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  • 1
    Electronic Resource
    Electronic Resource
    Effects of nest paper hydrocarbons on nest and nestmate recognition in colonies ofPolistes metricus say (1995)
    Springer
    Journal of insect behavior 8 (1995), S. 103-113 
    Details
    ISSN: 1572-8889
    Keywords: nestmate recognition ; cuticular hydrocarbons ; wasp nests ; Polistes metricus ; Hymenoptera ; Vespidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The role of nest paper hydrocarbons in nest and nestmate recognition for the social waspPolistes metricus was examined. Newly emergedP. metricus workers maintained in the laboratory spent four days alone on a fragment of nest paper that was subjected to one of the following tretments: untreated, extracted with hexane to remove surface hydrocarbons, or extracted with extract reapplied. Test wasps were returned to their natal nest with nestmates and observed for 1 h. Time spent on nest by test wasp and its behaviors were recorded. Wasps exposed to untreated and reapplied nest fragments spent an average of 34.13 and 31.75 min on their nests, respectively, while wasps from extracted fragments averaged 17.19 min. Behavior of wasps exposed to extracted paper differed significantly from wasps exposed to paper with hydrocarbons. These results suggest that exposure to nest paper hydrocarbons is important for both nest and nestmate recognition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01990972
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  • 2
    Electronic Resource
    Electronic Resource
    Evaluation of methotrexate tissue exposure by in situ microdialysis in a rat model (1994)
    Springer
    Cancer chemotherapy and pharmacology 34 (1994), S. 297-301 
    Details
    ISSN: 1432-0843
    Keywords: Microdialysis ; Methotrexate ; Tissue ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The feasibility of using a microdialysis technique to obtain pharmacokinetic data on tissue exposure to methotrexate (MTX) was investigated. Microdialysis probes were implanted in the jugular vein, femoral muscle, and liver ofanesthetized male Wistar rats. MTX (100 mg/kg) was given as a bolus injection through an indwelling venous catheter, and blood samples were obtained through a second venous access and by microdialysis for a total of 6 h. Heparinized plasma, ultrafiltered plasma, and microdialysis effluent from tissue and venous probes were analyzed by high-performance liquid chromatography. Centrifugal ultrafiltration of rat plasma spiked in vitro with MTX (1–100 μM) revealed a mean binding to plasma proteins of 21%. In vitro microdialysis of this spiked plasma resulted in 23% relative recovery of the unbound fraction. In rats receiving MTX, plasma protein binding was 23% and the relative drug recovery as assessed with venous microdialysis probes was 18%. Plotting of unbound (i.e., ultrafiltrate) MTX concentrations in the blood against venous microdialysis perfusate values in the blood gave a good linear correlation with a coefficient of correlation (r 2) of 0.98. There was also a linear correlation between the total MTX concentrations in venous blood and the drug levels in microdialysis samples from muscle and liver (r 2=0.93 and 0.74, respectively). Area under the curve estimations were consistent with an MTX exposure of 30% and 46% for the muscle and liver as compared with the circulation. The present study demonstrates that the microdialysis technique can provide reproducible data on tissue exposure to MTX in an animal model and indicates that the methodology is adaptable to clinical settings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686036
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  • 3
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of different doses of methotrexate at steady state by in situ microdialysis in a rat model (1995)
    Springer
    Cancer chemotherapy and pharmacology 36 (1995), S. 283-289 
    Details
    ISSN: 1432-0843
    Keywords: Microdialysis ; Methotrexate ; Steady state Rat ; Tissues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We used a microdialysis technique to monitor extracellular methotrexate (MTX) levels during the steady state in a rodent model. Microdialysis probes were implanted in the muscle, liver, and kidney of anesthetized male Wistar rats. MTX (18.75–500 mg/kg) was given as a continuous infusion through a venous catheter, and blood samples were obtained through a second venous catheter. Heparinized plasma, ultrafiltered plasma, microdialysis effluent from tissues, and tissue samples (obtained at the end of experiments) were analyzed for MTX content by high-performance liquid chromatography (HPLC). Steady state was demonstrated in the blood and tissues from 2 h until the end of the experiments (6 h). Extracellular drug levels in muscle and liver displayed a linear correlation with doses, whereas kidney levels reached a plateau at an MTX dose of 150 mg/kg per 6 h. Microdialysis-fluid endpoint levels for muscle, liver, and kidney were positively correlated to the endpoint total tissue levels (r 2=0.80, 0.85, and 0.68, respectively). In the kidneys, the maximal relative tissue MTX accumulation was measured at a total dose of 75 mg/kg per 6 h. At higher doses, the relative drug sequestration declined to less than half of the values observed at this dose. This study demonstrates that the microdialysis technique can provide reproducible data on MTX tissue exposure in an animal model and that it offers a means of serial and reproducible monitoring of extracellular-tissue MTX levels at steady state and over a wide dose range. Pending additional studies, microdialysis may be a helpful technique for elucidating the kinetics of drug delivery to both targeted and toxicity-prone tissues during chemotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689044
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of extracellular methotrexate tissue levels by microdialysis in a rat model (1996)
    Springer
    Cancer chemotherapy and pharmacology 37 (1996), S. 394-400 
    Details
    ISSN: 1432-0843
    Keywords: Key words Microdialysis ; Methotrexate ; Tissue ; Recovery ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used a microdialysis technique to determine tissue methotrexate (MTX) levels during steady state in a rodent model. Two different approaches were employed to measure the actual extracellular MTX concentrations in muscle, liver, and kidney tissues of anesthetized Wistar rats. With the reduced-perfusion-rate technique, the flow in the microdialysis perfusate was gradually decreased toward zero to permit calculation of zero-flow intercepts. Using the net change technique, microdialysis probes were perfused with different MTX concentrations to allow an assessment of equilibrium drug levels. For these two methods to be used, drug concentrations in the matrix to be analyzed must remain unchanged during the experimental procedure. In the animal model, steady state was attained after 1.5 h and maintained throughout the rest of the experiments by the administration of MTX as continuous infusions through a venous catheter. In vitro and in vivo, both the reduced-perfusion-rate and net change techniques gave reproducible data that permitted the estimation of extracellular drug concentrations in the dialyzed tissue compartments. The data suggest that the level of unbound MTX in the circulation is fairly similar to the extracellular concentrations in the muscle and liver. In the kidney, MTX levels were measured to be 3–8 times higher than those of unbound, circulating MTX, and a considerable discrepancy between the two methods used for estimations was apparent. These results demonstrate that both the net change and reduced-flow microdialysis techniques can produce reproducible and precise data. The results may constitute a basis for determining recoveries and, thus, true extracellular drug levels during in vivo microdialysis of MTX. This may be of importance in delineation of the relationship between tissue MTX levels and outcome in a variety of normally inaccessible compartments during cancer pharmacotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002800050403
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  • 5
    Electronic Resource
    Electronic Resource
    Continuous intratumoral microdialysis during high-dose methotrexate therapy in a patient with malignant fibrous histiocytoma of the femur: a case report (1996)
    Springer
    Cancer chemotherapy and pharmacology 39 (1996), S. 267-272 
    Details
    ISSN: 1432-0843
    Keywords: Key words Microdialysis ; Methotrexate ; Tumor ; 7-Hydroxymethotrexate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used a microdialysis technique to assay intratumoral methotrexate (MTX) levels during high-dose (12 g/m2 given as a 4-h infusion) therapy in a 43-year-old man with a malignant fibrous histiocytoma in the medial femoral condyle. Additional microdialysis probes were implanted in muscle tissue contralateral to the tumor and in an antecubital vein. Microdialysis was attempted during the initial two high-dose courses, but the two latter probes were removed at the start of the second treatment cycle due to leakage. No attempt to correct for microdialysis recovery was made. The intratumorally localized probe gave reproducible data on tumor MTX exposure of 9.3–14% of unbound systemic MTX. There was a close correlation between tumor and systemic levels for both MTX and its major extracellular metabolite 7-hydroxymethotrexate. Although limited to the study of MTX pharmacokinetics in a single subject, the experiment demonstrates that intratumoral microdialysis may provide data on tumor drug exposure, although of an indirect nature and dependent on the probe characteristics, the flow rate, and, possibly, the time after probe implantation. We propose that the application of microdialysis may prove useful for elucidation of the relationship between local drug exposure and the therapeutic response in normally inaccessible compartments during cancer pharmacotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002800050571
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  • 6
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of different doses of methotrexate at steady state by in situ microdialysis in a rat model (1995)
    Springer
    Cancer chemotherapy and pharmacology 36 (1995), S. 283-289 
    Details
    ISSN: 1432-0843
    Keywords: Key words Microdialysis ; Methotrexate ; Steady state ; Rat ; Tissues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used a microdialysis technique to monitor extracellular methotrexate (MTX) levels during the steady state in a rodent model. Microdialysis probes were implanted in the muscle, liver, and kidney of anesthetized male Wistar rats. MTX (18.75–500 mg/kg) was given as a continuous infusion through a venous catheter, and blood samples were obtained through a second venous catheter. Heparinized plasma, ultrafiltered plasma, microdialysis effluent from tissues, and tissue samples (obtained at the end of experiments) were analyzed for MTX content by high-performance liquid chromatography (HPLC). Steady state was demonstrated in the blood and tissues from 2 h until the end of the experiments (6 h). Extracellular drug levels in muscle and liver displayed a linear correlation with doses, whereas kidney levels reached a plateau at an MTX dose of 150 mg/kg per 6 h. Microdialysis-fluid endpoint levels for muscle, liver, and kidney were positively correlated to the endpoint total tissue levels (r 2=0.80, 0.85,  and 0.68, respectively). In the kidneys, the maximal relative tissue MTX accumulation was measured at a total dose of 75 mg/kg per 6 h. At higher doses, the relative drug sequestration declined to less than half of the values observed at this dose. This study demonstrates that the microdialysis technique can provide reproducible data on MTX tissue exposure in an animal model and that it offers a means of serial and reproducible monitoring of extracellular-tissue MTX levels at steady state and over a wide dose range. Pending additional studies, microdialysis may be a helpful technique for elucidating the kinetics of drug delivery to both targeted and toxicity-prone tissues during chemotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689044
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  • 7
    Electronic Resource
    Electronic Resource
    Surface lipids of social waspPolistes melricus say and its nest and nest pedicel and their relation to nestmate recognition (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 2229-2241 
    Details
    ISSN: 1573-1561
    Keywords: Polistes metricus ; Hymenoptera ; Vespidae ; social wasps ; cuticular hydrocarbons ; nestmate recognition ; nest pedicel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In eight replicate laboratory tests wherePolistes metricus adults were allowed to choose between their own nest, a second nest, and neither nest, they selected their own nest 66% of the observed time. When the surface hydrocarbons had been extracted from the nests, the wasps chose their own nest only 8% of the time, but after the hydrocarbons were reapplied to the surface of the respective nests, they selected their own nest 47% of the time. These changes are significant. The cuticular lipids were analyzed from individualP. metricus adult females collected from 13 colonies. Surface lipids were recovered from the paper and pedicels of their nests. Eighteen hydrocarbons were identified in these lipid fractions. The major components of the wasp cuticular lipids weren-heptacosane,n-nonacosane, methylhentriacontane, and methyltritriacontane. Factor analysis revealed that extracts of pedicels are all similar in composition, while cuticle and paper extracts vary, sometimes similarly according to colony identity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01026933
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  • 8
    Electronic Resource
    Electronic Resource
    Cuticular lipid profiles of queens, workers, and males of social waspPolistes metricus say are colony-specific (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 2307-2321 
    Details
    ISSN: 1573-1561
    Keywords: Polistes metricus ; Hymenoptera ; Vespidae ; cuticular hydrocarbons ; discriminant analysis ; nestmate recognition ; social wasps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The cuticular lipids ofPolistes metricus queens, workers and males from seven laboratory-maintained colonies were extracted and analyzed by combined gas chromatography-mass spectrometry. Males had higher proportions of alkenes (20.5%) in their cuticular lipids than did queens (2.3%) or workers (7.7%). Discriminant analyses of the cuticular lipid profiles of the adult wasps showed that males group separately from females. Additional analyses showed that queens group with their respective workers by colony and that queens group even more closely with males by colony. The most distinct groupings occurred with workers only by colony and with males only by colony. Stepwise discriminant analyses showed that each type of grouping was dependent upon a different combination of cuticular lipids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033205
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  • 9
    Electronic Resource
    Electronic Resource
    Discriminant analysis of cuticular hydrocarbons of social waspPolistes exclamans viereck and surface hydrocarbons of its nest paper and pedicel (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 785-797 
    Details
    ISSN: 1573-1561
    Keywords: Polistes exclamans ; Hymenoptera ; Vespidae ; cuticular hydrocarbons ; discriminant analysis ; nest pedicel ; nestmate recognition ; social wasps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The articular lipids were analyzed from individualPolistes exclamans workers collected from 10 nests. Surface lipids were also recovered from the paper and pedicels of these nests. Twenty-two hydrocarbons were identified in these lipid fractions. The major components of the wasp cuticular lipids weren-heptacosane,n-nonacosane, methylhentriacontane, and methyltritriacontane. Discriminant analysis of the hydrocarbon profiles of the adult wasps showed that the wasps group together according to their respective colonies. Several colonies from the same geographical location clustered more closely together than colonies from diverse locations. The nest papers and pedicels did not group with the wasps from their respective colonies, but the nest papers clustered together separately, as did the nest pedicels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00994615
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  • 10
    Electronic Resource
    Electronic Resource
    Cuticular hydrocarbons of the paper wasp,Polistes fuscatus: A search for recognition pheromones (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 1677-1687 
    Details
    ISSN: 1573-1561
    Keywords: Polistes fuscatus ; Hymenoptera ; Vespidae ; cuticular hydrocarbons ; discriminant function analysis ; nestmate recognition ; social wasps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The cuticular chemicals of 124 individual wasps (foundresses and workers) from 23 colonies ofPolistes fuscatus were analyzed. The compounds identified, all of which were hydrocarbons, were similar to those of other vespid wasps in that the bulk of the hydrocarbons were 23–33 carbons in chain length. However, the hydrocarbon profile ofP. fuscatus differed from those of its congeners in its proportions of straight-chain alkanes, methylalkanes, and alkenes. Three of the 20 identified hydrocarbons, 13- and 15-MeC31, 11,15- and 13,17-diMeC31, and 13-, 15-, and 17-MeC33, had properties postulated for recognition pheromones: colony specificity, efficacy in assigning wasps to the appropriate colony, heritability, lack of differences between foundresses and workers, and distinctive stereochemistry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02059889
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