Search PubMed⌕ Search

Biomedical subjects

G Bauer

Publications and source records attributed to G Bauer.

At least 163 records · Page 9Linked to original sources
PubMed1999

Hypertonic saline induces prostacyclin production via extracellular signal-regulated kinase (ERK) activation.

BACKGROUND: Hypertonic saline (HTS) resuscitation exerts protective effects in reperfusion injury including a decrease in pulmonary vascular resistance and an increase in microvascular perfusion and cerebral blood flow; however, the mediators of these effects are unknown. Prostacyclin (PGI2) is a paracrine mediator with two main effects, vasodilation and inhibition of platelet aggregation. We hypothesized that HTS may induce PGI2 production by endothelial cells. METHODS: Human umbilical vein endothelial cells (HUVECs) were treated with varying concentrations of NaCl. After 12 h of incubation, the supernatant was assayed for 6-keto-prostaglandin F1, a stable metabolite of PGI2, by ELISA. Phospho-specific ERK-1 and ERK-2 mitogen-activated protein kinase (MAPK) antibody, which recognizes only activated ERK, was used to determine ERK activation status by Western blotting. RESULTS: Addition of 20-100 mM NaCl or endotoxin [lipopolysaccharide (LPS)] induced PGI2 production by HUVECs. HTS and LPS induced ERK-1 and ERK-2 activation. PGI2 production was inhibited when the HUVECs were pretreated with PD 98059, a specific inhibitor of ERK phosphorylation. CONCLUSION: These data suggest that HTS induces PGI2 production in HUVECs. In addition, HTS and LPS induce activation of ERK which is required for PGI2 production. HTS resuscitation may improve microvascular circulation and decrease reperfusion injury via induction of PGI2 production by endothelial cells.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Evaluation of a putative major susceptibility locus for juvenile myoclonic epilepsy on chromosome 15q14.

Juvenile myoclonic epilepsy (JME) is a genetically determined common subtype of idiopathic generalized epilepsy (IGE). Significant evidence for linkage has been reported for a susceptibility locus for JME in the chromosomal region 15q14 that harbors the gene encoding the alpha7 subunit of the neuronal nicotinic acetylcholine receptor (CHRNA7). The present study was designed to test the earlier linkage finding and to explore whether this susceptibility locus is involved in the epileptogenesis of a broader spectrum of IGE syndromes. Multipoint parametric and nonparametric linkage analyses with seven microsatellite polymorphisms encompassing the region of the CHRNA7 gene were performed using two diagnostic schemes of JME-related traits in two groups of multiplex families ascertained through probands with either JME (n = 27) or idiopathic absence epilepsy (n = 30). The present linkage study failed to replicate evidence for a major susceptibility locus for JME in the region encompassing the CHRNA7 gene. In addition, we found no hint in favor of linkage to 15q14 under the broad diagnostic scheme in any of the sets of families. If genetic variation in this region confers susceptibility to JME, then its effect size might be too small or its occurrence too rare to be detected in the investigated families.

Adolescent↗
PubMed1999

Stable transduction of quiescent CD34(+)CD38(-) human hematopoietic cells by HIV-1-based lentiviral vectors.

We compared the efficiency of transduction by an HIV-1-based lentiviral vector to that by a Moloney murine leukemia virus (MLV) retroviral vector, using stringent in vitro assays of primitive, quiescent human hematopoietic progenitor cells. Each construct contained the enhanced green fluorescent protein (GFP) as a reporter gene. The lentiviral vector, but not the MLV vector, expressed GFP in nondivided CD34(+) cells (45.5% GFP+) and in CD34(+)CD38(-) cells in G0 (12.4% GFP+), 48 hr after transduction. However, GFP could also be detected short-term in CD34(+) cells transduced with a lentiviral vector that contained a mutated integrase gene. The level of stable transduction from integrated vector was determined after extended long-term bone marrow culture. Both MLV vectors and lentiviral vectors efficiently transduced cytokine-stimulated CD34(+) cells. The MLV vector did not transduce more primitive, quiescent CD34(+)CD38(-) cells (n = 8). In contrast, stable transduction of CD34(+)CD38(-) cells by the lentiviral vector was seen for over 15 weeks of extended long-term culture (9.2 +/- 5.2%, n = 7). GFP expression in clones from single CD34(+)CD38(-) cells confirmed efficient, stable lentiviral transduction in 29% of early and late-proliferating cells. In the absence of growth factors during transduction, only the lentiviral vector was able to transduce CD34(+) and CD34(+)CD38(-) cells (13.5 +/- 2.5%, n = 11 and 12.2 +/- 9.7%, n = 4, respectively). The lentiviral vector is clearly superior to the MLV vector for transduction of quiescent, primitive human hematopoietic progenitor cells and may provide therapeutically useful levels of gene transfer into human hematopoietic stem cells.

ADP-ribosyl Cyclase↗
PubMed1999

[Tibiocalcaneal fusion for the treatment of talar necrosis. An analysis of 21 cases].

Between 1986 and 1996, 21 patients had a tibiocalcanear arthrodesis. Indications for surgery were in all cases either osteomyelitis or avascular necrosis of the talus. External stabilisation was used in 17 patients due to severe soft tissue damage or extensive infection of the talus, internal screw fixation was used in four patients. There were eight complications in seven patients, one patient had a below the knee amputation. The leg length discrepancies after resection of the talus was equalized in four cases with callus distraction using an Ilisarov ring fixator. Follow up evaluation was available in 18 patients after an average of 38 months (12-86 mo.). There were no infectious recurrencies during the follow up period and a solid fusion was achieved in all patients that were followed. According to a modified Kitaoka score, results were excellent and good in 12 of the 18 patients. External stabilisation, especially the Ilisarov ring fixator is the primary method of treatment in cases with severe infection or soft tissue damage.

Adult↗
PubMed1999

Foreign body asphyxiation--an autopsy study.

PURPOSE: Food asphyxiation is a common problem whenever and wherever people eat. A knowledge of predisposing factors might help to prevent this problem. SUBJECTS AND METHODS: We reviewed 34,476 consecutive autopsies done during a 14-year period (1984 to 1997) at the Institute of Forensic Medicine, Vienna. Demographic features and predisposing factors were determined for the 191 cases of fatal foreign body asphyxiation. RESULTS: Old age, poor dentition, and alcohol consumption were frequent findings. Other risk factors included chronic disease, sedation, and eating risky foods. On 120 (63%) of the 191 occasions, observers were present at the time of the incident and subsequently called the Emergency Service. In 110 (92%) cases, neither the observers nor the majority of the emergency medical technicians and physicians who would have been able to intervene recognized the definite diagnosis. Only 10 cases were correctly identified during cardiopulmonary resuscitation. CONCLUSIONS: These fatal accidents could be prevented easily. Effective prevention depends on understanding the nature and frequency of accidental deaths due to asphyxiation and the factors that lead to their occurrence and having a high degree of suspicion.

Adolescent↗
PubMed1999

Phagocytic killing of microorganisms by radical processes: consequences of the reaction of hydroxyl radicals with chloride yielding chlorine atoms.

Chloride anions and hydrogen peroxide serve as substrates for myeloperoxidase (MPO) in order to produce hypochlorous acid (HOCl) as one of the major killing agents of phagocytic leukocytes. Apart from this role of being a substrate for the MPO-reaction the chloride anion has been considered as unreactive and has not been implicated in radical reactions which contribute to the killing process. From the inherent reactivities of the pertinent radicals (as determined by pulse radiolysis experiments), the great abundance of chloride, and the most probable distribution of reactants within the phagosome, we deduce estimates for the average life-time and free diffusion path-length in this milieu and arrive at a model according to which chloride ions enter into radical chains and influence the killing of ingested bacteria to an extraordinarily high extent. We propose that hydroxyl radicals--despite some controversial arguments in the literature--may still be considered as important contributors to cell killing especially since we show that their reactions are made more effective by producing chlorine radicals in a cyclic process. We furthermore present arguments how the phagocyte may protect itself from harmful actions of HOCl and H2O2 after the superoxide-generating activity of NADPH oxidase is turned off.

Bacteria↗
PubMed1999

[Traumatic dislocation of long fingers at the metacarpophalangeal joint while bowling--case report of an extremely rare injury].

The case of a 55-year old male patient, who got a luxation of the four long fingers while bowling, is presented. After reposition, fixing in "Intrinsic-plus"-position for two weeks and accompanied physiotherapy, a good functional result of the right hand was obtained. Mechanism of accident, diagnosis, therapy and complications are discussed.

Athletic Injuries↗
PubMed1999

[Achilles tendon rupture: epidemiology, etiology, diagnosis and current treatment possibilities].

Treatment of Achilles tendon rupture is up to date not standardized. Open surgical repair in different techniques, percutaneous repair and conservative treatment is controversial in discussion. The following paper shows the different techniques used today in Achilles tendon rupture. Results are represented and discussed. Followed by a recommendation of treatment in acute Achilles tendon ruptures.

Achilles Tendon↗
PubMed1998

Self-organized growth of three- dimensional quantum-Dot crystals with fcc-like stacking and a tunable lattice constant

The self-organization of pyramidal PbSe islands that spontaneously form during strained-layer epitaxial growth of PbSe/Pb1-xEuxTe (x = 0.05 to 0.1) superlattices results in the formation of three-dimensional quantum-dot crystals. In these crystals, the dots are arranged in a trigonal lattice with a face-centered cubic (fcc)-like A-B-C-A-B-C vertical stacking sequence. The lattice constant of the dot crystal can be tuned continuously by changing the superlattice period. As shown by theoretical calculations, the elastic anisotropy in these artificial dot crystals acts in a manner similar to that of the directed chemical bonds of crystalline solids. The narrow size distribution and excellent control of the dot arrangement may be advantageous for optoelectronic device applications.

Journal Article↗
PubMed1998

Targeted transduction of CD34+ cells by transdominant negative Rev-expressing retrovirus yields partial anti-HIV protection of progeny macrophages.

Congenitally acquired HIV infection may be uniquely suited to treatment via genetic engineering of CD34+ hematopoietic stem/progenitor cells. However, current technologies yield only a small percentage of mature cells that carry the inserted genes, and expression is frequently suppressed. Since clinical trials employing these methodologies have been proposed for anti-HIV gene therapy of HIV-infected children, we wished to assess, by in vitro modeling, the expected limits of transduction efficiency, expression, and antiviral activity using currently available methods. We measured retrovirus-mediated transduction in cord blood progenitors and their in vitro-derived progeny macrophages by Mo-MuLV vectors expressing a transdominant negative Rev (RevTD). CFU-GM transduction efficiency ranged from 7 to 85%, with an average of 28%. Semiquantitative DNA PCR demonstrated < or =100 vector sequence copies per 1000 cells in monocyte/macrophage cultures, which were grown without selection to better model in vivo conditions. When challenged with the macrophagetropic HIV-1BaL isolate, cultured macrophages from mock-transduced CFU-GM colonies supported infection in eight of eight experimental cultures, control LXSN-transduced progenitors supported infection in six of eight cultures, while macrophages derived from RevTD-transduced CFU-GM colonies supported infection in four of eight cultures. Although these results support the ability of neo(r) retroviral vectors containing RevTD to inhibit HIV replication, they indicate that further optimization of transduction efficiency and sustained expression will be required for effective anti-HIV protection in vivo.

Antigens, CD34↗
PubMed1998

[Risk and procedure education in anesthesiology. Overview of Austrian and German legal regulations].

Informed consent is currently an ethical, medical and legal requirement. An increase in public discussion of real or supposed malpractice has led to critical attitude in patients and increased demands on informed consent by the courts. Unfortunately, the legal requirements of informed consent have developed from atypical situations involving dissatisfied and injured patients rather than from the more usual occurrences of physicians helping patients with subsequent patient satisfaction. In addition, laws have not set forth clear guidelines for physicians to follow. We review the elements of informed consent based on current Austrian and German jurisdiction in the particular field of anesthesiology and summarize the legal and medical realities in order to point out specific criteria for decision making.

Anesthesiology↗
PubMed1998

Human pathogenic Mycoplasma species induced cytokine gene expression in Epstein-Barr virus (EBV)-positive lymphoblastoid cell lines.

We addressed the question whether the in vitro interaction of two Epstein-Barr virus (EBV)-genome-positive B cell lines (EB-3 and HilB-gamma) with either Mycoplasma pneumoniae or M. hominis, with the < > mycoplasma species (M. fermentans, M. fermentans subsp. incognitus, M. penetrans, M. genitalium) or with mycoplasma species known to be mere commensals of the respiratory tract (M. orale and M. salivarium) would result in expression of mRNAs for IL-2, IL-2R, IL-4 and IL-6 as determined by reverse transcriptase (RT)-PCR after 4 and 24 h of cocultivation. The pattern of cytokine gene expression observed depended on (i) the origin of the transformed cell line, (ii) the pathogenicity of the Mycoplasma species, and (iii) the length of cocultivation. The EBV-immortalized lymphoblastoid cell line HilB-gamma showed mRNA expression for IL-2, IL-2-receptor, IL-4 and IL-6 peaking 24 h after stimulation with M. pneumoniae and all AIDS-related mycoplasma species tested. The Burkitt lymphoma cell line EB-3 showed a distinct and isolated strong II-2/IL-2 R-mRNA expression within 4 h after contact with the pathogenic and all of the AIDS related mycoplasma species. In neither EBV-containing cell line cytokine was gene expression detectable after stimulation with the commensal mycoplasma species, M. orale and M. salivarium, indicating species differences in the ability of mycoplasmas to interact with and stimulate B-cell lines. Our data suggest that some mcyoplasma species may act as immunomodulatory cofactors by eliciting inappropriate cytokine gene expression in B cells latently infected with EBV. Therefore, this cultivation model may prove useful in evaluating the pathogenetic potential of novel isolated mycoplasma species.

B-Lymphocytes↗
PubMed1998

[Dislocated cuboid fracture. Clinical aspects and therapy of a rare foot injury].

Fractures of the cuboid are very rare. During the last 10 years four patients with isolated fractures of the cuboid have been treated in our hospital. The displaced fractures were treated by open reduction, bone grafting where necessary, and internal fixation. At the time of follow-up the results concerning pain and function were good to excellent and better than those previously reported for conservative treatment. We recommend this treatment for fractures with displacement of one or more of the articular surfaces or with shortening of the lateral arch of the foot.

Adolescent↗
PubMed1998

The gene encoding the alpha1A-voltage-dependent calcium channel (CACN1A4) is not a candidate for causing common subtypes of idiopathic generalized epilepsy.

Mutations in the gene encoding the alpha1A-calcium channel subunit play a causative role in the epileptogenesis of absence seizures in tottering mutant mice. The present family-based association and non-parametric linkage study tested the hypothesis that allelic variants of the homologous human gene (CACN1A4) confer susceptibility to common subtypes of idiopathic generalized epilepsy (IGE). An expressed polymorphic CAG trinucleotide repeat in the 3' end of the CACN1A4 gene was assessed in 70 families ascertained through members with either childhood (CAE) and juvenile absence epilepsy (JAE), or juvenile myoclonic epilepsy (JME). Our association analysis using the haplotype-based haplotype relative risk statistic provided no evidence for an allelic association of the CAG repeat polymorphism with either IGE, or CAE and JAE, or JME. We found no relation between the CAG repeat length and susceptibility neither to IGE, nor to CAE and JAE, nor to JME. Non-parametric linkage analysis revealed no evidence for linkage of IGE traits with the CACN1A4 locus in 42 families of patients with either CAE or JAE. A weak trend towards an excess of allele sharing (identity by descent) among family members affected by an IGE was obtained in 26 families of JME patients (Z[NPL] = 1.25 at theta = 0.000, p = 0.057). Taken together, we found no statistically significant evidence that genetic variants of the CACN1A4 gene play a causative role in the pathogenesis of common subtypes of IGE in humans.

Alleles↗
PubMed1998

Increased gene transfer into human CD34+ progenitor cells using retroviral vectors produced by a canine packaging cell line.

Using retroviral supernatants derived from the amphotropic murine packaging cell line PA317 and the amphotropic canine packaging cell line (DA), cord blood and mobilized peripheral blood CD34+ cells were transduced with the vector LN (neomycin resistance) and the vector L-TR/TAT neo (neomycin resistance in conjunction with a double-hammerhead ribozyme conferring anti-HIV activity). Different multiplicities of infection (MOI) were applied in the setup according to vector titrations on NIH-3T3 cells. PA317-based supernatants were tested at MOI of 10 and 30. Purified concentrated DA-derived vector preparations were tested at MOI of 10, 30, 100, and 300. Immediately after transduction, CD34+ cells were plated into colony assays in the presence and absence of G418 to evaluate the amount of gene transfer and potential toxic effects of the vectors on colony growth. The remaining cells were subjected to G418 selection in liquid culture for 12 days and subsequently challenged with HIV-1JR-FL to test for efficacy of the anti-HIV gene in macrophages derived from transduced CD34+ cells. Transduction by the PA317-packaged vectors was maximal at the lowest MOI used and did not increase with increasing MOI. In contrast, transduction by the DA-packaged vectors could be progressively increased using increased MOI. The net transduction efficiency per unit of reverse transcriptase activity in the DA vector preparations was 8.7-fold higher than in the PA317 vector supernatants. HIV-1 challenge of the cells transduced by the ribozyme vector derived from the PA317 packaging cells resulted in a 1.5 log inhibition of p24 output compared with the control cells containing neomycin resistance only. A 2.5 log inhibition of p24 output could be observed in the cell population transduced with DA-packaged vector supernatants. Compared with retroviral supernatants from PA317 packaging cell lines, DA packaging line-derived vector preparations demonstrated higher transduction efficiency into CD34+ cells, particularly at higher MOI, and increased efficacy of the transferred anti-HIV gene when challenged with HIV-1JR-FL. The increase in transduction efficiency may be due to a higher ratio of intact vs. defective vector particles in the DA-derived vector preparations.

Animals↗
PubMed1998

Replication analysis of a putative susceptibility locus (EGI) for idiopathic generalized epilepsy on chromosome 8q24.

PURPOSE: The present replication study was designed to test the validity of a previously mapped susceptibility locus (EGI) for common subtypes of idiopathic generalized epilepsy (IGE) in chromosomal region 8q24. METHODS: Thirty-eight multiplex families of probands with common IGE syndromes were included in the present study. Parametric and nonparametric multipoint linkage analyses were conducted between the IGE trait (either "idiopathic" generalized seizure or generalized spike-wave EEG discharges) and three microsatellite polymorphisms (D8S256, D8S284, D8S1128) encompassing the putative EGI locus. RESULTS: Parametric and nonparametric multipoint linkage analysis provided no evidence for linkage between the IGE trait and the markers encompassing the putative EGI locus. Moreover, we noted no indication favoring linkage to this chromosomal region in two distinct subsets of families subdivided by the absence (n = 18) or presence (n = 20) of family members with juvenile myoclonic epilepsy (JME). CONCLUSIONS: We failed to replicate evidence of a major locus (EGI) for common familial IGE in chromosome region 8q24. On the contrary, our present parametric linkage results provide evidence against linkage across the region under a broad range of genetic models. If there is a susceptibility locus for IGE in this region, the effect size or the proportion of linked families is too small to detect linkage in these families. Taking into account the problems in replicating initial linkage claims in oligogenic traits, further linkage studies in additional family sets are necessary to evaluate the validity of the previous linkage finding.

Chromosome Mapping↗
PubMed1998

TGF-beta and FGF-trigger intercellular induction of apoptosis: analogous activity on non-transformed but differential activity on transformed cells.

Transforming growth factor (TGF)-beta as well as fibroblast growth factor (FGF) are able to trigger intercellular induction of apoptosis. Interaction of either cytokine with non-transformed cells results in the production and release of apoptosis inducing factor (AIF) which is specifically directed against transformed cells. In both cases, AIF production is inhibited by the antioxidant N-Acetylcysteine, indicating that similar or identical signalling pathways are utilized. Whereas TGF-beta sensitizes transformed cells by down modulation of their endogenous survival factors, FGF is devoid of a similar activity. Therefore TGF-beta triggers and enhances intercellular induction of apoptosis by interaction with non-transformed and transformed cells, whereas the activity of FGF is based only on the interaction with non-transformed cells.

Animals↗