ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • pharmacokinetics  (109)
  • Lepidoptera  (97)
  • Hymenoptera  (47)
  • phosphorus  (42)
  • Coleoptera  (39)
  • Yeast  (35)
  • Turbulence
  • Springer  (364)
  • Annual Reviews
  • Blackwell Publishing Ltd
  • Springer International Publishing
  • Springer Nature
  • 2020-2024
  • 2005-2009
  • 1990-1994  (364)
  • 1985-1989
  • 1980-1984
  • 1970-1974
  • 1990  (364)
Sammlung
Schlagwörter
Verlag/Herausgeber
  • Springer  (364)
  • Annual Reviews
  • Blackwell Publishing Ltd
  • Springer International Publishing
  • Springer Nature
  • +
Erscheinungszeitraum
  • 2020-2024
  • 2005-2009
  • 1990-1994  (364)
  • 1985-1989
  • 1980-1984
  • +
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 57 (1990), S. 77-83 
    ISSN: 1570-7458
    Schlagwort(e): Age ; pteridine ; Pectinophora ; Lepidoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé En chromatographie liqudde à haute performance (HPLC) à détection par fluorescence, 4 composés ptéridiniques: la xanthoptérine, l'isoxanthoptérine, la 6-bioptérine et la ptérine ont été décelés dans les têtes de P. scutigera Holdaway (Lep. Gelechiidae) adultes. Un autre composé, dénommé ‘xanthoptérine modifiée’, a été décelé aussi dans les têtes de papillons; de même l'isoxanthoptérine a été décelée dans les thorax et abdomens. Les concentrations de ces ptérines ont été dosées dans les têtes des papillons de 2 à 50 jours au laboratoire à 25°C. Les concentrations d'isoxatthoptérine ont été dosées dans les thorax et les abdomens de 2 à 40 jours. La xanthoptérine de la ‘xanthoptérine modifiée’ diminuent nettement avec l'âge, tandis que la ptérine diminue plus lentement et que la 6-bioptérine se maintient pratiquement sans changements. L'isoxanthoptérine diminue dans les têtes de mâles de 38,3 ng/tête à 2 j à 22,7 ng/tête à 50 j, mais chez les femelles les concentrations augmentent nettement de 41,2 ng/tête à 2 j à 150,4 ng/tête à 50 j. Des modifications de même type ont été observées dans les thorax et les abdomens des mâles et des femelles. Les modifications de concentration de la ‘xanthoptérine modifiée’ des têtes de papillons peuvent être utilisées pour évaluer l'âge physiologique de mâles et des femelles de P. scutigera. La confiance dans ces estimations peut être améliorée en se référant aux concentrations d'isoxanthoptérine dans les thorax des mâles et au rapport isoxanthoptérine/‘xanthoptérine modifiée’ dans les têtes de femelles.
    Notizen: Abstract The amounts of four pteridine compounds, xanthopterin, isoxanthopterin, 6-biopterin and pterin and a further unidentified substance, termed ‘modified xanthopterin’, were determined in the heads of adult Pectinophora scutigera (Holdaway) (Lepidoptera: Gelechiidae), aged between 2 and 50 days and reared in the laboratory at 25°C. The level of isoxanthopterin was also determined in the thoraces and abdomens of moths aged between 2 and 40 days. The levels of xanthopterin, and ‘modified xanthopterin’ decreased markedly in the heads of males and females with increasing moth age, while those of pterin decreased more slowly and 6-biopterin remained largely unchanged. Isoxanthopterin decreased in male heads from 38.3 ng/head at 2 days to 22.7 ng/head at 50 days, but in females levels increased from 41.2 ng/head at 2 days to 150.4 ng/head at 50 days. Similar changes in the amounts of isoxanthopterin with increasing moth age were observed in male and female thoraces and abdomens. The results are discussed in relation to using pteridine compounds for estimating the physiological age of P. scutigera.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 3 (1990), S. 277-287 
    ISSN: 1572-8889
    Schlagwort(e): parasitoid behavior ; heritable traits ; Microplitis croceipes ; Hymenoptera ; Braconidae ; allelochemical ; flight response ; host location
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The heritable nature of differential responses by Microplitis croceipes(Cresson) (Hymenoptera: Braconidae) to airborne allelochemicals was investigated. Four isofemale lines were tested for three generations in a flight tunnel. Flight response was found to be strongly dependent on the familial origin, with two highly responsive lines being clearly differentiated from two less responsive ones. Each isofemale line could also be recognized by typical behaviors that suggested that M. croceipesfemales may inherit independent characters of sensory acuity to plant and to host chemicals and of learning ability.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 3 (1990), S. 85-104 
    ISSN: 1572-8889
    Schlagwort(e): Hymenoptera ; Vespidae ; Belonogaster petiolata ; rubbing behavior ; sternal gland ; ant predation ; defensive allomone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Females of the social wasp, Belonogaster petiolata,rub the secretion of van der Vecht's gland, located on their terminal gastral sternite, onto the nest pedicel. In bioassays, the secretion was repellent to two species of ants, while shortchain acids were effective releasers of rubbing behavior. Rubbing was associated with pedicel enlargement and departure from the nest in preemergence colonies. Its frequency was high where wasps were often exposed to ants and low where ants were rare or absent. Rubbing also decreased significantly from the pre-to the postemergence stage of the colony cycle. In both stages, subordinate foundresses rubbed more often than queens or workers. These observations support the hypothesis that rubbing behavior and the secretion of van der Vecht's gland function in chemical defense of the nest against ant predation. The general morphology of the gland in B. petiolataresembles that of the four other independent-founding polistine wasp genera.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    ISSN: 1572-8889
    Schlagwort(e): cotton bollworm ; Heliothis armigera ; Lepidoptera ; Noctuidae ; sex pheromone ; flight tunnel ; male behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Six compounds were identified from gland extracts of the cotton bollworm, Heliothis armigera(Hubner): (Z)-11-hexadecenal (Z11-16:Ald), (Z)-9-hexa-decenal (Z9-16:Ald), hexadecanal, (Z)-11-hexadecenol (Z11-16:OH), (Z)-7-hexadecenal (Z7-16:Ald), and (Z)-9-tetradecenal (Z9-14:Ald). Each of the compounds that were identified was examined for its ability to elicit sexual responses from male moths in a flight tunnel. Males flew upwind to Z11-16:Ald alone, but greater levels of copulatory responses were evoked with the addition of 2.5% Z9-16:Ald to the Z11-16:Ald. Addition of hexadecanal to the binary mixture had no effect in raising the behavioral response of the males in the flight tunnel. The effect of Z7-16:Ald on male flight depended on the loading. The addition of 1% of this component to 2 mg of the binary mixture reduced levels of copulatory response, but the same addition (1 %) to 10 μg of the binary mixture increased copulatory response. The addition of 79-14:Ald or Z11-16:OH to the binary mixture reduced behavioral responses of males. High loadings of the binary mixture (200–2000 μg) were better than a low loading (10 μg) in eliciting response of males.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 3 (1990), S. 241-250 
    ISSN: 1572-8889
    Schlagwort(e): antipredator behavior ; prey caching ; Ammophila ; Formica ; foraging behavior ; Hymenoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Many solitary ground-nesting wasps in the families Pompilidae and Sphecidae excavate nests after capturing prey for provisions. These wasps generally cache their immobilized prey temporarily during nest excavation, frequently by suspending the prey in a plant (”aerial caching”). Here I test the hypothesis that aerial caching by Ammophila spp. wasps (Sphecidae) functions to reduce prey theft by generalist predators, Formica spp. ants. Foraging ants removed baits placed on the ground more rapidly than baits suspended in plants; mean half-lives for ground and aerial baits were 14.5 and 145.7 min, respectively (mean values for experiments 1–3). Ant foraging activity decreased during the midday. Ant interference with nesting activities of Ammophila spp. also decreased during the midday, paralleling observed fluctuations in ant foraging activity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 3 (1990), S. 271-276 
    ISSN: 1572-8889
    Schlagwort(e): Coleoptera ; Scarabaeidae ; Cotinis nitida (L.) ; beetle flight ; pheromone bioassay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 3 (1990), S. 359-379 
    ISSN: 1572-8889
    Schlagwort(e): ant ; aggression ; kin discrimination ; Rhytidoponera confusa ; Hymenoptera ; Formicidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Significant variation in aggressiveness and kin discrimination ability occurs between different laboratory colonies of the ant Rhytidoponera confusa.Different colonies show consistently high (or low) levels of aggression toward nonnestmates over 4–19 weeks. Earlier studies excluded colony size and the natural presence or absence of the queen in colonies and differences in hunger as possible sources of variation. The present study excluded the number of larvae in colonies and the time of the light period of the light cycle when recognition tests were carried out. Highly significant variation occurs between the kin discrimination ability of individual workers in any particular colony. Approximately 28% of the workers in colonies of R. confusashowed very poor kin discrimination. Much of the colony's kin discrimination is carried out by a small number of highly aggressive workers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 54 (1990), S. 173-180 
    ISSN: 1570-7458
    Schlagwort(e): Encapsulation ; evolutionary relationships ; host suitability ; parasitization ; parasitoid complexes ; Diadegma armillata ; Hymenoptera ; Ichneumonidae ; Lepidoptera ; Yponomeutidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'étude a porté sur la valeur de 8 représentants européens du genre Yponomeuta (Lep., Yponomeutidae) comme hôtes pour Diadegma armillata (Hym., Ichneumonidae). La présence, l'état du parasitoïde, le nombre de chenilles contenant un hyménoptère et la mortalité des chenilles on été examinés par dissection et par élevage des chenilles attaquées en conditions contrôlées. Pour examiner si la mortalité des chenilles saines et parasitées diffèrent, des chenilles non contaminées par l'ichneumonide ont été utilisées comme témoins. De plus, des chenilles provenant de différentes parties des Pays-Bas et d'Allemagne ont été disséquées pour connaître leur taux de parasitisme par D. armillata. La valeur des diverses espèces diffère considérablement. Les dissections montrent que cela provient de différentes aptitudes à l'encapsulation des œufs du parasite. La comparaison des taux observés par la dissection des chenilles des différentes parties des Pays-Bas et d'Allemagne montre une surprenante uniformité pour les populations d'origines géographiques différentes. Les observations sur l'encapsulation par les différentes espèces d'yponomeutes correspondent assez bien aux différences observées parmi les divers complexes parasitaires dans lesquels D. armillata intervient. Certains éléments montrent cependant que le taux d'attaques victorieuses (sans tenir compte d'une éventuelle encapsulation ultérieure) contribue aussi aux différences observées entre les complexes parasitaires. Le classement des espèces d'yponomeutes en 3 catégories, d'après leur valeur comme hôte, montre un remarquable parallélisme avec les relations phylogéniques mises en évidence par analyse des allozymes: les espèces présentant une forte proportion d'encapsulation sont celles qui ont divergé précocement au cours de l'évolution du genre, tandis que les espèces ayant divergé le plus récemment présentent un pourcentage intermédiaire ou sont incapables d'encapsuler les œufs de D. armillata.
    Notizen: Abstract The suitability as a host of Diadegma armillata (Gravenhorst) (Hymenoptera, Ichneumonidae) was determined for eight West-European representatives of the genus Yponomeuta Latreille (Lepidoptera, Yponomeutidae) by dissecting and rearing parasitized larvae under controlled conditions. The suitability of the various species differed considerably, and dissection showed that this was mainly due to the ability of the host species to encapsulate the parasitoid eggs. Encapsulation by Yponomeuta-species corresponded fairly well to the differences between the parasitoid complexes concerning D. armillata. Classifying the Yponomeuta-species into three categories according to their suitability, showed a remarkable parallelism with the phylogenetic relationships as determined by allozyme comparison: species showing high encapsulation rates are those that have diverged early in the evolution of the genus, whereas the more recently evolved species showed an intermediate percentage or were not able to encapsulate eggs of D. armillata.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 54 (1990), S. 219-224 
    ISSN: 1570-7458
    Schlagwort(e): Diabrotica virgifera virgifera ; Coleoptera ; Chrysomelidae ; corn ; life-stage occurrence ; planting date
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Dans les conditions de l'est du Sud Dakota (USA), 3 dates de semailles de maïs et 3 dates de contamination avec des œufs de D. virgifera virgifera LeConte ont servi à imposer ou à empêcher la synchronisation des éclosions des œufs et par conséquent des développements ultérieurs. Les dates médianes d'apparition de chacun des 3 stades larvaires et des imagos ont été déterminées en relation avec les unités de température et le nombre de jours depuis la contamination. Aucune différence significative entre les dates médianes d'apparition n'a été mise en évidence par utilisation des unités de température; par contre, ces différences deviennent significatives lorsque l'on utilise le nombre de jours depuis la contamination. Des paramètres fiables sont nécessaires pour prédire la présence des différentes stades de cet insecte. En dépit des différentes conditions imposées pour cette étude, la méthode la moins capricieuse pour prédire l'apparition d'un stade larvaire et l'émergence des adultes est la somme de températures avec une base de 11°C.
    Notizen: Abstract Under field conditions in eastern South Dakota, USA three different planting dates of corn and three times of egg infestation were used to imposed synchronous and asynchronous timing of corn growth and Diabrotica virgifera virgifera LeConte egg hatch and subsequent development. Median occurrence of each of the three larval stages and of the adult stage for each of the infestation-planting treatments was determined by relating occurrence to thermal units and to days after infestation. No significant differences were found among the treatments for median occurrence of each life stage when the thermal unit approach was used. However, significant differences were found among treatments for median occurrence when the day after infestation approach was used. Consistent parameters are needed for prediction of the occurrence of life stages of this insect. Despite the various imposed conditions, this study indicates that the least variable method of predicting life stage occurrence and adult emergence of D. v. virgifera was the use of thermal unit accumulations (base 11°C).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 55 (1990), S. 47-57 
    ISSN: 1570-7458
    Schlagwort(e): Campoletis sonorensis ; parasitoid ; Hymenoptera ; Ichneumonidae ; Heliothis virescens ; cotton ; potential host community location ; host location
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les comportements d'évaluation de l'effectif d'hôtes potentiels et de la position des hôtes par C. sonorensis (Hyméno.: Iccheumonidae) ont été quantifiés pour déterminer les séquences significatives des événements comportementaux. La localisation de la colonie potentielle d'hôtes est apparue comme une séquence régulière des événements comportementaux. Une fois que le parasitoïde a localisé une colonie potentielle, on a constaté que la recherche au hasard des hôtes se poursuit jusqu'à ce qu'il ait la démonstration qu'il s'agit d'une plante attaquée. La localisation par le parasitoïde d'un hôte certain a consitué une autre séquence régulière des événements comportementaux terminant la localisation de l'hôte. L'influence de pieds de coton intacts, de pieds abîmés mécaniquement et de pieds occupés par des chenilles du 3ème stade de l'hôte et de plantes dont les chenilles ont été retirées juste avant l'expérience a été déterminée en modifiant la composition du complexe hôte/plante. Des femelles naïves de C. sonorensis ont montré en présence de pieds de coton intacts apparemment toutes les séquences comportementales de vol impliquées dans la localisation d'une colonie potentielle d'hôtes. Une fois que le parasitoïde a atteint la colonie potentielle d'hôtes, la présence de dégâts de l'hôte n'a pas modifié le temps passé sur la plante, mais a modifié le temps consacré à la prospection.
    Notizen: Abstract Wind tunnel flight behavior of inexperienced female Campoletis sonorensis (Cameron) (Hymenoptera; Ichneumonidae) in response to its larval host Heliothis virescens (F.) (Lepidoptera: Noctuidae) feeding on the host plant cotton (Gossypium hirsutum L.) is described. The flight behavioral sequence was determined by quantification of frequencies of observed behaviors and probabilities of first-order behavioral transitions. Comparison of inexperienced C. sonorensis flights to undamaged and damaged cotton indicated that stimuli from undamaged plants alone are adequate to elicit the complete flight behavioral sequence observed in response to H. virescens feeding on cotton. Parasitoid foraging behavior was also analyzed after landing on the stimulus. This behavior appeared to be random in its initial stages, but became sequential after location of evidence of a host. Analysis of foraging on undamaged and 3 treatments of damaged cotton resulted in the determination that parasitoids tend to remain on damaged plants longer than undamaged plants although no significant difference was detected. C. sonorensis spent a greater percentage of their time foraging on host damaged plants than on undamaged plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 46 (1990), S. 700-704 
    ISSN: 1420-9071
    Schlagwort(e): Coleoptera ; Tenebrionidae ; Tribolium confusum ; defesive secretion ; biosynthesis of 1-alkenes ; oxidative decarboxylation ; anti-elimination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The terminally unsaturated hydrocarbons of the defensive secretion ofTribolium confusum are biosynthesized from fatty acids by oxidative decarboxylation. The process involves an enantiospecific cleavage of the C−H bond of thepro-(S) C(3)−H atom and simultaneous decarboxylation of the acid into an 1-alkene and carbon dioxide via ananti-periplanar transition state geometry (anti-elimination). The stereochemistry of this biotranformation is identical in all respects with the same reaction in higher plants. The mechanism seems to be of general importance for the biosynthesis of many vinylic substructures of natural products from oxygen-containing precursors.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic sciences 52 (1990), S. 199-220 
    ISSN: 1420-9055
    Schlagwort(e): Eutrophication ; lake management ; phosphorus ; ecosystem ; chlorophyll-a ; mathematical modelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We compare results of a new model for predicting the short term inter annual changes in chlorophyll-a (chl-a) in lakes after reductions in total phosphorus (TP) to predictions made by least squares regression models. In the new method, slopes of chl-a/TP graphs (both axes in mg · m−3) are depicted in frequency diagrams and used to extract information on the expected, short term chl-a/TP response. The short term response for nine shallow (〈 10 m deep) and nutrient rich lakes to changes in TP was found to be: Chl-a = 0.49 · TP + 17.3, and for nine deep, P-limited lakes: Chl-a = 0.08 · TP + 3.5. If the TP-reduction is known to be greater than 10 mg · m−3, the expected slope increases to 0.58 for shallow lakes and to 0.26 for deep lakes. The slope, 0.58, is 8% lower than the slope for the long term response calculated by regression for the shallow lakes. For deep lakes the slope, 0.26, is 2 to 3 times higher than that calculated by regression, indicating that reductions in TP for deep lakes give greater effects than least squares regression equations suggest. We have also calculated the reduction in TP which will give about 80% probability that a reduction in chl-a will be observed next year. For shallow, P-limited lakes this reduction is about 30 mg · m−3 (5% of average initial in-lake TP concentration), and for deep lakes about 14 mg · m−3 (35% of average initial in-lake TP concentration).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic sciences 52 (1990), S. 256-268 
    ISSN: 1420-9055
    Schlagwort(e): Vertical mixing ; stratification ; phosphorus ; Lake Constance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Depth variable vertical eddy diffusion coefficients for heat (K z) were calculated from continuously measured temperature profiles in Überlinger See (western part of Lake Constance). The temperatures were averaged over vertical intervals of 10 m yielding 14 discrete values (maximum depth of Überlinger See: 147 m). A linear fit from 10 June to 29 September 1987 was used to smooth the significant temperature fluctuations caused by internal seiches of Lake Constance. Assuming horizontal homogeneity for the smoothed data the Gradient-Flux-Method was applied to compute vertical diffusion coefficientsK z at different depths using the depth variable volumes and surfaces of the 14 layers. The resulting mean diffusion coefficients for the period from June to September are 0.04 cm2/s near the thermocline and up to 0.8 cm2/s in deeper strata (accuracy: ± 50%). It is shown that horizontal mixing between Überlinger See and Obersee (main lake) alters the computation ofK z by less than 50%. A relationship betweenK z and stability (Brunt-Väisälä) frequencyN is found which corresponds well to the theory of internal wave induced turbulence. Combining the diffusion coefficients with measured phosphorus profiles, a phosphorus flux from the hypolimnion to the epilimnion of (0.7 ± 0.4) mg P m−2 d−1 was calculated, corresponding to about 20% of the average external loading per area of Lake Constance in 1986.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 56 (1990), S. 15-21 
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Chrysomelidae ; corn rootworms ; age-specific survival ; age-specific fecundity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé D. virgifera virgifera LeConte a été placé sur des régimes nutritifs mimant l'évolution des tissus du maïs disponsibles dans le champ lorsque les insectes éclosent est aux stades suivants du maïs: 1) après émergence de l'épi mâle, mais avant l'apparition des barbes et l'émission du pollen; 2) lors de la présence de barbes et de l'émission de pollen; 3) après la pollinisation et quand les barbes ont bruni. Un quatrième régime a été fourni pendant toute l'expérience comprenant des barbes vertes, du pollen et des feuilles. Les pontes moyennes des femelles pendant les 12 semaines de l'étude on été 125, 235, 179 et 441 pour les régimes 1, 2, 3 et 4. Les dates de mort de la moitié des adultes a été 7,2, 7,2, 6,7 et 8,8 semaines pour respectivement les mêmes régimes. Les femelles du régime 1 pondent à un âge plus avancé que les femelles des régimes 2 et 3. L'influence des changements de la qualité alimentaire du maïs au fur et à mesure du vieillissement des plantes et deDiabrotica, a été déterminée par la survie au bout de 48 heures d'insectes éclos depuis peu et d'autres maintenus en cage sur des lots de maïs à différents stades poussant en serre depuis des temps plus ou moins longs. Plus les plantes sont âgées, plus la survie des 2 groupes deDiabrotica diminue, mais plus vite chez les lots d'insectes âgés.
    Notizen: Abstract Adult corn rootworm beetles,Diabrotica virgifera virgifera LeConte, were maintained on three dietary regimes which mimicked the progression of corn tissues that would be available in the field for beetles eclosing when corn was in the following growth stages: (A) after tassels had emerged but prior to silking and pollen shed; (B) while plants were silking and shedding pollen; and (C) after pollination was complete and silks had turned brown. A fourth regime (D) was established in which green corn silks, pollen, and leaves were provided throughout the study. The mean number of eggs laid per female over the 12-week duration of the study was 125, 235, 179, and 441 for regimes A, B, C, and D, respectively. Median length of life was 7.2, 7.2, 6.7, and 8.8 weeks for regimes A, B, C, and D respectively. Beetles in regime A laid a greater proportion of their eggs at an older age than did beetles from regimes B and C. To further investigate the influences on survival of changes in food quality of corn as plants and beetles aged, newly-eclosed beetles and beetles that had been maintained in caged plots of corn growing in a greenhouse for various lengths of time were caged on corn at different stages of growth, and the proportion of beetles surviving for 48 h was determined. Survival decreased as plants aged for both groups of beetles, but decreased at a faster rate for old than for young beetles.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 56 (1990), S. 23-30 
    ISSN: 1570-7458
    Schlagwort(e): Lepidoptera ; Noctuidae ; Mamestra brassicae ; sex pheromone ; calling behaviour ; calling posture ; diel periodicity of calling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La périodicité quotidienne de l'appel et les effets de l'âge et de la photopériode ont été examinés sur des femelles vierges deMamestra brassicae (Lépido., Noctuidae). Aucun appel n'a été observé pendant la première scotophase; la plupart des femelles appelaient pour la première fois pendant les 2e et 3e scotophases après l'émergence, quelle que fût la photopériode. Les papillons conservés à 16 J/8 N ont commencé à appeler beaucoup plus tard que ceux dont la photopériode était 18 J/6 N. En vieillissant, les papillons appelaient significativement de plus en plus tôt. Avec 16 J/8 N, la moyenne du moment du début de l'appel a diminué de la scotophase 2 à la scotophase 3, après laquelle il s'est stabilisé autour de 260 min après le début de la scotophase. Avec 18 J/6 N, le moment du début de l'appel a diminué jusqu'à la scotophase 4, et s'est stabilisé ensuite autour de 130 min après le début de l'obscurité.
    Notizen: Abstract Die periodicity of calling and the effect of age and photoperiod on calling behaviour were studied in virgin females of the cabbage moth,mamestra brassicae L. (Lepidoptera: Noctuidae). No calling activity was observed during the first scotophase. Most females called for the first time during the 2nd or 3rd scotophase after emergence, regardless of the photoperiod. Moths maintained under 16L: 8D started calling significantly later in the scotophase than those maintained under 18L: 6D. With increasing age, moths initiated calling significantly earlier. Under the 16L: 8D photoregime, the mean onset calling time decreased from scotophases 2 to 3, after which it stabilized around ca. 260 min after the start of the scotophase. With 18L: 6D, the onset of calling decreased until scotophase 4, and subsequently stabilized around ca. 130 min after lights off.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 56 (1990), S. 61-69 
    ISSN: 1570-7458
    Schlagwort(e): Diapause termination ; postdiapause development ; development threshold ; thermal constant ; Aphelinus mali ; Hymenoptera ; Aphelinidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'achèvement de la diapause en conditions naturelles ou simulant l'hiver, les effets des températures inférieures à zéro sur le développement après la diapause et les relations entre la vitesse de développement après la diapause et les températures constantes ou en thermopériodes ont été examinés sur des populations néerlandaises d'A. mali (Hymenop.; Aphélinidae). Les taux d'achèvement de la diapause de larves hivernantes étaient semblables en conditions naturelles ou simulées. La plupart des larves ont terminé leur diapause la dernière semaine de février. Quelques larves femelles sont restées en diapause jusqu'à fin mars. L'exposition pendant 2 semaines des larves sorties de diapause à −10 °C ne compromet pas leur survie ou leur taux de développement après la diapause. Les larves ayant diapause peuvent terminer leur développement et les adultes émerger des pucerons momifiés aux températures constantes comprises entre 12 et 24 °C. Bien que quelques larves achèvent leur développement à 10 °C, peu émergent. La température seuil théorique de développement après la diapause (to) a été de 9,4 °C et la constante thermique (K), 136,5 degrés-jours. Pour la première émergence et pour 50% d'émergences, les valeurs de K étaient respectivement: 121,4 et 134,8. Le nombre d'unités thermiques pour la première émergence et pour 50% d'émergences était le même à température constante ou avec une thermopériode.
    Notizen: Abstract Diapause termination under natural and simulated overwintering conditions, the effect of subzero temperature on postdiapause development and the relationship between postdiapause development rate and constant and fluctuating temperatures was studied in a Dutch population ofAphelinus mali Hald. (Hymenoptera: Aphelinidae). The rate of diapause termination was similar in larvae overwintering under natural and simulated conditions. Most larvae had terminated diapause by the last week of February. Some female larvae may have remained in diapause until the end of March. The exposure of postdiapause larvae to −10°C for two weeks did not affect their survival or postdiapause development rate. PostdiapauseA. mali larvae could complete development and the adults emerge from their mummified aphid hosts at constant temperatures from 12 to 24°C. Although some larvae completed postdiapause development at 10°C, few emerged. The theoretical threshold temperature (to) for postdiapause development was 9.4°C and the thermal constant (K) 136.4 degree-days. K was 121.4 and 134.8 for first and 50% emergence, respectively. The number of heat units accumulating above 9.4°C to 1st and 50% emergence was similar under constant and fluctuating temperatures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 55 (1990), S. 1-10 
    ISSN: 1570-7458
    Schlagwort(e): Parasitoid ; hemocytes ; inhibition of encapsulation ; Hymenoptera ; Lepidoptera hosts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'ichneumonide Campoletis sonorensis Carlson, endoparasitoïde larvaire, se développe dans de nombreuses espèces de Lépidoptères. Son statut de généraliste est dû, notamment, à son aptitude à déjouer les défenses immunitaires de ses hôtes, c.a.d. la formation d'une capsule d'hémocytes autour de l'oeuf ou de la larve parasite. Cependant, chez le noctuide Spodoptera frugiperda J.E. Smith, C. sonorensis est encapsulé dans 40% des larves qu'il parasite. Nous avons étudié la population hémocytaire de deux catégories de larves de S. frugiperda, celles qualifiées de ‘résistantes’ à C. sonorensis, et qui arrêtent son développement, et celles ‘susceptibles’ où le parasitoïde échappe à l'encapsulation. Cinq types d'hémocytes ont été identifiés: les prohémocytes (PR), les sphérulocytes (SP), les granulocytes (GR), les plasmatocytes (PL) et les oenocytoïdes (OE). Chez les hôtes susceptibles et résistants, le parasite provoque une baisse identique de la concentration totale des hémocytes dans l'hémolymphe (THC). Par contre, les PLs sont davantage affectés chez les hôtes susceptibles que chez ceux résistants au parasitoïde. Les résultats montrent que, chez les hôtes susceptibles, 1) le nombre des PLs dans l'hémolymphe est davantage diminué, et 2) leur aptitude d'adhérence in vitro est davantage inhibée. Il existe donc une corrélation positive entre le degré de pathologies qui affectent les PLs de l'hôte et l'incapacité de celui-ci à encapsuler le parasitoïde. Ceci tend à démontrer le rôle-clé des PLs dans la réaction immunitaire d'encapsulation chez S. frugiperda, comme chez de nombreux insectes. De plus, ce résultat renforce l'hypothèse selon laquelle C. sonorensis éviterait l'encapsulation en agissant sur les hémocytes de l'hôte, et plus particulièrement sur les PLs. Inversement aux PLs, les GRs sont moins abondants dans l'hémolymphe des hôtes qui encapsulent C. sonorensis. Les GRs pourraient donc participer à la formation de la capsule hémocytaire. Il est possible que plusieurs facteurs contribuent à protéger C. sonorensis de l'encapsulation. Néanmoins, les pathologies affectant les hémocytes des hôtes parasités sont probablement une manifestation majeure de l'effet immunosuppresseur du parasitoïde. Les effets de C. sonorensis sur les hémocytes des larves parasitées peuvent être reproduits chez des larves saines, en leur injectant de ‘venin’ extrait des glandes du calyx des femelles parasitoïdes. Ces sécrétions provenant de la glande du calyx, et normalement injectées dans l'hôte lors de l'oviposition, sont probablment responsable, au moins en partie, de l'effet immunosuppresseur du parasitoïde. Ces résultats peuvent être comparés à ceux obtenus chez l'hôte Heliothis virescens Fabricius (lépidoptère, noctuide) qui n'encapsule jamais C. sonorensis. Bien que le parasitoïde provoque les mêmes effets pathologiques sur les hémocytes des hôtes de S. frugiperda et d'H. virescens, on constate que l'effet apparait quelques heures après l'oviposition chez H. virescens, contre 48 heures post-oviposition chez S. frugiperda. Ce délai pourrait contribuer à la résistance immunitaire de certaines larves de S. frugiperda, ‘résistantes’, à C. sonorensis.
    Notizen: Abstract The egg and larval stages of the generalist endoparasitoid Campoletis sonorensis Carlson (Hymenoptera: Ichneumonidae), which normally avoid the hemocytic reaction of many Lepidopteran host species, are encapsulated in 40% of Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) larvae. The effect of parasitism on inhibiting the spreading ability of S. frugiperda plasmatocytes in vitro is more pronounced in susceptible larvae which fail to encapsulate the parasitoid than in resistant ones permitting parasitoid development. This suggests that induction of plasmatocyte pathology is relevant to the successful evasion of encapsulation by the parasitoid. Some granular cells disappear from the hemolymph of the parasitized resistant larvae, which implicates their involvement in the encapsulation reaction. Calyx fluid of C. sonorensis injected into host larvae produced effects on host hemocytes identical to natural parasitism. Several mechanism may cooperate to protect the parasitoid from encapsulation. The pathological reactions by the host plasmatocytes is one main manifestation of the ‘immunosuppressive’ parasitoid effect. Results are discussed in regard to the known effects of C. sonorensis on Heliothis virescens Fabricius (Lepidoptera: Noctuidae) larval hemocytes which are totally unable to respond with a successful cellular defense reaction.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 6 (1990), S. 157-164 
    ISSN: 1476-5535
    Schlagwort(e): Lignocellulosic waste ; Yeast ; Ethanol production ; Optimization study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Hardwood hemicellulose hydrolysate has been utilized as a substrate for ethanol production. Among the three different yeasts tested, the best performances have been obtained, in decreasing order, usingPachysolen tannophilus, Candida shehatae andPichia stipitis. Several pretreatments of this raw material have been studied to improve ethanol yields; in one such pretreatment a strain ofP. tannophilus produced ethanol with a yield of 0.29 gethanol/gsugars (gP/gS); which is only 15% less than the values observed with synthetic media. Neither aeration nor acetone addition improved the fermentation of this substrate; in fact, only a marked stimulation of biomass growth has been observed at the expense of both ethanol and xylitol production.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 17 (1990), S. 269-273 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Actin ; Intron ; Antisense RNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Using Northern blot analysis we have detected an approximately 840 nucleotide-long RNA which is complementary to the 5′ leader sequence and the first ten nucleotides of the coding sequence of the yeast actin (ACT1) messenger RNA. We have determined two transcription start sites for this actin antisense RNA (ASR1), both within the ACT1 intron, at about 80 and 90 nucleotides downstream from the 5′ splice site. Analysis of a cDNA clone showed that this RNA species overlaps the entire trailer sequence and approximately 20 nucleotides of the coding sequence of the nearby yeast YPT1 gene.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 20
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Mutants ; Cytochrome ; Mitochondria ; Oxidative phosphorylation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary This paper reports studies of bioenergetic modifications in a TTR1 single-nuclear mutant, isolated as resistant to triethyltin, an inhibitor of mitochondrial ATPase, and effective in cAMP-dependent protein phosphorylation. This mutant appears to have lost the wildtype cell ability to respond to a decrease of oxygen concentration in the growth medium by a decrease of cytochrome concentration in the cell. ATP synthesis rate in mutant cells in both the prestationary and stationary phase of growth appeared increased in comparison to wild-type cells, as too was respiration rate. A comparative study of mitochondria extracted from wild-type and from TTR1 mutant cells showed an increase in respiration rate, an increase in ATP synthesis rate, and an increase in TPP+ uptake in mutant mitochondria. The specific ATPase activity, as well as its sensitivity to TET, appears to be similar for mitochondria extracted from both strains. It was proposed that the modification of mitochondrial biogenesis in the TTR1 mutant may be due to a response of the cell to an increase in ATP hydrolysis caused by the mutation. It is also possible that the modification in cAMP-dependent protein kinase regulation which appeared to occur in this mutant affects protein(s) involved in mitochondrial biogenesis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 21
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Chromosome mapping ; Acidic ribosomal proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary DNA probes from the genes encoding the acidic ribosomal proteins L44, L44′ and L45, as well as from reporter genes for chromosomes IV, VII, XII and XV, have been hybridised to Southern blots of Saccharomyces cerevisiae DNA resolved by pulsed field gel electrophoresis. The protein L44′ and protein L45 genes have been found to hybridise to chromosome IV, identified by the CAT1 gene probe, while the protein L44 probe hybridises with a band containing chromosomes VII and XV, identified by the ATPase 1 and HIS3 genes respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 22
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Ribosomal protein gene ; Sequence analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two genes encoding ribosomal protein YL41 were cloned from Saccharomyces cerevisiae chromosomal DNA. Both genes contain an uniterrupted region of only 75 nucleotides coding for a protein of 3.3 kD. Within the coding regions the nucleotide sequences are virtually identical, whereas in both the 5′-and 3′-flanking regions the two genes differ significantly from each other. The deduced protein shows an arginine and lysine content of 68 percent, i.e., 17 out of 25 residues, and the basic residues are evenly distributed over the molecule. When compared to the ribosomal protein sequences currently available no counterpart to YL41 could be found in prokaryotes and it seems likely that YL41 is a eukaryotespecific ribosomal protein.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 23
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Trans-acting Factor ; RAP1
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We show by deletion mutagenesis, followed by in vivo and in vitro analysis, that the binding of a protein factor to the upstream activation sequence (USA) of the Saccharomyces cerevisiae glycolytic gene PYK, encoding pyruvate kinase, is required for efficient transcription of the corresponding coding region. In addition, gel electrophoretic mobility shift and DNase I protection studies, involving yeast gene products expressed in E. coli, suggest that this trans-acting DNA-binding protein is encoding by the RAP1 gene. The identification of RAP1 binding sites located within the UAS element of the yeast PYK, PGK (phosphoglycerate kinase) and ENO1 (enolase) genes, and in the 5′-upstream region of the ADHI (alcohol dehydrogenase) gene, suggests that a mechanism of coordinate gene expression involving several of the glycolytic genes may exist in yeast.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 18 (1990), S. 485-491 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Ty elements ; Virus like particles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Electron microscopic analysis of thin sections of Saccharomyces cerevisiae NCYC74 has revealed the presence of many clumped cytoplasmic particles that morphologically resemble Ty element virus-like particles (VLPs). Accumulation of Ty VLPs has only previously been observed in S. cerevisiae strains that over-express a cloned Ty element. The particles in NCYC74 co-purify with Ty RNA, Ty-specific antigens and a reverse transcriptase activity. Furthermore, they appear to be recognised by antibodies to Ty VLPs during indirect immunofluorescence experiments. These observations provide compelling evidence that the cytoplasmic particle in NCYC74 are indeed Ty VLPs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 18 (1990), S. 29-39 
    ISSN: 1432-0983
    Schlagwort(e): Recombination ; DNA repair ; UV irradiation ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A novel synthetic locus is described that provides a simple assay system for characterizing mitotic recombinants. The locus consists of the TRP1 and HIS3 genes inserted into chromosome III of S. cerevisiae between the CRY1 and MAT loci. Defined trp1 and his3 alleles have been generated that allow the selection of interchromosomal recombinants in this interval. Trp+ or His+ recombinants can be divided into several classes based on coupling of the other alleles in the interval. The tight linkage of the CRY1 and MAT loci, combined with the drug resistance and cell type phenotypes that they respectively control, facilitates the classification of the recombinants without resorting to tetrad dissection. We present the distribution of spontaneous recombinants among the classes defined by this analysis. The data suggest that the recombination intermediate can have regions of symmetric strand exchange and that co-conversion tracts can extend over 1–3 kb. Continuous conversion tracts are favored over discontinuous tracts. The distribution among the classes defined by this analysis is altered in recombinants induced by UV irradiation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 26
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Mitochondrial RNA splicing ; Nuclear pet - mutant ; Group I introns
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have studied the role of the product of the nuclear gene PET157 in mitochondrial pre-mRNA splicing. Cytoduction experiments show that a mitochondrial genome deleted for the three introns bI3, aI5 and aI6 is able to suppress the pet157-1 mutation: the strain recovers respiratory competency indicating that the product of the PET157 gene is only required for mitochondrial premRNA splicing. Characterization of the high molecular weight pre-mRNAs which accumulate in the pet157 mutant demonstrate that the product of the PET157 gene is required for the excision of two group I introns bI3 and aI6 (corresponding to aI5β) located in the cob-box and coxI genes respectively. Furthermore, the pet157 mutant strain accumulates the bI3 maturase in the form of a polypeptide of 50K (p50) previously observed in mitochondrial mutants defective in the excision of bI3. We have shown by restriction analysis and allelism tests that the pet157-1 mutation is allelic to the nuclear mrs1 mutation, previously described as specifically blocking the excision of bI3. Finally, revertants obtained by the deletion of bI3 or aI6 from the mitochondrial DNA were isolated from the MRS1 disrupted allele, confirming the involvment of the product of the MRS1/PET157 gene in the excision of the two introns bI3 and aI6.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 27
    ISSN: 1432-0983
    Schlagwort(e): S. cerevisiae ; Yeast ; Cadmium resistance ; CAD2 gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A cadmium-resistant strain, X3382-3A, which is able to grow in a medium containing 0.2 mM cadmium sulfate, was picked out from our laboratory stock strains of Saccharomyces cerevisiae. The cadmium resistance of this strain is controlled by a single dominant nuclear gene, denoted as CAD2. The locus of CAD2 was mapped by gene linkage to a site 15.5 centimorgans to the right of the his7 locus on the right arm of chromosome II. The cadmium resistance of the strain carrying CAD2 was evaluated for its properties of cadmium uptake, cadmium distribution and cadmium-metallothionein formation, in comparison with those of some other strains. The results suggest that the novel type of cadmium resistance controlled by CAD2 does not involve production of a cadmiumm-metallothionein.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 17 (1990), S. 179-183 
    ISSN: 1432-0983
    Schlagwort(e): Heme ; Cytochromes ; Regulation ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Simultaneous effects of mutations in the transcriptional regulatory genes, HAP1, HAP2 and HAP3, on all respiratory cytochromes of Saccharomyces cerevisiae were determined. Cytochrome behavior in hap mutants and in cyc4 and rhm1 mutants, altered in regulation of 5-aminolevulinate synthase, was compared. Although hap mutants were isolated as trans-acting, transcriptional regulators of the CYC1 (iso-1-cytochrome c) gene, each mutant exhibits partial deficiencies in all cytochrome types. In hap2 and hap3 strains all cytochromes were decreased proportionally to about 40–50% of wild type values. In contrast, hap1 caused a decrease in all cytochromes and an accumulation of a pigment, probably Zn porphyrin. Apparently apocytochrome and heme biosynthesis retain coordination in hap2 and hap3, but not in hap1, mutants. Unlike cyc4 and rhm1 mutants, hap mutants do not exhibit 5-aminolevulinate-dependent restoration of cytochromes. The hap1 mutant grew at nearnormal rates on glycerol, whereas hap2 and hap3 mutants grew very slowly. The frequency of [rho-] was high (16–18%) in hap2 and hap3 strains. Results are consistent with generalized control of mitochondrial replication directed by the HAP1-HAP2 system and heme-directed control of formation of all apocytochromes mediated by HAP1. Neither system exerts all-or-nothing control.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 17 (1990), S. 275-280 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; DNA replication ; Effect on mutation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Incubation in YPD medium under permissive conditions when DNA replication is going on, strongly stimulates the induction of cdc+ colonies of UV-irradiated cells of yeast strains HB23 (cdc8-1/cdc8-3), HB26 (cdc8-3/cdc8-3) and HB7 (cdc8-1/cdc8-1). Inhibition of DNA replication by hydroxyurea, araCMP, cycloheximide or caffeine or else by incubation in phosphate buffer pH 7.0, abolishes this stimulation. Thus the replication of DNA is strongly correlated with the high induction of cdc+ colonies by UV irradiation. It is postulated that these UV-induced cdc+ colonies arise as the result infidelity in DNA replication.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 30
    ISSN: 1432-0983
    Schlagwort(e): Yarrowia lipolytica ; 7SL RNA ; Essential genes ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Cells containing a deletion of either the SCR1 or SCR2 genes, which code for the 7SL RNA component of the signal recognition particle (SRP) homologue, were found to be viable. Two independent approaches demonstrated that cells containing deletions of both genes were inviale. Therefore, Yarrowia lipolytica contains two (and only two) functional 7SL RNA genes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 31
    ISSN: 1432-0983
    Schlagwort(e): Mitotic recombination ; Hyper-recombination ; RAD50 ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mutations in the RAD50 gene of Saccharomyces cerevisiae have been shown to reduce double strand break repair, meiotic recombination, and radiation-inducible mitotic recombination. Several different point mutations (including ochre and amber alleles) have been previously examined for effects on spontaneous mitotic recombination and did not reduce the frequency of recombination. Instead, the rad50 mutations conferred a moderate hyper-rec phenotype. This paper examines a deletion/interruption allele of RAD50 that removes 998 of 1312 amino acids and adds 1.1 kb of foreign DNA. The results clearly indicate that spontaneous mitotic recombination can occur in the absence of RAD50; in fact, the frequency of recombination is elevated over the wild-type cell. One possible interpretation of these observations is that the initiating lesion in spontaneous recombination events in mitosis might not be a double strand break.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 32
    ISSN: 1432-0983
    Schlagwort(e): Flow cytometry ; Rhodamine 123 ; Respiratory chain ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The cationic lipophilic dye Rhodamine 123 (Rh123) is selectively enriched in mitochondria in a membrane potential-dependent manner. Application of drugs which interfere with the electron flow of the respiratory chain lead to a severe reduction of mitochondrial dye uptake. In this communication we show that the same effect is observed after Rh123-staining of respiratory-deficient yeast mutants. Based on this observation we used flow cytometry to discriminate respiratory-compentent and respiratory-deficient yeast cells. Combined with a cell sorter we were able to selectively enrich respiring and non-respiring yeast cells, repectively, from a mixture of cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 17 (1990), S. 459-464 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; QH2: cytochrome c oxidoreductase ; Mitochondrial biogenesis ; Transcription
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In Saccharmmyces cerevisiae, the COR2 gene codes for the 40 kDa subunit II of the QH2: cytochrome c oxidoreductase, an enzyme of the mitochondrial respiratory chain. Regions in the 5′ flank of this gene important for regulated expression were identified by assaying β-galactosidase activities in cells carrying different COR2-lacZ fusion genes. Sequences downstream of position-201 relative to the translational initiation codon are sufficient to confer regulation by carbon source, whereas sequences downstream of position-153 do not give rise to significant expression. A binding site for the abundant general transcription factor GFI is present in the region between-201 and-153 just upstream from sequences which resemble the consensus DNA recognition sequence of the regulatory protein complex HAP2/HAP3: 5′-TNATTGGT-3′. By quantitating RNA levels and assaying β-galactosidase activities we show that synthesis of COR2, which is not a hemoprotein, is regulated by HAP1, HAP2/HAP3 and heme.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 17 (1990), S. 465-472 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Mutant ; Triethyltin chloride ; Protein phosphorylation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Three mutants of Saccharomyces cerevisiae resistant to triethyltin (an inhibitor of mitochondrial ATPase) on non-fermentative media, and non-resistant to this drug on fermentative media, were isolated and named TTR1, TTR2 and TTR3. Apart from triethyltin resistance, these mutants show the following common characteristics: (1) Increased intracellular cytochrome c concentration. (2) Increased respiration rate. (3) Decreased growth yield. (4) Increased growth sensitivity to several drugs inhibiting oxidative phosphorylation: namely, CCCP (permeabilizing inner mitochondrial membrane to protons), valinomycin (permeabilizing inner mitochondrial membrane to potassium) and oligomycin (inhibitor of mitochondrial ATPase). (5) Increased sensitivity to carbon source starvation. For each mutant, these characteristics appeared to be due to a single pleiotropic nuclear mutation. Mutation TTR1 causes additional phenotypic characteristics which do not appear in mutants TTR2 and TTR3: (1) Pinkish coloration of colonies which is more pronounced after a long growth period. (2) Inability of the cells to store glycogen. (3) Growth defect of the cells on a galactose-containing medium. (4) Inability of a diploid homozygote mutant strain to sporulate. All these phenotypic characteristics have already been described in yeast mutants deregulated in cAMP-dependant protein phosphorylation. Crossing of a strain bearing the TTR1 mutation with a strain mutated in the adenylate cyclase structural gene suggested that the TTR1 phenotype is due to a modification in regulation of cAPK by cAMP, making cell multiplication possible without intracellular cAMP.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 17 (1990), S. 493-497 
    ISSN: 1432-0983
    Schlagwort(e): Mitochondria ; Yeast ; Petites
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A pleiotropic, respiration-deficient mutant was isolated from the petite negative yeast Pachysolen tannophilus after UV mutagenesis. The mutant is unable to utilize xylose, arabinose, galactose or glycerol, and shows no detectable respiration when grown on glucose. Cytochrome c oxidase, xylose reductase and xylitol dehydrogenase activities are lacking. Mitochondrial ultrastructre is altered. The results support the hypothesis that functioning mitochondria are necessary for xylose utilization in this organism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 36
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Ty2 ; Protein/DNA binding ; Transcription
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A series of transposable element-induced mutations at the HIS4 locus in Saccharomyces cerevisiae have been attributed to the transposition of a Ty element into the 5′ regulatory region of this gene. Various Ty-containing His+ revertants have been isolated and the HIS4/Ty junction region sequenced. The only difference found in this region between a His- and a weak His+ strain was a single point mutation, an A→G transition. The position of Ty remained unaltered. Examination of lacZ fusion plasmids further implicated this A→G transition as being reponsible for the altered phenotype, the bp transition representing an allele of a cis-acting regulatory element. Subsequent gel retardation and methylation interference experiments revealed that this A→G mutation enabled the binding of a trans-acting factor (TyBf) in vitro. In this paper we show that the TyBf binding site is in a region of chromatin hypersensitive to digestion by DNase I. The binding site is protected in vivo from digestion with exonuclease III, suggesting the presence of a bound protein in His+ (“on”) but not His- (“off”) Ty-containing strains. We propose that a trans-acting factor binding in vivo, presumably TyBf, is responsible for the activation of HIS4 expression in these insertion mutants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 37
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Mitochondria ; Cytochrome c oxidase ; Post-translational regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Biogenesis of functional cytochrome c oxidase in yeast requires the product of the nuclear gene SCO1. Strains deleted for this gene fail to accumulate the mitochondrially-synthesized cytochrome c oxidase subunits I and II, despite the presence of the respective mRNAs. Here we present data which demonstrate that the observed phenotype does not result from a failure to translate the mRNAs, but from a preferential degradation of the newly synthesized subunits. The SCO1 protein is therefore involved in a post-translational step in the accumulation of cytochrome c oxidase subunits I and II. We propose that the SCO1 protein is required for the correct assembly of both subunits into the cytochrome c oxidase complex.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Microchimica acta 101 (1990), S. 273-279 
    ISSN: 1436-5073
    Schlagwort(e): aluminium analysis ; phosphorus ; sulfur ; chlorine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Multi-step procedures for the determination of phosphorus, sulfur and chlorine are described and tested against established methods and on reference materials. Phosphorus is separated as hydrogen phosphide, extracted as phosphomolybdic acid, reduced to molydenum blue and measured photometrically (detection limit 0.05 μg/g). Sulfur is separated after reduction as hydrogen sulfide or by means of pyrohydrolysis and measured by ICP-OES (detection limit 0.1 μg/g). Chloride can be measured by ion chromatography after pyrohydrolytic separation (detection limit 0.1 μg/g). The determination of sulfur was also successfully tested on copper and steel samples.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 26 (1990), S. 253-269 
    ISSN: 1573-0867
    Schlagwort(e): Nitrogen ; phosphorus ; sulphur ; nutrient balances ; surface waters ; North Sea ; Baltic Sea ; eutrophication ; hypertrophication ; primary production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Dissolved inorganic nitrogen and phosphorus, their relationship to each other (DIN/DIP) as predisposing (nutrient) factors, as well as prevailing weather as a triggering factor all work together to induce the primary production and hence the eutrophication (hypertrophication) process in surface waters. Sulfate likewise is a decisive predisposing factor influencing the eutrophication process by reducing N availability but increasing P availability and thus acting towards an N limitation of the primary production. This is one of the reasons why marine (coastal) waters and estuaries often exhibit N limitation with respect to primary production, while freshwater ecosystems often tend to exhibit P limitation. Within the N and P balance of agriculture of some countries of Western Europe (Netherlands, Denmark, Switzerland, FRG, UK and Sweden for N, resp. Netherlands, FRG and GDR for P) more the level than the efficiency of the N and P applications indicates the extent of the nutrient surplus. Despite 59–73% N utilization in plant production, the rate of 13–23% for agriculture as a whole equals to the 12–21% efficiency of N use in animal production. The varying N surplus in agriculture in the separate countries of 124 to 465 kg N ha−1 a−1 is determined almost exclusively by the level of the N application and not by its efficiency. The situation is similar for P: In spite of P utilization in plant production of 59–76%, P utilization in total agriculture is only 11–38%, or comparable to the P efficiency within animal production of 10–34%. The differing P excess balance of 55 to 88 kg P2O5 ha−1 a−1 is influenced by the level of the P application. The N and P efficacy of total agriculture hence is determined almost completely by that of animal production, since 83–95% (N basis) and 76–94% (P basis) of the total plant production (on top of the nationally varying levels of N and P use via imported feeds) are fed to animals — with the low N and P utilization cited above. Agriculture's share of the N and P emissions into surface water of several countries/regions in Western Europe (FRG, Netherlands, Italy, Denmark, Switzerland, Norway) ranges from 37 to 82% resp. 27 to 38%. Its share in the flus into the North Sea catchment basin will be about 60% for N and 25% for P related only to the anthropogenic material carried by the rivers. Agriculture's share in the atmospheric N emissions into the North and Baltic Seas can be estimated at about 65% or 55%, resp. while the remaining approx. 35% or 45%, resp. are traceable primarily to anthropogenic burning processes. For agriculture the priority lies in limiting N emissions into surface water caused by leaching, erosion and NH3 emissions, and reducing P emissions mainly through soil conservation (protection against erosion) and water protection. As regards N this means a demand for comprehensive protection of groundwater and atmosphere differentiated according to the potential for losses or the risk of losses on a site, also outside the protection zones. As regards P only those areas can be included in the demand for reduction of emissions that are actually threatened by erosion or surface runoff. Plenty of short-term and long-term measures are available to agriculture to reduce N and P emissions. Especially the long-range measures (such as creating nutrient balances on farms and fields, the integration of animal and plant production, maintaining maximum livestock densities according to the ability of areas to absorb nutrients, altered feeding programs in animal nutrition, changes in livestock keeping (slurry→deep litter), increasing the internal and external recycling of N and P) are capable of bringing about a satisfactory degree of success within the next 20 to 30 years.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 26 (1990), S. 229-235 
    ISSN: 1573-0867
    Schlagwort(e): Grass ; wheat ; nitrogen nutrition ; dilution curve ; mineral content ; mineral removal ; phosphorus ; potassium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The important effect of nitrogen in changing the patterns of mineral content and mineral removal is analysed for grass swards and wheat. Different models are proposed; accumulated dry matter developed throughout a growing period is shown to be an excellent reference for assessing the evolution of the plant mineral content and the mineral removal the growing crop. Applications in diagnosing mineral nutrition status and optimising fertilizer use are proposed and discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Chemoecology 1 (1990), S. 3-11 
    ISSN: 1423-0445
    Schlagwort(e): alarm recruitment ; evaporation kinetics ; age polyethism ; (+)—limonene ; alkaloid ; hexanoic nitrile ; Hymenoptera ; Formicidae ; Myrmicinae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The antMyrmicaria eumenoides is a significant arthropod predator. For rapid attraction of large numbers of nestmates to newly discovered food sources the ants use an efficient recruitment communication system based on the poison gland secretion. Workers exhibit age-based division of labour. Young workers perform brood-care; their poison gland reservoir develops and reaches its final size of ≈ 0.5 µl at an age of ≥ 6 weeks, when they become foragers. The secretion deposited during combat with enemies or prey is composed of equal amounts of both a high volatile and a low volatile fraction. Within the high volatile fraction (+)—limonene is the main component (97%) and is the only olfactory trigger to alert ants in the vicinity and to recruit them to places of combat, where they assemble. Ants respond to synthetic (+)—limonene in exactly the same way as to the poison gland secretion when applied at the same airborne concentrations. Further components of the high volatile fraction are four additional monoterpene hydrocarbons and hexanoic nitrile. The high volatile and the low volatile fraction of the poison gland secretion each have dual functions: The low volatiles, of which the main component is an alkaloid, serve as a fixative and extend the effective period of the limonene signal by modifying its evaporation kinetics. On the other hand the high volatile recruitment signal (+)—limonene is also the solvent for the alkaloid and enhances its spreading on the surface of the cuticle of arthropod enemies or prey.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 42
    ISSN: 1423-0445
    Schlagwort(e): chemical defence ; comparative sequestration ; feeding guilds ; insect herbivory ; natural enemies ; cardenolides ; Lepidoptera ; Danainae ; Danaus plexippus (L.) ; Homoptera ; Aphidae ; Aphis nerii B. de F. ; Asclepiadaceae ; Asclepias curassavica L
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Cardenolide sequestration by a hemimetabolous aphid and a holometabolous butterfly from the neotropical milkweed,Asclepias curassavica L., is compared. The oleander aphid,Aphis nerii B. de F., sequestered a similarly narrow range of cardenolide concentrations to the monarch butterfly,Danaus plexippus (L.), from the wide range of concentrations available in leaves of A.curassavica. However, A.nerii sequestered significantly less cardenolide (269 µg/0.1 g) thanD. plexippus (528 µg/0.1 g). The honeydew excreted by A.nerii was comprised of 46% cardenolide. The complete polarity range of 25 cardenolides detected by thin layer chromatography in A.curassavica was represented in the 17 whole aphid cardenolides and the 20 aphid honeydew cardenolides detected. D.plexippus sequestered a narrower polarity range of 11 cardenolides, having eliminated low polarity cardenolide genins and glycosides. It is suggested that these chemical differences may be related to interactions among the broad feeding tactics of sucking or chewing milkweed leaves, life history constraints of holometabolyversus hemimetaboly, the distribution of milkweed food resources in space and time, and the dynamics of natural enemies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 43
    ISSN: 1423-0445
    Schlagwort(e): variation of secondary substances ; pharmacophagy ; pyrrolizidine alkaloids ; Lepidoptera ; Ithomiinae ; Aeria olena ; Tithorea harmonia ; Mechanitis polymnia ; Apocynaceae-Echitoideae ; Solanaceae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The primitive, Apocynaceae-feeding Ithomiine,Tithorea harmonia, incorporates dehydropyrrolizidine alkaloids (PAs) from its larval foodplant (Prestonia acutifolia), rarely visiting PA sources pharmacophagously in the adult; females show higher concentrations of PAs than males, with similar variance. The close relativeAeria olena (feeding onP. coalita, without PAs) shows similar PA concentrations in both sexes and greater variation in males, like more advanced Solanaceae-feeding Ithomiine such asMechanitis polymnia, which likeA. olena obtain PAs by pharmacophagy in the adult (mainly males). This difference is due to the dynamics of PA incorporation in these species. Little variation in PA content was found among allopatric populations of the same species, but variation in available PA sources in different months was correlated with different average storage levels in the butterflies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 44
    ISSN: 1423-0445
    Schlagwort(e): toxin sequestration ; predation ; human dietary hazard ; cantharidin ; Coleoptera ; Meloidae ; Epicauta vittata ; Rana ; Hirudo ; Nerodia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Frogs(Rana pipiens) fed on blister beetles (Meloidae) or cantharidin, retain cantharidin systemically. After cessation of feeding, they void the compound relatively quickly. Systemic cantharidin does not protect frogs against ectoparasitic feeding by leeches(Hirudo medicinalis) or predation by snakes(Nerodia sipedon). As suggested by our data, and from reports in the early literature, ingestion of cantharidin-containing frogs can pose a health threat to humans.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 45
    ISSN: 1423-0445
    Schlagwort(e): chemical defense ; mimicry ; evolutionary strategies ; hostplants ; cyanogenesis ; linamarin ; pyrrolizidine alkaloids ; Lepidoptera ; Acraeinae ; Asteraceae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary American Acraeinae butterflies often ingest large amounts of dehydropyrrolizidine alkaloids (PAs) from their Asteraceae hostplants in both larval and adult stages, but do not normally store these compounds for defence, instead biosynthesizing large amounts of the cyanogenic glucoside linamarin in all stages. This defence syndrome (rejection of plant toxins andde novo synthesis of protective chemicals) is considered to be the most evolved among aposematic (unpalatable mimicry-model) butterflies, as are the Acraeinae and Heliconiini which also synthesize cyanogens. Storage or minimal processing of larval hostplant-derived defensive chemicals is widespread and characterizes the most primitive model groups; an intermediate series (Danainae/Ithomiinae) also obtains the principal defensive chemicals (PAs) from plants, but mostly in the adult stage. These syndromes are discussed and contrasted with the pattern seen in Chrysomelidae beetles, wherede novo synthesis is widespread and considered primitive.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Chemoecology 1 (1990), S. 81-85 
    ISSN: 1423-0445
    Schlagwort(e): phototoxicity ; harmane ; harmine ; harmalol ; alpha-terthienyl ; skimmianine ; Lepidoptera ; Oecophoridae ; Depressaria pastinacella ; parsnip webworm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The parsnip webworm,Depressaria pastinacella (Lepidoptera: Oecophoridae), feeds exclusively on apiaceous hostplants containing furanocoumarins, compounds capable of oxygen-dependent and oxygen-independend photosensitization. Despite high titers of antioxidant enzymes relative to other herbivorous insects, webworms cannot tolerate nonhost photosensitizers such as alpha-terthienyl or beta-carboline alkaloids at dietary concentrations of 0.01% or less. Tolerance of skimmianine, a furano-quinoline alkaloid, may be due to its structural resemblance to furanocoumarins, which are metabolized by cytochrome P450 monooxygenases in this species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Chemoecology 1 (1990), S. 69-76 
    ISSN: 1423-0445
    Schlagwort(e): green leaf volatile ; semiochemical ; synomone ; volatile attractant ; tritrophic ; host location ; parasitoid behavior ; Hymenoptera ; Braconidae ; Microplitis ; Ichneumonidae ; Netelia ; Lepidoptera ; Noctuidae ; Heliothis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 48
    ISSN: 1423-0445
    Schlagwort(e): taste aversion ; toxicology ; chemical defense ; cardiac glycoside ; cardenolides ; digitoxin ; pyrrolizidine alkaloids ; monocrotaline ; Mammalia ; Muridae ; Peromyscus ; Reithrodontomys ; Lepidoptera ; Danainae ; Danaus plexippus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Of three common mouse species at the Mexican overwintering sites of the monarch butterfly, onlyPeromyscus melanotis eats monarchs. We hypothesized thatP. aztecus andReithrodontomys sumichrasti reject monarchs because they are more sensitive to the bitter taste and/or toxic effects of the cardiac glycosides (CGs) and pyrrolizidine alkaloids (PAs) in the butterflies. Two-choice preference tests revealed no difference in taste avoidance thresholds to free base and N-oxide forms of the PA, monocrotaline, but very different avoidance thresholds to the CG, digitoxin. Avoidance thresholds forR. sumichrasti andP. aztecus were, in respective order, 1020 and 34 times less than that forP. melanotis. We also tested the toxic sensitivity of juvenile mice by chronically feeding diets containing digitoxin or monocrotaline at concentrations similar to those used in the preference tests. No species developed CG toxicity, but bothP. melanotis andP. aztecus developed moderate PA toxicity (R. sumichrasti was not tested for PA toxicity).P. aztecus grew more slowly and manyP. melanotis had hepatic metabolic lesions. Thus, the three mouse species responded very differently to the taste and toxic properties of CGs and PAs at ecologically relevant concentrations: 1) CGs were taste rejected by all species exceptP. melanotis, while PAs were not; and 2) PAs were toxic, while CGs were not.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 49
    ISSN: 1423-0445
    Schlagwort(e): pheromone ; attractant ; triene ; tetraene ; hydrocarbon ; Insecta ; Coleoptera ; Nitidulidae ; Carpophilus freemani
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Males ofCarpophilus freemani Dobson (Coleoptera: Nitidulidae) produce an aggregation pheromone to which both sexes fly in a wind-tunnel bioassay. The major pheromone component (ca. 30 ng per male per day in volatile collections) was identified as (2E,4E,6E)-5-ethyl-3-methyl-2,4,6-nonatriene. A minor component, (2E,4E,6E,8E)-7-ethyl-3,5-dimethyl-2,4,6,8-undecatetraene, was 3–10% as abundant as the major triene and was 5–20% as active when compared at relative doses ranging from natural proportions to 1:1. These compounds act synergistically: a mixture of major and minor components in natural proportions attracted more than twice as many beetles as the major component alone, and the mixture fully accounted for the activity of male-derived volatile collections. Six other male-derived conjugated hydrocarbons, ranging from 2% down to 0.04% as abundant as the major component, were also identified. These are (in order of decreasing bioassay activity when compared on an equal-weight basis): (3E,5E,7E)-6-ethyl-4-methyl-3,5,7-decatriene, (2E,4E,6E)-5-ethyl-3-me-thyl-2,4,6-octatriene, (3E,5E,7E,9E)-8-ethyl-4,6-dimethyl-3, 5,7,9-dodecatetraene, (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6, 8-undecatetraene, (3E,5E,7E)-5-ethyl-7-methyl-3,5,7-undecatriene, and (2E,4E,6E)-3,5-dimethyl-2,4,6-nonatriene. All structure identifications were confirmed by synthesis. In the wind tunnel, the pheromone acted synergistically with “host”-type volatiles such as propyl acetate, valeric acid, and ethanol. This concept was verified by fields tests in California, in which there was dramatic synergism between the pheromone and fermenting host materials. Pheromone biosynthesis is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Chemoecology 1 (1990), S. 124-130 
    ISSN: 1423-0445
    Schlagwort(e): taste aversion ; chemical defense ; predatory attack patterns ; insectivory ; cardiac glycosides ; cardenolides ; Mammalia ; Muridae ; Peromyscus ; Reithrodontomys ; Lepidoptera ; Danainae ; Danaus plexippus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Peromyscus melanotis is the only one of three mouse species that eats monarch butterflies at their overwintering sites in Mexico. I tested two hypotheses: 1)P. aztecus avoids monarchs because of a bitter taste aversion to cardiac glycosides (CGs) and an inability to reject CG-rich body parts; 2)Reithrodontomys sumichrasti avoids monarchs principally because of a bitter taste aversion to the CGs. None of the species are sensitive to the toxic effects of ingested CGs. Feeding responses of laboratory-reared mice of each species to monarchs with low, medium and high CG concentrations were compared. BothP. aztecus andR. sumichrasti ate significantly fewer of all three types of monarchs thanP. melanotis. ForP. aztecus andR. sumichrasti, the number of monarchs eaten decreased with increasing CG concentration, whereas forP. melanotis, the number remained constant.Peromyscus melanotis andR. sumichrasti developed a feeding technique for rejecting the CG-laden cuticular material, which reduced the bitterness of ingested monarch material. However,R. sumichrasti displayed the technique significantly less often thanP. melanotis; andP. aztecus never developed it. I conclude that high taste sensitivity to CGs and less versatile food handling preventP. aztecus andR. sumichrasti from overcoming the monarch's chemical defenses.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 51
    ISSN: 1423-0445
    Schlagwort(e): secretion-grooming ; pygidial glands ; chemical defence against microorganisms ; respiration ; aquatic beetles ; Coleoptera ; Hydradephaga ; Gyrinidae ; Haliplidae ; Noteridae ; Hygrobiidae ; Dytiscidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary All Hydradephaga investigated so far crawl onto land when exposed to an increase in water temperature and light intensity and spread the secretion from their pygidial glands over the body surface (“secretion-grooming”). The secretions have antimicrobial properties and are mainly applied to hydrofuge body regions important for aquatic respiration. Experimental prevention of secretion-grooming leads to the loss of the respiratory air bubble and a significant increase in mortality. These findings support the view that the secretion-grooming of adephagous aquatic beetles, like in some aquatic Heteroptera, inhibits the growth of microor-ganisms, thus preventing the contamination and wetting of the cuticular respiratory structures. Thus it keeps functional the air-retaining hydrophobous body regions essential for aquatic respiration. A model is presented on how secretion-grooming may have evolved in the Hydradephaga. Other possible functions of the pygidial gland secretions are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Pure and applied geophysics 132 (1990), S. 457-479 
    ISSN: 1420-9136
    Schlagwort(e): Turbulence ; mesures aéroportées ; fluctuation de pression ; presso-corrélations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Résumé Nous avons décrit dansBardeau et al. (1987), la réalisation, le fonctionnement et les tests d'un microdébitmètre basé sur l'anémométrie à fil chaud. Il a été particulièrement montré que cet appareil était bien adapté aux mesures de pression et pression différentielle avec une grande sensibilité et une très faible constante de temps. Nous présentons ici les applications qui ont été faites de ce capteur aux mesures à haute résolution à bord d'avions instrumentés pour la recherche atmosphérique. L'avion utilisé était spécialement équipé pour les mesures de turbulence et permettait donc l'acquisition d'un grand nombre de paramètres indispensables à l'analyse des données de ce capteur. Dans les applications aéronautiques qui ont été faites, le capteur a surtout été utilisé en tant que variomètre. Les comparaisons avec les mesures standards d'altitude par pression et couplages pression-données inertielles montrent que cet instrument pourrait apporter une contribution intéressante dans le domaine de la mesure à haute fréquence des fluctuations de pression.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1209-1211 
    ISSN: 1420-9071
    Schlagwort(e): Pheromone ; E-myrcenol ; ipsdienol ; Ips duplicatus ; Coleoptera ; Scolytidae ; Picea abies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Males of the Eurasian bark beetleIps duplicatus, when feeding in host Norway spruce (Picea abies (L.) Karst.), produced and released ipsdienol andE-myrcenol, which we show to be aggregation pheromone components. Bioassays using walking beetles indicated thatE-myrcenol in synergistic combination with ipsdienol is essential for attraction. Synergism ofE-myrcenol and ipsdienol released at natural rates in the forest was also demonstrated with a new technique using mechanical slow-rotation of sticky traps.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 54
    ISSN: 1432-041X
    Schlagwort(e): Athalia rosae ; Hymenoptera ; Thelytoky ; Automixis ; Gynandromorph
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mature eggs dissected from ovaries of unmated females of Athalia rosae (Hymenoptera: Tenthredinidae), if placed on a filter-paper soaked with distilled water, are activated and develop to haploid males. Occasionally, however, diploid females develop from these artificially activated eggs. Treatment of mature unfertilized eggs dissected from diploid females with ice-cold temperatures immediately before activation and with a high temperature (36° C) upon and immediately after activation resulted in the production of diploid males, diploid females, triploid females and gynandromorphs at high frequency. The same treatment of mature unfertilized eggs dissected from triploid females resulted in the production of only triploid survivors. These results, together with the results on the segregation of a marker mutation, yellow fatbody (yfb), appear to indicate that meiotic divisions were complete in the treated eggs, and that all four nuclei became potentially capable of participating in development with or without automictic fusion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 46 (1990), S. 269-273 
    ISSN: 1420-9071
    Schlagwort(e): Sex pheromone ; biosynthesis ; Lepidoptera ; Epiphyas postvittana ; deuterium-labelling ; (E)-11-tetradecenyl acetate ; (E,E)-9,11-tetradecadienyl acetate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Fatty acyl moieties present in the female sex pheromone gland of the lightbrown apple moth,Epiphyas postvittana, include the analogues of the two sex pheromone components, (E)-11-tetradecenyl acetate and (E,E)-9,11-tetradecadienyl acetate. Application of deuterium-labelled fatty acids followed by analysis by gas chromatographymass spectrometry showed that biosynthesis of the two pheromone components involved initial Δ11-desaturation of myristic and palmitic acids respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 56
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 395-397 
    ISSN: 1432-1041
    Schlagwort(e): atropine ; exercise ; pharmacokinetics ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Seven healthy males (19–32 y) underwent each of four separate conditions in a repeated measures design. Five of these subjects underwent an additional trial. In four of five trials subjects received 2.0 mg atropine sulfate intramuscularly in the anterolateral portion of the left thigh: at rest (T1); following completion of a single exercise (Ex) bout (T2), (Each bout consisted of 25 min of stationary cycling at 40% VO2 max with 5 min of seated rest), prior to three Ex bouts (T3) and following one and prior to three Ex bouts (T5). Trial 4 (T4) was the same as T3 with the substitution of a saline placebo. Serum samples were collected over a 12 h period and atropine concentration was determined by RIA. Ex trials were compared to T1. Ex prior to atropine (T2) significantly decreased the mean volume of distribution (Vz, 278 vs 2321). Ex in T3 significantly decreased the serum half life (t1/2, 4.2 vs 3.5 h), Vz (278 vs 1981), and clearance (CL, 763 vs 638 ml·min−1) and significantly increased the peak concentration (Cp, 6.7 vs 12.3 ng·ml−1) and area under the curve (AUC, 44.1 vs 53.1 ng·ml−1). In T5, Ex significantly decreased the t1/2 (3.4 h), Vz (182 l) and CL (575 ml·min−1) and significantly increased the absorption rate constant (ka, 0.482 vs 1.1 min−1), elimination rate constant (ke, 0.0012 vs 0.0015 min−1), Cp (14 ng·ml−1) and AUC (53.3 ng·h·ml−1). These results demonstrate that moderate Ex either prior to and/or immediately following drug administration has the capacity to significantly modify atropine pharmacokinetics.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 57
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 343-346 
    ISSN: 1432-1041
    Schlagwort(e): indomethacin ; cerebrospinal fluid ; pharmacokinetics ; protein binding ; analgesic activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma and cerebrospinal fluid (CSF) concentrations of indomethacin have been determined in 52 patients hospitalized for nerve-root compression pain. Samples of blood and CSF were collected at the same time in each subject, 0.5 to 12 h after a single intramuscular injection of 50 mg indomethacin. Analgesic effect was assessed by the absolute and percentage variation in Huskisson's visual analogue scale between dosing and sampling. According to its high lipid solubility, indomethacin rapidly crossed the blood-brain barrier, being detected in CSF 0.5 h after administration. After attainment of equilibrium within 2 h, the CSF level exceeded the free plasma level. Since the drug was extensively bound to serum albumin (99.7±0.1%), this phenomenon may represent a slight degree of binding of indomethacin in CSF. The analgesic activity was not related to either the plasma or CSF concentration of indomethacin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 58
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 523-524 
    ISSN: 1432-1041
    Schlagwort(e): tolbutamide ; hydroxytolbutamide ; carboxytolbutamide ; urinary excretion ; age ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Tolbutamide (1 g/70 kg) was administered as a single intravenous dose to 31 healthy, non-smoking, drug-free males between 23 and 87 years old and the total amounts of hydroxy and carboxytolbutamide excreted in 24 h were measured. There was a significant decrease in the urinary recovery of both metabolites with age. The reason for these findings is not known at the present time and may be associated with the decrease in creatinine clearance observed in these subjects or other changes in the pharmacokinetics of tolbutamide which are currently being investigated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 59
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 499-503 
    ISSN: 1432-1041
    Schlagwort(e): 2-mercaptopropionylglycine ; body clearance ; half-life ; pharmacokinetics ; protein binding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of 2-mercaptopropionylglycine (2-MPG) was studied in ten healthy volunteers after a single i. v. injection of 250 mg (1532 μmol). The total and non-protein-bound concentrations versus time curves were best described by a three-exponential function with terminal half-lives of 55 and 59 h respectively. Body clearance based upon the total concentration was estimated to be 105 and 231 ml/min based on the non-protein-bound 2-MPG. The corresponding values for Vss were 99 l and Vss,n 173 l, and for Vγ485 l and Vγ,n 1121 l respectively. 75% of the dose was excreted in the urine, mainly during the first 6 h after injection. The proportion of non-protein-bound 2-MPG diminished exponentially during the first 15 h and then levelled off at about 30%. There was a nonlinear increase in the non-protein-bound fraction of 2-MPG as the total plasma concentration of the drug increased.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 60
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 526-527 
    ISSN: 1432-1041
    Schlagwort(e): phenytoin ; posture ; pharmacokinetics ; plasma levels
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 61
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 487-490 
    ISSN: 1432-1041
    Schlagwort(e): sulphadimethoxine ; plasma concentration ; skin blister fluid concentration ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The time-dependent concentration curves of sulphadimethoxine in plasma and cantharidin-induced skin blister fluid have been evatuated following a single oral dose of 1 g. In contrast to other drugs, sulphadimethoxine exhibited two-stage penetration into the blister fluid, the second peak concentration being higher than the first. The maximum plasma concentration of 94.1 mg·l−1 was observed after 4 h, and in skin blister fluid the first peak of 25.6 mg·l−1 was found after 7 h, and the second of 58.0 mg·l−1 occurred after 30 h. The penetration of sulphadimethoxine into skin blister fluid, defined as the ratio of the AUC there to that in plasma was 0.748. The results suggest that sulphadimethoxine penetrates into skin blister fluid to a great extent from plasma and achieves concentrations exceeding the MIC for susceptible pathogens, but it requires a relatively long time to do so.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 62
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 209-211 
    ISSN: 1432-1041
    Schlagwort(e): Isradipine ; hypertension ; pharmacokinetics ; pharmacodynamics ; clinical trial
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In conjunction with a multicentre clinical trial of the calcium antagonist isradipine in hypertension, pharmacokinetic and pharmacodynamic studies were conducted in 9 subjects. An initial dose of 5 mg (capsule formulation) of isradipine was given orally. The mean Cmax, tmax and AUC(0–8) were 6.0 ng · ml−1, 1.5 h and 15.1 h · ng · ml−1 respectively. Seven subjects repeated the study at steady state after 10 week's dose titration with isradipine. Cmax, tmax and AUC(0–8) were 3.7 ng · ml−1, 1.2 h and 12.2 h · ng · ml−1 respectively indicating that the drug does not accumulate over time. Control of blood pressure paralleled plasma isradipine concentrations which suggested that the drug should be given at least twice daily. Pharmacokinetic studies performed in conjunction with clinical trials can provide valuable information about the patterns of drug response.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 63
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 583-586 
    ISSN: 1432-1041
    Schlagwort(e): ranitidine ; piroxicam ; interaction ; pharmacokinetics ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effects of piroxicam (40 mg) on the pharmacokinetics of ranitidine (150 mg) and of ranitidine (150 mg bid) on the pharmacokinetics of piroxicam (20 mg) were assessed in two 2-way crossover studies in two groups of 18 healthy male subjects. In the first study there were no statistically significant differences between the pharmacokinetic variables for ranitidine in the presence or absence of piroxicam. The mean maximum plasma concentration (Cmax) was 467 ng·ml−1 for ranitidine alone and 466 ng·ml−1 in the presence of piroxicam; mean area under the plasma concentration vs time curve (AUC) was 2460 h·ng ml−1 and 2551 h·ng ml−1 respectively; and the mean terminal half-life (t 1/2) was 3.6 h and 3.8 h respectively. In the second study there were no statistically significant differences between the pharmacokinetic variables for piroxicam in the presence or absence of ranitidine. The mean Cmax was 2.1 μ·ml−1 in the presence of placebo and 2.0 μg·ml−1 in the presence of ranitidine respectively; mean AUC was 133 h·μg ml−1 and 137 h·μg ml−1 respectively, and the mean t 1/2 was 53.6 h and 54.5 h respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 64
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 613-614 
    ISSN: 1432-1041
    Schlagwort(e): Thioridazine ; debrisoquine polymorphism ; pharmacokinetics ; adverse effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 65
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 255-258 
    ISSN: 1432-1041
    Schlagwort(e): theophylline ; mequitazine ; drug interaction ; pharmacokinetics ; asthma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effect of an oral anti-allergic drug, mequitazine, on the pharmacokinetics of theophylline has been investigated in seven asthmatic patients. They received chronic theophylline therapy (a sustained-release theophylline tablet 200–400 mg b.d. at 12 h intervals) and coadministered mequitazine 6 mg for 3 weeks. Plasma theophylline concentration-time curves and the urinary excretion of theophylline and its major metabolites before and after coadministration of mequitazine were compared. No significant change in the pharmacokinetic parameters of theophylline or in the urinary recovery of unchanged drug and its metabolites was observed. Thus, mequitazine did not influence the pharmacokinetics of theophylline and it should be safe for coadministration to asthmatic patients on chronic theophylline therapy.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 66
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 259-263 
    ISSN: 1432-1041
    Schlagwort(e): tacrine ; amyotrophic lateral sclerosis ; postoperative sedation ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of 9-amino-1,2,3,4-tetrahydroacridine; tacrine, THA, was studied after intravenous administration and following the first and last oral doses of a seven week clinical trial involving 8 patients with amyotrophic lateral sclerosis, ALS. Two surgical patients given intravenous THA for reversal of postoperative sedation were also included. Plasma concentration of THA and in some cases the metabolite, 1-hydroxy-THA, were assayed using a selective and sensitive method with high performance liquid chromatography. After an intravenous dose of 30 mg THA, the plasma concentrations were fitted to a two-compartment model. Plasma clearance showed a threefold interindividual variation with a mean of 2.42 l·h−1. Volume of distribution, Vα varied 100–680 l with a mean of 349 l. The plasma half-lives of distribution and elimination were 1.8 and 98.2 min, respectively. Oral bioavailability showed large interindividual differences and ranged 6–36% in the four subjects studied. After seven weeks treatment with oral THA, plasma concentrations immediately prior to medication were below 10 ng/ml in three patients and above 100 ng/ml in two patients. At the same occasion the plasma metabolite concentrations considerably exceeded those of THA. THA medication was associated with side effects in the majority of the patients.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 67
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 269-273 
    ISSN: 1432-1041
    Schlagwort(e): flecainide ; quinine ; pharmacokinetics ; metabolism inhibition ; drug interaction ; renal transport
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of flecainide and its two sequential metabolites, both free and conjugated, its pharmacodynamics, and the influence of simultaneously administered quinine, have been studied in 10 healthy subjects. The study comprised two, 48-h open phases at an interval of 1 week. Flecainide acetate 150 mg was given as a 30-min i.v. infusion and quinine sulphate orally 500 mg×3 over 24 h. Quinine administration did not change the apparent volume of distribution or the renal clearance of flecainide, but it significantly reduced its systemic clearance (9.2 vs 7.6 ml · kg−1 · min−1), thus increasing the elimination half-life (9.6 vs 11.5 h). The amount of flecainide transformed to its first, meta-O-dealkylated metabolite (MODF) fell with no change in the renal excretion of the latter, either in its free or conjugated forms. This finding, in association with a fall in amount of the second, meta-O-dealkylated lactam metabolite (MODLF) recovered in its conjugated forms in the urine, suggests that quinine inhibits both the first and the second steps of the sequential metabolism of flecainide. When the subjects received quinine in addition to flecainide, the PR interval in the ECG was slightly more prolonged than with flecainide alone. Due to the study design, an effect of quinine per se and the consequence of increased serum flecainide levels could not be distinguished.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 68
    ISSN: 1432-1041
    Schlagwort(e): celiprolol ; renal failure ; pharmacokinetics ; enantioselective kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of the ß1-selective adrenergic antagonist (R,S)-celiprolol has been studied after oral administration of 200 mg celiprolol-HCl to 8 healthy volunteers and 8 patients with various degrees of impaired renal function. No significant difference was found between the two enantiomers in the control group or in the patients. In healthy volunteers an average of 9.8% of the dose of R-(+)-celiprolol and 9.5% of S-(-)-celiprolol was recovered unchanged in the urine. Renal impairment reduced the urinary excretion of both enantiomers to the same extent according to the severity of the uraemia, producing higher AUCs. Nevertheless, the terminal half-lives of the R- and S-enantiomers were not significantly different between the groups. Dosage reduction in patients with renal impairment does not seem to be necessary.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 69
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. S53 
    ISSN: 1432-1041
    Schlagwort(e): nitrates ; pharmacokinetics ; pharmacodynamics ; nitrate tolerance ; isosorbide-5-mononitrate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Healthy male volunteers received three different dose regimens of a controlled-release form of isosorbide-5-mononitrate (IS-5-MN; 60 mg per tablet). Dose regimen I consisted of a single daily dose of 60 mg given for 5 days. Dose regimen 11 was started with a dose of 60 mg, followed by 30 mg 12 h later and thereafter every 8 h. The last dose, on the 5th day was again 60 mg. In dose regimen III60 mg followed by 30 mg 6 h later were administered every day for 5 days. The peripheral arterial and venous effects of IS-5-MN during the first and last dosing interval were followed by changes in the finger pulse curve, standing systolic blood pressure, heart rate, and venous distensibility. Plasma concentrations of IS-5-MN were measured frequently following the first and the last dose. Following dose regimen I all hemodynamic effects produced by the first dose were maintained during the study. The maximal plasma concentrations were about 400 ng/ml and the trough value, lower than 100 ng/ml. Following dose regimen II the hemodynamic effects of IS-5-MN and sublingual glyceroltrinitrate were completely abolished on the 5th day. Trough plasma concentrations were approximately 300 ng/ml during the entire study period. Following dose regimen III pronounced hemodynamic effects were seen on the 1st day. However, a significant attenuation of the hemodynamic effects was measured on the 5th day, when trough plasma concentrations were between 100 and 230 ng/ml. There was a significant negative correlation between the magnitude of hemodynamic effect remaining on the 5th day (measured by the area under the finger pulse curve) and the trough plasma concentration. Thus, the maintenance of minimum plasma concentrations of IS-5MN of 300 ng/ml or higher produces a rapid development of hemodynamic nitrate tolerance, whereas no tolerance was found when the plasma concentrations were allowed to decline below 100 ng/ml before the next dose was given. A significant attenuation of hemodynamic effects was found when minimum plasma concentrations were between 100 and 230 ng/ml. The degree of attenuation in this concentration range increased with increasing trough plasma concentrations.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 70
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 189-190 
    ISSN: 1432-1041
    Schlagwort(e): Diltiazem ; bioinequivalence ; plasma concentration ; dissolution ; pharmacokinetics ; commercial brands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A bioequivalence study of three brands of regular diltiazem — Angizem (A), Dilzem (B) and Herbesser (C) has been carried out in 5 healthy, male volunteers. After a single oral dose of 60 mg of each preparation, the mean AUC(0–8 h) and Cmax of preparation B was significantly higher than of brands A and C. The tmax of A and B was significantly lower than of C. B had a higher dissolution rate in vitro (98.8% dissolved in 45 min) than A and C. Thus, there was bioinequivalence of the three brands of diltiazem, due partly to differences in dissolution and perhaps in part to a first pass effect.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 71
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 199-201 
    ISSN: 1432-1041
    Schlagwort(e): netilmicin ; pharmacokinetics ; diurnal variation ; circadian rhythm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Netilmicin 1.5 mg/kg body weight was administered intravenously every 8 h for 2 days to 8 patients with normal renal function. Significant elevation of mean and trough plasma concentrations was found at 05.00 h and 09.00 h. This was considered to be due to circadian variation, with possible accumulation during the night. The clinical importance of this phenomenon in relation to the development of aminoglycoside toxicity awaits further investigation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 72
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 507-513 
    ISSN: 1432-1041
    Schlagwort(e): Anthracyclines ; cancer patients ; iodo-doxorubicin ; doxorubicin ; pharmacokinetics ; metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of doxorubicin (DOX), iodo-doxorubicin (I-DOX) and their metabolites in plasma has been examined in five patients each receiving 50 mg/m2 of both anthracyclines as a bolus injection. Terminal half-life, mean residence time (MRT), peak plasma concentration Cmax, and area under the curve (AUC) appeared smaller for I-DOX, whereas its plasma clearance (CLp) and volume of distribution at steady state (Vss) were larger than for DOX. The major metabolite of I-DOX was iodo-doxorubicinol (I-AOL) followed by doxorubicinol aglycone (AOLON). The AUC of I-AOL was 6-times larger than that of its counterpart AOL, which is the major metabolite of DOX. AOLON generated after I-DOX administration is a further important metabolite, as its AUC was 10-times larger than that of AOLON generated from DOX. The other aglycones, such as doxorubicin aglycone (AON) and the 7-deoxy-aglycones were only minor metabolites after either I-DOX or DOX injection. The ratio AUCI-AOL/AOL/AUCI-DOX/DOX was 27 in the case of I-DOX and 0.4 after DOX. The terminal half-lives of the cytostatic metabolites I-AOL and AOL were similar, although a longer MRT for AOL was calculated. Both metabolites had much longer MRTs than their parent drugs. The MRTs of the aglycones AOLON and AON were greater than those of the 7-deoxy-aglycones after both I-DOX and DOX. Approximately 6% DOX and less than 1% I-DOX were excreted by the kidneys during the initial 48 h. About 5% of I-DOX was excreted via the kidneys as I-AOL. Aglycones were not detected in significant amounts. The plasma concentrations of all compounds measured were highest during the first few minutes after administration of I-DOX and DOX. The I-AOL concentration was comparable to that of I-DOX immediately after the injection, due to very rapid metabolism within the central compartment (vascular space) by the aldoketo reductase system in the erythrocytes. The plasma concentration-time curves of (7d)-aglycones showed a second peak between 2 and 9 h after injection, suggesting enterohepatic circulation of metabolites lacking the daunosamine sugar moiety.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 73
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 577-581 
    ISSN: 1432-1041
    Schlagwort(e): Benzbromarone ; elimination phenotypes ; pharmacokinetics ; metabolism ; genetic variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Following oral administration of the uricosuric drug benzbromarone two major metabolites appear in the circulation, 1'-hydroxy-benzbromarone (M1), and a second product (M2) of unknown structure. The plasma concentrations of the parent drug and of M1 and M2 have now been compared in two different elimination phenotypes, 10 subjects who eliminated the drug rapidly (S1–10) and one individual (S11) whose elimination capacity was impaired, presumably due to genetic variation (S11). The AUC (0–96) of the parent drug in S11 was 145 gmg · ml−1 h, and in the other individuals it averaged 18.3 (11.4–24.5) μg · ml−1 h. The plasma elimination half life of benzbromarone was 3.34 (1.77–5.24) h in the rapid eliminators, and 13.08 h in the subject with the elimination defect. The mean plasma elimination half life of the metabolites in S1–10 amounted to 20.1 (11.9–41.2) h for M1, and 17.2 (12.9–30.7) h for M2. In S11 the plasma elimination half life of M1 was prolonged to 76.6 h, and of M2 to 75.4 h. Thus, the elimination defect in S11 was not restricted to the parent drug, but it also involved the two major metabolites M1 and M2. This might be a consequence of a hepatic enzyme deficiency, or be due to impairment of drug excretion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 74
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 603-605 
    ISSN: 1432-1041
    Schlagwort(e): Galanthamine ; Alzheimer's disease ; stereoselectivity ; cholinesterase inhibition ; side effects ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effect of galanthamine (GAL) and its 2 major metabolites on human cholinesterases has been explored. Epigalanthamine, a diastereomer of GAL, was 130-times less potent in vitro in its effect on acetylcholinesterase (AChE) in erythrocytes than the parent compound, and it did not differ significantly from the ketone galanthaminone. In vivo, the maximal 36–55% inhibition of AChE was approached 30 min after oral administration of 10 mg GAL. The duration of the catalytic inhibition corresponded to an elimination half-life of approximately 5–7 h. GAL was well tolerated in 8/8 healthy volunteers, and 3/4 Alzheimer patients tolerated the drug up to a daily dose of 40 mg.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 75
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 165-167 
    ISSN: 1432-1041
    Schlagwort(e): Cyclosporin A ; ponsinomycin ; pharmacokinetics ; drug interaction ; macrolide antibiotic ; renal transplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The influence of treatment with ponsinomycin, a new macrolide antibiotic, on the pharmacokinetics of cyclosporin A has been studied in 10 renal transplant patients. The pharmacokinetics of cyclosporin A was investigated at steady state, before and during treatment with ponsinomycin. On average, the blood levels of cyclosporin A were doubled by the macrolide, possibly due to a decrease in elimination or/and to an increase in absorption. Ponsinomycin should be use very carefully in patients treated with cyclosporin A.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 76
    ISSN: 1432-1041
    Schlagwort(e): Flurbiprofen ; sustained-release formulation ; tolerance ; pharmacokinetics ; adverse reaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetic profile of 200 mg sustained-release flurbiprofen capsules was compared in nine elderly (mean age 84.2 years) and 10 young (mean age 38.1 years) patients with arthritis. After a single capsule, a 48 h plasma concentration profile was performed. The patients then took 1 capsule daily for a further 13 days with plasma levels of the drug being measured pre-dose on alternate days. Following ingestion of the last capsule, a further 48 hour plasma concentration profile was performed. These results were compared with each other and with computer predicted data obtained from dosing with 200 mg conventional flurbiprofen (as 100 mg b.d.). In both young and elderly patients, the two 48 h plasma concentration profiles confirmed the sustained-release characteristics of the capsule. There was no evidence of dose-dumping, although, in one elderly patient with a partial gastrectomy, higher plasma concentrations were observed. Inter- and intra-patient variability was acceptable. A steady-state was achieved within the predicted four days in both groups and there was no evidence of accumulation with the daily dosing interval. A mean steady-state level of approximately 6 μg/ml was achieved for both populations. Computer predicted data for 200 mg conventional flurbiprofen (as 100 mg b.d.) showed a pre-dose/peak range of 1–12 μg/ml. The pre-dose/peak ranges for the young and old patients were 4–10 μg/ml and 4–8 μg/ml respectively. One young patient developed a hypersensitivity reaction of moderate severity; one young and four elderly patients developed a low haemoglobin concentration during the study. No other changes in haematological or biochemical parameters were seen.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 77
    ISSN: 1432-1041
    Schlagwort(e): metoprolol ; oral osmotic drug delivery system (OROS) ; food intake ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The influence of food intake on the bioavailability of metoprolol from an OROS system has been investigated. No significant difference was found between OROS administration to fasting subjects or after breakfast in any of the kinetic parameters (AUC, Cmax, tmax, C24 and lag time). Therefore, metoprolol OROS can be administered with breakfast.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 78
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 385-389 
    ISSN: 1432-1041
    Schlagwort(e): Levodopa ; Parkinson's disease ; pharmacokinetics ; pharmacodynamics ; modeling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Five patients with severe Parkinson's disease were characterized with respect to their pharmacokinetic and pharmacodynamic responses to levodopa given: orally, intravenously (three different infusion rates) and intraduodenally. The best therapeutic infusion rate in the intravenous study was used for the intraduodenal infusion of levodopa. A lag time between plasma concentration and effect following oral administration was seen in three of the five patients and this disequilibrium was estimated as the rate constant ke0 using model-independent analysis. The plasma concentration-effect relationship was similar for the three modes of administration and in all patients the therapeutic plasma concentration for full mobility was 〉4–5 μg·ml−1. The disequilibrium half-life for development of effect after oral administration was calculated to be about 30 min. The patients remained clinically stable during the period of the intraduodenal infusion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 79
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 569-572 
    ISSN: 1432-1041
    Schlagwort(e): Bopindolol ; cirrhosis ; antipyrine ; pharmacokinetics ; side effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma concentration-time curve of the hydrolysis product of bopindolol has been investigated in 14 patients with cirrhosis and in 15 healthy volunteers given a single oral dose of 2 mg bopindolol. Cirrhosis was confirmed by history and clinical examination or liver biopsy. The time to maximum concentration, maximum concentration and AUC of hydrolyzed bopindolol were similar in the patients and controls. However, the elimination half-life was 6.0 h in controls and 9.5 h in cirrhotics. Antipyrine clearance was markedly decreased in patients with cirrhosis, but no correlation was found with the pharmacokinetic parameters of hydrolysed bopindolol. Although the AUC was not significantly altered in patients with cirrhosis, the longer half-life of hydrolysed bopindolol suggests impairment of its disposition in liver disease, which could lead to significant accumulation of drug during chronic dosing.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 80
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 335-341 
    ISSN: 1432-1041
    Schlagwort(e): digoxin ; atrial fibrillation ; infusion ; pharmacokinetics ; simulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Using available data on time-concentration and time-effect relationships in normal persons the results of infusion of digoxin in various time periods were simulated and compared with administration of digoxin by bolus injections, using a three-compartment pharmacokinetic model to which a separate small side-effect compartment was subsequently added. The validity of the simulations was tested in 11 patients with rapid atrial fibrillation. Serum digoxin concentrations, ventricular rate and side effects were monitored in a double-blind study comparing an infusion of 1.5 mg digoxin over 6 h with administration of three bolus injections of 0.5 mg digoxin 8 h apart. In agreement with the predictions of the model, the maximal fall in ventricular rate was reached after 8–9 h in the infusion group and after 19–20 h in the bolus injection group, without any detectable difference in side effects. There were certain discrepancies between the results of the clinical study and the predictions of the model, e.g. in serum digoxin concentrations, perhaps due to impaired clearance in the patients. However, it is concluded that the tested model is valid in elderly patients with rapid atrial fibrillation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 81
    ISSN: 1432-1041
    Schlagwort(e): benazepril ; benazeprilat ; ACE inhibitor ; pharmacokinetics ; pharmacodynamics ; elderly ; adverse effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and pharmacodynamics of a single oral dose benazepril·HCl 10 mg have been studied in 15 healthy volunteers aged 65 to 80 y. The kinetics of unchanged benazepril and its active metabolite benazeprilat did not differ significantly in males and females, so the combined kinetic data from all 15 elderly subjects were compared with a historical control group of 19–32 year-old healthy men treated in the same way. The disposition of benazepril was not affected by age. The time to maximum plasma concentration, tmax (0.5 h) and elimination half-life (0.6 h) in the elderly were the same as in young subjects. The kinetics of benazeprilat was slightly changed in the elderly; although its tmax (1.5 h) was not affected, Cmax and the AUC were 20–40% greater. The elimination half-life of benazeprilat during the first 24 h after doing in the elderly was increased by about 20% to 3.2 h. The renal plasma clearance of benazeprilat (18.1 ml·min−1) was about 20% smaller than in the young subjects. An average of 18.5% of the dose was recovered as benazeprilat in the 24 h urine from the elderly subjects, which was similar to the recovery in the young subjects. Both benazepril and benazeprilat were highly bound to serum proteins (96 and 95%, respectively). Mean systolic and diastolic blood pressures in the elderly were reduced by a maximum of 37/16 mm Hg at 6 h, in association with a small rise in pulse rate. Treatment was generally well tolerated. Three of the 15 subjects reported clinical adverse experiences judged to be possibly drug related, namely headache, abdominal pain and cold extremities.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 82
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 489-491 
    ISSN: 1432-1041
    Schlagwort(e): irtemazole ; dose-response relationship ; pharmacokinetics ; uricosuric drugs ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Irtemazole 12.5 to 50 mg in 6 healthy, normouricaemic subjects caused a maximal decrease in plasma uric acid (after 8 to 12 h) of 46.5%. The uricosuric effect began during the first 60 min after drug administration and it lasted for 7 to 24 h. Renal uric acid excretion returned to its base line value after 8 to 16 h and uric acid clearance after 10.0 to 12.0 h. Doses of irtemazole between 12.5 and 37.5 mg produced a dose-related rise in the uricosuric effect. There was no essential difference between the uricosuric effect of 37.5 mg and 50 mg irtemazole. The D50 dose (that producing a half-maximal effect) was between 16.3 mg and 34.2 mg, (average 24.7 mg). The value of irtemazole in the management of hyperuricaemia and gout remains to be determined.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 83
    ISSN: 1432-1041
    Schlagwort(e): ibuprofen ; rheumatoid arthritis ; enantiomer ; stereoselectivity ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary S(+)-, R(−)- or racemic ibuprofen was administered orally to volunteers in doses of 150 mg, 300 mg and 500 mg pure S(+)-, 300 mg pure R(−)- and 600 mg racemic ibuprofen. The pharmacokinetic parameters in humans showed that S(+)-ibuprofen was not inverted to R(−)-ibuprofen, whereas R(−)-ibuprofen was inverted to S(+)-ibuprofen to a variable degree. S(+)-ibuprofen and R(−)-ibuprofen given alone more rapidly reached significantly higher maximal plasma concentrations than after the same doses of the racemic compound. The elimination half-lives and clearance values for all three forms of ibuprofen were comparable. The mean residence time of S(+)-ibuprofen after R(−)- and racemic ibuprofen was significantly longer than after administration of the pure S(+)-enantiomer. Judged by the AUC, the bioavailability of S(+)-ibuprofen was independent of the dose within the range tested. Administration of S(+)-ibuprofen to 6 rheumatic patients showed that the pharmacokinetic behaviour of S(+)-ibuprofen in patients was similar to that found in volunteers. S(+)-ibuprofen proved to be an effective analgesic antirheumatic drug in the dose range 1 to 1.5 g/day.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 84
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 547-549 
    ISSN: 1432-1041
    Schlagwort(e): piroxicam ; tenoxicam ; cholestyramine ; pharmacokinetics ; enterohepatic circulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary To assess the extent of enterohepatic recycling of piroxicam and tenoxicam, their pharmacokinetics have been compared in the absence and presence of concomitant treatment with cholestyramine. In a randomized crossover study 6 healthy volunteers received piroxicam and tenoxicam 20 mg p.o., alone or with cholestyramine 24 g/day for 4 days. Cholestyramine increased piroxicam & tenoxicam elimination approximately 2-fold (t1/2 50.3 vs 28.1 h and 73.6 vs 35.8 h, respectively). It also increased the apparent clearance (Cl/f) of piroxicam and tenoxicam by 58% and 112%. When cholestyramine was administered, the t1/2 of piroxicam & tenoxicam were correlated (r=0.89), which suggests that their hepatic biotransformation is under a common control. It is concluded that: piroxicam and tenoxicam are eliminated to a large and comparable extent through the biliary route, and the administration of cholestyramine may help to accelerate their elimination in cases of overdosage.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 85
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 579-582 
    ISSN: 1432-1041
    Schlagwort(e): d-sotalol ; d,l-sotalol ; pharmacokinetics ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of d-sotalol has been studied in six healthy volunteers given single doses of 0.25, 0.50, 1, 2 mg·kg−1 i.v. and one 100 mg oral dose in comparison with the kinetics of 1 mg·kg−1 i.v. of dlsotalol. There was no significant difference in the disposition of the d-enantiomer and the racemate. The terminal half-life averaged 7.2 h, and the kinetics was linear, with a mean total clearance of 0.13 l·h−1·kg−1. Renal clearance of d-sotalol represented 56 to 77% of total clearance. The absolute systemic availability of oral d-sotalol was close to 100% and the elimination half-life of the oral-d-enantiomer was similar to that of the i.v. form (7.5 h).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 86
    ISSN: 1432-1041
    Schlagwort(e): Atenolol ; metoprolol CR ; elderly subjects ; subjective symptoms ; pharmacokinetics ; pharmacodynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In a double-blind, randomised, cross-over study, the pharmacokinetic/dynamic effects and subjective symptoms of a new controlled-release (CR) formulation of metoprolol (50 and 100 mg) have been compared with atenolol (50 mg) and placebo in 20 elderly healthy subjects. The metoprolol CR formulation displayed an even plasma concentration-time profile over the dosage interval while atenolol produced a peak at 2–4 h. All three active treatments produced significant β1-blockade at 24 h compared to placebo. Four hours after dose intake, the degree of β1-blockade was significantly greater with conventional atenolol 50 mg than with either dose of metoprolol CR. Subjective well-being was examined with a self-administered questionnaire (MSE-profile), including three dimensions: Contentment, Vitality and Sleep. No significant differences were detected between placebo and either dose of metoprolol CR. At 2 h, following atenolol, a deterioration in Vitality was observed compared to placebo and metoprolol CR 100 mg. At the end of the dosage interval there was no longer any significant difference between the treatments. Perceived leg fatigue during exercise, evaluated 4 h after dosing, was more pronounced during treatment with atenolol than metoprolol CR 50 mg. The results suggest that the metoprolol CR formulation was not associated with significant effects on subjective well-being, whereas atenolol caused a deterioration at the time of the peak plasma concentration of the drug.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 87
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 587-593 
    ISSN: 1432-1041
    Schlagwort(e): prenylamine ; racemic drug ; stereoselectivity ; metabolism ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of S-(+)- and R-(−)-prenylamine was studied in eight healthy volunteers given single and repeated oral doses of the racemic drug. Distinct differences in various pharmacokinetic parameters were found between the S- and R-enantiomer. The maximum plasma concentrations and AUCs of the R-enantiomer exceeded those of the S-enantiomer five-fold; the apparent oral clearance of the S-form was five-times and the renal clearance three-times higher than of the R-form. Acid catalyzed hydrolysis of urine samples released more S-prenylamine, indicating stereoselective glucuronidation of unchanged prenylamine. Plasma protein binding also differed between the two enantiomers, generally with a higher unbound fraction of the S-form, whereas analysis of the bound fractions showed that prenylamine was bound to different plasma proteins with inverse stereoselectivity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 88
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 599-603 
    ISSN: 1432-1041
    Schlagwort(e): Isradipine ; cirrhosis ; systemic ; calcium antagonist ; aminopyrine breath test ; serum bile acids ; galactose elimination ; pharmacokinetics ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of the dihydropyridine calcium antagonist isradipine has been examined in 8 healthy volunteers, 7 patients with non-cirrhotic chronic liver disease (CLD), and 8 patients with biopsy-proven cirrhosis (CIR). Isradipine was simultaneously given orally (12C 5 mg) and i.v. (13C 1 mg). Systemic availability was significantly increased from 17% and 16% in controls and CLD, respectively, to 37% in CIR. The corresponding systemic clearances averaged 1.1, 0.9 and 0.61 · min−1, the reduction in cirrhotics being significant. Both aminopyrine demethylation capcity, a measure of hepatic microsomal function, and indocyanine green disappearance, a measure of hepatic perfusion, were correlated with the reduction in systemic clearance, and the reduction in oral clearance was correlated with the reciprocal of the serum bile acid concentration. The loss of first-pass extraction should be considered when this calcium antagonist is given perorally in patients with hepatic cirrhosis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 89
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 595-598 
    ISSN: 1432-1041
    Schlagwort(e): flecainide ; pharmacokinetics ; absorption ; non-parenteral administration ; healthy subjects ; rectal administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The absorption kinetics of different pharmaceutical formulations of orally and rectally administered flecainide have been assessed in a cross-over study in 7 healthy volunteers. The subjects received single doses of flecainide after a washout period of at least one week. A tablet, an oral solution, a rectal solution and a 10 min i.v. infusion during 10 min each containing 100 mg flecainide were administered to the subjects in a randomized order. The mean absolute bioavailability was 98%, 78% and 81% for the rectal and oral solutions and the tablet. The lag time after administration of the oral solution was 0.33 h and it was 0.86 h after the tablet and 0.18 h after the rectal solution. The mean time to the peak serum concentration (tmax) after the rectal solution (0.67 h) was shorter than after either the tablet (4 h) or oral solution (1 h). The maximum serum concentration (Cmax) was 0.29 mg · 1−1 after the rectal solution, 0.14 mg · 1−1 after the tablet and 0.17 mg · 1−1 after the oral solution. All the volunteers showed significantly higher serum flecainide concentrations during the first 20 min of the absorption phase after rectal administration of 100 mg flecainide as a solution compared to its oral administration. In conclusion: based on the absolute bioavailability, Cmax, tmax, and lag times, rectal administration of flecainide solution gave a better absorption profile than after oral tablet or solution.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 90
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 605-608 
    ISSN: 1432-1041
    Schlagwort(e): albendazole ; albendazole sulphoxide ; absorption ; elimination ; benzimidazole ; pharmacokinetics ; echinococcosis ; cholestasis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of albendazole and its main metabolite, albendazole sulphoxide, have been examined after giving a single oral dose of 200 mg albendazole to 19 patients with either Echinococcus multilocularis or E. granulosus, 5 of whom had significant extrahepatic obstruction due to the underlying disease. The AUC of albendazole sulphoxide was increased in the latter patients (mean 122 μmol · h · l−1 compared to 17 μmol · h · l−1 in the non-obstructed group). Obstructed patients had delayed absorption, ka averaging 0.39 compared to 1.41 h−1 in non-obstructed patients. The corresponding elimination rate constant, ke was also prolonged, averaging 0.041 and 0.13 h−1 in the two groups, respectively. Four patients were restudied after complete or partial resolution of the cholestasis. The pharmacokinetic parameters in them had returned towards values comparable to those in the non-obstructed patients.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 91
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 609-615 
    ISSN: 1432-1041
    Schlagwort(e): Terguride ; partial dopamine agonist ; pharmacokinetics ; endocrine effects ; pituitary hormones ; 6β-OH cortisol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma levels of the partial dopamine agonist, terguride, were measured by RIA in healthy volunteers after a single i. v. dose of 50 μg and on the first and seventh day of an oral treatment with 250 μg, 500 μg and 750 μg b. d. Basal and releasing hormone (TRH, GHRH, CRF, LHRH) — stimulated pituitary hormone secretion (PRL, TSH, GH, FSH, LH) and cortisol were also determined by RIA. Following the i. v. injection, plasma terguride levels declined biphasically, with half-lives of 0.2 and 1.5 h; total clearance was 17 ml·min−1·kg−1. the oral bioavailability of terguride over all doses was about 20%. Basal and TRH-stimulated prolactin levels were dose-dependently depressed, but the secretion of other hormones remained unaffected. Tolerance of terguride was excellent and there was no negative effect on performance or mood, nor on mixed-function oxygenase activity, assessed as urinary 6β-OH cortisol.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 92
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 261-265 
    ISSN: 1432-1041
    Schlagwort(e): Frusemide ; probenecid ; phenprocoumon ; anticoagulant ; drug interaction ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary We have studied the pharmacokinetics of phenprocoumon with and without co-administration of frusemide and probenecid in two groups of 17 healthy volunteers. Frusemide 40 mg b.i.d. for 7 days did not interact with phenprocoumon to a significant extent. Probenecid 500 mg q.i.d. for 7 days significantly accelerated the overall elimination of phenprocoumon, as indicated by a decrease in AUC from 295 to 157 μg · h · ml−1, and a reduction in the fraction of the dose excreted by the kidneys. The data are consistent with inhibition of the glucronidation of phenprocoumon by probenecid. Its accelerated elimination may be a consequence of the increased formation of hydroxylated metabolites.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 93
    ISSN: 1432-1041
    Schlagwort(e): Hypertension ; perindopril ; hydrochlorothiazide ; ACE inhibition ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacodynamic effects and acceptability of perindopril (4 mg daily) and hydrochlorothiazide (25 mg daily) given alone or in combination for 1 month were investigated in a double-blind, placebo controlled, parallel group study. The pharmacokinetics of perindopril and its active metabolite perindoprilat and the time course of angiotensin converting enzyme inhibition were studied for 72 h following the last dose of treatment in the two appropriate groups. Similar decreases in blood pressure were seen 24 h after the last dose of perindopril or hydrochlorothiazide (11/7 mm Hg supine) given alone at these doses. The effect of these drugs given together was additive on diastolic blood pressure and synergistic on systolic blood pressure (24.5/12.6 mm Hg supine) taking into account the placebo response. The significant increase in plasma renin activity produced by perindopril alone was potentiated by concurrent administration of hydrochlorothiazide. The formation of perindoprilat was slightly reduced in the group also receiving hydrochlorothiazide and there was a very small reduction in ACE inhibition in this group. Perindopril, whether given alone or in combination with hydrochlorothiazide, was well tolerated and produced no clinically significant change in routine haematology or serum biochemistry. The additive or synergistic effects of perindopril and hydrochlorothiazide on blood pressure must be due to their complementary physiological actions and not to a pharmacokinetic interaction.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 94
    ISSN: 1432-1041
    Schlagwort(e): Furosemide ; triamterene ; drug combination ; absorption ; urine sodium ; urine potassium ; fixed combination ; healthy volunteers ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The absorption and diuretic effect of furosemide 40 mg alone (F), and of the free (F+T) and the fixed (FT) combinations of furosemide 40 mg and triamterene 50 mg have been compared in 12 healthy young men. A slight reduction in the area under the concentration-time curve (AUC) of plasma furosemide was found for the fixed combination (AUC480) F 2.58 μg · h · ml−1; F+T 2.46 μg · h · ml−1; FT 1.97 μg · h · ml−1. There was a significant reduction in the AUC480 of plasma triameterene (F+T 204.9 μg · h · l−1; FT 130.2 μg · h · l−1). Sodium excretion after F+T and FT was more pronounced than after F (F+T 302 mmol; FT 311 mmol; F 259 mmol). When compared to F alone, there was a reduction in the 24-hour potassium excretion after F+T as well as after FT (F 121 mmol; F+T 104 mmol; FT 107 mmol). It is concluded that the absorption of triamterene was significantly reduced after ingestion of the fixed combination tablet. However, in healthy male adults this had no influence on its natriuretic and potassium-sparing effect as compared to the free combination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 95
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 39 (1990), S. 607-608 
    ISSN: 1432-1041
    Schlagwort(e): ivermectin ; pharmacokinetics ; plasma protein binding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Human pharmacokinetic data on the new antiparasitic agent, ivermectin, are scanty. For the evaluation of its disposition a specific HPLC assay with sensitive fluorescence detection was developed. Applying equilibrium dialysis, plasma protein binding of ivermectin was measured in five healthy individuals and it averaged 93.2±4.4% (SD). Such strong binding should be taken into consideration, especially in patients with malnutrition or with diseases in which a decrease in plasma proteins and consequently a higher free fraction of ivermectin could be expected.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 96
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 165-169 
    ISSN: 1432-1041
    Schlagwort(e): nicotine ; cimetidine ; ranitidine ; pharmacokinetics ; H2-receptor antagonists ; hepatic oxidation ; renal secretion ; tobacco smoking ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In a randomized, double-blind, cross-over experiment, 6 healthy consenting male subjects were administered cimetidine 600 mg or ranitidine 300 mg or placebo p.o. q12h×2 days. Nicotine bitartrate was administered i.v. on day 2 (1 ug/kg/min)×30 min. After cimetidine mean nicotine total and metabolic clearances were decreased by 30% and 27% while after ranitidine the clearances were decreased by 10% and 7% respectively. Since smokers regulate their smoke intake based in large part on their nicotine blood levels these results suggest that the diminished nicotine total clearance in the presence of cimetidine could be important in assisting smoking reduction or cessation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 175-179 
    ISSN: 1432-1041
    Schlagwort(e): diflunisal ; smoking ; pharmacokinetics ; sex-differences ; oral contraceptive steroids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The single dose pharmacokinetics of diflunisal were studied in 4 groups of 6 young volunteers: control men, control women, women taking low estrogen oral contraceptive steroids (OCS), and women smokers (10–20 cigarettes/day). The plasma clearance of diflunisal was significantly higher in men (0.169 ml·min−1·kg−1) and in women on OCS (0.165 ml·min−1·kg−1) as compared to control women (0.108 ml·min−1·kg−1). Partial metabolic clearances of diflunisal by the three conjugative pathways (phenolic and acyl glucuronide formation, sulphate conjugation) were all increased in men and women OCS users as compared to control women. Statistically significant increases, however, were only observed for the partial metabolic clearance of diflunisal by phenolic glucuronidation between men and women (2.91 vs. 1.85 ml·min−1 respectively), and for the partial clearance by acyl glucuronidation between OCS users and control women (4.81 vs. 3.01 ml·min−1 respectively). Smoking resulted in a moderate increase (35%) in plasma diflunisal clearance. However, a significant reduction in total urinary recovery of diflunisal and its glucuronide and sulphate conjugates was found in smokers (70.5% in smokers as compared to 84.2–87.2% in the 3 other study groups). Consequently, smoking may have induced hydroxylation, a minor oxidative metabolic pathway of diflunisal recently discovered in man.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 98
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 181-184 
    ISSN: 1432-1041
    Schlagwort(e): cyclosporin A ; diabetic children ; pharmacokinetics ; dose adjustment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Cyclosporin A (CsA) pharmacokinetics was studied in 19 diabetic children (mean age: 10.6 y). They were divided into prepubertal (I) and pubertal (II) groups according to plasma oestradiol or testosterone concentrations. The kinetic study was performed after a 72 h wash out period and a single oral dose of 7.5 mg/kg CsA. CsA in blood was measured by HPLC. The kinetic parameters: Cmax, tmax, t1/2, AUC, CL/f, Vz/f and tss were calculated. No significant difference was found between the two groups. A significant negative correlation was found between Vz and both total cholesterol (r=0.46), VLDL+LDL−cholesterol (r=−0.49) and VLDL+LDL−phospholipids (r=−0.58). CsA kinetics at steady-state were simulated by superimposition of single dose kinetics derived from each single dose. Measured steady-state blood concentrations were correlated (r=0.80) with the values predicted by the simulation. The results suggest that CsA adjustment dosage of the CsA may be performed after a single oral dose using blood levels measured by HPLC. This procedure requires validation in further studies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 189-193 
    ISSN: 1432-1041
    Schlagwort(e): estramustine phosphate ; prostatic cancer ; gastrointestinal absorption ; food intake ; calcium ; drug interaction ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effect of milk and food on the pharmacokinetics of estramustine phosphate was investigated in six patients with prostatic cancer. In a randomized three-way cross-over study, the patients were given single doses of the drug together with low calcium water, low calcium food and milk. The evaluation was based upon the plasma concentration of two metabolites, estromustine and estrone, as parent drug could not be detected in plasma. The tmax and lag time of estromustine were significantly increased by milk and food intake and Cmax and AUC were significantly decreased. In comparison with water, the AUC of estromustine was 41% when the drug was taken with milk and 67% after simultaneous intake of standardized food. Corresponding figures for the peak values were 32 and 57%, respectively. The effect of milk and food intake on the pharmacokinetics of estrone was similar. Studies in vitro demonstrated that the dissolution of estramustine phosphate disodium was markedly impaired in the presence of calcium. It was concluded that the rate and extent of absorption of estramustine phosphate were decreased when the drug was taken with milk or food due to the formation of a poorly absorbable calcium complex. To obtain high and reproducible absorption of Estracyt®, the drug should not be taken together with milk, milk products or other calcium-rich food or drugs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 38 (1990), S. 405-406 
    ISSN: 1432-1041
    Schlagwort(e): pirenzepine ; renal insufficiency ; haemodialysis ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetic properties of pirenzepine following administration of a single, 50 mg oral dose were evaluated in three groups of subjects: group I, end stage renal disease requiring maintenance haemodialysis (CLCR 0 to 10 ml·min−1); group II, moderate renal insufficiency (CLCR 10 to 30 ml·min−1); and group III, mild renal dysfunction (CLCR 30 to 70 ml·min−1). Additionally, subjects in group I received a 50 mg dose on a non-dialysis day and at least one week later, a 50 mg dose during haemodialysis. There was a linear relationship (r = 0.97) between pirenzepine renal clearance and renal function as measured by creatinine clearance. The harmonic mean terminal half-life for pirenzepine was 17.3 h in subjects with end stage renal disease, 18.0 h in subjects with moderate renal insufficiency and 14.7 h in subjects with mild renal dysfunction. Haemodialysis reduced the level of circulating pirenzepine by approximately 25%. The mean arterial to venous plasma pirenzepine ratio during hemodialysis was 1.29 (range 1.02–1.56). Based on subjective reporting of adverse experiences and clinical observation, pirenzepine appeared to have had a wide margin of safety in these patients. Dry mouth was the most frequently reported adverse experience attributable to pirenzepine administration. A reduction in dose or dosing frequency may be warranted only in end state renal disease (CLCR 0 to 10 ml·min−1).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...