Search PubMed⌕ Search

Biomedical subjects

R Franke

Publications and source records attributed to R Franke.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Behavior therapy oriented group therapy for anxiety disorders in neurorehabilitation].

The following are the experiences we have made with a group therapeutical care of patients suffering from anxiety disorders during neurorehabilitation. After individual analysis of content and background of anxiety disorders the patient receives a coping in group therapy process focussing on the main issue of anxiety on psychic consequences, knowing the background of the manner of anxiety and origin and elaborating long time strategies to cope anxiety. Our two years experiences show, that especially group therapy leads to facilities and economy of the therapeutical process.

Adaptation, Psychological↗
PubMed1987

Deoxylysolecithin and a new biphenyl detergent as solubilizing agents for bovine rhodopsin. Functional test by formation of metarhodopsin II and binding of G-protein.

The protein-detergent interaction in rhodopsin-detergent micelles has been investigated by using formation of metarhodopsin II (MII) as a monitor. Two detergents of different structural rigidity have been applied. One of them is [3-(lauroyloxy)propyl]phosphorylcholine, which has a high conformational flexibility in its hydrophobic moiety like most of the known detergents for rhodopsin. This deoxylysolecithin was originally designed as a detergent for membrane proteins by Weltzien [Weltzien, H. U. (1979) Biochim. Biophys. Acta 559, 259-287]. The other detergent, which is highly rigid in its hydrophobic part, has been developed for this study. It consists of a biphenyl derivative and a hydrophilic octaethylene oxide group. Both the formation kinetics of MII and the position of its equilibrium with its tautomeric form, metarhodopsin I (MI), strongly differed in the deoxylysolecithin and biphenyl detergent. Deoxylysolecithin caused very fast MII formation and shifted the equilibrium strongly to MII, like other detergents with alkyl chains as the hydrophobic part. In the biphenyl detergent, however, formation of MII was slow and the MI/MII equilibrium similar to that in the native system. For rhodopsin reconstituted in lipid bilayers, normal MII formation requires a well-adjusted fluidity of the hydrocarbon environment of the protein [Baldwin, P. A., & Hubbell, W. L. (1984) Biochemistry 24, 2633-2639], which was explained by an appropriate interfacial pressure at the protein-lipid interface. Extension of this concept would indicate that in the micellar core a degree of fluidity comparable to that of the disk membrane is just achieved with the highly rigid biphenyl structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Immunohistochemical studies with antibodies to myosins from the cytoplasm and membrane fraction of human blood platelets.

Antibodies were raised to myosins extracted from the cytoplasm and solubilized membranes of human blood platelets. Both antibodies had similar titers as shown by enzyme-immunoassay and bound to the same sites as shown by immunohistochemistry. They were specific for cytoplasmic myosins (e.g., in human white blood cells, platelets and fibroblasts and rat endothelial cells). They showed no crossreaction with human or rat smooth muscle.

Animals↗
PubMed1985

7-substituted-4-hydroxyquinoline-3-carboxylic acids as inhibitors of dehydrogenase enzymes and of the respiration of Ehrlich ascites tumor cells: multivariate analysis and quantitative structure-activity relationship for polar substituents.

The inhibitory activities of a set of nine 7-substituted-4-hydroxyquinoline-3-carboxylic acids against three dehydrogenase enzymes and one whole cell system (Ehrlich ascites tumor cells) have been subjected to principal component analysis. The results clearly indicate that activity against the whole cell test system cannot directly be attributed to inhibition of the enzymes evaluated. The enzyme systems are reflected by the first component that can be identified with polar and steric parameters while hydrophobic effects are absent. The second component is entirely due to the inhibition of ascites cell respiration that depends primarily on hydrophobicity.

Analysis of Variance↗
PubMed1985

Substructural QSAR approaches and topological pharmacophores.

For large and diverse data sets, simple QSAR methods based on linear and additive models can no longer be applied. In such cases topological methods using descriptors directly derivable from two-dimensional chemical structures provide a useful alternative. The results of such analyses can be used for lead optimization, to guide biological testing and even aid in the design of novel compounds. Various types of topological descriptors and algorithms are briefly discussed. Which of those is to be selected depends on the objective of the investigation and the properties of the data set. Two new methods, LOGANA and LOCON, are discussed in some more detail. With the help of these methods, substructural patterns ("topological pharmacophores") characteristic of compounds possessing a certain biological property can be evaluated. Both methods are designed in such a way that full use can be made of the data handling capacity of computers while maintaining an optimal impact of the experience of the researcher. They are model-free and do not require any mathematical knowledge. While LOGANA deals with semiquantitative or even qualitative biological data, LOCON can be applied to activity data on a continuous scale. The basic procedure in both cases consists in the stepwise combination of substructural descriptors by the logical operations "and," "or" and "not." With a simple example the utility of the methods is demonstrated.

Amides↗
PubMed1984

[Appearance of fresh vertebral body fractures on the bone scintigram].

Based on observations on 27 patients technetium-99m-diphosphonate scintigram is recommended as two-stage-investigation. During the first 12 hours no activity and up to 48 hours only slight activity can be seen in contrast to a marked take-up of the tracer after 6 to 8 days. This enables a timing of the fracture, which can be of importance in compensation and legal disputes.

Adolescent↗
PubMed1984

Effect of the temporal pattern of a given noise dose on TTS in guinea pigs.

To show the effect of the temporal pattern of acoustic stimulation on TTS 15 min, guinea pigs were subjected to isoenergetic noises with the same spectrum. The exposures in a first experimental series were continuous noises and noise bursts. The continuous noise was presented with different durations and levels but always with the same energy. The noise burst stimulation consisted of a constant number of bursts with different interstimulus intervals. Both duration and repetition rate were shown to affect the TTS 15 min measured for these isoenergetic stimuli. A duration of 225 to 1800 s and a repetition rate of one per second produced the greatest TTS 15 min. In a second experimental series continuous noise and acoustic impulses with the same spectrum and 100-Hz repetition rate were presented at different levels. In this case the waveform of the stimulus (phase spectrum) was shown to have an effect on TTS 15 min.

Acoustic Stimulation↗
PubMed1982

Cochlear mechanisms at low frequencies in the guinea pig.

The study of the cochlear microphonic and of the intracochlear sound pressure in guinea pigs shows that the behavior of the cochlea at very low frequencies is controlled by three discrete elements: (a) the compliance of the whole basilar membrane; (b) the acoustic resistance of the helicotrema; (c) the compliance of the round window. The part of each of these elements has been established. The compliance of the whole basilar membrane produces constant amplitudes at frequencies lower than the minimum frequency at which a travelling wave is present (130 Hz). In fact, this constant amplitude range is limited by connection of the two cochlear scalae through the helicotrema resistance. This protecting mechanism produces an attenuation slope for frequencies lower than 80 Hz. The compliance of the round window does not modify the slope of the cochlear microphonic, but it induces a constant sound pressure in scala tympani up to 200 Hz. Decreasing of the sound pressure in the scala vestibuli is, therefore, limited for frequencies less than 30 Hz by this constant value of the sound pressure in scala tympani.

Acoustic Stimulation↗
PubMed1980

Intracochlear sound pressure measurements in guinea pigs.

The intracochlear sound pressure in guinea pigs was measured in the scala vestibuli of the first, second and third turns as well as in the scala tympani of the first and second turns. The acoustic stimuli were pure tones delivered over the frequency range 30--20 000 Hz at sound levels ranging from 60 to 100 dB. The results achieved show the sound pressure in scala vestibuli to be practically in phase in the first three turns. In scala tympani the pressure varies within wide limits when passing from the first to the second turn, but it is equal to the pressure in scala vestibuli at frequencies in excess of the best frequency of the point considered. The difference in instantaneous pressure acting on the basilar membrane exhibits the characteristics of a traveling wave. This pressure difference corresponds to the displacement of the basilar membrane evaluated from recordings of the microphonic potential.

Basilar Membrane↗
PubMed1980

On the rational selection of test series. 1. Principal component method combined with multidimensional mapping.

A method for the rational selection of optimal test series with high data variance and low collinearities is presented (PCMM method). The method combines the technique of multidimensional mapping originally introduced by Wootton and colleagues with the principal component method, and it is superior to other selection methods with respect to its collinearity decreasing power. Two examples of the application of PCMM are given, and the results are compared with corresponding results from other selection techniques.

Chemical Phenomena↗
PubMed1980

On the rational selection of test series. 2. Two-dimensional mapping of intraclass correlation matrices.

A rational design of optimal test series can be performed by two-dimensional mapping of intraclass correlation matrices (TMIC method). The method results in a two-dimensional map from which substituents can be selected by simple inspection. Different test series can be obtained from the same map so that synthetic feasibility can easily be taken into account. The approach closely corresponds to the usual way of thinking of organic chemists, and the test series evaluated for an example show high data variance and low collinearities.

Chemical Phenomena↗
PubMed1980

The evaluation of topological pharmacophores by heuristic approach.

A simple approach to evaluate logical pharmacophores on the base of topological features is described. It is based on considerations of the relative frequencies of structural features within different classes of activity. Shannon's entropy is used in the case of more than two classes. To obtain a pharmacophore a stepwise interactive procedure is performed. The algorithm is applied to fungicidal carboxamides and beta-adrenergic phenethylamine agonists and antagonists. In both cases meaningful pharmacophores could be obtained.

Chemistry, Pharmaceutical↗
PubMed1980

Informational content of discrete data from parallel test with similar biological objects: selection of key tests.

Results from parallel tests with similar biological objects are frequently interrelated. If the data are discrete which is a typical situation in biological mass-screening, the information-theoretical concept of Shannon's entropy can be used to unreval redundancies within such test and to recognize tests with high informational content. This concept was applied to two examples from the screening for fungicidal activity, and the results were compared with activity-activity relationships obtained from pattern recognition and with variance analysis. There was good agreement, and the entropy calculation indeed yielded a very sensitive measure for the informational structure of the data. If the informational structure is known redundant tests may be eliminated. If the evaluation of quantitative structure-activity relationships is attempted it is furthermore possible to restrict the calculations to key tests with high information.

Antifungal Agents↗