsequently, to death as a warning for the clinician. Hydrogen peroxide is suggested a major substrate for the in vivo production of the potent oxidizing free radical species "hydroxy radical." No direct evidence for its in vivo production from hydrogen peroxide has been described so far. Using the principle of o-tyrosine determination we studied the formation of the hydroxy radical in the postmortem brain of the infant given intravenous hydrogen peroxide in comparison to postmortem brain samples from five infants. o-Tyrosine is formed by hydroxy radical attack on free and bound phenylalanine and was increased twofold in the brain of the infant given hydrogen peroxide. The significant increase of brain malondialdehyde, a major product and indicator of lipid peroxidation, paralleled the findings of hydroxy radical attack, suggesting that this reactive species has been leading to elevated lipid peroxidation. We propose that the generation of lipid peroxidation and the hydroxy radical from hydrogen peroxide can take place in humans.

Brain↗

Exclusion of linkage between idiopathic generalized epilepsies and the GABAA receptor alpha 1 and gamma 2 subunit gene cluster on chromosome 5.

Hereditary factors play a major role in the etiology of idiopathic generalized epilepsies (IGEs). The pivotal function of ionotropic gamma-aminobutyric acid type A receptors (GABRs) in inhibitory neurotransmission in the mammalian central nervous system suggests that they may be involved in epileptogenesis and genetic predisposition to IGEs. Dinucleotide repeat polymorphisms associated with the human GABAA receptor alpha 1 (GABRA1) and gamma 2 subunit (GABRG2) gene cluster on chromosome 5q32-q35 offer the opportunity to test whether these candidate genes confer susceptibility to IGEs. Our linkage analyses in 63 families ascertained through IGE patients with either juvenile myoclonic epilepsy, juvenile absence epilepsy or childhood absence epilepsy do not support the hypothesis that variants within the GABRA1 and GABRG2 gene cluster contribute a frequent major gene effect to the expression of the common familial IGEs.

Base Sequence↗

Lack of linkage between idiopathic generalized epilepsies and the gene encoding the neural cell adhesion molecule.

Hereditary factors play a major role in the etiology of idiopathic generalized epilepsies (IGEs). The frequent neuropathological occurrence of microdysgeneses in the brain of IGE patients implies that genes regulating neural migration and cell adhesion might be involved in epileptogenesis of age-related generalized seizures. Our present linkage study tested the hypothesis that DNA sequence variants associated with the gene encoding the neural cell adhesion molecule (NCAM) confer genetic susceptibility to IGE traits in 57 families ascertained through patients with either juvenile myoclonic epilepsy, juvenile or childhood absence epilepsy. Our consistently negative results provide evidence against a common major effect of NCAM gene variants to the expression of IGEs with age-related onset from childhood to adolescence.

Adult↗

[Functional deficits of the foot after calcaneus fracture].

The present study investigated the clinical and functional outcome of calcaneal fractures. 14 patients were evaluated at a mean follow-up of 52 months. Two groups, group A with good and group B with poor calcaneal restoration were distinguished by Böhler's angle. Ten normal subjects were used for comparison. Clinical results were evaluated with a questionnaire, radiography and range of motion measurements. Plantar pressure patterns were recorded with a capacitive pressure distribution platform. A comparison of the injured and healthy foot of all patients revealed a load shift towards lateral foot regions. A comparison of the patient groups with the controls did not reveal more pronounced changes in the poorly restored group. The results demonstrate that a disturbance of foot function persists even after long healing.

Adult↗

Tenodesis versus carbon fiber repair of ankle ligaments: a clinical comparison.

To compare the clinical and functional outcomes after using different reconstruction methods for chronic ankle instability, the authors followed 2 groups of patients after 69 and 72 months, respectively. Thirty patients (mean age, 28; range, 23-39 years) were treated with modified Evans tenodesis. Twenty-three patients (mean age, 32.2; range, 22-39 years) underwent total replacement of the lateral ankle ligaments by carbon fibers. The protocol of the retrospective study included a questionnaire, clinical examination, radiographic stress diagnostics, and gait analysis with use of the EMED-SF system. Dorsiflexion and inversion were significantly restricted after tenodesis in contrast to the carbon fiber replacement. Although radiographic stability was improved after surgery for both groups, progress of the arthrosis could not be stopped. After tenodesis, the measurement of plantar pressure distribution revealed a 20% increase of midfoot loading as compared with the opposite foot, whereas symmetrical loading of both feet was found after carbon fiber replacement. Additionally, the tenodesis feet had a significantly increased loading of the medial side of the foot. It was concluded that tenodesis and anatomic reconstruction of ankle ligaments lead to subjectively similar results. Foot function and range of motion, however, were less influenced after anatomic repair.

Adult↗