Biomedical subjects

K Steinbach

Publications and source records attributed to K Steinbach.

At least 19 recordsLinked to original sources

PubMed2004

[Patients as partners. Tumor patients and their participation in medical decisions].

Between March 2002 and August 2003 as part of the research project "Patients as partners -- tumour patients and their participation in medical decisions" tumour patients undergoing palliative therapy (n=272) were interviewed and asked about their level of information, their desired place to die and whether they had prepared an advance directive. Furthermore, 72 relatives of deceased patients who had been looked after by the project's palliative care team were given a similar questionnaire including questions concerning their knowledge about disease and prognosis, the actual place of death and the relevance of advance directives. According to patients and relatives, information particularly about prognosis is unsatisfactory. Of the inter-viewed patients, 75% said they wanted to die at home and 15% in a hospital. According to their relatives, 36% of the patients looked after by the palliative care team had an advance directive. The survey of the relatives showed a significant relation between the preparation of an advance directive and dying at the desired place. According to the relatives, medical and health reasons, hope for an improvement up to the very end,acute worsening of the condition and deficits in medical care were important reasons for dying in hospital against the patient'swish. In future, advance directives should be used as an aid for communication and the planning of care. Therefore, cooperation between doctors and patients based on a partnership is necessary. The required competence in communication should be improved.

Adolescent↗

PubMed2004

Prognostic significance of right ventricular extrasystoles.

UNLABELLED: Extrasystoles (RVES) from the right ventricular outflow tract (RVOT) are a common arrhythmia in routine ECGs. METHODS: In this prospective study 56 consecutive patients with RVES (22 males, 34 females) were examined for morphological and/or functional right ventricular (RV) abnormalities by 12-lead, Holter, exercise ECGs, transthoracic echocardiography and signal averaging. The follow-up time was 3.1-15.8 years (arithmetic mean +/- SD = 7.2 +/- 1.6 years; median, 6.9 years). Patients with hyperthyroidism, structural cardiovascular and/or lung diseases were excluded. RESULTS: A total of 57.1% of the patients with RVES presented with echomorphologic abnormalities of the right ventricle (RV). In 26.8% the echomorphologic right ventricular abnormalities progressed in 33.3% of patients with normal RVs at baseline (group I) and in 21.9% of those with abnormal RVs at baseline (group II). No significant differences were found between the 2 patient groups in terms of age at onset, family history, ECG changes, late potentials and malignant right ventricular outflow tract arrhythmias on 24-h and exercise ECGs. While females predominated in group I, males were numerous in group II (p = 0.006). Sustained ventricular tachycardia, syncope or sudden death were absent throughout the follow-up. CONCLUSION: Patients with RVES carry a good prognosis in terms of morbidity and mortality no matter whether echomorphologic abnormalities are present or not.

Adult↗

PubMed2003

Conversion of adamsite (phenarsarzin chloride) by fungal manganese peroxidase.

Fungal manganese peroxidase was found to convert the persistent chemical warfare agent adamsite (phenarsarzin chloride) in a cell-free reaction mixture containing sodium malonate, Mn(2+) ions, and reduced glutathione. The organo-arsenical compound disappeared completely within 48 h accompanied by the formation of a more polar metabolite with a clearly modified UV spectrum. Thus, As(III) in the adamsite molecule was oxidized by manganese peroxidase to As(V) which added dioxygen and released chloride.

Arsenicals↗

PubMed2001

Tissue-specific neuro-glia interactions determine neurite differentiation in ganglion cells.

Guided formation and extension of axons versus dendrites is considered crucial for structuring the nervous system. In the chick visual system, retinal ganglion cells (RGCs) extend their axons into the tectum opticum, but not into glial somata containing retina layers. We addressed the question whether the different glia of retina and tectum opticum differentially affect axon growth. Glial cells were purified from retina and tectum opticum by complement-mediated cytolysis of non-glial cells. RGCs were purified by enzymatic delayering from flat mounted retina. RGCs were seeded onto retinal versus tectal glia monolayers. Subsequent neuritic differentiation was analysed by immunofluorescence microscopy and scanning electron microscopy. Qualitative and quantitative evaluation revealed that retinal glia somata inhibited axons. Time-lapse video recording indicated that axonal inhibition was based on the collapse of lamellipodia- and filopodia-rich growth cones of axons. In contrast to retinal glia, tectal glia supported axonal extension. Notably, retinal glia were not inhibitory for neurons in general, because in control experiments axon extension of dorsal root ganglia was not hampered. Therefore, the axon inhibition by retinal glia was neuron type-specific. In summary, the data demonstrate that homotopic (retinal) glia somata inhibit axonal outgrowth of RGCs, whereas heterotopic (tectal) glia of the synaptic target area support RGC axon extension. The data underscore the pivotal role of glia in structuring the developing nervous system.

Animals↗

PubMed2000

Regulatory cell interactions between retinal ganglion cells and radial glia during axonal and dendritic outgrowth.

Neuronal differentiation and the formation of cell polarity are crucial events during the development of the nervous system. Cell polarity is a prerequisite for directed information flux within neuronal networks. In this article, we focus on neuro-glial cell interactions that influence the establishment of neural cell polarity and the directed outgrowth of axons versus dendrites. The cellular model discussed in detail is the retinal ganglion cell (RGC) of the chick retina, which is investigated by a comprehensive set of in vitro assays. The experiments demonstrate that retinal microenvironment determines axon vs. dendrite formation of RGCs. The instructive differences in different retinal microenvironments are substantially influenced by radial glia. Different glial domains support or inhibit axon vs. dendrite outgrowth. The data support the notion that neuro-glial interactions are crucial for directed neurite outgrowth.

Animals↗

PubMed2000

Risk evaluation of ventricular tachycardia using wavelet transform irregularity of the high-resolution electrocardiogram.

A new method for analysis of high-resolution ECG signals using a wavelet transform based on a modified Morlet function is presented. A polynomial filter is used to reduce low-frequency, high-amplitude noise components in the analysed signals. The method is tested on test ECG signals with simulated late potentials and finally verified on two post-infarction patient (PP) groups: 62 PPs with ventricular tachycardia and 44 PPs without arrhythmia. A new quantitative parameter, the irregularity factor, is proposed for discrimination between the study groups. The results show a significant difference in the parameter values for tachycardia patients compared with those for patients without arrhythmia. The sensitivity of the proposed method is 85%, and the specificity is 93%.

Adult↗

PubMed1999

[Secondary prevention following coronary intervention. Survey of 13 intervention centers in Austria].

Risk factor control has been shown to reduce the incidence of coronary events in patients with or without preceding infarction. Secondary prevention should therefore be borne in mind by every cardiologist. In order to test this concept and/or to promote secondary prevention in our country, the following survey was conducted by our working group for epidemiology and prevention. All interventional centres of the country (7 million inhabitants) were asked to report relevant data of 50 consecutive patients with PTCA in a structured questionnaire. Thirteen centres responded and we report the data of 650 patients. The mean proportion of women was 28%, the mean age 61.1 years and the mean stent rate 49.8%. The indications for PTCA varied widely: stable angina 10-74%, unstable angina 10-86%, primary PTCA 0-22%. The risk factor history was distributed as follows: diabetes 12-46% (mean 22.3%), hypertension 32-68% (mean 54.2%), current smoking 6-56% (mean 21.9%), and total cholesterol (TChol) > 200 mg/dl: 30-78% (mean 60.3%). Current lipid values were available for T chol. in 44-100% (mean 84.5%) and for LDL in 4-100% (mean 67.1%). Dietary counselling by a dietician was done in 4-100% of patients (mean 35.6%) Information concerning the hazards of smoking was given to 25-100% (mean 83.6%) of current smokers. Drug treatment at hospital discharge was as follows: 84-100% (mean 93.1%) received ASA, 24-74% (mean 49.8%) ticlopidine, 6-84% (mean 53.3%) nitrates, 34-82% (mean 60.2%) beta blockers, 10-70% (mean 39.5%) ACE inhibitors, 4-74% (mean 4 7.2%) lipid lowering drugs, 7-48% (mean 17.8%) calcium antagonists, 0-12% (mean 6.1%) digitalis and 0-28% (mean 13.6%) diuretics. Follow-up data were collected in 4 centres at 6 months post discharge and were available for 174 patients. Here we found an increase in the prescription of calcium antagonists, digitalis and statins. The following conclusions were drawn at a conference in which all centres participated: lipid values should be available for each patient at PTCA, dietary counselling should be initiated for every patient during hospitalisation (and continued by the family physician) and the national cardiac society should promote guidelines for the use of drugs in which the variation in use is too wide at present. It should be ensured that these guidelines are implemented not only in patients after AMI but also in those after PTCA.

Adrenergic beta-Antagonists↗

PubMed1999

Oxaceprol is as effective as diclofenac in the therapy of osteoarthritis of the knee and hip.

In this multicentre (five centres in Germany), randomised, double-blind, comparative study, 150 patients with painful degenerative joint disease according to EULAR criteria received either oxaceprol (200 mg three times daily) or diclofenac (25 mg three times daily) for 20 days. Joint function, the primary variable, assessed according to Lequesne's indices, improved equally in both treatment groups to a clinically relevant degree. Joint mobility improved by approximately 60% in both groups. By the end of therapy in both groups, the period of pain-free walking time had more than doubled and subjectively evaluated pain perception (VAS) was reduced by almost 50% without any significant differences between the treatments. The incidence of adverse drug reactions was similar in both groups but oxaceprol induced milder symptoms. Oxaceprol is as effective and better tolerated than diclofenac in the treatment of osteoarthritis.

Administration, Oral↗

PubMed1998

[Sub-pectoral implantation of defibrillators: intraoperative data and long-term outcome].

UNLABELLED: The present study examined the perioperative mortality and morbidity and lead-related complications in patients who had a defibrillator with a transvenous lead system and subpectoral implantation of the generator. Fifty-four out of 57 consecutive patients (95%) received a transvenous lead system. One patient had an acceptable defibrillation threshold with an additional subcutaneous patch whereas no sufficient defibrillation threshold was found in another 2 patients. Two patients died due to congestive heart failure after implantation. Perioperative complications were observed in 4 patients (7%) including pericardial effusion, pocket hematoma, injury of the plexus brachialis and a pneumothorax. None of these complications required surgical intervention. Fifty-five patients were discharged from the hospital. During 27 +/- 10 months none of these patients died. Lead-related complications were observed in 3 patients (5.5%) including microdislocation in two and a outer conductor fracture in one of the lead. CONCLUSION: Technical advancement such as a non-thoracotomy lead system and smaller devices have made the onc-incision approach and subpectoral implantation of the ICD generator clinical routine. Nevertheless complications related to the lead system can occur. Therefore frequent controls of patients with ICD are necessary.

Adult↗

PubMed1998

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine. I. Derivatization.

A new method for the selective determination of aromatic amines is presented, which is based on the solid-phase extraction at pH 9 and subsequent derivatization of the analytes to the corresponding iodobenzenes. These can selectively and sensitively be determined with gas chromatography and electron-capture detection. Separation of at least 30 compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were investigated, and only in six cases no derivatives were obtained. Limits of quantitation were between 0.5 and 8 micrograms 1(-1), but may still be lowered with higher sample volumes or different injection techniques. The application to water samples revealed the suitability for the investigation of ground, leachate and wastewater.

Amines↗

PubMed1998

Anaerobic degradation and transformation of p-toluidine by the sulfate-reducing bacterium Desulfobacula toluolica.

The ability of the strictly anaerobic sulfate-reducing bacterium Desulfobacula toluolica (strain Tol2) to cometabolically degrade p-toluidine (p-methylaniline) while using toluene as the primary source of carbon and energy has been studied. This organism has been shown to modify and degrade toluidine in dense cell suspensions when no other source of carbon and energy is added. The metabolism led to the formation of a variety of metabolites. From these metabolites a biphenyl-like compound as well as phenylacetic acid have been identified by means of HPLC/MS techniques. The probable conversion of p-toluidine to p-aminophenylacetic acid and phenylacetic acid as dead end products suggested that this organism initiates p-toluidine degradation by the carboxylation of the methyl group. If this could be validated in further experiments, it would be the first time that a toluidine was carboxylated at the methyl moiety by an anaerobic, sulfate-reducing bacterium.

Bacteria, Anaerobic↗

PubMed1998

Highly polar metabolites of nitroaromatic compounds in ammunition wastewater.

Transformation processes of nitroaromatic compounds (NAC) are described that lead to polar and highly hydrophilic metabolites in ammunition waste water. For the identification of proposed metabolites, several analytical methods for the separation and determination of these compounds were developed and applied to the investigation of a former ammunition plant and its surroundings. The compound classes which were investigated include nitro and amino substituted toluenesulfonic acids, nitrobenzoic acids, aminobenzoic acids and nitromethylphenols. Method development was usually done with high performance liquid chromatography and ion pairing or ion suppression techniques. In the leachate water of a disposal site of a former ammunition plant in Stadtallendorf, Germany, 15 compounds from the above-mentioned categories have been found to be present in concentrations up to a few hundred microgram/L. The presence of so many polar compounds suggest that current and future surveying programs should include representative analytes of the investigated categories.

Biotransformation↗

PubMed1997

Psychoneuroimmunological correlates of persisting sciatic pain in patients who underwent discectomy.

Patients suffering from persisting sciatic pain 8 weeks following discectomy were compared with patients displaying low complaints and healthy, pain-free volunteers regarding their interleukin-6 (IL-6) levels, morning cortisol levels and degree of psychological distress. Whereas serum concentrations of IL-6 were measured by collecting blood samples between 0945 and 2400 h in intervals of 45 min, morning cortisol levels were obtained by sampling saliva on five ensuing measurements, beginning immediately after awakening. In addition, questionnaires aimed at measuring depressive mood, somatic symptoms, coping and chronic stress were filled out by the subjects. The patients with ongoing pain displayed significantly elevated IL-6 levels and an attenuated elevation of cortisol secretion after awakening compared to the two other groups. Patients with persisting pain were also suffering more frequently from depressive mood and ongoing work-related strains. In addition, maladaptive coping strategies were favoured by these patients. The presented data support the hypothesis that the persistence of pain in many of the concerned patients may significantly be related to dysfunctional reciprocal relations between neural, endocrine and immune function.

Adult↗

PubMed1997

Laser catheter coagulation of atrial myocardium for ablation of atrioventricular nodal reentrant tachycardia. First clinical experience.

A new technique for ablation of atrioventricular nodal reentrant tachycardia, using catheter-directed continuous wave Nd-YAG laser light, 1064 nm, via a novel pin-electrode laser catheter, was applied in 10 patients aged 15-63 years (mean 43 years). A total of 22 laser pulses, 1-5 per patient, at 20 or 30 W, of 10-45 s (mean 27 s) were aimed at the postero-inferior aspect of the tricuspid annulus. In all patients the tachycardia was rendered non-inducible at baseline as well as during orciprenaline administration. The amplitudes of the local atrial potentials diminished from 2.0 +/- 0.5 before to 0.4 +/- 0.4 mV after ablation, atrio-His intervals increased from 73 +/- 7 to 157 +/- 36 ms. Anterograde atrioventricular nodal refractory periods (212 +/- 31 vs 238 +/- 31 ms) and Wenckebach rate (174 +/- 8 vs 167 +/- 8 beats.min-1) did not change significantly (P > 0.05). There were no complications or recurrent arrhythmias in a follow-up of 12-35 (mean 27) months. Anatomically guided laser catheter coagulation of the postero-inferior aspect of the tricuspid valve ring is a safe and effective method for the cure of patients with common atrioventricular reentrant tachycardia.

Adult↗

PubMed1997

Present and future role of ambulatory Holter monitoring for arrhythmia risk stratification.

Risk stratification for arrhythmogenic events and sudden death in patients with organic heart disease, particularly those with coronary heart disease and a history of MI, continues to be one of the major tasks of clinical cardiologists, although advanced management strategies including thrombolysis, acute PTCA and surgical intervention dramatically reduced the percentage of sudden deaths following acute MIs, Noninvasive studies like resting and exercise ECG, echocardiography, signal averaging, 24-hour ECG, and radionuclide studies, as well as invasive techniques such as electrophysiologically programmed electrostimulation and coronary angiography, are being used routinely. Ambulatory Holter monitoring is an established noninvasive technique for risk stratification. There is evidence showing that its predictive potential for arrhythmogenic risks is enhanced, if more than one parameter is analyzed. Absence of ST segment changes and a normal HRV are the parameters signaling out low-risk patients. The use of additional parameters which escape electrocardiographic recording, like ventricular function and myocardial ischemia, improve the accuracy of predicting arrhythmogenic events. The most predictive combination of risk parameters is, however, still poorly understood. Future research should define normal ranges of parameters recordable by H-ECG, solve technical problems of recording data and analyzing them. In addition, the accuracy of measuring QT duration and documenting late potentials should be improved by more sophisticated methods. But it is unrealistic to expect that the QT interval will become amenable to automatic analysis in all patients. A fully automatic QT analysis without visually checking the measuring points at the tip and the end of the T wave for their consistency is hardly conceivable. The documentation of late potentials, in turn, is limited by artefacts caused by muscle contraction during physical activity. Clinical aspects, e.g., the predictability of arrhythmogenic events in patients with cardiomyopathies and valvular disease should be addressed. This will require studies combining the predictive potentials of rhythmologic and hemodynamic data.

Arrhythmias, Cardiac↗

PubMed1996

Bioremediation of 2,4,6-trinitrotoluene-contaminated soils by two different aerated compost systems.

Two composting systems were compared on a laboratory scale as a bioremediation technology for degradation or immobilization of 2,4,6-trinitrotoluene (TNT) in contaminated soils. The first compost was aerated from the beginning whereas the second compost was only aerated after an anaerobic prephase of 65 days. In the first compost system the TNT concentration declined rapidly by 92% but, at the end, TNT could be partially recovered. During the anaerobic prephase of the second compost system, TNT was almost completely converted to aminodinitrotoluenes, which during the subsequent aeration almost entirely disappeared. In addition, the second compost generated less toxic material than the first one as confirmed by inhibition of bioluminescence of Vibrio fischeri. These data show that microbiological TNT-degradation systems can be successfully designed which are prerequisite for an efficient bioremediation of contaminated soils.

Aerobiosis↗

PubMed1996

Microbial transformation of 2,4,6-trinitrotoluene in aerobic soil columns.

2,4,6-Trinitrotoluene (TNT)-contaminated soil material of a former TNT production plant was percolated aerobically in soil columns. Nineteen days of percolation with a potassium phosphate buffer supplemented with glucose or glucose plus ammonium sulfate caused an over 90% decline in the amount of extractable nitroaromatics in soils containing 70 to 2,100 mg of TNT per kg (dry weight). In the percolation solution, a complete elimination of TNT was achieved. Mutagenicity and soil toxicity were significantly reduced by the percolation process. 4-N-Acetylamino-2-amino-6-nitrotoluene was generated in soil and percolation fluid as a labile TNT metabolite.

Journal Article↗

PubMed1996

[Catheter ablation of accessory atrioventricular conduction pathways in all locations--consecutive results of a new curative therapy of paroxysmal supraventricular tachycardia].

Accessory atrioventricular pathways are a frequent cause of paroxysmal supraventricular tachycardias. This study analyses our results with a recently developed therapeutic approach-radiofrequency (RF) catheter ablation. This was applied in 150 consecutive patients (97 men, 53 women, mean age 42 +/- 15 years) with a total of 159 accessory pathways in all locations. All but 4 patients were symptomatic, with a spectrum ranging from palpitations (146 patients), syncope (39 patients) to aborted sudden death (2 patients). Prior to ablation, 115 patients had received long-term treatment with up to 4 antiarrhythmic drugs unsuccessfully. The mean number of applied current pulses was 12 +/- 14, and the mean cumulative procedure duration was 256 +/- 243 minutes, with a cumulative fluoroscopy time of 49 +/- 72 minutes. Patients with left-sided pathways were approached via the retrograde aortic approach in 88/90 cases. One-hundred fifteen patients were treated in a single session, repeat sessions were required in the remaining 35 patients. The predominant sites of interruption of right-sided and left-sided accessory pathways were their atrial and ventricular insertion, respectively. Long-term cure was achieved in 141 patients (94%), non-life-threatening complications were observed in 3 patients (2%). These results compare well with published studies on large patient collectives and demonstrate that RF catheter ablation, which is highly cost effective, is the therapy of choice to cure symptomatic patients with accessory atrioventricular pathways in all locations.

Adult↗