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Biomedical subjects

M Wilhelm

Publications and source records attributed to M Wilhelm.

At least 217 records · Page 12Linked to original sources
PubMed1984

Selective cloning of Bacillus subtilis xylose isomerase and xylulokinase in Escherichia coli genes by IS5-mediated expression.

A fragment of Bacillus subtilis DNA coding for xylose isomerase and xylulokinase was isolated from a BamHI restriction pool by complementation of an isomerase-defective Escherichia coli strain. The spontaneous insertion of IS5, which occurred during the very slow growth of the E. coli xyl- cells on xylose, allowed the expression of the cloned Bacillus genes in E. coli. Without IS5 insertion, the xylose genes were inactive in E. coli. Deletion experiments indicated that the control of the expression resides within a 270-bp long region at the right end of IS5. Deletion of this region led to a loss of expression, which could be restored by insertion of the lacUV5 promoter fragment at the deletion site. Sequence analysis showed that the site of IS5 insertion is 195 bp upstream from the putative ATG initiation codon of the xylose isomerase structural gene. This ATG is preceded by a ribosome binding sequence and two hexamers also found in promoter regions of other Bacillus genes. Deletion and mutagenesis analysis led to a preliminary map of the Bacillus xylose operon.

Aldose-Ketose Isomerases↗
PubMed1979

[EEG-activity patterns in visual information processing: characteristics, variance-analytical deliminiation, discriminance-analytical determination of undispensable variables and scale level].

1. In order to determine the variable distributions of 5 activation dependent EEG activity patterns occurring during visual information processing, mean values and standard deviations of the percental quantities of the frequencies 4, 5, ..., 13 Hz, 14 to 20 Hz and 21 to 30 Hz, as well as the mean amplitudes in the frequency bands 3.5 ... 7.4 Hz, 7.5 ... 13.4 Hz and 13.5 to 30 Hz were determined on corresponding to 10 s samples. It could be demonstrated by regression analysis that an interval scale level can be assumed already on the basis of cethe percental quantities in the three last mentioned frequency bands. 2. On the basis of 18 relevant variables, all the adjacent activity patterns could be separated from each other by means of univariate variance analysis at pairwise mean value comparison by at least two variables. 3. After stepwise reduction of dispensable variables in the framework of a linear discriminance analysis an optimal set of variables was determined, comprising the percental quantities of the frequencies 4, 5, 6, 10, 12 Hz, and 14 to 20 Hz, as well as the mean value of the amplitudes in the frequency band 3.5 to 7.4 Hz. In 4 our of 5 elementary discriminance functions, the mean values calculated for each pattern were significantly distinguishable from each other (analysis of variance, Newman-Keuls test). 4. By linear regression analysis it could be shown that the classification system of the EEG activity patterns at visual information processing can be mapped on an interval scale after the reduction of variables, too. Finally, data about the reliability of the scoring procedure are presented.

Adult↗
PubMed1977

Selective inhibition of noradrenaline and serotonin uptake by C 49802-B-Ba and CGP 6085 A.

The effects of two new compounds, 1-(1-methylamino-2-hydroxy-3-propyl)-dibenzo[b,e]bicyclo[2,2,2]octadiene-HCl (C 49802-B-Ba) and 4-(5,6-dimethyl-2-benzofuranyl) piperidine HCl (CGP 6085 A), on noradrenaline (NA) and serotonin (5-HT) uptake were investigated in different test systems, CGP 6085 A is a very potent and selective inhibitor of 5-HT uptake in rat brain (ED50 1-4 mg/kg p.o., depending on test system). Doses up to 1000 mg/kg p.o. did not inhibit NA uptake. C 49802-B-Ba is a potent and selective inhibitor of NA uptake in rat brain (ED50 5-10 mg/kg p.o. depending on test system) and heart (ED50 1.5 mg/kg p.o.). At 300 mg/kg p.o., this compound caused no inhibition of 5-HT uptake.

Animals↗
PubMed1977

[Repeated characterization, analysis of variance limitation and discrimination analysis classification of EEG-activity patterns in human sleep].

1. To describe quantitatively and to deliminate nine EEG sleep patterns, mean values and standard deviations of abundances of the frequencies 0.8 ... 1.8 c/sec, 2...3.5 c/sec, 4...13c/sec, 14 to 17 c/sec, 18 to 22 c/sec, and 23 to 40 c/sec as well as of the average amplitudes in selected frequency ranges were calaculated and the distributions represented. 2. All nine EEG activity patterns could be separated by means of univariate and multivariate analyses of variance on the basis of all 28 as well as the 17 indispensable variables. 3. In the course of a stepwise reduction of variables within the framework of a linear discriminant analysis an optimal set of 17 variables was determined for the separation of the patterns, comprising: the percent quantity of the frequencies 0.8 ... 3.5 c/sec, 7 ... 9 c/sec and 18 to 40 c/sec as well as the average amplitudes in the frequency ranges 0.8 to 3.5 c/sec and 7.5 to 40 c/sec. 4. By linear regression analyses it could be shown that the sleep scording system used, can be reflected on an interval scale with the aid of discriminant functions; this can be achieved on the basis of the optimal set of variables as well as of the five most indispensable variables. 5. Finally the degree of the objectivity of the scoring procedures was demonstrated. Advantages and disadvantages of sleep scoring systems were discussed and possibilities of the utilization of results suggested, also in respect to the further development of the automatic recognition of EEG activity patterns.

Analysis of Variance↗
PubMed1975

[Variance and discriminatory analyses for the classification of wakefulness-dependent EEG patterns].

1. To describe 8 alertness-dependent EEG activity patterns to be observed during wakefulness with eyes closed, mean values and standard deviations of the frequencies 4, ..., 13, 14 to 17, 18 to 22 and 23 to 40 c/sec, of the percentage activity in the theta, alpha and beta bands as well as of the theta and alpha amplitudes were calculated. 2. On the basis of 18 variables significant differences between 7 activity patterns were ascertained by means of univariate and multivariate analyses of variance. 3. In the course of stepwise reduction of variables within the framework of a linear discriminatory analysis, an optimal set of variables was determined for the separation of the patterns comprising the following variables: mean value and standard deviation of the alpha amplitudes and mean value of the theta amplitudes as well as the percent quantity of the frequencies 3, ..., 7, 10, 14 to 17 and 23 to 40 c/sec. 4. By means of a linear regression analysis it was shown that the EEG scoring system can be reflected on an interval scale. In connection with results on the reliability of the methods used the results were discussed.

Analysis of Variance↗