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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell reports 9 (1990), S. 173-177 
    ISSN: 1432-203X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cell cultures of Panax ginseng and Catharanthus roseus producing secondary metabolites were preserved in liquid nitrogen or under mineral oil for six months. The growth behaviour and the ability of the cultures to produce ginsenosides or indole alkaloids were measured after a recovery period and compared with cultures maintained by frequent subcultivation during the same period. Neither growth kinetics nor the degree of vacuolization during growth were affected by the long term preservation. Some changes in secondary metabolism were however found, indicating that preservation under mineral oil does not preserve the productivity of cell cultures whereas the cryogenic method does.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1432-1971
    Schlagwort(e): Operated congenital heart defect ; Children ; Signal-averaged electrocardiography ; Late potentials ; Arrhythmias
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract After corrective surgery for congenital heart defects, scars may create fractionation and delay of the electrical signals in the heart muscle, providing a substrate for arrhythmias. Signalaveraged electrocardiograms (SAECGs) were obtained from 33 children after right ventriculotomy, on average 6 years after surgery, and from 38 healthy controls of the same age. The duration of the filtered QRS complex (fQRS), the duration of the low amplitude signal (〈40μV) in the terminal QRS complex (LAS40), and the root mean square amplitude of the terminal 40 ms of the QRS complex (RMS40) were determined. The values of fQRS ≥117 ms, RMS40≤25μV, and LAS40≥35 ms, which were beyond the mean ±2 SD of the healthy controls, were considered abnormal. Most patients had right bundle branch block and therefore a prolonged fQRS. Late potentials were defined as present if both the RMS40 and LAS40 were abnormal. Altogether nine patients (27%) had late potentials. In the patients with late potentials the incidence of serious ventricular arrhythmias was 44% (4 of 9) and in the patients without late potentials 0% (0 of 24). In seven patients with enlargement of the right ventricle, the incidence of arrhythmias was 57% (4 of 7) when late potentials were present and 0% (0 of 7) when they were absent. In the present study late potentials were associated with a history of arrhythmias, especially when the right ventricle was enlarged. Therefore the SAECG may be useful for determining the risk of serious arrhythmia events in children operated for congenital heart defects.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1432-1971
    Schlagwort(e): Cardiac modeling ; Localization ; Magnetocardiography ; Ventricular pre-excitation ; Wolff-Parkinson-White syndrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Magnetocardiographic mapping was performed on a 2-year-old boy who suffered from the Wolff-Parkinson-White syndrome in association with a complex congenital heart defect. The pre-excitation site was determined noninvasively from the measured cardiac magnetic fields. The location was in the same anatomic region as found by intraoperative epicardial mapping. This result shows that magnetocardiography can be helpful for determining an accessory pathway also in patients with grossly abnormal cardiac anatomy.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 45 (1993), S. 191-193 
    ISSN: 1432-1041
    Schlagwort(e): Torsades de pointes ; Terfenadine ; Itraconazole ; QT-interval ; drug-interaction ; pharmacokinetics ; drug metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Terfenadine, a nonsedating H1-selective antihistamine, is widely used in many countries. We report pharmacokinetic results in a patient who developed a prolonged QT-interval in ECG and symptomatic torsades de pointes ventricular tachycardia as a consequence of the interaction of itraconazole and terfenadine. Both drugs were taken in the recommended doses: terfenadine 60 mg b.d. and itraconazole 100 mg b.d. Terfenadine metabolism was delayed by itraconazole, leading to an increased level of unmetabolised terfenadine. Seven weeks after the cessation of itraconazole treatment, terfenadine was rapidly metabolized to its active metabolite and did not prolong the QT-interval when given as a single provocation dose (120 mg). The findings suggest that intraconazole in therapeutic doses inhibits terfenadine metabolism. It is also possible that unmetabolised terfenadine alone, without an increased level of its active metabolite, may cause torsades de pointes. The concomitant use of terfenadine and itraconazole (and ketoconazole) should be avoided.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1573-4927
    Schlagwort(e): nucleic acid hybridization ; ribosomal RNA ; ribosomal RNA gene number ; sequence divergence ; tree frogs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Hyla chrysoscelis (2n = 24) and H. versicolor (2n = 48) are a diploid-tetraploid species pair of tree frogs. Hybridization saturation of isolated 125I-labeled ribosomal RNAs (rRNAs) with filter-immobilized DNA shows that there are twice as many rRNA genes in the tetraploid as in the diploid. For the diploid, saturation occurs at 0.037%, from which it is calculated that there are about 618 copies of the (18 S + 28 S) rRNA genes per haploid genome. Analysis of the extent of hybridization and also the thermal stability of homologous and heterologous hybrids shows that considerably more base substitutions have occurred in the tetraploid rDNA genes than in the diploid since their divergence. This is interpreted to reflect either a relaxation of the gene regulatory “correction” mechanism hypothesized to be responsible for the maintenance of identical tandem rRNA genes in the tetraploid or a release of one gene set from the normal selective constraints.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Biotechnology letters 12 (1990), S. 519-524 
    ISSN: 1573-6776
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Growth kinetics and indole alkaloid production ofCatharanthus roseus hairy root cultures were studied in shake flasks and in a small scale fermenter. A logistic growth model commonly used for microbes described well the growth of hairy roots. Of the several parameters analyzed during the cultivation of hairy roots, a linear relationship between sucrose consumption and dry weight increase was obtained. This suggests the validity of sugar analysis as a means in monitoring the growth of hairy roots in fermenters.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Herzschrittmachertherapie & Elektrophysiologie 11 (2000), S. 229-234 
    ISSN: 1435-1544
    Schlagwort(e): Key words Magneto cardiography – arrhythmia risk evaluation –¶signal-averaged electrocardiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We have applied various methods to extract parameters from high-resolution magnetocardiographic (MCG) and electrocardiographic (ECG) recordings for characterizing the risk of life-threatening arrhythmias. The methods include detection of late fields and late potentials at the end of the QRS, abnormalities in spectral variability and signal fragmentation during the QRS, and variability in the heart rate. In addition, we have developed methods to convert MCG signals measured with any sensor configurations to a common presentation form. The signal processing methods have been implemented on a user-friendly interface which allows fast and easy use in a clinical environment.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 18 (1989), S. 79-93 
    ISSN: 1573-5044
    Schlagwort(e): Agrobacterium rhizogenes ; Catharanthus roseus ; hairy root cultures ; indole alkaloids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hairy root cultures of Catharanthus roseus were established by infection with six different Agrobacterium rhizogenes strains. Two plant varieties were used and found to exhibit significantly different responses to infection. Forty-seven hairy root clones derived from normal plants and two derived from the flowerless variety were screened for their growth and indole alkaloid production. The growth rate and morphological appearance showed wide variations between the clones. The alkaloid spectra observed were qualitatively but not quantitatively very similar to that of the corresponding normal plant roots. No vindoline or deacetyltransferase activity could be detected in any of the cultures studied. O-acetylval-lesamine, an alkaloid which has not been previously observed in C. roseus was identified from extracts of hairy root clone No. 8. Two root clones were examined for their growth and alkaloid accumulation during a 26-day culture period. Alkaloid accumulation parallelled growth in both clones with ca. 2 mg ajmalicine and catharanthine per g dry weight being observed.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Biotechnology techniques 8 (1994), S. 61-66 
    ISSN: 1573-6784
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Hairy roots of Catharanthus roseus were cultivated in three different types of bioreactors. The best growth and indole alkaloid production was achieved in an airsparged bioreactor with no other mixing. In the stirred bioreactor or in the bioreactor with medium circulation the roots did not grow, suggesting that hairy roots of C. roseus are more sensitive to stress than root cultures of many other plant species.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 558-562 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Digitalis lanata cell cultures grown as small undifferentiated aggregates in suspension culture can be redifferentiated into green embryos that produce cardenolides. The possibility of using a statistical (Box-Wilson) experimental design to study the effects of four different variables on growth, differentiation, and cardenolide production of D. lanata tissue cultures are investigated. The results of the analyses were processed by linear regression analysis. Mathematical models explaining the effects of the variables were developed. The concentration of maltose and the NO3-—NH4+ ratio were found to be significant variables for both growth and cardenolide production. The size of the inoculum was also important.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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