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Biomedical subjects

F Köhler

Publications and source records attributed to F Köhler.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1981

[Post-mortem radiological studies of human coronary ostia (author's transl)].

A double contrast method was used for the radiological study of human coronary ostia at post-mortem. The angle between the coronaries and the aorta averaged 44 degrees on the left and 102 degrees on the right; the diameter of the ostia averaged 4.83 mm. on the left and 3.83 mm. on the right. Comparative studies in life are unknown. There was a relationship between the sum of the ostium diameters and the weight of the heart up to 500 grams. Measurements of the volume/elasticity relationship showed considerable homogeneity of the ostia and neighbouring vessels with respect to the mechanical properties of their walls. The possibilities of measuring changes in vessel diameter due to pressure changes (diastole/systole) during a coronary angiogram in a living patient are discussed.

Adolescent↗
PubMed1981

[Macroscopic and micrometric examination of pressure-fixed human coronary orifices (author's transl)].

The aortic roots with coronary orifices and coronary vessels were pressure-fixed in 54 postmortal hearts, by means of a special method. Two origin and one course anomaly of coronary vessels were found. A missing supravalvular ridge usually limiting the distal extent of the sinus Valsalvae was of no importance with regard to the regular function of the aortic valves. Atherosclerotic deposits were found more often in front of and in the orifices than directly behind them. In both atherosclerotic free and atherosclerotic orifices, the "cranial" walls proved to be on average thicker than "caudal" walls. The difference was greater on the left than on the right. In arteriosclerotic cases, this difference became on average considerably larger on the left, but remained relatively equal on the right side. Taking the hemodynamic conditions of the aortic root into account, the findings suggest that the angles between the aortic root and the coronary vessels have an influence on the wall thickness of the ostia. This possibly explains the more frequent occurrence of ostial stenoses on the right side. A smaller exit angle therefore appears advantageous in cases of artificial orifices, too.

Aged↗