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Biomedical subjects

F Köhler

Publications and source records attributed to F Köhler.

At least 19 recordsLinked to original sources
PubMed1999

Characterization of the DNA-binding and dimerization properties of the nuclear orphan receptor germ cell nuclear factor.

The orphan receptor germ cell nuclear factor (GCNF) is a member of the superfamily of nuclear receptors. During development, GCNF exhibits a restricted brain-specific expression pattern, whereas GCNF expression in the adult is germ cell specific. Therefore, the receptor may participate in the regulation of neurogenesis and reproductive functions. No natural GCNF target gene has yet been identified, but recent data demonstrate specific and high-affinity binding of GCNF either to the direct repeat DNA element AGGTCAAGGTCA (DR0) or to extended half-sites, such as TCAAGGTCA. In this study, we show that murine GCNF (mGCNF) can bind as a homodimer to extended half-sites, thus describing a novel property within the nuclear receptor superfamily. Homodimeric binding to extended half-sites requires the presence of a dimerization function within the mGCNF DNA-binding domain (DBD) and a novel dimerization surface encompassing the putative helix 3 and the helix 12 region of the mGCNF ligand-binding domain (LBD). In addition, the mGCNF LBD has the potential to adopt different conformations with distinct dimerization properties. The helix 12 region of the mGCNF LBD not only regulates the switch between these dimerization conformations but also dictates the DNA-binding behavior and transcriptional properties of the different dimerization conformations. In summary, our findings describe unique DNA-binding and dimerization properties of a nuclear receptor and suggest a novel mechanism that allows mGCNF to modulate target gene activity.

Amino Acid Sequence↗
PubMed1997

Surgical removal of atrial septal defect occlusion system-devices.

OBJECTIVE: Since 1976 a number of similar transvenous atrial septal defect occlusion systems have been developed and applied to prevent surgical intervention with extracorporeal circulation and the complications involved. One of them is the so called atrial septal defect occlusion system (ASDOS-device; Dr Ing Osypka, Germany). METHOD AND RESULTS: In our institution, eight ASDOS-devices were implanted in adults during the last year. In six individual cases, these devices were explanted because of thrombosis, residual shunts, deformations of the umbrella, disconnection of the system and atrial perforation with hemopericard. This occured 17-380 days after the implant. The surgical removal was uncomplicated in all cases. CONCLUSIONS: Because the complication rate of the ASDOS-device was unacceptably high, surgical repair was preferred.

Adult↗
PubMed1996

The multi-dimensionality of the FIM motor items precludes an interval scaling using Rasch analysis.

Rasch analysis scaling is said to produce an interval scale of Functional Independence Measure (FIM) motor function items. Rasch analysis requires that the data to be analysed represent the influence of a single underlying unidimensional variable. A unidimensional interval scale of activities of daily living means that a person who can perform the most difficult item on a scale can also perform the easiest item. For a FIM motor function interval scale, the ability to climb stairs would imply necessarily and ability to eat normally. As this need not be the case, the FIM motor items do not constitute an adequate interval scale. Eating and walking are different activities, and a unidimensional construct linking them is unsatisfactory. A principal components analysis of the admission FIM motor function items of 515 consecutive patients admitted to an inpatient rehabilitation unit revealed that more than one significant factor was necessary to explain the variance in scores. The counter-factual and statistical evidence argues that a unidimensional construct does not underly the FIM motor function items, and the use of Rasch analysis will not lead to a description of interval properties of the FIM motor function items.

Activities of Daily Living↗
PubMed1995

[Venous angioplasty and Wallstent implantation in emergency treatment of superior vena cava syndrome caused by tumor].

HISTORY AND CLINICAL FINDINGS: A 58-year-old man was hospitalized because of threatened asphyxia resulting from massive obstruction to neck vein flow and increased venous markings over the ventral and dorsal thorax. The previous year he had received radiotherapy (total of 55.8 Gy) for squamous cell carcinoma in the right upper lobe of the lung (primary stage T2 N2 M0). The signs of venous congestion had developed over several months. TESTS: Emergency phlebography demonstrated obstruction to superior vena cava (SVC) flow by tumour compression. TREATMENT AND COURSE: It was possible to pass the SVC obstruction with a hydrophilic guide-wire and then perform a balloon angioplasty, followed later by implantation of two intraluminal expandable stents ("Wallstent"). The dyspnoea quickly improved after the successful recanalization. The day after the intervention palliative radiotherapy of the SVC obstruction was begun. But increased venous markings over the thorax recurred, but without dyspnoea, after 4 1/2 months free of signs of venous congestion. Repeat phlebography again demonstrated complete obstruction of the SVC by the tumour. Recanalization by balloon angioplasty was again achieved. CONCLUSIONS: This case underlines the value of percutaneous balloon angioplasty with stent implantation as supplementary treatment in the late stages of SVC obstruction by tumour.

Angioplasty, Balloon↗
PubMed1994

Slow cortical potential biofeedback and the startle reflex.

The negativity of slow cortical potentials (SCP) of the surface EEG is a measure of brain excitability, correlating with motor and cognitive preparation. Self-control of SCP positivity has been shown to reduce seizure activity. Following SCP biofeedback from a central EEG electrode position, subjects gained bidirectional control over their SCP. The current study used a modified feedback methodology, and found a positive relationship between negativity and magnitude of EMG startle response (a measure of cortical and subcortical arousal, particularly aversive response disposition). Greater success in SCP differentiation was associated with self-report of less relaxation during negativity training.

Adult↗
PubMed1990

Transfer of hygromycin resistance into Brassica napus using total DNA of a transgenic B. nigra line.

The successful transfer of a marker gene (hpt gene) from Brassica nigra into B. napus via direct gene transfer was demonstrated. Total DNA was isolated from a hygromycin-resistant callus line, which contained three to five copies of the hpt gene. This line had been produced via direct gene transfer with the hygromycin resistance-conferring plasmid pGL2. The treatment of B. napus protoplasts with genomic DNA of B. nigra (HygR) resulted in relative transformation frequencies of 0.1-0.4%. Similar transformation rates were obtained in direct gene transfer experiments using B. napus protoplasts and plasmid pGL2.

Brassica↗
PubMed1990

[Chloroma in the blastic crisis of chronic myeloid leukemia--MR tomography findings].

Granulocytic sarcomas are rare manifestations of diseases of the white corpuscles. The incidence of this type of disease is not yet known because it is so rare. We observed two patients, who had had a chronic myeloid leukemia for several years, and in whom such a tumor occurred during the development of a blastomatous crisis. Both patients were examined by MRI. With this method it is possible to depict changes of the bone marrow as well as extramedullary lesions. MRI is a highly sensitive, but a less specific method.

Adult↗
PubMed1989

[Incidence of intravenous thrombolytic therapy and fatalities in patients with acute transmural myocardial infarct (Q infarct). A study of observations from 1984 to 1987].

All patients admitted to the ICU with acute myocardial infarction (MI) were treated by the same protocol since 1984. We report the results in Q-wave-MI of 1987 compared to 1984. Age (67.2 +/- 12.4 vs. 66.8 +/- 11.4 years), sex distribution (70.1% vs. 71.9% male), time elapse between begin of symptoms and admittance to the hospital (15.5 +/- 27.0 vs. 15.0 +/- 32.5 hours) were similar in both years, but the total number of definite Q-MI decreased by 22% from 135 (1984) to 105 (1987). Inhospital mortality (20% vs. 23%) and ICU mortality (14% vs. 20%) tended to decrease, although differences did not reach statistical significance. This was paralleled by an increase in the rate of i.v. thrombolytic therapy from 17% (1984) to 28% (1987) of all patients with Q-MI. The percentage of patients who definitely received i.v. thrombolysis when all indication criteria were present and all contraindicatory factors excluded increased from 47% (1984) to 97% (1987). We conclude, that the performance of i.v. thrombolysis in all patients, who fulfill the general accepted criteria for thrombolysis may improve clinical course and outcome in a given population of patients with acute Q-wave-infarction.

Aged↗
PubMed1989

[Effectiveness and hemodynamic mechanism of action of blood pressure lowering by intravenous labetalol in patients with a critical increase in blood pressure].

Labetalol (L) was intravenously given to ten patients with an acute elevation of arterial blood pressure above to 200 to 100 mmHg. Blood pressure was controlled in 9 of 10 patients (less than or equal to 170/100 mmHg) with 50 mg in 4, 100 mg in 4 and 200 mg L in 1 patient. In 9 responders, systolic pressure decreased from 207 +/- 20 to 161 +/- 9, diastolic pressure from 107 +/- 11 to 90 +/- 8, and mean pressure from 140 +/- 11 to 113 +/- 5 mmHg, and all pressures remained at these levels during a 25 min control period. Heart rate decreased significantly from 87 +/- 20 to 69 +/- 11 per min and cardiac index from 3.2 +/- 0.8 to 2.6 +/- 0.61/min x m2. Stroke volume index remained unchanged. Total peripheral resistance and pulmonary artery occlusion pressure were not significantly altered but tended to increase, resulting in a small shift to the right of the ventricular function curve. Pulmonary vascular resistance increased significantly from 236 +/- 108 to 314 +/- 132 dyn x sec x cm-5 and mixed venous oxygen saturation decreased from 70 +/- 5 to 65 +/- 8%. Peripheral resistance was considerably higher and cardiac index lower in patients with a heart rate below 70/min. We conclude that L effectively lowers the arterial blood pressure in hypertensive crisis, but the substance should not be used in patients with heart rates below 70/min, as in this case the beta-blocking effect may supervene resulting in a high-resistance low-output state.

Adult↗
PubMed1989

[Predictive value of a combined physiologic-therapeutic oriented score system in patients of intensive internal medicine].

171 consecutive patients of a medical intensive care unit (age 18 to 81 years, mortality 24.6%) who were treated in the ICU for at least 72 hours were investigated in order to test the hypothesis, that the combination of therapeutic scoring (TISS) and physiologic scoring (APS) may improve the prognostic significance of score systems and/or the severity of disease classification in critically ill patients. Discrimination of survivors and non-survivors of the combined score was comparable to the results of isolated scores. A higher weighting of the physiology parameters in the combined score did not improve its prognostic significance. On the other hand, only the combined score implicated a linear increase of mortality with increasing score point values. - We conclude, that the combined score system improves the severity of disease classification in critically ill medical patients.

Adolescent↗
PubMed1983

Coronary rheothermia: a quasi non-invasive method for controlling bypass patency.

A method based on the principle of thermodilution was developed for a quasi non-invasive permeability control of aortocoronary bypass. An epivascularly-attached thermistor records the cooling of the bypass wall when, following the intravenous injection of 5 to 10 ml of a NaCl solution at 4 degrees C, a bolus of cooled blood passes through the bypass. During cardiosurgical intervention, the thermistor is attached to the venous bridge by one or 2 sutures. The efferent cable goes through the thorax wall and is coupled to a subcutaneously implanted telemetric amplifier unit. The influence of the vessel wall on the perivascular temperature signal, as compared to the intravascular one, was studied in acute and chronic animal experiments. In acute experiments the perivascular peak of temperature was found to be lower than the intravascular one. Continuous measurements over 9 days showed variations in the perivascular signals which must have been due to changes in the thermal capacity of the tissue coupled to the thermistor as well as to changes in resistance caused by a variable extent of scarred area and by the varying water content of the wound bed. These variables will continue to keep rheothermia within the limitations of a method with primarily binary results (= bypass: open or closed). Given stable coupling conditions after full development of the scar around the thermistor, the signal falsification by the then constantly coupled tissue capacity becomes calculable such as to obtain semiquantitative results which, theoretically should vary predominantly with cardiac output.

Animals↗