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  • pharmacokinetics  (2,025)
  • Drosophila  (737)
  • Chemistry
  • Springer  (2,797)
  • Alliance for Coastal Technologies
  • 1
    Electronic Resource
    Electronic Resource
    Human Interindividual Variability in Parameters Related to Health Risks (1999)
    Springer
    Risk analysis 19 (1999), S. 711-726 
    Details
    ISSN: 1539-6924
    Keywords: variability ; exposure ; susceptibility ; risk assessment ; pharmacokinetics ; pharmacodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This paper reviews existing data on the variability in parameters relevant for health risk analyses. We cover both exposure-related parameters and parameters related to individual susceptibility to toxicity. The toxicity/susceptibility data base under construction is part of a longer term research effort to lay the groundwork for quantitative distributional analyses of non-cancer toxic risks. These data are broken down into a variety of parameter types that encompass different portions of the pathway from external exposure to the production of biological responses. The discrete steps in this pathway, as we now conceive them, are: •Contact Rate (Breathing rates per body weight; fish consumption per body weight) •Uptake or Absorption as a Fraction of Intake or Contact Rate •General Systemic Availability Net of First Pass Elimination and Dilution via Distribution Volume (e.g., initial blood concentration per mg/kg of uptake) •Systemic Elimination (half life or clearance) •Active Site Concentration per Systemic Blood or Plasma Concentration •Physiological Parameter Change per Active Site Concentration (expressed as the dose required to make a given percentage change in different people, or the dose required to achieve some proportion of an individual's maximum response to the drug or toxicant) •Functional Reserve Capacity–Change in Baseline Physiological Parameter Needed to Produce a Biological Response or Pass a Criterion of Abnormal Function Comparison of the amounts of variability observed for the different parameter types suggests that appreciable variability is associated with the final step in the process–differences among people in “functional reserve capacity.” This has the implication that relevant information for estimating effective toxic susceptibility distributions may be gleaned by direct studies of the population distributions of key physiological parameters in people that are not exposed to the environmental and occupational toxicants that are thought to perturb those parameters. This is illustrated with some recent observations of the population distributions of Low Density Lipoprotein Cholesterol from the second and third National Health and Nutrition Examination Surveys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007045922532
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  • 2
    Electronic Resource
    Electronic Resource
    Evaluation of the Uncertainty in an Oral Reference Dose for Methylmercury Due to Interindividual Variability in Pharmacokinetics (1999)
    Springer
    Risk analysis 19 (1999), S. 547-558 
    Details
    ISSN: 1539-6924
    Keywords: MeHg ; pharmacokinetics ; PBPK model ; variability ; risk assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract An analysis of the uncertainty in guidelines for the ingestion of methylmercury (MeHg) due to human pharmacokinetic variability was conducted using a physiologically based pharmacokinetic (PBPK) model that describes MeHg kinetics in the pregnant human and fetus. Two alternative derivations of an ingestion guideline for MeHg were considered: the U.S. Environmental Protection Agency reference dose (RfD) of 0.1 μg/kg/day derived from studies of an Iraqi grain poisoning episode, and the Agency for Toxic Substances and Disease Registry chronic oral minimal risk level (MRL) of 0.5 μg/kg/day based on studies of a fish-eating population in the Seychelles Islands. Calculation of an ingestion guideline for MeHg from either of these epidemiological studies requires calculation of a dose conversion factor (DCF) relating a hair mercury concentration to a chronic MeHg ingestion rate. To evaluate the uncertainty in this DCF across the population of U.S. women of child-bearing age, Monte Carlo analyses were performed in which distributions for each of the parameters in the PBPK model were randomly sampled 1000 times. The 1st and 5th percentiles of the resulting distribution of DCFs were a factor of 1.8 and 1.5 below the median, respectively. This estimate of variability is consistent with, but somewhat less than, previous analyses performed with empirical, one-compartment pharmacokinetic models. The use of a consistent factor in both guidelines of 1.5 for pharmacokinetic variability in the DCF, and keeping all other aspects of the derivations unchanged, would result in an RfD of 0.2 μg/kg/day and an MRL of 0.3 μg/kg/day.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007017116171
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  • 3
    Electronic Resource
    Electronic Resource
    Das Rückstandsverhalten von Chloramphenicol nach intramuskulärer Applikation beim Schwein (1985)
    Springer
    European journal of nutrition 24 (1985), S. 113-119 
    Details
    ISSN: 1436-6215
    Keywords: Chloramphenicol ; pharmacokinetics ; residue ; pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Residues of Chloramphenicol (CAP) were examined in 24 pigs after intramuscular injection of 30 mg CAP/kg body weight. Two pigs were slaughtered after 3, 6, 12,18, 24, 36 hours, 2, 3, 6, 10, 21 and 30 days, respectively. CAP-concentrations were determined in muscle, blood, urine, liver, kidney, bile, and fat. Methods used were gas-liquid chromatography and radioimmunoassay. Detection limits reached were 1−5 ppb. The concentration-time curves obtained reflected a long elimination phase and allowed only calculation of this half-life. Elimination half-life was estimated to be for muscle, blood and urine 160–170 hours, for kidney 310 and for bile 250 hours. Significant correlations were found to exist between CAP-concentrations in plasma and muscle. It appears that blood would be a good body fluid for monitoring CAP-residues in tissue.
    Notes: Zusammenfassung Zur Untersuchung des Rückstandsverhaltens von Chloramphenicol (CAP) wurden 24 Mastschweine, 24–28 Wochen alt, intramuskulär mit 30 mg CAP/kg Körpergewicht behandelt und je 2 Tiere nach 3, 6, 12, 18, 24, 36 Stunden, 2, 3, 6, 10, 21 und 30 Tagen geschlachtet. Die CAP-Gehalte in Muskulatur, Blut, Urin, Leber, Niere, Galle und Fett wurden gaschromatographisch und radioimmunologisch bestimmt. Die Nachweisgrenze beider Methoden liegt in Abhängigkeit von der Matrix zwischen 1 und 5 ppb. Die erhaltenen Kinetiken weisen eine terminale Elimination auf, deren Halbwertszeiten für Muskulatur, Blut und Urin ca. 160–170 Stunden, für Niere 310 Stunden und für Galle 250 Stunden betragen. Die CAP-Konzentration in Muskulatur und Blut weisen eine signifikante, lineare Korrelation auf. Blutuntersuchungen könnten deshalb als Screening-Methode bei umfangreichen Rückstandskontrollen eingesetzt werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02020458
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  • 4
    Electronic Resource
    Electronic Resource
    Enzymatic and pharmacokinetic studies on the metabolism of branched chain α-keto acids in the rat (1983)
    Springer
    European journal of nutrition 22 (1983), S. 14-26 
    Details
    ISSN: 1436-6215
    Keywords: branched chain α-keto acids ; 4-methyl-2-oxopentanoate, 3-methyl-2-oxopentanoate ; 3-methyl-2-oxobutyrate ; dehydrogenation ; transamination ; pharmacokinetics ; absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Michaelis-Konstanten und Aktivitäten von Dehydrogenasen und Transaminasen der drei verzweigten α-Ketosäuren Keto-Valin, Keto-Leucin und Keto-Isoleucin in Leber, Niere, Skeletmuskel und Gehirn von Ratten werden mitgeteilt. Nach oraler Zufuhr passieren nur 11–22% der Ketosäuren unverändert die Leber. Aus pharmakokinetischen und Resorptions-Untersuchungen erhaltene Blutspiegel an Ketosäuren werden zu den Michaelis-Konstanten in Beziehung gesetzt. Bei den geringen Konzentrationen an Ketosäuren nach oraler Zufuhr kann angenommen werden, daß die oxidativen Prozesse in den nichthepatischen Geweben über die Transaminierung überwiegen. Daten über die Wachstumseffizienz von verzweigtkettigen α-Ketosäuren im Vergleich zu den entsprechenden Aminosäuren stimmen mit dieser Vorstellung überein. Bei intravenöser Verabreichung müßten die Voraussetzungen für Transaminierung besser sein als nach oraler Zufuhr. Auf der Basis von Daten aus der Literatur werden die Übertragbarkeit unserer Befunde auf den Menschen und die verschiedenen Faktoren, welche die Effizienz der verzweigten α-Ketosäuren durch Einwirkung auf ihren Stoffwechsel beeinflussen können, diskutiert.
    Notes: Summary Miehaelis-constants and enzyme activities for dehydrogenation and transamination of the three branched chainα-keto acids in liver, kidney, skeletal muscle, and brain of rats are reported. After oral load only 11–22 % of the keto acids pass the liver unchanged. Blood levels in pharmacokinetic and absorption studies are related to the Michaelis-constants. At the low keto-acid concentrations after oral application, dehydrogenation in the non-hepatic tissues is supposed to prevail over transamination. Data on feed efficiency of branched chain α-keto acids reported in the literature support this view. The chance for transamination is better after intravenous administration. The transferability of our data to humans, and various factors influencing the efficiency of branched chain α-keto acids are discussed in connection with data reported in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02020781
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  • 5
    Electronic Resource
    Electronic Resource
    Genetic and phenotypic variation for flight ability in the cactophilicDrosophila species,D. aldrichi andD. buzzatii (1995)
    Springer
    Entomologia experimentalis et applicata 76 (1995), S. 25-35 
    Details
    ISSN: 1570-7458
    Keywords: dispersal ; flight duration ; cactophilic ; Drosophila ; age effects ; body size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The flight ability ofDrosophila aldrichi (Patterson & Crow) andD. buzzatii (Patterson & Wheeler) using tethered flights, was measured with respect to age-related changes, genetic variation and adult body size variation induced by rearing at different larval densities.Drosophila buzzatii flew for much longer thanD. aldrichi, especially females, but age-related changes in flight duration were significant only forD. aldrichi. Effects of body size on flight ability were significant inD. buzzatii, but not inD. aldrichi. InD. buzzatii, there was a significant genotype-environment interaction (larval density × line) for flight duration, with short and average flight duration isofemale lines showing longer flights, but a long flight duration line shorter flights as body size decreased (i.e., as larval density increased). Heritability estimates for flight duration were similar in the two species, but flight duration showed no significant genetic correlations with developmental time, body size or wing dimensions (except for one wing dimension inD. buzzatii). Although not significantly different between the species, heritabilities for life-history traits (adult size and developmental time) showed contrasting patterns — with higher heritability for body size (body weight and thorax length) inD. buzzatii, and higher for developmental time inD. aldrichi. In agreement with limited previous field evidence,D. buzzatii is better adapted for colonization than isD. aldrichi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382308
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  • 6
    Electronic Resource
    Electronic Resource
    Pre-exposure affects the olfactory response of Drosophila melanogaster to menthol (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 175-181 
    Details
    ISSN: 1570-7458
    Keywords: Olfactory response ; Drosophila ; menthol ; bioassay ; trap assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A modification of the trap assay (Woodard et al., 1989) was used to evaluate the response of Drosophila melanogaster (Meigen) to food media containing menthol. Dose-response curves for flies to mentholic foods were produced for flies that had been pre-exposed to menthol, during development and adult life, and flies that had not been exposed to menthol before the assay. Mentholic food media were less attractive to Drosophila than plain food medium. Rearing flies on a medium containing menthol reduced their aversion to some concentrations of menthol. The rearing effect was not simply due to lowered general activity levels resulting from developing in a medium containing menthol. There was a threshold concentration of menthol in the rearing medium below which we found no induced behavioural change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003509802181
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  • 7
    Electronic Resource
    Electronic Resource
    Environmental effects on cytoplasmic incompatibility and bacterial load in Wolbachia-infected Drosophila simulans (1998)
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 13-24 
    Details
    ISSN: 1570-7458
    Keywords: Drosophila ; cytoplasmic incompatibility ; Wolbachia ; temperature ; antibiotics ; density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of high temperatures, antibiotics, nutrition and larval density on cytoplasmic incompatibility caused by a Wolbachia infection were investigated in Drosophila simulans. Exposure of larvae from an infected stock to moderate doses of tetracycline led to complete incompatibility when treated females were crossed to infected males; the same doses only caused a partial restoration of compatibility when treated males were crossed to uninfected females. In crosses with treated females, there was a strong correlation between dose effects on hatch rates and infection levels in embryos produced by these females. Ageing and rearing males at a high temperature led to increased compatibility. However, exposing infected females to a high temperature did not influence their compatibility with infected males. Male temperature effects depended on conditions experienced at the larval stage but not the pupal stage. Exposure to 25 °C reduced the density of Wolbachia in embryos compared with a 19 °C treatment. Low levels of nutrition led to increased compatibility, but no effect of larval crowding was detected. These findings show the ways environmental factors can influence the expression of cytoplasmic incompatibility and suggest that environmental effects may be mediated by bacterial density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003043814761
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  • 8
    Electronic Resource
    Electronic Resource
    Conserving genetic variability of a wild insect population under laboratory conditions (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 233-239 
    Details
    ISSN: 1570-7458
    Keywords: inbreeding ; colonization ; isofemale line ; Drosophila ; Diptera ; Leptopilina boulardi ; Cynipidae ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé D. melanogaster (Meigen) a été utilisé pour tester la capacité des lignées isofemelles à conserver la variabilité génétique d'une population naturelle. Deux types d'expériences ont été réalisées. L'une a consisté à déterminer la variabilité génétique de 3 locus enzymatiques pour 32 lignées isofemelles à la première et à la 23ème génération d'élevage au laboratoire. L'autre a consisté à tester la capacité des larves à éliminer un parasitoïde par le processus d'encapsulation après 8 années d'élevage au laboratoire. D'une façon générale, certaines lignées isofemelles perdent de la variabilité durant les 23 générations de l'étude. Mais la fréquence globale des allèles reste inchangée si l'on considère l'ensemble des 32 lignées. Le seul allèle rare observé a également été conservé. Les modifications des fréquences allèliques à chacun des locus ont lieu de façon indépendante les unes des autres. La variabilité génétique d'un caractère biologique, la capacité des larves à encapsuler le parasitoïde, a également varié, mais elle a pu être restaurée à un niveau proche de la population initiale en rassemblant plusieurs individus de chacune des lignées.
    Notes: Abstract Drosophila melanogaster (Meigen) was used to test the power of isofemale lines in preserving genetic variability. We performed experiments in two ways. One series consisted of measuring the genetic variability for three enzymatic loci in 32 isofemale lines, in the first and 23rd generations of culture. In the second series, we tested the capacity of the larvae to eliminate a parasitoid by encapsulation after eight years of laboratory breeding. In general, individual isofemale lines appeared to change during the 23 generations of the study, but the global frequency of these alleles among the 32 isofemale lines stayed relatively unchanged. The only rare allele observed was also conserved. Changes in allozyme frequencies at any one locus were independent of those at other loci. Genetic variation of a biological trait, the capacity of the larvae to encapsulate a parasitoid, also changed, but it could be restored to a level close to that of the starting population by mass hybridizing together individuals of each line.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02383432
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  • 9
    Electronic Resource
    Electronic Resource
    Behavioural induction in Drosophila: timing and specificity (2000)
    Springer
    Entomologia experimentalis et applicata 94 (2000), S. 159-171 
    Details
    ISSN: 1570-7458
    Keywords: Drosophila ; induction ; habituation ; associative learning ; T-maze olfactometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments reported in this paper investigate the properties of a change in the responsiveness of adult Drosophila melanogaster induced by exposure to different rearing media. This effect has previously been described as habituation or associative learning. Exposure to food medium containing 0.08% menthol induced a positive response to menthol odour in a T-maze olfactometer. A brief (one hour) exposure to mentholic food just before testing was sufficient to induce a change in responsiveness. The effect did not persist through periods of more than an hour of separation from mentholic medium. Effects induced by exposure to a single compound were not specific to that compound alone. Menthol-reared flies (MRFs) differed from plain reared flies (PRFs) in their responsiveness to the odours of benzaldehyde and ethyl acetate, as well as menthol, and exposure to ethyl acetate induced a change in response to menthol odour. That there was an induced positive response to menthol in MRFs suggests that conventional habituation is insufficient to explain the induced change in responsiveness, but the generalised nature of this behavioural induction in MRFs is hard to explain in terms of associative learning. The mechanism underlying the induction remains elusive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003998715018
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  • 10
    Electronic Resource
    Electronic Resource
    Host Preference Among Populations of Drosophila mojavensis (Diptera: Drosophilidae) that Use Different Host Cacti (1998)
    Springer
    Journal of insect behavior 11 (1998), S. 691-712 
    Details
    ISSN: 1572-8889
    Keywords: cactus ; Drosophila ; geographic variation ; host preference behavior ; Sonoran Desert ; volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have suggested that all populations of cactophilic Drosophila mojavensis prefer pitaya agria cactus, Stenocereus gummosus, over all other potential hosts for feeding and breeding, including populations that inhabit areas where no agria grows. We sampled five geographically isolated populations of D. mojavensis from nature to assess host choice within and between populations. Host choice tests were performed in a laboratory “olfactometer” by allowing adult D. mojavensis to choose between plumes of synthetic volatile cocktails of two widespread host cacti. Overall, each population showed significant preference for agria volatiles with one exception: a mainland Sonora population that uses organ pipe cactus in nature exhibited preference for organ pipe volatiles, suggesting a possible shift in host preference. The degree of preference for agria volatiles was greatest in a population from southern California that use California barrel cactus as a host. Since southern Californian populations of D. mojavensis are thought to be derived from those in Baja California, preference for agria volatiles is considered a retained ancestral trait. Three populations from Baja California and mainland Mexico that use agria in the wild expressed lower, but similar preferences for agria volatiles. Because populations of D. mojavensis are ancestral to those in mainland Mexico, Arizona, and California, the shift from agria to alternate hosts has not been accompanied by strong changes in host preference behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022398809881
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