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  • 1
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Protein modification by ADP-ribose polymers is a common regulatory mechanism in eukaryotic cells and is involved in several aspects of brain physiology and physiopathology, including neurotransmission, memory formation, neurotoxicity, ageing and age-associated diseases. Here we show age-related misregulation of poly(ADP-ribose) synthesis in rat cerebellum as revealed by: (i) reduced poly(ADP-ribose) polymerase-1 (PARP-1) activation in response to enzymatic DNA cleavage, (ii) altered protein poly(ADP-ribosyl)ation profiles in isolated nuclei, and (iii) cell type-specific loss of poly(ADP-ribosyl)ation capacity in granule cell layer and Purkinje cells in vivo. In particular, although PARP-1 could be detected in virtually all granule cells, only a fraction of them appeared to be actively engaged in poly(ADP-ribose) synthesis and this fraction was reduced in old rat cerebellum. NAD+, quantified in tissue homogenates, was essentially the same in the cerebellum of young and old rats suggesting that in vivo factors other than PARP-1 content and/or NAD+ levels may be responsible for the age-associated lowering of poly(ADP-ribose) synthesis. Moreover, PARP-1 expression was substantially down-regulated in Purkinje cells of senescent rats.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Weed research 33 (1993), S. 0 
    ISSN: 1365-3180
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Possible mechanism(s) of resistance to auxinic herbicides in wild mustard (Sinapis arvensis L.) were investigated by characterizing responses of susceptible and resistant biotypes to 2,4-D, di-camba or picloram. No differences between bio-types were observed in absorption, translocation, or metabolism of foliar-applied radiolabelled herbicides. In contrast, the levels of ethylene production varied between biotypes. The susceptible biotype produced twofold and sixfold more ethylene than the resistant biotype within 4 h and 44 h of herbicide application, respectively. These results suggest that the mechanism of resistance in wild mustard is not due to differences in absorption, translocation, or metabolism. Ethylene production studies imply that resistance to auxinic herbicides may be attributed to altered target site(s) of action. Bases physiologiques de la résistance aux herbicides auxiniques d'un biotype de moutarde des champs (Sinapis arvensis L.)Les mécanismes possibles de la résistance aux herbicides auxiniques chez la moutarde des champs (Sinapis arvensis L.) ont été recherchés en caractérisant les réponses de biotypes résis-tants et sensibles au 2,4-D, au dicamba et au pi-clorame. Aprés application des herbicides radioactifs sur le feuillage, aucune différence d'absorption, de migration ou de métabolisme n'a été observée. Par contre, la production d'éthylene différait entre les biotypes. Le biotype sensible produisait 2 et 6 fois plus d'éthylène que le biotype sensible, respectivement 4 et 44 heures après l'application d'herbicide. Ces résultats sug-gèrent que la résistance aux herbicides auxiniques chez la moutarde des champs n'est pas due à des différences d'absorption, de migration ou de métabolisme mais pourrait provenir d'une altération du site d'action.Physiologische Untersuchung der Resistenz eines Acker-Senf-(Sinapis arvensis-) Biotyps gegenüber WuchsstoffherbizidenDer mögliche Mechanismus der Resistenz gegenüber Wuchsstoffherbiziden beim Acker-Senf (Sinapis arvensis L.) wurde unhand der Reaktion von empfindlichen und resistenten Biotypen gegenüber 2,4-D, Dicamba oder Picloram untersucht. Hinsichtlich Absorption, Translokation oder Metabolismus der auf die Blätter applizierten, radioaktiv markierten Her-bizide wurden keine Unterschiede beobachtet. Die Ethylenbildung variierte jedoch zwischen den Biotypen. Der empfindliche produzierte in-nerhalb 4 oder 44 Stunden nach der Herbizid-applikation 2-bzw. 6mal mehr Ethylen als der resistente. Aus den Ergebnissen läßt sich schließen, daß beim Acker-Senf der Resisten-zmechanismus nicht in der Absorption, der Translokation oder dem Metabolismus liegt, sondern die Ethylenbildung daran beteiligt ist, wo die Wirkorte fur die Wuchsstoffherbizide liegen.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 513 (1987), S. 0 
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Archives of environmental contamination and toxicology 35 (1998), S. 302-308 
    ISSN: 1432-0703
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Medizin
    Notizen: Abstract. For nearly 50 years, the fingernail clam (Musculium transversum) was believed to be virtually eliminated from the Illinois River. In 1991, workers began finding substantial populations of M. transversum in the Illinois River including several beds in and around the highly polluted Chicago Sanitary District. In order to determine if populations of M. transversum from polluted sites exhibited any genetic response to the high levels of toxins and to examine the genetic structure of several populations of M. transversum for any changes due to the population crash, starch-gel electrophoresis was performed on M. transversum from three Illinois River localities and four Mississippi River basin locations. The sampled populations produced an inbreeding coefficient (FIS) of 0.929, indicating that the populations were highly inbred. The results of a suspected founder effect due to a bottleneck was suggested by an FST= 0.442. The isozyme Glucose-6-phosphate isomerase-2 (Gpi-2) produced allelic frequency patterns that were consistent with expected patterns of a pollution-tolerant allele. Polluted sites exhibited elevated frequencies of Gpi-2 100 whereas nonpolluted sites exhibited elevated frequencies of Gpi-2 74 . This frequency pattern suggested that natural selection was occurring in populations under severe toxic pressures, leading to an increase in the frequency of the allele Gpi-2 100 . Therefore, Gpi-2 100 is a possible pollution-tolerant mutation in M. transversum.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Archives of environmental contamination and toxicology 27 (1994), S. 426-430 
    ISSN: 1432-0703
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Medizin
    Notizen: Abstract The pulmonary inflammatory response to NO2 exposure was measured by evaluating a series of biochemical and cellular parameters in rat bronchoalveolar lavage fluid. Animals were exposed to 9 mg/m3 (5 ppm) or 18 mg/m3 (10 ppm) of the gas for 24 h or 7 days. After bronchoalveolar lavage collection, a differential count of polymorphonuclear leukocytes, macrophages, and lymphocytes was done. A significant increase in polymorphonuclear leukocytes was found after 24 h of exposure, and after 7 days the number of macrophages increased significantly. After 7 days of exposure to 9 mg/m3 of NO2 (a dose that under our conditions did not induce migration of cells in the bronchoalveolar spaces) the ex vivo phorbol myristate acetate-induced superoxide anion production by resident cells was inhibited. After 24 h and 7 days of exposure to 18 mg/m3 of NO2, phorbol myristate acetate-induced superoxide anion production was lower than in the control group. The migration of polymorphonuclear leukocytes in the bronchoalveolar lavage fluid was not associated with any real increase in elastase. However, there was a dose- and time-dependent increase in α1-proteinase inhibitor in response to both 9 and 18 mg/m3 of NO2. Total glutathione was significantly increased in blood by 24 h treatment with 9 or 18 mg/m3 of NO2, whereas blood oxidized glutathione was not affected. In lung tissue we observed only a significant increase of oxidized glutathione after 24 h of exposure to 9 and 18 mg/m3 of NO2. These data suggest that many biochemical and cellular parameters are altered after acute or subacute exposure to relatively high doses of NO2, especially in the first 24 h. The increase of α1-proteinase inhibitor and blood glutathione can be considered a prompt protective response to the toxic injury.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 28 (1985), S. 135-138 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; cadralazine ; vasodilators ; chlorthalidone ; atenolol ; side-effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The antihypertensive efficacy of a new long-lasting vasodilator, cadralazine, and the diuretic chlorthalidone have been compared in hypertensive patients receiving concurrent treatment with atenolol. After a 4-week run-in period with atenolol alone 100 mg/day, two groups of 10 patients whose diastolic blood pressure exceeded 100 mm Hg were given for a period of 65 days either cadralazine 15 mg/day or chlorthalidone 25 mg/day, according to a randomized, double-blind, between-patients design. Compared to atenolol alone, both cadralazine and chlorthalidone induced a statistically and clinically significant decrease in blood pressure. The antihypertensive effect did not differ significantly between groups. Good compensation of the atenolol-induced decrease in heart rate was obtained with cadralazine, whereas during atenolol + chlorthalidone treatment at times the standing heart rate was significantly lower than during treatment with atenolol + cadralazine. Side-effects, many of which were already present during atenolol treatment, occurred with a similar frequency in both groups. It is concluded that atenolol + cadralazine and atenolol + chlorthalidone are equally well tolerated, acceptable and effective in the treatment of hypertension, but that further studies are warranted to explore the potential haemodynamic advantages of the cadralazine + atenolol combination.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The chromosomes of the diploid Hyla chrysoscelis and its tetraploid sibling species H. versicolor were studied with AgNO3 staining and in situ hybridization to determine the chromosome location of the 18S and 28S ribosomal RNA (rRNA) genes. A total of 236 Hyla chrysoscelis from 34 localities in 15 U.S. states and 100 H. versicolor from 15 localities in 12 states were examined. The rRNA gene sites were extremely variable in H. chrysoscelis, and also variable, but to a lesser extent, in H. versicolor. The most common rRNA gene site in both H. chrysoscelis and H. versicolor was on the short arm of chromosome 6. All of the rRNA gene locations seen in H. versicolor were also seen in H. chrysoscelis, supporting the hypothesis that the tetraploid H. versicolor arose from H. chrysoscelis. Although polymorphic rRNA gene sites in H. versicolor may reflect the positions of the rRNA genes in H. chrysoscelis ancestors, the origin of the extreme variability of such sites in H. chrysoscelis seems more obscure. Possible explanations include inversions, translocations, mobile genetic elements or a combination of some or all of these.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 64 (1993), S. 487-509 
    ISSN: 0945-3245
    Schlagwort(e): 65M60
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary It is well-known that periodic solutions of semilinear wave equations can be obtained as critical points of related functionals. In the situation that we studied, there is usually an obvious solution obtained as a solution of linear problem. We formulate a dual variational problem in such a way that the obvious solution is a local minimum. We then find additional non-obvious solutions via a numerical mountain pass algorithm, based on the theorems of Ambrosetti, Rabinowitz and Ekeland. Numerical results are presented.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1573-0743
    Schlagwort(e): dobutamine stress echocardiography ; myocardial scintigraphy ; SPET ; Sestamibi ; pharmacological stress testing ; coronary artery disease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Simultaneous dobutamine stress echocardiography (DSE) and99mTc-MIBI-SPET (DMS) for the evaluation of the presence and the extent of coronary artery disease (CAD) were assessed for a head to head comparison regarding the diagnostic accuracy of the two tests. Methods and Results: Forty-five consecutive patients (33 males and 12 females: 53±6.8 yr.) underwent exercise electrocardiography and simultaneous dobutamine stress echocardiography and MIBI-SPET imaging. Coronary angiography was performed in all patients (significant coronary stenosis 〉 50%). On the basis of the results of exercise electrocardiogram the pre-test probability for coronary artery disease (Diamond's algorithm) was low (45.6±12.7 %). The overall specificity, sensitivity and predictive accuracy of Echo-dobutamine stress test for diagnosis of the presence or absence of CAD were: specificity 82%, sensitivity 76%, diagnostic accuracy 80%, positive predictive value 90%, negative predictive value 40%. The overall specificity, sensitivity and predictive accuracy of MIBI-SPET-dobutamine test for diagnosis of the presence or absence of CAD were: specificity 86%, sensitivity 87%, diagnostic accuracy 84%, positive predictive value 97%, negative predictive value 54%. MIBI-SPET-dobutamine test showed a significantly higher sensitivity in comparison with ECHO-dobutamine test (P〈0.05). Conclusion: Both noninvasive methods for the detection of CAD showed a good diagnostic accuracy. Nevertheless the SPET model showed an higher sensitivity in comparison with DSE model, essentially in the presence of a lower extent of CAD and during submaximal test.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1434-601X
    Schlagwort(e): 25.70.Lm ; 24.60.Ky
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract It is shown that the Partially Overlapping Molecular Level Model (POMLM) accounts for the experimental results of the dissipative28Si +48Ti collision around 210 MeV incident energy. The general trend of the properties of the fluctuations as well as the average angular distributions are reproduced by the same set of main parameters. A general consistency is also found between the present data and the data obtained in previous work on the same colliding system performed at lower incident energy (around 123 MeV).
    Materialart: Digitale Medien
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