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  • Lepidoptera  (172)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 22 (1983), S. 185-194 
    ISSN: 1436-6215
    Keywords: sugar substitutes ; D-glucose ; bioavailability ; D-glucitol (D-sorbitol) ; D-mannitol ; Palatinit® ; D-glucosyl-α(1→1)-D-mannitol ; D-glucosyl-α(1→6)-D-glucitol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Zur Vertiefung des Verständnisses vom Stoffwechsel des Zuckeraustauschstoffes Palatinit® wurden seine zwei Bestandteile D-Glucosyl-α(1→1)-D-mannit und D-Glucosyl-α(1→6)-D-glucit [D-Glucosyl-α(1→6)-D-sorbit] nach dem Verfahren von Karimzadegan et al. auf ihre Glucose-Bioverfügbarkeit an ketotischen Ratten untersucht. Bei Umwandlungsraten in Glucose von 6 bzw. 20 % für Mannit und Glucit (Sorbit) sowie von 39 bzw. 42% für Glucosylmannit und Glucosylglucit erhält demnach der metabolische Glucose-Pool nicht das volle Glucose-Äquivalent aus diesen Verbindungen. Von dem Anteil an präformierter Glucose in den Glucosylhexiten — theoretisches Maximum 50 % — sind nur 36 % aus Glucosylmannit bzw. 32 % aus Glucosylglucit bioverfügbar. Die im Vergleich zur Theorie verminderte Bioverfügbarkeit von Glucose aus Palatinit® wird auf partiellen mikrobiellen Abbau in unteren Darmabschnitten zurückgeführt. Die an Ratten erhaltenen Ergebnisse werden auch für alle anderen Spezies gelten, welche in Caecum und/oder Colon Kohlenhydrate vergären. Die Unterschiede zwischen D-Glucosyl-α(1→1)-D-mannit und D-Glucosyl-α(1→6)-D-glucit werden durch unterschiedliche Verzögerung der Glucoseresorption im Dünndarm, wo auch D-Glucit angreift, bedingt. Die Ermittlung der Glucose-Bioverfügbarkeit gewährt weitgehende Einblicke in das Schicksal von Kohlenhydraten einschließlich der Symbiose zwischen Säugetier und Mikroorganismen im Dickdarm. Da ein ziemlich vollständiger Überblick über die metabolischen Konsequenzen nach ihrer Zufuhr erhalten wird, sollte das Verfahren zur Messung der Bioverfügbarkeit von Glucose daher bei Abschätzungen der Lebensmittelsicherheit anderer Zuckeraustauschstoffe ebenfalls angewandt werden.
    Notes: Summary For the sake of metabolic insight into the fate of the sugar substitute Palatinit®, its two components D-glucosyl-α(1→1)-D-mannitol and D-glucosyl-α(1→6)-D-glucitol [D-glucosyl-α-(1→6)-D-sorbitol] were assayed for glucose bioavailability by the procedure of Karimzadegan et al. using ketotic rats. With conversion rates into glucose of 6 and 20 %, respectively, for free mannitol and glucitol (sorbitol), 39 % for glucosylmannitol and 42 % for glucosylglucitol, the metabolic glucose pool of the rat does not receive the full carbohydrate complement of these compounds. The preformed glucose moiety of the glucosylhexitols is bioavailable by 36 and 32 %, respectively, from glucosylmannitol and glucosylglucitol, with 50 % as theoretical maximum. Less than theoretical bioavailability of glucose from Palatinit® is ascribed to microbial attack in the hindgut. The data on rats are held valid also for other species demonstrating carbohydrate fermentation in the caecum and/or colon. Differences between D-glucosyl-α(1→1)-D-mannitol and D-glucosyl-α(1→6)-D-glucitol are caused by a differential delay of glucose absorption in the small intestine, also exerted by D-glucitol. The deep metabolic insight offered by the glucose bioavailability assay into the fate of carbohydrates includes the mammal-microbial symbiosis in the large bowel. Since a rather complete survey of the metabolic consequences after their intake can be obtained, the assay system should be generally applied in assessments of food safety also of other sugar substitutes.
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  • 2
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    Springer
    Colloid & polymer science 261 (1983), S. 188-189 
    ISSN: 1435-1536
    Keywords: Polymerization ; kinetics ; redox polymerization ; acrylamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 3
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    Springer
    Colloid & polymer science 262 (1984), S. 366-373 
    ISSN: 1435-1536
    Keywords: kinetics ; isothermal crystallization ; polymer ; spherulite ; differential scanning calorimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In the DSC technique, isothermal crystallization experiments are usually performed on thin flat specimens, but their interpretation generally uses theories developed for an unbounded volume. In this paper, isothermal crystallization of spherical entities in the volume limited by two parallel infinite planes is considered. Our model, derived from Avrami's theory, gives an analytical expression for the transformed volume fraction as a function of time. It is shown that the influence of thickness becomes important when thickness becomes of the order of or smaller than the average spherulite radius. The main effects of a decreasing thickness are a slower crystallization kinetics and a decrease in the Avrami exponent. These results can be used to interpret experimental data obtained in isothermal polymer crystallization.
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  • 4
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    Colloid & polymer science 261 (1983), S. 621-625 
    ISSN: 1435-1536
    Keywords: Polyamide 6 ; crystallisation ; kinetics ; titania
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The kinetics of isothermal and nonisothermal crystallization of polyamide-6 (PA6) containing titania was studied by means of DSC. It was found thatTiO 2 causes an acceleration in the crystallization of polyamide-6 and lowers the value of the Avrami exponent,n. The presence of TiO2 does not affect equilibrium melting pointT m 0 , glass temperatureT g, or surface free energiesσ e andσ of the basal and lateral surfaces.
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  • 5
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; reproduction ; tebufenozide ; methoxyfenozide ; ecdysone agonist ; Argyrotaenia velutinana ; Choristoneura rosaceana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects on the fecundity and fertility of redbanded leafroller, Argyrotaenia velutinana (Walker), and obliquebanded leafroller,Choristoneura rosaceana (Harris), exposed as adults to surfaces treated with the ecdysone agonists tebufenozide (RH-5992) and methoxyfenozide (RH-2485) were examined. The first part of the study consisted of recently emerged moths being exposed to treated surfaces continuously throughout their lives (including mating and oviposition). Continuous exposure to tebufenozide- or methoxyfenozide-treated surfaces significantly reduced the mean number of eggs laid and the percent of eggs that hatched in both species. The second part of the study involved exposure of recently emerged virgin moths (by sex) to treated surfaces for 24 h, after which, the exposed moths were paired with a nontreated partner to mate and oviposit on nontreated surfaces. In this experiment, for A. velutinana, significant reductions in fecundity occurred only when the female was exposed to methoxyfenozide-treated surfaces. Significant reductions in A. velutinana egg fertility occurred with both male and female exposure in the methoxyfenozide treatments and only female exposure in the tebufenozide treatments. For C. rosaceana, significant reductions in fecundity occurred with both male and female exposure in the tebufenozide and methoxyfenozide treatments. Significant reductions in C. rosaceana egg fertility occurred with both male and female exposure in the tebufenozide treatments and only with female exposure in the methoxyfenozide treatments.
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  • 6
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    Entomologia experimentalis et applicata 95 (2000), S. 217-227 
    ISSN: 1570-7458
    Keywords: antifeedant ; drimane ; mechanism of action ; sensory response ; toxicity ; habituation ; behavioural observation ; structure-activity relationship ; Pieris brassicae ; Lepidoptera ; Pieridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We tested 11 analogous synthetic drimane antifeedant compounds for their feeding inhibiting effects on larvae of the large white butterfly Pieris brassicae L. (Lepidoptera: Pieridae) in no-choice tests on the host plant Brassica oleracea L. Furthermore, we observed larval feeding behaviour in no-choice tests to analyze temporal effects of five drimanes. The results show that the five analogous antifeedants differentially influence feeding behaviour and locomotion activity. Warburganal and polygodial are most likely sensory mediated antifeedants. Habituation to these compounds occurs soon after the onset of the tests (i.e., within 0.5–1.5 h). Compound 5 and confertifolin are probably not direct, sensory mediated antifeedants. After 0.5–1.5 h of exposure, these compounds inhibit not only feeding, but also locomotion behaviour, indicating postingestive, toxic effects. Isodrimenin inhibits feeding from the onset of the test and is probably a sensory mediated antifeedant. No habituation occurs to this compound, indicating that isodrimenin is either a very strong antifeedant or that it additionally has postingestive, toxic effects. Topical application of the drimanes on the larval cuticle revealed feeding inhibiting effects, but these could not be related to the occurrence of postingestive feeding inhibiting effects, indicating that this method is inappropriate to show possible postingestive effects of drimanes in P. brassicae. In conclusion, the behavioural observations performed in this research indicate that analogous drimanes inhibit feeding by P. brassicae larvae through multiple mechanisms of action. The results show that, when developing a structure activity relationship (SAR) for a series of antifeedants, it is important to distinguish the mode of action which underlies inhibition of feeding.
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  • 7
    ISSN: 1570-7458
    Keywords: Cnaphalocrocis medinalis ; rice leaffolder ; Lepidoptera ; Pyralidae ; sex pheromone ; geographical variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sex pheromone components of the Japanese rice leaffolder moth, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) were identified from ovipositor extracts of virgin females as (Z)-11-octadecenal, (Z)-13-octadecenal, (Z)-11-octadecen-1-ol and (Z)-13-octadecen-1-ol at a ratio of 11:100:24:36 by GC-EAD, GC, GC-MS. The total amount was estimated to be ca.0.9 ng/female. Field bioassays in Kagoshima, Japan, showed that the two aldehydes are essential for male attraction and the alcohols may have a synergistic effect on the aldehydes. A rubber septum containing 0.9 mg of the four components at the natural ratio was shown to be an effective lure for monitoring this pest in Japan. The above four components are quite different from the sex pheromone components reported previously for the same species of either Philippine or Indian origin; components were shown to be (Z)-11-hexadecenyl acetate and (Z)-13-octadecenyl acetate at a ratio of 98:2 in the Philippine blend and 1:10 in the Indian blend. Furthermore, in the field tests in Japan, neither the Philippine blend nor the Indian blend showed any attractive activity, while the Japanese blend attracted significant numbers of male moths. These results suggest that there are remarkable geographical variations in the sex pheromone composition of this species or there are several distinct species using different sex pheromone blends.
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  • 8
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    Entomologia experimentalis et applicata 97 (2000), S. 137-147 
    ISSN: 1570-7458
    Keywords: Etiella zinckenella ; Etiella hobsoni ; Lepidoptera ; Pyralidae ; soybean ; development ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments conducted in West Java, Indonesia investigated the developmental biology and reproductive behavior of two sympatric soybean pod borers, Etiella zinckenella Treitschke and E. hobsoni Butler (Lepidoptera: Pyralidae). It was determined that: (1) significant interspecific differences occurred between the egg, larval, pupal and total egg-to-adult developmental periods of laboratory raised E. zinckenella and E. hobsoni; (2) the pre-pupal and total egg-to-adult development periods of female E. zinckenella were significantly shorter than for males; (3) the longevity of virgin female E. zinckenella was significantly longer than that of virgin males, or virgin male and female E. hobsoni; (4) interspecific differences occurred in the female: male sex-ratios of laboratory raised adults; (5) peak mating for both species occurred on the second night after eclosion; (6) interspecific differences occurred in the temporal distribution of calling and mating behaviors; (7) repeated mating was observed for both species at a very low frequency; (8) interspecific mating did not occur; (9) female E. zinckenella were significantly more fecund than E. hobsoni; (10) the duration in copulo of E. zinckenella was significantly longer than that of E. hobsoni; and (11) wingtraps baited with virgin females caught only conspecific males, and reduced numbers of males were captured in traps simultaneously baited with virgin females of both species. This study demonstrates distinct biological differences and reproductive isolation between the two Etiella spp.
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  • 9
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    Fire technology 20 (1984), S. 47-63 
    ISSN: 1572-8099
    Keywords: Extinguishment ; fire modeling ; mass loss ; heat release ; char ; reflash ; sprinklers ; radiant flux ; kinetics ; reaction rate ; heat loss ; ash ; latent heat ; spray density ; extinguishing agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract The Ad Hoc Mathematical Fire Modeling Working Group was organized about seven years ago to facilitate voluntary cooperation and coordination in developing mathematical fire modeling capability. The group has a steering committee of representatives of agencies that support fire modeling and related research. These include the National Bureau of Standards' Center for Fire Research, Factory Mutual Research Corp., the Naval Research Laboratory, NASA, and the Federal Aviation Agency. The Group holds plenary meetings when it seems desirable to do so (about once each 1 1/2 years), and workshops on topical subjects. Three workshops were held in 1983. Normally, Group meetings are held before or after other meetings at which a number of interested personnel would likely be present. Minutes are mailed to those who attended and to others (including European and Japanese personnel) who have indicated interest. This workshop was arranged by Ron Alpert of Factory Mutual Research Corp. and held at their facilities at Norwood, MA, in November 1983.
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  • 10
    ISSN: 1570-7458
    Keywords: calling behaviour ; periodicity ; sex pheromone ; attraction inhibitor ; attraction synergist ; field tests ; Lepidoptera ; Gracillariidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Females of the leaf miner moth Phyllonorycter acerifoliella (Z.) [=Ph. sylvella (Hw.)] and Ph. heegerella (Z.) (Lepidoptera: Gracillariidae: Lithocolletinae) release their sex pheromone at the beginning of photophase. The periodicity of the `calling' behaviour of Ph. acerifoliella females was established. Three compounds from calling virgin Ph. heegerella females were collected by the Solid Phase Micro Extraction (SPME) technique and identified as (Z)-8-tetradecenyl acetate (Z8-14:OAc), tetradecyl acetate (14:OAc) and (Z)-8-tetradecenol (Z8-14:OH) in the ratio (88±3):(2±0.6):(10±5) by capillary gas chromatography and mass spectrometry. Field trapping experiments demonstrated that the first two compounds are important for the attraction of conspecific males. Z8-14:OAc was found to be attractive when tested separately, while 14:OAc acted as synergist. The attractivity of the three component blend was reduced by 10% admixture of either (E)-10-dodecenyl acetate (E10-12:OAc) or (Z)-10-tetradecenyl acetate (Z10-14:OAc). Field tests of Z10-, Z8- and E10-14:OAc, identified from Ph. acerifoliella females, demonstrated that the first two compounds were essential for the attraction of conspecific males; so both are sex pheromone components. The attractivity of the three component blend of Z10- Z8- and E10-14:OAc was reduced by 10% admixture of (E)-10-dodecenol (E10-12:OH). The following four semiochemical compounds, Z8-14:OAc, Z8-14:OH, E10-14:OAc and 14:OAc, identified from phyllonoryctid females, as well as two sex attraction antagonists for Ph. acerifoliella and Ph. heegerella males, E10-12:OAc and Z10-14:OAc, are new for the family Gracillariidae. The results of field trapping experiments revealed mechanisms ensuring the specificity of the chemocommunication systems in Ph. acerifoliella, Ph. heegerella and Ph. ulmifoliella (Hb.) moths.
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  • 11
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    Entomologia experimentalis et applicata 97 (2000), S. 339-346 
    ISSN: 1570-7458
    Keywords: crygenes ; PCR ; Lepidoptera ; Spodoptera ; insecticidal activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thirty-five strains of the entomopathogenic bacterium Bacillus thuringiensisactive on Spodoptera exigua, were characterized by means of serological identification and determination of crygene contents by PCR. The insecticidal activity of these 35 strains was further confirmed against S. exiguaand tested against two other species of the same genus: S. littoralisand S. frugiperda. The results indicate that serovars aizawai, thuringiensis, and kurstakiwere the most frequent within S. exigua-active strains and that serovar aizawaihad the highest number of strains exhibiting toxicity against the three species bioassayed. The presence in crygenes as determined by PCR suggests a non random distribution of some crygenes among serovars. Genes cry1C, cry1D, and cry1E, which are known to code for proteins toxic against Spodopteraspecies, were very common within S. exigua-active strains, specially in those belonging to serovar aizawai. However, some strains harbouring one or more of these genes were not toxic to S. littoralisor S. frugiperda; and some strains lacking all of the Spodoptera-active genes were found to be toxic to all three species. This suggests differences in the expression levels among strains bearing toxic genes and the involvement of other genes toxic to Spodopteraspecies. Since strains sharing the same crygenes exhibited different host ranges, the results indicate the need to perform toxicity bioassays in addition to other tests (serological identification and PCR) in order to determine the insecticidal activity of B. thuringiensisstrains.
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  • 12
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    Journal of solution chemistry 11 (1982), S. 339-346 
    ISSN: 1572-8927
    Keywords: Carbon dioxide ; hydrolysis ; aqueous solution ; kinetics ; activation volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pressure dependence of the dehydration reaction of H2CO3 was measured in acidic aqueous solution for pressures up to 1 kbar using a high-pressure stopped-flow instrument. The corresponding volume of activation was found to be 6.4±0.4 cm3-mol−1 at 25°C and 0.5 ionic strength. Volume equation calculations result in a value of −9.9±1.9cm3-mol−1 for the volume of activation for the hydrolysis of CO2 under the same conditions. For the first time, the reaction mechanism can be interpreted in terms of dissociative and associative modes, respectively. These data are used to construct an overall reaction volume profile.
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  • 13
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    Journal of insect behavior 13 (2000), S. 881-900 
    ISSN: 1572-8889
    Keywords: three-dimensional ; flight track recording ; orientation ; pheromones ; plant volatiles ; image analysis ; real time ; Lobesia botrana ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A computer-controlled video system for real-time recording of insect flight in three dimensions is described. The flight paths of moths were recorded in a flight tunnel using two CCD cameras placed adjacent to each other at angles of 45 and 135° to the flight tunnel axis and separated by a distance of 120 cm. They were connected to two 28-level gray-scale frame grabbers via two external synchronizers. The two-dimensional coordinates of the flying insect were obtained from the two cameras at 40-ms intervals and transferred to host computer for processing and monitor for real-time display. Due to speed limitation in the image acquisition hardware, construction of the three-dimensional file was carried off-line. The flying insect was rendered as a dark spot in a bright background using a homogeneous light source. As the insect enters into the field of view of the two cameras, the light distribution changes, and the frame grabber detects only those variation in the light distribution which results from a flying insect. The target insect can be as small as 3 pixels and can be tracked in a stereoscopic field of view 60 cm long and 50 cm high. A method was developed that allowed for scalar scoring of various pheromone sources to assess their attractiveness using vector flight parameters. This method was applied successfully for optimization of pheromone blend of the grapevine moth, Lobesia botrana.
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  • 14
    ISSN: 1572-8927
    Keywords: Temperature jump ; kinetics ; thermodynamics ; TRIS ; iminodiacetic acid ; magnesium ion ; phenol red
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Equations describing the temperature jump amplitudes associated with a system of two coupled reactions (TRIS-phenol red) as well as the ternary system (Mg2+-iminodiacetic acid-phenol red) are presented. The termodynamic parameters calculated from experimentally measured temperature perturbation amplitudes using a multiparametric curve fitting procedure are found to be in good agreement with those determined from pH- and costant rate thermometric titrations. For phenol red, pK I =7.55, ΔH I =3.45 kcal, and for Mg2+ iminodiacetic acid, log K M =2.84, ΔH M =3.25 kcal, were obtained. It is shown that this method can be used to determine accurate thermodynamic enthalpy changes over a narrow temperature interval of less than 1.0°C from a single experiment requiring about 50 μl of sample solution.
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  • 15
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    Journal of solution chemistry 12 (1983), S. 771-781 
    ISSN: 1572-8927
    Keywords: Ultrasonics ; kinetics ; aqueous solution ; iso-butyl cellosolve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ultrasonic absorption and velocity measurements in aqueous solution of iso-butyl cellosolve (ethylene glycol iso-butyl ether) as a function of the concentration are reported. The two relaxational absorptions have been attributed to the perturbation of the equilibria expressed by AB⇌A+B and Aα(1/n)An where A is the solute, B is the solvent, AB is the complex and A n is the solute aggregate. The rate constants for each step have been determined. From the concentration dependence of the maximum excess absorption per wave length, the enthalpy change and the volume change for the reaction between the solute and the solvent have been determined for aqueous solutions of butyl cellosolve (ethylene glycol n-butyl ether), iso-butyl cellosolve and propyl cellosolve (ethylene glycol n-propyl ether). The results are consistent with a hydrogen bonding reaction. The effect of the ethers on water structure are considered and it is clear that the fraction of water molecules which can hydrogen bond to the solute decreases with the increasing hydrophobicity of the solute.
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  • 16
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    BioMetals 13 (2000), S. 29-35 
    ISSN: 1572-8773
    Keywords: bioavailability ; inflammation ; iron ; malabsorption ; rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Inflammatory conditions of the gastrointestinal tract and iron-deficiency anemia are very common in humans. Acute intestinal inflammation was pathologically established in rats by intraluminal administration of acetic acid into the duodenum and the proximal jejunum. The study included two control groups of intact (untreated) rats and sham-operated (saline-treated) rats for each intestinal segment. A third group of rats received acetic acid. The acetic acid-induced inflammatory process was established histopathologically and biochemically. Two days after treatment, iron absorption was measured using ligated 10-cm loops of proximal jejunum or ligated duodenum in which 59Fe was injected intraluminally (n=6 in each group). In another four control groups (intact and sham-operated for each intestinal segment) and two acetic acid-treated groups, serosal-luminal secretion of 59Fe was measured after intravenous injection (n=5 in each group). 59Fe transfer from the lumens of the duodenum and jejunum to the portal system was significantly lower in those rats in whom inflammation was induced by acetic acid. There was no apparent serosal-luminal secretion of intravenously injected 59Fe in any of the studied groups. We conclude that acetic acid-induced intestinal inflammation significantly reduces iron absorption by the duodenum and the proximal jejunum.
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  • 17
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    Adsorption 6 (2000), S. 137-147 
    ISSN: 1572-8757
    Keywords: adsorption ; kinetics ; linear driving force model ; process design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The Linear Driving Force (LDF) model for gas adsorption kinetics is frequently and successfully used for analysis of adsorption column dynamic data and for adsorptive process designs because it is simple, analytic, and physically consistent. Yet, there is a substantial difference in the characteristics of isothermal batch uptake curves on adsorbent particles by the LDF and the more rigorous Fickian Diffusion (FD) model. It is demonstrated by using simple model systems that the characteristics of the adsorption kinetics at the single pore or the adsorbent particle level are lost in (a) evaluating overall uptake on a heterogeneous porous solid, (b) calculating breakthrough curves from a packed adsorbent column, and (c) establishing the efficiency of separation by an adsorptive process due to repeated averaging of the base kinetic property. That is why the LDF model works in practice.
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  • 18
    ISSN: 1572-879X
    Keywords: ammonia synthesis ; kinetics ; ruthenium catalysts ; promotional effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of NH3 synthesis over carbon-based ruthenium catalysts promoted with barium or alkali was studied. Both the ammonia partial pressure dependencies of the reaction rates (T = 400°C, p = 63 bar, H2 : N2 = 3 : 1) and the pressure variations of the activity (T = 370°C, p= 4–63 bar, H2 : NN2 = 3 : 1) were found to be different for Ba and for the alkali (K, Cs). Ba–Ru/C proved to be more sensitive to the NH3 content and to the total pressure. The rate of synthesis over the alkali-promoted catalysts is, in turn, much stronger influenced by the ruthenium dispersion. TOFs of NH3 synthesis for the promoted samples at 370°C and 4 bar (Ba 0.085 1/s, Cs 0.05 1/s, K 0.035 1/s) are significantly higher than that for the Ru(0001) basal plane (0.0085 1/s results from the literature data at 370°C, 2 bar). The most active Ru/C samples (Ba or Cs) exceed significantly the fused iron catalyst, especially at high conversions.
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  • 19
    ISSN: 1572-8927
    Keywords: Enthalpies of reaction ; heats of reaction ; kinetics ; ester hydrolysis ; microcalorimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The conditions under which the Picker flow microcalorimeter can be used to measure enthalpies and rates of reactions were investigated. For this purpose, systematic studies were made of the enthalpies of neutralization of HCl, HBr, HNO 3 , acetic, proprionic, and butyric acids with NaOH, enthalpies of hydrolysis of methyl and ethyl acetate with NaOH, and the reaction rates of the ester hydrolysis with NaOH. The general procedure and various sources of error are discussed and it is concluded that enthalpies of slow reactions can be measured to about 1% when the calorimeter is operated in the quasi-isothermal mode and the reaction rates to about 3% when operated in the quasi-adiabatic mode.
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  • 20
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    Topics in catalysis 11-12 (2000), S. 327-333 
    ISSN: 1572-9028
    Keywords: hydrodenitrogenation ; toluidine ; methylcyclohexylamine ; kinetics ; nickel-promoted molybdenum sulphide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The hydrodenitrogenation (HDN) of o-toluidine and its reaction intermediates was studied over a NiMo/γ-Al2O3 catalyst. The kinetics of the HDN of methylcyclohexylamine and of the hydrogenation of cyclohexene were also studied. Hydrogenation of o-toluidine alone produces methylcyclohexene and methylcyclohexane. When a sufficient quantity of cyclohexene is added during the HDN of toluidine, methylcyclohexylamine, the first intermediate in the hydrogenation of toluidine, becomes detectable. Because of its strong adsorption constant and high rate constant for reacting further to methylcyclohexene and methylcyclohexane, methylcyclohexylamine is not observed in the HDN of toluidine. Adding cyclohexene decreases the adsorption of methylcyclohexylamine, thus enabling its detection. The rate and adsorption constants of methylcyclohexylamine and cyclohexene in the HDN of methylcyclohexylamine were calculated by fitting the kinetic data to a Langmuir–Hinshelwood equation. A two-site model was used to describe the surface reactions, with one site for the methylcyclohexylamine reactions and the other for the cyclohexene reaction.
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  • 21
    ISSN: 1570-7458
    Keywords: host-plant relations ; host variation ; Malacosoma americanum ; Malacosoma disstria ; Lasiocampidae ; Geometridae ; Lepidoptera ; niche breadth ; specialization ; plantinsect interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Raupen von Malacosoma americanum (F.), einer oligophagen Art, die sich vor allem auf Prunus und andern baumartigen Rosaceen entwickelt, wurden verglichen mit Raupen der polyphageren Verwandten M. disstria Hb. und zwar im Hinblick auf deren Empfindlichkeit auf Unterschiede im Blatt ihrer gemeinsamen Wirtspflanze, Prunus serotina Ehrh. Das Puppengewicht und die Entwicklungszeit bis zur Verpuppung wurden gemessen bei Raupen, welche auf Blättern von freiwachsenden und von beschatteten Jungpflanzen gezüchtet worden waren. Die Blattunterschiede hatten eine ausgesprochene Wirkung, aber es gab keine Unterschiede in der Reaktion der beiden Arten. Dieser Vergleich lässt vermuten, dass die Empfindlichkeit auf intraspezifische Unterschiede der Wirtspflanzenqualität bei wirtsspezifischen und polyphagen Arten gleich ist. Indessen dürften sich laut anderen Resultaten einige Insektenarten anders verhalten.
    Notes: Abstract Larvae of Malacosoma americanum (F.)(Lepidoptera: Lasiocampidae) an oligophagous species that feeds primarily on Prunus and other rosaceous trees, were compared to larvae of the more highly polyphagous congener M. disstria Hb., with respect to their sensitivity to variation in the foliage of a common host plant, Prunus serotina Ehrh. Pupal weight and time to pupation were measured on larvae reared on foliage from open-grown and from shaded saplings. The difference in foliage had a pronounced effect, but no difference was evident between the species in their response to the variation in foliage. This comparison implies that sensitivity to intraspecific variation in host quality does not differ between host-specific and generalized species. However, results from other species suggest that some species of insects do differ in this respect.
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  • 22
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    Entomologia experimentalis et applicata 30 (1981), S. 106-110 
    ISSN: 1570-7458
    Keywords: assimilation efficiency ; growth efficiency ; niche breadth ; specialization ; hostplant relations ; plant-insect interactions ; Malacosoma americanum ; Malacosoma disstria ; Lasiocampidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Raupen von Malacosoma americanum, einer oligophagen Art, die sich vor allem auf Prunus und andern baumartigen Rosaceen. entwickelt, wurden mit Raupen der polyphageren Verwandten M. disstria in Hinblick auf die Verwertung der Blätter ihres gemeinsames Wirtes Prunus serotina verglichen. Wirerhielten ähnliche Werte wie sie früher für andere Lepidopteren publiziert worden waren und zwar in Bezug auf die üblichen Messwerte, Anteil verwertete Nahrung, Wachstum in Trockengewicht pro Einheit gefressene oder verwertete Nahrung. Zudem unterschieden sich die beiden Arten in keiner Masszahl für Effizienz. Unsere Resultate sind im Einklang mit der Folgerung, das spezialisierte phytophage Insekten ihre Wirtspflanzen nicht besser ausnützen als as polyphage Arten tun.
    Notes: Abstract Larvae of Malacosoma americanum (F.) an oligophagous species that feeds primarily on Prunus and other rosaceous trees, were compared to larvae of the more highly polyphagous congener M. disstria Hb., with respect to the efficiency of utilization of the foliage of a common host plant, Prunus serotina Ehrh. We obtained values similar to those reported for other Lepidoptera for the commonly used measures of the fraction of ingested food that was assimilated, and for the growth in dry weight per unit of food ingested or assimilated. Moreover, the two species did not differ in any measure of efficiency. Our results are compatible with the conclusion that specialized phytophagous insects do not use their host plants with greater physiological efficiency than do generalized insects.
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  • 23
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    Entomologia experimentalis et applicata 34 (1983), S. 174-178 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; Maruca testulalis ; Pod borer ; Development ; Nutritional suitability ; Host plant ; Crotalaria ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les possibilités de développement larvaire de Maruca testulalis sur les fleurs de huit espèces végétales ont été examinées en laboratoire. La comparaison a porté sur Crotalaria retusa, C. juncea, C. saltiana, C. misereniensis, C. mucronata, C. amazonas, Cajanus cajan et l'hôte principal de cette chenille, Vigna unguiculata. En tenant compte de la mortalité larvaire et des indices de croissance (G.I.), ces plantes ont été divisées en trois catégories principales: 1 celles provoquant une mortalité larvaire de 0–30% et ayant des G.I. ≥60%, constituent les plantes hôtes convenables (Vigna unguiculata seule); 2 les plantes qui provoquent une mortalité larvaire de 30≤50% et ont des G.I. de 30 à 60% de la plante hôte principale (Cajanus cajan, Crotalaria amazonas, C. saltiana, C. mucronata; 3 les plantes qui causent 50–100% de mortalité larvaire et dont les G.I. sont inférieurs à 30% de la plante hôte principale (Crotalaria retusa, C. juncea, C. misereniensis). Les résultats déjà publiés sur les choix du lieu de ponte des femelles et l'utilisation de C. juncea comme plante piège, sont discutés à la lumière de ces données nouvelles.
    Notes: Abstract Flowers of eight plant species were evaluated under laboratory conditions for their suitability as larval growth media for the cowpea pod borer, Maruca testulalis. The plants tested were Crotalaria retusa, C. juncea, C. saltiana, C. misereniensis, C. amazonas, Cajanus cajan and the principal host of the borer, Vigna unguiculata (cowpea), was included for comparison. Based on the data obtained on larval mortality and growth indices (GI) the plants were divided into 3 categories namely: I: Those causing 0–30% mortality and having GI value ≥60% form suitable host plants. This group only included V. unguiculata. — II: Those plant species causing 30≤50% larval mortality and having GI value 30%≤60% of the principal host plant (Cajanus cajan, Crotalaria amazonas, C. saltiana, C. mucronata). This group of species is marginally suitable as hosts. — III: Plants causing 50–100% larval mortality and having GI value ≤30% of principal host plant (C. retusa, C. juncea and C. misereniensis). Previously published data on the oviposition preference of the adult moth are discussed in the light of the present findings and the use of C. juncea as a possible trap crop.
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    Entomologia experimentalis et applicata 34 (1983), S. 203-205 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Sesiidae ; Synanthedon vespiformis ; Paranthrene tabaniformis ; Chamaesphecia empiformis ; Chamaesphecia tenthrediniformis ; Attractants ; Pheromones ; Clearwing moths ; Nemapogon
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  • 25
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    Entomologia experimentalis et applicata 30 (1981), S. 280-292 
    ISSN: 1570-7458
    Keywords: Allozyme variation ; Lepidoptera ; Yponomeuta padellus ; evolutionary stages ; F-statistics ; panmixis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le degré de différenciation génétique en allozymes à des niveaux divers de divergence évolutive (populations conspécifiques, sibling species et non-sibling species) d'Yponomeuta a été déterminé. Les distances génétiques entre des sibling species ou des non-sibling species sont très larges. Il en est conclu que de telles estimations ne fournissent pas beaucoup d'informations sur le phénomène de spéciation même. Des coéfficients de reproduction consanguine (F ST) ont été calculés pour des populations d'Y. padellus provenant de six plantes-hôtes. La valeur moyenne F STest .030±.012. Les valuers de F ST des populations recueillies sur Crataegus, (plante-hôte habituelle d'Y. padellus), sont inférieures 2–3.5 fois à celles des populations de l'ensemble des autres plantes-hôtes. L'apparition de races en fonction de l'hôte, mesurée par les différences importantes dans de fréquences des allozymes entre populations sympatriques sur plusieurs plantes-hôtes, a été examinée dans quatre régions. Il apparaît ainsi que la formation de races en fonction de l'hôte se produit chez Y. padellus et que la spéciation sympatrique est un évènement très vraisemblable.
    Notes: Abstract The amount of genetic differentiation at various levels of evolutionary divergence (conspecific populations, sibling species and non-sibling species) in Yponomeuta was determined. Genetic distances between siblings or non-siblings were found to cover a wide range. It is concluded that such estimates do not give much information on the speciation process itself. Inbreeding coefficients were calculated for populations of Y. padellus from a total of six host plants. The grand mean F ST value is 0.030±0.012. F ST values for populations sampled from Crataegus, the common food plant of Y. padellus, are 2–3.5 times smaller than those for populations from the other food plants taken together. Host race formation, as measured by significant differences in allozyme frequencies between sympatric populations on two or more food plants, was investigated in four areas. Host race formation seems to occur in Y. padellus and sympatric speciation is a likely event.
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  • 26
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    Entomologia experimentalis et applicata 34 (1983), S. 20-26 
    ISSN: 1570-7458
    Keywords: Dioryctria abietella ; Cone pyralid ; Lepidoptera ; Pyralidae ; Sex pheromone, (Z,E)-9,11-tetradecadienyl acetate ; Single sensillum recordings ; Electroantennography ; Gas chromatography ; Mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'analyse en chromatographie gazeuse associée à une détection électroantennographique a montré que l'acétate (Z,E)-9,11-tétradécadiényle (Z,E)-9,11–14:Ac est l'un des composants de la phéromone de Dioryctria abietella Schiff (Lepid.: Pyralidae). Couplage chromatographie en phase gazeuse spectrometrie de masse a montré la présence d'acétate tétradécadiényle avec un spectre de masse et un indice de rétention identiques au Z,E-9,11–14:Ac Un récepteur cellulaire sensible à la fois au Z,E-9,11–14:Ac et à un extrait de la femelle a été identifié sous l'antenne du mâle. Les analyses des antennogrammes et de la cellule isolée ont étayé la caractérisation du composant de la phéromone comme étant Z,E-9,11–14:Ac. Un récepteur cellulaire additionnel sensible à l'acétate (Z.)-9-tétradécadiényle et à l'acétate (Z.E.)-9,12-tétradécadiényle a été trouvé sur l'antenne du mâle, mais il n'était pas activé par l'extrait de la femelle. Sur le terrain Z,E-9,11–14:Ac, présenté seul, attirait des nombres importants de mâles de D. abietella. L'addition de l'acétate (Z)-9-tétradécényle a inhibé l'attraction des mâles par les pièges.
    Notes: Summary Gas chromatographic analyses coupled with electro-antennographic detection indicated that (Z,E)-9,11-tetradecadienyl acetate (Z,E-9, 11–14:Ac) is a pheromone component of the cone pyralid Dioryctria abietella. Gas chromatographic-mass spectrometric analyses confirmed the presence of a tetradecadienyl acetate with mass spectrum and retention index identical to Z,E-9,11–14:Ac. A receptor cell sensitive to both Z,E-9,11–14:Ac and the female extract was identified on the male antenna. An additional receptor cell sensitive to (Z)-9-tetradecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate was found on the male antenna but was not activated by the female extract. In the field Z,E-9,11–14:Ac presented alone attracted significant numbers of male D. abietella. Addition of (Z)-9-tetradecenyl acetate inhibited the attraction of males to traps.
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  • 27
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    Entomologia experimentalis et applicata 36 (1984), S. 15-16 
    ISSN: 1570-7458
    Keywords: sex attractants ; Lepidoptera ; Noctuidae ; Orthosia incerta ; Orthosia cruda ; fruit pest ; Z9-14:Ac ; Z9-14:Ald ; Z11-16:Ac ; Z11-16:Ald
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  • 28
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    Entomologia experimentalis et applicata 34 (1983), S. 65-70 
    ISSN: 1570-7458
    Keywords: Insect growth regulators ; Anti-juvenile hormone ; Fluoromevalonate ; Precocious metamorphosis ; Premature pupation ; Ecdysis ; Fall webworm ; Hyphantria cunea ; Lepidoptera ; Arctiidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Fluormevalosäure (FMev), bekannt als ein spezifischer Inhibitor der Biosynthese des Juvenilhormons (JH) in Insekten, wurde in 0,1–50 μg/Tier Dosis topikal an 3., 4. und 5. Larvenstadien von Hyphantria cunea getestet. Die Raupen wurden auf einem semi-synthetischen, künstlichen Nährboden bei 25° und unter Langtagsbedingungen (18 : 6 St., Licht/Dunkel) gezüchtet. Diese Verbindung rief drei verschiedene Typen spezifischer Reaktionen hervor: 1) verfrühte Metamorphose, 2) gehemmte Häutung und 3) verlängerte Larvenentwicklung. Vor der verfrühten Verpuppung wurde normales Verhalten beobachtet. Die Larven des 3. oder 4. Stadiums häuteten sich meist erst nach einem interkalaren Larvenstadium in verfrühte Puppen. Unter den drei Larvenstadien erwies sich das 5. Stadium gegen die Anti-JH-Verbindung am empfindlichsten. In allen getesteten Entwicklungsphasen wiesen die frisch gehäuteten Larven die höchste Empfindlichkeit gegen FMev auf. Nach der Häutung wurde stufenweises Absinken der FMev-Empfindlichkeit beobachtet, im 5. Larvenstadium verursachte die Verbindung jedoch selbst am letzten Tag des Wachstums zu einen relativ hohen Prozentzahl verfrühte Verpuppung. Eine zweite typische Wirkung von FMev war die Hemmung der Häutungsprozesse. Zwei grundlegende Stufen der Häutungsstörungen unterschieden sich voneinander: 1) Als Folge der Anwendung hoher Dosen von FMev konnte die Mehrzahl der Raupen die alte Larvenkutikula nicht öffnen und ging deswegen in kurzer Zeit zugrunde. 2) Bei Behandlung mit niedrigen Dosen der Anti-JH-Verbindung häuteten sich einige Hyphantria-Larven scheinbar normal; nach der Häutung waren aber alle unfähig, die normalen Bewegungen und die Nahrungsaufnahme fortzusetzen. Auch die vorzeitigen Puppenhäutungen wurden in meisten Fällen durch die Anti-JH-Behandlung gehemmt. Die morphogenetischen Wirkungen von FMev konnten durch eine topikale Behandlung mit Hydroprene, einem hochaktiven JH-Analogen, vollständig oder teilweise verhindert werden.
    Notes: Summary Fluoromevalonate (FMev, ZR-3516) known as an inhibitor of JH biosynthesis was topically applied in 0.1 to 50 μg/specimen doses to the 3rd, 4th, and 5th instar caterpillars of Hyphantria cunea Drury. The anti-JH compound induced 3 main types of specific responses: 1) precocious metamorphosis, 2) inhibition of ecdysis, and 3) prolongation of larval development. Precocious pupation was accompanied by behavioural events typical of normal pupation. Third and 4th instar larvae metamorphosed prematurely mostly with the intervention of an intercalary larval instar. The 5th instar exhibited the highest sensitivity to the anti-JH agent. Within each larval stage the freshly moulted insects proved to be the most susceptible to FMev. Afterwards, the incidence of morphogenetic reaction gradually decreased with age. In another fraction of Hyphantria larvae not responding with precocious pupation, FMev evoked varying degrees of ecdysial disturbance which always resulted in the death of caterpillars. In most cases the anti-JH compound inhibited the premature pupal moult, too, and these affected insects died as tanned pharate pupae. A complete or partial “rescue” from the effects of FMev was elicited, if simultaneously or subsequently, a single topical dose of a JH analogue, hydroprene was also administered.
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    Adsorption 6 (2000), S. 349-357 
    ISSN: 1572-8757
    Keywords: sulfadiazene ; adsorption ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract To investigate the nature of interactive forces between sulfadiazene molecules and alumina surface the experiments were performed for the adsorption of sulfadiazene (SD) from its aqueous sulution onto the alumina surfaces at 25 ± 0.2°C and the influence of factors such as increasing concentration of SD (4.0–20.0 × 10−3 mol cm−3), the time required for adsorption equilibrium, pH (2.0–12.0) and temperature (5–45°C) of the adsorption medium, the presence of ions like Cl−, SO2− 4 and PO3− 4 (0.01–0.30 M) and organic solvents (5% v/v) were observed on the course of adsorption of SD. Various adsorption and kinetic parameters such as adsorption coefficient, the rate constants for adsorption and desorption were also evaluated. The results of the above cited studies facilitated to formulate the mechanisms of interaction between SD and alumina surfaces. From application view point the present work may be a potential tool for an effective chromatographic separation of sulfa drugs from industrial effluents.
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    Catalysis letters 64 (2000), S. 65-75 
    ISSN: 1572-879X
    Keywords: NO reduction ; CH3OH ; La2O3 ; methyl nitrite ; kinetics
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    Topics: Chemistry and Pharmacology
    Notes: Abstract Nitric oxide (NO) reduction by methanol was studied over La2O3 in the presence and absence of oxygen. In the absence of O2, CH3OH reduced NO to both N2O and N2, with selectivity to dinitrogen formation decreasing from around 85% at 623 K to 50–70% at 723 K. With 1% O2 in the feed, rates were 4–8 times higher, but the selectivity to N2 dropped from 50% at 623 K to 10% at 723 K. The specific activities with La2O3 for this reaction were higher than those for other reductants; for example, at 773 K with hydrogen a specific activity of 35 μmol NO/s m2 was obtained whereas that for methanol was 600 μmol NO/s m2. The Arrhenius plots were linear under differential reaction conditions, and the apparent activation energy was consistently near 14 kcal/mol with CH3OH. Linear partial pressure dependencies based on a power rate law were obtained and showed a near‐zero order in CH3OH and a near‐first order in H2. In the absence of O2, a Langmuir–Hinshelwood type model assuming a surface reaction between adsorbed CH3OH and adsorbed NO as the slow step satisfactorily fitted the data, and the model invoking two types of sites provided the best fit and gave thermodynamically consistent rate constants. In the presence of O2 a homogeneous gas‐phase reaction between O2, NO, and CH3OH occurred to yield methyl nitrite. This reaction converted more than 30% of the methanol at 300 K and continued to occur up to temperatures where methanol was fully oxidized. Quantitative kinetic studies of the heterogeneous reaction with O2 present were significantly complicated by this homogeneous reaction.
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    Catalysis letters 69 (2000), S. 103-107 
    ISSN: 1572-879X
    Keywords: dicyclopentadiene ; Wacker oxidation ; Pd(AcO)2 ; benzoquinone ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation of dicyclopentadiene catalyzed by palladium(II) acetate and benzoquinone in the presence of perchloric acid was studied. Tricyclodecenone in high selectivity (85–98%) at a conversion of dicyclopentadiene up to 76% was obtained. The kinetic model assumed the significant inhibition complexation between dicyclopentadiene and tricyclodecenone with the catalytic species.
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    Entomologia experimentalis et applicata 30 (1981), S. 123-127 
    ISSN: 1570-7458
    Keywords: Sex Pheromones ; Repellent ; Heliothis armigera ; Heliothis zea ; Lepidoptera ; Noctuidae ; cotton bollworm ; corn earworm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'examen en olfactomètre a porté sur les réactions face à d'autres femelles de la même espèce, de femelles vierges ou ayant copulé d'Heliothis armigera Hübner et H. zea Boddie. Le lot comprenait 8 femelles, vierges ou ayant copulé en présence d'une femelle vierge ou ayant copulé. Les 4 combinaisons possibles de femelles vierges et de femelles ayant copulé ont été examinées avec 12 répétitions pour chaque espèce. Un extrait de l'extrémité de l'abdomen de femelles vierges d'une espèce a été présenté aux femelles de l'autre espèce pour examiner les possibilités de réactions interspécifiques aux phéromones. Pour chaque espèce, les réactions interspécifiques de répulsion entre femelles ont été hautement significatives par rapport aux témoins, à l'exception toutefois des réactions de femelle ayant copulé face à des femelles ayant elles aussi copulé. Les répulsions moyennes chez H. armigera et H. zea pour les 8 femelles de chaque expérience ont été: a) vierges en présence d'une vierge: 7,33 et 7,66; b) vierges en présence d'une femelles ayant copulé: 5,76 et 5,58; c) femelles ayant copulé en présence d'une vierge: 4,67 et 4,83. Les différences sont hautement significatives entre chaque paire de moyennes et entre chaque paire et le lot témoin; 3,17; 3,17; 3,42; 4,00 pour H. armigera; 3,17; 3,50; 2,83 et 3,75 pour H. zea. Les femelles vierges des deux espèces, H. armigera et H. zea ont présenté une réaction de répulsion en présence d'un extrait de l'abdomen de l'autre espèce; les répulsions moyennes étant respectivement 5,53 et 5,33 contre 3,83 et 3,58 pour le lot trémoin. On peut en conclure que ces répulsions doivent entraîner une tendance à la répartition uniforme.
    Notes: Abstract An olfactometer was used to determine the effect of pheromones released by females of the bollworms Heliothis armigera (Hübner) and H. zea (Boddie) on females of the same species. Four combinations of virgin and mated females were tested for repellency of one to the other. Evidence is presented that females of the two bollworms were repelled by females of the same species. In addition, extracts of virgin female abdomens of each species repelled virgin females of the other species.
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    Entomologia experimentalis et applicata 34 (1983), S. 155-162 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Braconidae ; Lepidoptera ; Nymphalidae ; Apanteles bignellii ; Euphydryas aurinia ; Multivoltinism ; Synchronisation ; Weather
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung In einer Population von Euphydryas aurinia (Rottemburg) bei Oxford, England treten während einer Generation von E. aurinia drei Normalgenerationen von Apanteles bignellii Marshall auf. Jede Generation des Parasitoids kann charakterisiert werden durch das befallende Wirtsstadium und durch die aus einem Wirt schlüpfende Zahl Parasitoide. Parasitoide schlüpfen in Normalgenerationen aus dem 3., dem 4. und dem 6. Stadium des Wirts; in Ausnahmegenerationen schlüpfen sie aus dem 2. und 5. Stadium. Bis zu 70 Parasitoide können aus einer Altraupe (6. Stadium) schlüpfen und die Dauer dieses Stadiums kann bis auf 2 Wochen verlängert werden. Die Ausnahmegenerationen von A. bignellii aus Zweitlarven dürften aus Eiablagen in frühe Erstlarven stammen. Fünftlarven des Wirts, aus denen Parasitoide schlüpfen, sind ungewöhnlich klein und fressen nicht; sie dürften das Resultat sein eines Uebermasses von Apenteles-Eiern, die in frühe Viertlarven gelegt wurden. Die Synchronisation zwischen dem Parasitoiden und dem Wirt während der Zeit, da E. aurinia im Puppen-, Adult- oder Eistadium ist, wird aufrechterhalten durch ein verlängertes Coconstadium von Apanteles. Die Puppen des Parasitoiden entwickeln sich normal und die Adulten schlüpfen, bleiben aber bis 4 Wochen lang im Cocon, bevor sie sich eine Ausgangsöffnung machen. Das Wetter kann den Parasitierungsgrad der letzten Wirtsstadien beeinflussen. Wenn der Frühling kalt ist mit klarem Himmel, kann die Synchronisierung zwischen Parasitoiden, die aus Viertlarven des Wirts schlüpfen und potentiellen Fünft- und Sechtstlarven des Wirts schlecht werden. Die Entwicklung von Apanteles-Puppen wird durch die Umgebungstemperatur beeinflusst, während E. aurinia-Larven ihre Temperatur erhöhen, indem sie sich sonnen und deshalb rasch wachsen. Wenn die Parasitoiden unter solchen Bedingungen schlüpfen, sind die meisten potentiellen Wirte schon verpuppt und damit nicht mehr geeignet für die Parasitierung. Die Mechanismen der Synchronisation und der Wettereinfluss auf diese Vorgänge wird diskutiert.
    Notes: Abstract The gregarious endoparasite, Apanteles bignellii Marshall is specific to the nymphalid butterfly, Euphydryas aurinia (Rottemburg) in the British Isles. The synchronisation between host and parasitoid is described at a site near Oxford, England where both occur. Three regular generations of A. bignellii occur in one generation of the host in the studied population. Relevant features of the biology of A. bignellii and E. aurinia are described, including a method of distinguishing the number of Apanteles larval instars based upon shed cuticle remnants. Mechanisms for host-parasitoid synchronisation are outlined, especially a protracted parasitoid cocoon stage when the host is unavailable for attack during the chrysalis, adult and egg stages. Cool, but sunny weather conditions in spring can influence the degree of parasitisation experienced by final instar host caterpillars. The timing of adult A. bignellii emergence and subsequent attack on early instar hosts can lead to additional, partial, generations of parasitoids from second and fifth instar hosts.
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  • 34
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    Entomologia experimentalis et applicata 35 (1984), S. 159-167 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Geometridae ; Ectropis excursaria ; larval dispersal ; colour polymorphism ; phototaxis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Acht Experimente wurden durchgeführt, um einige der Faktoren zu studieren, die das Wanderverhalten der Larven (Raupen) eines polyphagen Geometriden (Ectropis excursaria (Guenée)) beein-flussen. 1. Larven sind positiv phototaktisch. Die positive Phototaxis ist negativ mit Fasten, Alter und Populationsdichte korreliert. Bei hohen Temperaturen ist sie nicht mehr nachweisbar. 2. Das Wanderverhalten der Larven wird durch die Populationsdichte beeinflußt, wodurch annähernd eine konstante Dichte erhalten bleibt. Das Verhalten der individuellen Larven is dabei nicht statistisch homogen. Es gibt ‘Wanderer’ und ‘Nicht-Wanderer’. 3. Diese Verhaltensunderschiede stehen möglicherweise im Zusammenhang mit physiologischen und morphologischen Faktoren, die den individuellen Fortpflanzungserfolg und das überleben beeinflussen können; ‘Wanderer’ sind dunkler, entwickeln sich schneller und das Gewicht ihrer Puppen ist niedriger als das der ‘Nicht-Wanderer’. 4. Eine der larvalen Farbvarianten zeigte eine Präferenz für einen von zwei angebotenen Hintergründen.
    Notes: Abstract The dispersive behaviour of larvae of a polyphagous, wide-spread geometrid (Ectropis excursaria (Guenée)) was studied by examining responses to environmental and endogenous variables. It was found that differences in behaviour can be affected by environmental factors such as light, temperature, density, and plant background as well as some physiological and morphological features. The implications of these relationships are discussed as adaptative strategies to a varying environment.
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  • 35
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    Entomologia experimentalis et applicata 35 (1984), S. 177-193 
    ISSN: 1570-7458
    Keywords: induction of feeding preference ; host plants ; non-host plants ; Manduca sexta ; Sphingidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Vingt-deux espèces de plantes, dont 10 planteshôtes (Solanées), ont été testés comme plantes alimentaires pour des chenilles de ler stade de Manduca sexta. Sur cet ensemble, seulement 12 plantes (dont 9 plantes hôtes) induisaient la prise de nourriture et permettaient la croissance jusqu'au 5ème stade. La diversité des résultats suggère que les plantes pouvaient être classées en hôtes, non-hôtes acceptables et non-hôtes refusés. En utilisant le test du choix alimentaire préférentiel entre deux rondelles de feuilles, les chenilles néonates de ler stade ont préféré nettement les plantes-hôtes aux autres. Cette préférence initiale pour les plantes-hôtes était préservée quand les cheniles étaient élevées sur plantes-hôtes, mais devenait moins nette ou disparaissait pour des chenilles élevées sur d'autres plantes acceptées. Ainsi l'oligophagie ches M. sexta n'est pas induite, mais doit être héritée. Les chenilles néonates, aussi bien que celles de 5ème stade, présentent des préférences hiérarchisées parmi les plantes hôtes ou non. La seule frontiere nette observée était entre espèces de plantes acceptables ou non. Les hiérarchies préférentielles des chenilles du 5ème stade différaient légèrement lors-qu'elles avaient été élevées sur deux plantes-hôtes différentes. La différence essentielle était l'observation d'une préférence accrue pour l'espèce ayant servi à l'élevage, mais deux autres plantes-hôtes changaient aussi de position hiérarchique. La cause de ces changements de préférence a été approfondie, les chenilles étant élevées sur des feuilles de chaque espèce acceptable (hôte ou non). Leurs préférences alimentaires ont été définies en utilisant des combinaisons diverses (hôte x hôte, hôte x non-hôte acceptable, non-hôte acceptable x non-hôte acceptable). L'induction de la préférence alimentaires a été obtenue dans ces trois associations. Ceci montre que l'induction des choix alimentaires chez M. sexta n'est pas limitée aux plantes-hôtes. Le degré d'induction de la préférence alimentaire variait de très fort à indécelable; il dépendait de l'association examinée. La source de la variabilité de cette induction a été examinée en fonction de la relation entre la force de l'induction et les rapports taxonomiques des plantes associées. La relation obervée était inversée pour M. sexta. L'examen des données de la littérature ont révélé une relation du même type pour les autres espèces de Lépidoptères.
    Notes: Abstract Ten host plant (Solanaceae) and twelve non-host plant species were tested as foodplants for first instar larvae of the tobacco hornworm, Manduca sexta. Only nine host and three non-host plant species elicited feeding and supported growth up to fifth instar. The range of acceptability suggested that plants be divided into hosts, acceptable non-hosts, and unacceptable non-hosts. Using the two-choice feeding preference test we found that the initial preference for hosts was preserved when larvae were reared on hosts, but was less strong or absent for larvae reared on acceptable non-hosts. Thus oligophagy in the tobacco hornworm is not induced, but must be inherited. Newly-hatched first instar larvae and fifth instar larvae showed a preference hierarchy among both hosts and non-hosts. Fifth instar larvae reared separately on two different host species showed slightly different preference hierarchies among hosts. The preference for the rearing plant was increased and also two other host species changed positions in hierarchies. Feeding preferences of larvae reared on hosts or acceptable non-hosts were determined using plant combinations of host vs. host, host vs. acceptable non-host, and acceptable non-host vs. acceptable non-host. Induction of feeding preference was found in all three of these categories. This shows that induction of feeding preference in the tobacco hornworm is not restricted to host plant species. The degree to which feeding preferences were induced ranged from very strong to undetectable and dependend on the plant species paired. The strength of induction in the tobacco hornworm was found to correlate inversely with taxonomic relatedness of the plant species paired. Analysis of induction data from the literature revealed a similar correlation for other lepidopteran species.
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  • 36
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    Entomologia experimentalis et applicata 35 (1984), S. 255-261 
    ISSN: 1570-7458
    Keywords: method ; dry matter ; budget ; Lepidoptera ; phytophagous ; gravimetry ; area ; accuracy ; precision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les budgets en matière sèche consommée par des lépidoptères ont été comparés par les méthodes gravimétrique et planimétrique. La méthode gravimétrique est basée sur le rapport poids sec/poids frais de feuilles consommées par les chenilles. Avec la méthode planimétrique, la quantité d'aliment proposée aux chenilles est déterminée par les tracés de la surface des feuilles et le contenu de matière sèche par unité de surface des feuilles. La méthode de planimétrie permet l'utilisation de plus grands rameaux de feuilles et de cages d'élevage extérieures en gaze. Il n'y avait pas de différence appréciable dans les éléments du budget (croissance, ingestion et déjection), ni aucune différence dans la variabilité observée des données attribuable à la méthode utilisée. Cependant, la variabilité attendue d'après la précision des mesures avec la méthode gravimétrique est inférieure à celle de la méthode planimétrique. est inférieure à celle de la méthode planimétrique. Des éléments expérimentaux, inhérents à la méthode gravimétrique, introduisent une variabilité dans les mesures que l'on n'a pas avec la méthode planimétrique. 30–60% de la variabilité dans la consommation ont été attribués à des paramètres internes à la chenille, même quand elles provenaient toutes de la même ooplaque.
    Notes: Abstract Gravimetric and a combination areal-gravimetric methods for determining dry matter budgets for leaf eating Lepidoptera were compared. The gravimetric method is based on dry weight/live weight ratios of the leaves fed to the larvae. In the areal-gravimetric method, the quantity of food offered to the larvae is determined from the area of leaf tracings and the dry matter content per unit area of the leaves. The areal-gravimetric method permits the use of larger leaf sprays and an open, gauze enclosed rearing chamber. There were no consistent differences in budget factors (growth, ingestion or egestion), nor were there any differences in the observed variability of the data attributable to the method used. However, the expected variability based on instrument precision for the gravimetric method is less than for the areal-gravimetric method. Experimental factors inherent in the gravimetric method introduce variability to the measurements that are not present in the areal method. Thirty to 60% of the variability in budget factors was attributed to intrinsic properties of the larvae, even though the larvae were taken from the same egg masses.
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  • 37
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    Entomologia experimentalis et applicata 34 (1983), S. 121-122 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; Earias insulana ; Bollworm ; Artificial diets ; Insect fecundity
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  • 38
    ISSN: 1437-5613
    Keywords: Key words Herbivory ; Plant–herbivore interaction ; Lepidoptera ; Cruciferous plants ; Vegetation texture
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    Topics: Biology
    Notes: Abstract Correlation between plant size and reproductive output may be modified by herbivory in accordance with host plant density and the presence of nonhost plants. To elucidate the effects of nonhost plant density and host plant density on the intensity of herbivory and reproductive output of the host plant in relation to plant size under natural conditions, we investigated the abundance of three lepidopteran insects, Plutella maculipennis, Anthocharis scolymus, and Pieris rapae the intensity of herbivory, and fruit set of their host plant, Turritis glabra (Cruciferae). To elucidate the effects of nonhost and host plant density, we selected four categories of plots under natural conditions: low density of nonhost and high density of host plants; low density of both nonhost and host plants; high density of both nonhost and host plants; and high density of nonhost and low density of host plants. The plant size indicated by stem diameter was a good predictor of the abundance of all herbivorous species. The effects of density of nonhost and host plants on the abundance of insects varied among species and stages of insects. As the abundance of insects affected the intensity of herbivory, herbivory was more apparent on larger host plants in plots with low density of both nonhost and host plants. Consequently, the correlation between plant size and the number of fruits disappeared in low plots with density of both nonhost and host plants. In this T. glabra– herbivorous insect system, the density of nonhost plants and host plants plays an important role in modifying the relationship between plants and herbivores under natural conditions.
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  • 39
    ISSN: 1437-5613
    Keywords: Key words Community patterns ; Lepidoptera ; Route order ; Species richness ; Species distribution ; Environmental disturbance
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    Topics: Biology
    Notes: Abstract Kitahara and Fujii, in 1994, analyzed the butterfly communities along a gradient of human disturbance by applying the generalist/specialist concept. Butterfly species were classified into generalist or specialist species based on their voltinism (seasonal time dimension) and potential larval resource breadth (food dimension). The community structure and species composition showed the systematic changes along the gradient. To verify the generality of those trends, we monitored five grassland butterfly communities with varying degrees of human disturbance twice a month during 1985 by the line transect method at the foot of Mt. Fuji, central Japan, and analyzed their structure in a manner similar to that employed by Kitahara and Fujii. Most results were consistent with the patterns recognized by Kitahara and Fujii. The route (community) order based on increasing human disturbance was strongly and negatively correlated with butterfly species richness but with neither butterfly species diversity (H′) nor evenness (J′). Also, the degree of human disturbance was significantly and negatively correlated with the number of specialist species, but not with that of generalists, in a community. Butterfly species richness was more strongly correlated with the number of specialist species than with that of generalists. Our analyses also showed that the generalist species were distributed more widely over the communities than were the specialists. However, in contrast to the trend revealed by Kitahara and Fujii, there was no significant difference in the population densities and in the spatial population variability between the two species groups. As a whole, our analyses confirmed the consistency of most community patterns detected by Kitahara and Fujii. The causes of the inconsistencies in some patterns were thought to be mainly the present habitat conditions with a relatively short growing season at high altitudes.
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  • 40
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    Nutrient cycling in agroecosystems 56 (2000), S. 59-68 
    ISSN: 1573-0867
    Keywords: bicarbonate-extractable potassium ; muriate of potash ; potassium ; potassium chloride ; relative effectiveness ; silicate rock powder ; Triticum aestivum ; Trifolium subterraneum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Granite (silicate) rock dust, a by-product of quarry operations, is being advocated and used as a fertilizer in the wheatbelt of south-western Australia (WA). The dust is insoluble and based on its nutrient element content (1.9% K and 0.3%P and negligible N) it is not expected to be a useful fertilizer. Previous laboratory studies and glasshouse experiments in WA suggest the dust is a slow release K fertilizer. This paper extends the previous studies to consider the dust as an NP or K fertilizer in the year of application in a field experiment on a soil deficient in N, P and K. In addition, the effectiveness of the dust as a K fertilizer was compared with the effectiveness of KCl (muriate of potash), the K fertilizer used in WA at present, in glasshouse experiments using K deficient soils. In the field experiment, compared with NP fertilizer or NPK fertilizer (urea, supplying N; superphosphate, providing P, S, Ca, Cu, Zn and Mo; KCl providing K), the dust had no effect on grain yield of wheat (Triticum aestivum); in fact dust applied at 20 t ha-1, for unknown reasons, reduced yields by about 65% compared to the nil (no fertilizer, no dust) treatment. Relative to the nil treatment, applying NPK fertilizer increased yields about threefold, from 0.54 to 1.79 t ha. The glasshouse experiments showed that, relative to KCl, the dust was from about 0.02 to 14% as effective in K deficient grey sandy soils for producing dried tops of 30-day old wheat plants or 42-day old clover (Trifolium subterraneum) plants. In soils with adequate K (yellow sands, sandy loams or clays, loamy clays, clay loams and clays), neither KCl nor the dust affected yields of 30 to 42-day old wheat or clover plants grown in the glasshouse. In the glasshouse experiments, no yield depressions were measured for the dust applied up to 17 g dust per kg soil (equivalent to 17 t dust ha-1 mixed into the top 10 cm of soil in the field). It is concluded that the dust has no value as a fertilizer.
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    Nutrient cycling in agroecosystems 56 (2000), S. 117-123 
    ISSN: 1573-0867
    Keywords: labelled nitrogen ; Lolium perenne ; nitrogen cycling ; root biomass ; straw ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Large amounts of nitrogen (N) fertiliser (150–200 kg N/ha) are currently being applied to perennial ryegrass (Lolium perenneL.) seed crops in New Zealand. Due to increasing requirements for efficient use of N fertilisers and minimising nitrate contamination of the environment, a field experiment was established using 15N-labelled fertiliser to follow the fate of applied N. Urea-15N was applied to a perennial ryegrass seed crop in April (30 kg N/ha), August (30 kg N/ha), September (60 kg N/ha) and October (60 kg N/ha). The urea-15N was applied in solution and watered in to minimise volatilisation loss. At the time of harvest (December), 9% of the applied 15N was in the seed, 29% in the straw, 19% in the roots and 39% in the soil organic matter. Losses of 15N were minimal as the N was applied in several applications, each one at a relatively low rate, and at times when leaching was unlikely to occur. Ryegrass plants used a greater proportion of the N applied in September and October (61–65%) compared with that applied in April (44%). Consequently more N was recovered from the soil in the autumn application (57%) than from the September and October applications (28–44%). The availability of the residual fertiliser N to a subsequent wheat (Triticum aestivum L.) crop was studied in a glasshouse experiment. The residual fertiliser N was present in the soil and ryegrass roots and stubble. The wheat plants only recovered 7–9% of this residual N. Most of the N taken up by the wheat came from the soil organic N pool. Overall, applying a total of 180 kg N/ha to the ryegrass appeared to have minimal direct impact on the environment. In the short term N not used by the ryegrass plants contributed to the soil organic N pool.
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    Journal of insect conservation 4 (2000), S. 73-77 
    ISSN: 1572-9753
    Keywords: mapping ; database ; bias recording ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract We use data from the Mersey Valley zone (3×2 km area; N = 600 I ha squares) of the Greater Manchester butterfly atlas to investigate whether recorder visits are biased by access (viz. distance from recorder's home base) and by the locations of potential hot spots. In a multiple regression analysis, visits were found to correlate significantly both with distance from home base of the recorder and with the mean and maximum number of species found in squares. Sites close to the home base of the recorder were visited more frequently than those further afield and squares with more species were visited more frequently than those squares with fewer species. Visits were also made significantly more frequently to squares with greater numbers of butterfly resources (e.g. hostplants, nectar). Furthermore, recording is biased to and away from distinct land uses, which vary significantly in species richness. Reasons are given why these biases are to be expected at all scales. The message is that future distribution mapping should be based on rigorous sampling approaches.
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  • 43
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    Oecologia 122 (2000), S. 1-10 
    ISSN: 1432-1939
    Keywords: Key words Distribution ; Gregariousness ; Larval strategy ; Lepidoptera ; Thermoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Group-living in animal populations has many possible ecological and evolutionary explanations, including predator evasion and feeding facilitation. In insects, the thermal balance of solitary and gregarious larvae is likely to differ and may thus have important ecological consequences. The abilities of the larvae of four species of nettle-feeding nymphalid butterflies to thermoregulate were quantified in the field. Larval surface body temperatures of the gregarious Aglais urticae (small tortoiseshell) and Inachis io (peacock) and the solitary Polygonia c-album (comma) and Vanessa atalanta (red admiral) were measured for each instar, in both sunny and overcast conditions, over a seasonal range of temperatures. The results suggested two distinct larval thermal strategies. In the presence of direct sunlight, the exposed gregarious larvae of A. urticae and I. io regulated body temperatures at 32.5 and 31.5°C, respectively, while the temperatures of concealed larvae of P. c-album and V. atalanta were largely dependent on ambient temperatures. In the sun, the range of body temperatures recorded for A. urticae and I. io larvae was fairly narrow relative to ambient temperatures. This suggests a high degree of thermal control in these species. Modal body temperatures coincided with the temperature at which development rate is maximal. Regardless of whether changes in thermoregulation are a cause or consequence of the evolution of gregariousness, the combination of behavioural thermoregulation and gregariousness in larval insects has important implications for voltinism patterns and range extension (via increased development rates). Distributional responses of gregarious and solitary larvae to climatic warming may differ as a result of changes in cloud cover as well as changes in temperature.
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  • 44
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    Oecologia 122 (2000), S. 36-43 
    ISSN: 1432-1939
    Keywords: Key words Life history theory ; Longevity ; Ageing ; Mortality rate ; Lepidoptera
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    Topics: Biology
    Notes: Abstract  Life history theory predicts that organisms should only invest resources into intrinsic components of life span to the degree that it pays off in terms of reproductive success. Here, we investigate if the temporal distribution of mating opportunities may have influenced the evolution of intrinsic mortality rates in the butterfly Pararge aegeria (Satyrinae). In this species, females mate only once and the frequency of male mating opportunities depends on the temporal emergence pattern of virgin females. As expected, in a population from Madeira where females emerge continuously throughout the year, there was no sex difference in adult life span, while in a Swedish population with synchronised female emergence, males had significantly shorter life spans compared to females. A logistic mortality model provided the best fit to the observed change in age-specific mortality and all categories reached an asymptotic mortality rate of a similar magnitude. However, the Swedish males reached this mortality plateau more rapidly than the other categories. External mortality, due to water and food limitation, affected the pattern of sex-specific mortality but males from Sweden still had higher rates of mortality compared to all other categories. We argue that selection on male longevity is likely to be weaker in Sweden because under synchronised emergence, all females emerge and mate within a short period of time, after which male reproductive value will quickly approach zero. On Madeira, however, male reproductive value decrease more slowly with age since the probability of finding a receptive female is constant over the year.
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  • 45
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    European journal of clinical pharmacology 17 (1980), S. 111-116 
    ISSN: 1432-1041
    Keywords: zimelidine ; norzimelidine ; antidepressants ; pharmacokinetics ; bioavailability
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The systemic availability of a new antidepressant, zimelidine, and of its pharmacologically active metabolite, norzimelidine, was studied in six healthy male volunteers. Three single doses of zimelidine (25 mg and 100 mg orally and 25 mg i.v.) and two single doses of norzimelidine (25 mg orally and i. v.) were given to each volunteer allowing at least seven days between administrations. Plasma concentrations of zimelidine and norzimelidine were determined in serial blood samples by HPLC. Following oral zimelidine peak plasma concentrations of the metabolite were attained about 3 h after dosing. Oral administration of norzimelidine itself resulted in a plasma concentration profile for this compound that was similar to that observed after oral zimelidine. Utilising the plasma concentration data following intravenous infusion of each compound, the elimination half-lives for zimelidine and norzimelidine were calculated to be 5.1 h (range 4.3–6.0) and 15.5 h (range 10.6–22.9) respectively. The total body clearances of the 2 compounds were similar at 0.52 l · min−1 (range 0.26–0.70) for zimelidine and 0.56 l · min−1 (range 0.28–0.83) for norzimelidine. The substantially longer elimination half-life of norzimelidine was apparently the result of a larger volume of distribution (9.4 l · kg−1; range 7.8–11.4) for this metabolite, as compared to zimelidine (3.21 · kg−1; range 1.6–4.9). The calculated bioavailability of zimelidine was 26% (range 9.1–39) after the 25 mg oral dose, and 29% (range 14–46) after the 100 mg dose. The bioavailability of norzimelidine was 66% (range 36–91). However, oral administration of zimelidine resulted in as much or more norzimelidine reaching the systemic circulation, as the oral administration of norzimelidine itself. This is important as a large part of the activity of the drug may be due to the metabolite.
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  • 46
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    European journal of clinical pharmacology 19 (1981), S. 251-258 
    ISSN: 1432-1041
    Keywords: medigoxin ; digoxin ; dissolution rate ; proportionality ; bioavailability ; prediction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We compared our ability to predict the dose of medigoxin and of digoxin required to achieve a fixed serum concentration (the dose requirement) in 33 outpatients. Preliminary work supported the assumptions that the steady state glycoside concentration achieved was proportional to the daily dose given to an individual, and that the bioavailability of the different tablet presentations was similar for either glycoside. We were not able to predict the dose requirement from patient characteristics with any more certainty for medigoxin than for digoxin. Not only the between-patient variability in dose requirement, but also the within-patient variability, was similar for the two glycosides. However the digoxin used had a dissolution rate of over 90% in 1 h. When comparing medigoxin with digoxin of lower, or more variable dissolution rate, medigoxin may be preferable.
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  • 47
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    European journal of clinical pharmacology 18 (1980), S. 423-428 
    ISSN: 1432-1041
    Keywords: pyridostigmine ; myasthenia gravis ; pharmacokinetics ; bioavailability ; plasma levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of pyridostigmine was evaluated after intravenous injection in two healthy male volunteers and after oral administration to five subjects. Plasma concentrations of pyridostigmine were determined after ion pair extraction from plasma and analysis by gas chromatography — mass spectrometry with chemical ionization, using d6-pyridostigmine as internal standard. Degradation of pyridostigmine in vitro was compensated for by use of the deuterated internal standard and by rapid cooling and separation of plasma after blood sampling. After intravenous administration of pyridostigmine 2.5 mg the plasma elimination half-life was 1.52 h, the volume of distribution was 1.43 l/kg and the plasma clearance 0.65 l/kg × h. The pharmacokinetic constants were very similar after oral administration of pyridostigmine 120 mg; the elimination half-life was 1.78±0.24 h, the volume of distribution 1.64±0.29 l/kg and the plasma clearance was 0.66±0.22 l/kg × h. The bioavailability was calculated to be 7.6±2.4%. When pyridostigmine was taken together with food, the time to reach the peak plasma concentration was prolonged from 1.7 to 3.2 h. Bioavailability, however, was not influenced by concomitant food intake. “Steady-state” plasma concentrations of pyridostigmine were measured in myasthenic patients on their ordinary dose schedule of cholinesterase inhibitor drugs. More than a seven-fold difference in steady-state plasma concentration was found between patients taking approximately the same daily dose of pyridostigmine.
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  • 48
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    European journal of clinical pharmacology 21 (1981), S. 215-220 
    ISSN: 1432-1041
    Keywords: phenytoin ; cimetidine ; antipyrine test ; drug interaction ; drug metabolism ; kinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a prospective study in nine patients the effects of phenytoin and of cimetidine (1000mg/day) + phenytoin on the antipyrine test and serum phenytoin concentrations were studied. Serum phenytoin increased from the steady state level of 5.7±1.3 mg/l to 9.1±1.4mg/l after three weeks on cimetidine (p〈0.01), and fell to 5.8±1.2 mg/l within two weeks after withdrawal of cimetidine. The protein binding of phenytoin was not changed by cimetidine. After use of phenytoin for 2–4 months, antipyrine clearance increased from 0.67±0.06ml/min/kg to 1.61±0.22 ml/ min/kg, and antipyrine half-live fell from 10.9±1.3h to 4.5±0.6h as compared to the values before phenytoin treatment (p〈0.01). After three weeks combined use of cimetidine and phenytoin, antipyrine clearance was decreased to 1.01±0.07 ml/min/kg and antipyrine half-life was prolonged to 6.1±0.5h, (p〈0.01) compared to the values on phenytoin alone. The distribution volume of antipyrine was not affected by phenytoin nor by cimetidine + phenytoin. The half-life of cimetidine was 2.8±0.3h in the patients on longterm phenytoin treatment. There was a significant positive correlation (p〈0.001) between the increase in serum phenytoin concentration and the prolongation of antipyrine half-life caused by cimetidine. Thus, cimetidine increases serum phenytoin concentration, very probably by inhibiting its metabolism. Care should be taken in the concomitant use of cimetidine and phenytoin, and the dose of phenytoin should be modified according to the clinical symptoms and serum phenytoin concentrations.
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  • 49
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    European journal of clinical pharmacology 21 (1982), S. 343-350 
    ISSN: 1432-1041
    Keywords: orphenadrine ; single dose ; multiple doses ; bioavailability ; pharmacokinetics ; N-demethylorphenadrine ; metabolism ; dog ; man
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma concentrations of orphenadrine were measured by a specific gaschromatographic method in 5 healthy male volunteers after a single oral dose of orphenadrine hydrochloride 100mg. The single dose pharmacokinetic profile of orphenadrine was evaluated from these data. The elimination half-life ranged from 13.2–20.1 h after the commercial tablet formulation. Plasma concentrations, determined in volunteers and patients under different conditions of repeated oral administration of the same formulation of orphenadrine hydrochloride exceeded the theoretical values, predicted from the single dose pharmacokinetics, by a factor 2 to 3. The elimination half-lives after discontinuation of treatment showed a 2 to 3-fold increase over the single dose values. This demonstrates a clear discrepancy between the multiple and single dose pharmacokinetics of orphenadrine. Experiments in dogs suggested competition for biotransformation between orphenadrine and its metabolite N-demethylorphenadrine. Product inhibition of this type could explain the observed discrepancy.
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  • 50
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    European journal of clinical pharmacology 22 (1982), S. 225-228 
    ISSN: 1432-1041
    Keywords: pinazepam ; N-desmethyldiazepam ; kinetics ; metabolism ; human
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma profile of a single oral dose of pinazepam 10 mg was studied in 6 healthy male volunteers, aged 26 to 31 years. The concentrations of the parent compound and of its metabolite in plasma were measured by gas-chromatography. The peak plasma levels of pinazepam was 36.8±5.1 ng/ml and of N-desmethyldiazepam 150±13.3 ng/ml. The plasma concentration of the metabolite become higher than that of the parent compound shortly after administration, suggesting that pinazepam acts as a prodrug.
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  • 51
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    Keywords: indapamide ; bioavailability ; pharmacokinetics
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    Notes: Summary Two formulations of indapamide tablets (2.5 mg) were given as a 5.0 mg dose and the subsequent blood levels were compared to those obtained after administration of a 5.0 mg solution. The study was conducted as a randomized three-way crossover design using healthy male volunteers. The drug was well tolerated by all the subjects involved. The area under the blood concentration versus time curve, extrapolated to infinity was essentially the same for all three formulations (4.2, 4.7, and 4.4 µg-h/ml). Statistical comparison of the blood levels from the two tablets showed that one tablet had a significantly greater maximum blood concentration (263 vs 231 ng/ml) and a significantly shorter time of maximum blood concentration (2.3 vs 3.5 h). Cmax (333 ng/ml) and tmax (0.7 h) values for the solution were significantly higher than either tablet. The average half-life (β-phase) for all three formulations was 15 h, while the average systemic clearance was 20 ml/min. Indapamide has a low clearance rate and there was no evidence that the drug undergoes a first-pass effect.
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  • 52
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    European journal of clinical pharmacology 22 (1982), S. 545-551 
    ISSN: 1432-1041
    Keywords: oxcarbazepine ; kinetics ; disposition ; metabolites ; renal excretion ; volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Oxcarbazepine (oxcarb) 600 and 900 mg (2360 and 3540 µmol) was taken by 3 volunteers (2 ♀, 1 ♂; 45–67 kg; age 22–34 years) after an overnight fast. Blood, saliva and urine were collected for the next 72 h for assay of oxcarb, 10,11-dihydro-10-hydroxy-carbamazepine (OHcarb), and 10,11-dihydrotrans-10,11-dihydroxy-carbamazepine (diol). Oxcarb reached a maximum level of about 1 µg/ml (3.93 µmol/l) within 1 h and dropped below the detection limit (0.1 µg/ml=0.39 µmol/l) within 3 h. The active metabolite OHcarb appeared in the blood before oxcarb and reached the higher maximum level of 7.4 µg/ml (29 µmol/l) after 7 h. Thereafter serum levels decreased with a t1/2 of about 25 h, and after 40 h with a t1/2 of 9 h, the latter agreeing with the renal excretory t1/2 calculated from the urine data (10 h). The ratio of OHcarb concentration in saliva to that in plasma varied considerably (0.3–1.7; median 1; r〉0.9), whereas that of blood to plasma was 1.25 with only small variation (r〉0.98); OHcarb concentrations in erythrocytes were 50% higher than in plasma. Diol was detected in blood (maximum level 0.5 µg/ml=1.84 µmol/l) in 2 volunteers. 45% of the dose could be recovered in urine (Oxcarb 5%, OH-carb 36%, Diol 4%). Whereas Oxcarb was completely conjugated, only 25% of OHcarb was conjugated and diol was unconjugated.
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  • 53
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    European journal of clinical pharmacology 23 (1982), S. 59-64 
    ISSN: 1432-1041
    Keywords: morphine ; rectal administration ; i.m. administration ; gas chromatographic mass spectrometric analysis ; bioavailability ; plasma levels
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 21 healthy women undergoing gynaecological operations received rectal premedication with morphine 0.3 mg/kg body weight. Plasma concentrations of morphine were followed for 4 h by a GC/MS technique. In most patients the peak plasma concentration was reached after 30 min; the mean peak plasma level of morphine was 18 ng/ml (range 8.5–57 ng/ml). The bioavailability of rectal morphine was determined in 6 patients, who received an i.m. injection of morphine at a second operation. The mean bioavailability of rectal morphine was 31% (range 12%–61%). None of the patients showed any clinical sign of respiratory depression, and there was no increase in end-tidal carbon dioxide tension measured in 5 patients operated under spinal block.
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  • 54
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    European journal of clinical pharmacology 23 (1982), S. 235-240 
    ISSN: 1432-1041
    Keywords: ergotamine ; pharmacokinetics ; migraine ; plasma drug levels ; i.v. administration ; i.m. administration ; bioavailability
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of ergotamine has been investigated in migrainous patients using a new, specific, sensitive HPLC assay (detection limit 100 pg/ml plasma). 10 patients were given ergotamine tartrate 0.5 mg i.v. and 5 of them received the same dose i.m. 2–3 weeks later. Blood samples were collected for up to 54 h following administration and the plasma concentration were analysed. After intravenous administration the plasma ergotamine declined rapidly, with an initial distribution half-life of 3 min followed by a mean terminal half-life of 1.86 h (range 90–155 min). The mean total plasma clearance was 11.0 ml kg−1 min−1, and the volume of distribution (Vdβ ) was 1847.6 ml kg−1. Individual t1/2β showed a positive linear correlation with the individual Vdβ . The intramuscular absorption of ergotamine was rapid and maximum plasma levels were usually obtained 10 min following administration. The biological availability was incomplete and variable at 46.6% (range 28.3–60.8%).
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  • 55
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    European journal of clinical pharmacology 24 (1983), S. 127-136 
    ISSN: 1432-1041
    Keywords: statistical analysis ; nonparametric statistical methods ; bioavailability ; confidence interval ; ANOVA
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary For a two-way cross-over design, which appears to be the most common experimental design in bioavailability studies, 95%-confidence limits for expected bioavailability can be obtained by classical analysis of variance (ANOVA). If symmetry of the confidence interval is desired about zero (differences) or unity (ratios) rather than about the corresponding point estimator, Westlake's modification can be used. Two nonparametric methods and their adaptations to bioavailability ratios are reviewed, one based on Wilcoxon's signed rank test (Tukey), and the other on Pitman's permutation test. The necessary assumptions and the merits of these procedures are discussed. The methods are illustrated by an example of a comparative bioavailability study. A FORTRAN program facilitating the procedures is available from the authors upon request.
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  • 56
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    European journal of clinical pharmacology 24 (1983), S. 217-220 
    ISSN: 1432-1041
    Keywords: metoprolol ; pregnancy ; hypertension ; kinetics ; pre-eclampsia
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition of oral metoprolol was studied in 5 women during the last trimester of pregnancy and 3 to 5 months after delivery. After a single oral dose of 100 mg the individual peak plasma concentration in the pregnant state was only 20–40% of that after pregnancy. The plasma half-lives of metoprolol were about the same during (average 1.3 h) and after pregnancy (average 1.7 h). By contrast, the area under the plasma concentration versus time curve was much smallerduring (mean 262 nmol/l×h) thanafter (mean 1298 nmol/l×h) pregnancy, resulting in an average apparent oral clearance (Clo) of metoprolol that was 4.4times higher during (362 ml×kg−1 body-weight×min−1) than after pregnancy. The increased Clo in pregnancy is assumed to be due to enhanced hepatic metabolism of the drug. The possible clinical consequence of the difference in the disposition of metoprolol is discussed.
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  • 57
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    European journal of clinical pharmacology 24 (1983), S. 791-796 
    ISSN: 1432-1041
    Keywords: furosemide ; bioavailability ; diuretic effect ; urine sodium ; urine potassium ; power of ANOVA ; tablet formulations ; urinary flow rate ; normal volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The relative bioavailability and diuretic effect of 2 commercially available tablet preparations of furosemide 40 mg was examined in 10 healthy male volunteers. A close linear relationship between the urinary excretion rate of furosemide and the rate of sodium ion excretion in urine and/or flow rate of urine was demonstrated. There were no significant differences in the urinary excretion of furosemide, sodium and potassium ions or urinary volume following the oral doses. The difference in drug content affected the urinary recovery of furosemide over 24 h but had no effect on the pharmacological response. The analytical power of ANOVA using the various parameters of the responses to furosemide was no lower than when the parameters of urinary excretion of furosemide were used.
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  • 58
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    Keywords: prizidilol ; antihypertensive effect ; acute and long-term blood pressure control ; plasma renin activity ; acetylator phenotype ; antinuclear antibodies ; side effects ; kinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary After an initial placebo period of four weeks 24 patients with primary hypertension were treated with prizidilol, a hydrazinopyridazine derivative with combined vasodilator and non-selective beta-adrenoceptor blocking actions, for a dose titration period of 14 weeks. Prizidilol 200 to 800 mg was given once daily to achieve a target supine diastolic blood pressure (BP)〈90 mmHg. Supine and standing BP recorded 24–27 h after drug intake decreased from 172±17/106±6 mmHg (mean±SD) and 167±18/111±8 mmHg, respectively, after placebo to 159±16/99±8 and 154±18/101±9 mmHg after active treatment for six weeks (mean dose 447 mg), and to 154±16/97±7 and 148±14/97±7 mmHg after treatment for 14 weeks (mean dose 687 mg/day). A slight reduction in HR was seen after treatment for six weeks and in plasma renin activity and urinary methoxycatecholamine excretion after treatment for 14 weeks. A sustained decrease in BP was observed for 10 h after prizidilol 800 mg (n=9), with a maximum antihypertensive effect (mean reduction in supine BP 33/18 mmHg) 2.5 h after dosing, which coincided with the mean peak plasma concentration. The plasma elimination half-life of the drug was 3.9 h (range 2.0–8.9 h). Changing to a twice daily regimen in 17 patients (mean daily dose 748 mg at six months) did not produce any further reduction in the BP (recorded 12–15 h after dosing) as compared to the once daily regimen at 14 weeks. During treatment for up to 24 months, 16 patients did not achieve satisfactory BP control. Eight of them were withdrawn and eight received additional treatment with bendroflumethiazide (2.5–5 mg/day). In 7 of the latter satisfactory BP control was achieved. Side effects were few. Dizziness and tiredness occurred in four patients 2–5 h after prizidilol 600–800 mg once daily. These symptoms partly subsided when the subjects changed to a twice daily regimen. No ocular side-effects were found. Before treatment 13 out of 24 patients had a low titre of IgM antinuclear antibodies (ANA) and one patient also a low titre of IgG ANA. During treatment the frequency of patients with positive ANA-titres became higher, and after treatment for 12 months (n=17) 15 patients had positive IgM and seven patients positive IgG ANA-titres. However, the titres were low and no patient showed a clinical lupus erythematosus syndrome. There was no relation between acetylator phenotype of the patient and acute or longterm effecton BP, pharmacokinetics of the drug or the development of a raised ANA-titre.
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  • 59
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    European journal of clinical pharmacology 25 (1983), S. 237-241 
    ISSN: 1432-1041
    Keywords: triamterene ; bioavailability ; pharmacokinetics ; metabolism ; hydroxy triamterene sulphate ; urinary excretion ; i.v. administration ; first-pass-effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary With a new formulation, which made intravenous infusion of triamterene (TA) possible, plasma levels and urinary excretion rates of TA and its main metabolite (OH-TA-ester) were measured in a randomized, cross-over trial in 6 healthy volunteers given triamterene 10 mg i.v. and 50 mg p.o. TA and OH-TA-ester were determined by densitometric measurement of native fluorescence after thin layer chromatography. Distribution volumes of the central compartment of TA and OH-TA-ester were 1.49 l/kg and 0.11 l/kg, respectively. Terminal half-lives were 255 min for TA and 188 min for OH-TA-ester after i.v. administration. For TA total plasma clearance was 4.5 l/min and renal plasma clearance 0.22 l/kg. The formation of OH-TA-ester was very rapid and the concentration of the metabolite exceeded that of TA at all times. After i.v. administration the urinary recovery of TA and OH-TA-ester was 4.4% and 50.9%, respectively. The bioavailability of TA was 52%, corresponding to absorption of 83%. TA is partly eliminated by a first-pass-effect. The main metabolite of TA is OH-TA-ester, which is pharmacologically active.
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  • 60
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    European journal of clinical pharmacology 25 (1983), S. 449-453 
    ISSN: 1432-1041
    Keywords: canrenone ; pharmacokinetics ; plasma level ; bioavailability ; urinary excretion ; spironolactone
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Five healthy male volunteers received canrenoate-K 200 mg (Sincomen® pro injectione) by intravenous injection and one week later spironolactone 200 mg (Sincomen®-100) orally. Plasma levels and urinary excretion of unchanged canrenone were determined up to 24 h by a specific HPLC method. Following intravenous administration, the maximum plasma level of 2066±876 ng/ml was found after 29±15 min and thereafter the concentration declined with a half-life of 3.7±1.2 h. Total clearance was 4.2±1.7 ml/min·kg. After oral ingestion, the maximum concentration of 177±33 ng/ml was observed at 4.4±0.9 h. The absolute bioavailability of canrenone was 25±9%. Within 24 h, respectively 0.4 and 0.6 mg, canrenone were excreted by the kidney after intravenous and oral administration. The half-life of elimination was 4.9±1.8 h (i.v.) and 3.9±1.2 h (p.o.).
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  • 61
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    European journal of clinical pharmacology 26 (1984), S. 513-520 
    ISSN: 1432-1041
    Keywords: xipamide ; electrolyte excretion ; bioavailability ; elimination ; extrarenal clearance ; chronic renal failure ; furosemide ; hydrochlorothiazide ; amiloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of a single oral dose of 40 mg xipamide on urinary excretion of Na+, K+, Cl−, Ca2+ and Mg2+ in healthy subjects and in patients with varying degrees of renal impairment was compared with various conventional diuretics. Xipamide caused marked excretion of Na+ and Cl−, whereas the diuretic produced only moderate kaliuresis; urinary excretion of Ca2+ was increased in proportion to Na+, like the loop diuretics. Xipamide affected electrolyte excretion even in patients with a creatinine clearance below 30 ml/min, as do the loop diuretics, too. Therefore, the pharmacodynamic characteristics of xipamide are more like those of a loop diuretic than of a thiazide. Xipamide was good bioavailable, its t1/2β was 7 h and urinary recovery of the undegraded drug was 40% of the given dose. In renal insufficiency, t1/2β increased from 7 to only 9 h, yielding a moderate increase in the AUC. Urinary recovery of the drug was reduced in proportion to the reduction in the creatinine clearance of the patient. Therefore, significant extrarenal elimination of the diuretic must be postulated, which suffices to prevent significant drug accumulation in renal failure.
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  • 62
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    European journal of clinical pharmacology 24 (1983), S. 273-276 
    ISSN: 1432-1041
    Keywords: undernourished ; chlorquine ; kinetics ; plasma levels ; red cell uptake
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma and whole blood kinetics of chloroquine was studied in 7 normal and 8 undernourished subjects following a single oral dose of 600 mg. The terminal half-lives were similar in both groups. The AUC was also similar in the 2 groups, even though a higher dose per kg body weight was administered to the undernourished. This was probably because of faster clearance in this group. Chloroquine uptake by erythrocytes, its main site of action in malaria, was also comparable in the two groups. The plasma concentration of chloroquine over a period of time was found to be similar in 4 normal and 4 undernourished subjects following administration of 1.5 g of the drug in divided doses. The undernourished appear, therefore, to handle chloroquine in such a way that they do not suffer a greater risk of toxicity than normals.
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  • 63
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    European journal of clinical pharmacology 24 (1983), S. 525-527 
    ISSN: 1432-1041
    Keywords: theophylline ; airway obstruction ; biotransformation ; kinetics ; oral dosage
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Oral theophylline was given to 6 adults with airways obstruction. The initial dose was 125 mg daily and this was increased by 125 mg each week. The final total daily dose reached was determined by side effects and ranged from 500 mg to 1125 mg. At the end of each week and before the next dosage increment steady state, trough plasma theophylline concentrations were measured. For each individual and for the group as a whole there was a highly significant linear correlation between theophylline dose and trough plasma concentration. This indicates that for oral theophylline, in adults, dose-dependent kinetics do not play a significant role and dose may be adjusted without fear of a disproportionate rise in plasma concentration.
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    European journal of clinical pharmacology 27 (1984), S. 105-110 
    ISSN: 1432-1041
    Keywords: phenytoin ; epileptic women ; pharmacokinetics ; bioavailability ; pregnancy
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Five epileptic women needing to commence phenytoin therapy during pregnancy received a single intravenous and a single oral dose of phenytoin several days apart before starting regular intake of the drug. Plasma phenytoin concentration — time data were analysed by three different pharmacokinetic techniques. However assessed, the mean oral bioavailability of the drug proved to be about 90% of the intravenous bioavailability. This finding makes it unlikely that impaired bioavailability accounts for the increase in oral phenytoin dosage necessary in pregnancy to maintain plasma phenytoin concentrations at pre-pregnancy values. Phenytoin clearance in the pregnant subjects was approximately double the published values for phenytoin clearance in nonpregnant persons. This suggests that increased (metabolic) clearance accounts for the increased phenytoin dosage requirement of pregnancy.
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    European journal of clinical pharmacology 27 (1984), S. 491-494 
    ISSN: 1432-1041
    Keywords: amiodarone ; kinetics ; volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We studied three healthy volunteers after a single i.v. bolus of amiodarone, during 1 month of chronic oral dosing and after the discontinuation of the drug. Blood concentrations of amiodarone declined rapidly in a bi-exponential fashion after i.v. bolus. The terminal half-life ranged from 10 to 17 h; after discontinuation of chronic treatment the terminal half-lives were 8–21 days. The i.v. data, the trough levels during multiple dosing and the washout phase could be simultaneously fitted using a tri-exponential equation. The subjects were carefully monitored for cardiac and thyroid function. One subject had to stop taking amiodarone because of profound bradycardia. A reduction of serum TT3 and FT3 concentrations and an increase of serum rT3 and FT4 was found.
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  • 66
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    European journal of clinical pharmacology 27 (1984), S. 595-602 
    ISSN: 1432-1041
    Keywords: furosemide ; bioavailability ; generic tablet formulations ; intrasubject variability
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Intrasubject variation in bioavailability (rate and extent) and disposition of furosemide 40 mg was investigated using a repeated, randomized, double-blind cross-over study in 8 healthy subjects. Two generic tablet formulations (Lasix and Furix) and intravenous furosemide were compared on 6 separate days. Extensive intrasubject variability after oral administration was observed in AUC, mean absorption time (MAT) and urinary excretion. The variability (error variance) within the dosage forms was as large as that between the two generics. These variations most probably depended on the absorption process, since the repeated i.v. doses showed only marginal intrasubject variability. Absolute bioavailability was 56% for Lasix and 55% for Furix (AUC). The range was 20 to 84% between individuals and the maximal range within one individual was 20 to 61%. Confidence interval and Bayesian analysis showed a high probability of non-equivalence not only between but also within the generics when the separate cross-over experiments were analyzed (8 observations). When extending the analysis to 16 observations, bioequivalence was demonstrated for the two generic tablets. Rate of absorption, quantified as MAT, was 128 min for Lasix and 98 min for Furix (16 observations). Since MAT was significantly longer (p〈0.001) than the mean residence time after the i.v. dose (57 min), absorption was evidently the rate-limiting step in the overall kinetics of oral furosemide. Intraindividual variation in absorption is a confounding factor in bioavailability studies of furosemide using limited numbers of subjects. This is important to consider when designing and evaluating bioavailability studies for drugs showing these variations.
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  • 67
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    European journal of clinical pharmacology 18 (1980), S. 415-418 
    ISSN: 1432-1041
    Keywords: diclofenac ; acetyl salicylic acid ; intravenous bolus administration ; oral administration ; interaction ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Previous studies have shown that aspirin interacts with orally administered diclofenac sodium, causing reduced peak concentrations, lower levels and decreased areas under curves. In this study, diclofenac sodium was administered orally and intravenously with and without aspirin, to 6 healthy female volunteers. After intravenous dosing both plasma levels and areas under curves were significantly reduced although none of the rate constants was affected. The volume of distribution of diclofenac was increased as was the plasma clearance. Oral administration with aspirin also resulted in lower plasma levels, particularly peak levels, and areas under curves. Comparison of AUC's for both modes of administration with and without aspirin suggested that lower levels after oral administration were not due to impaired absorption. These observations are best explained by decreased protein binding and increased biliary excretion of diclofenac in the presence of salicylate.
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    European journal of clinical pharmacology 17 (1980), S. 285-293 
    ISSN: 1432-1041
    Keywords: tolbutamide ; chlorpropamide ; kinetics ; food ; age ; blood glucose ; plasma insulin
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food intake (standardized breakfast) on the oral single-dose kinetics and effects of tolbutamide (0.5 g) and chlorpropamide (250 mg) was investigated in young, healthy volunteers. The single-dose kinetics of the two drugs was also studied in elderly healthy subjects. There was great interindividual variation in the elimination rate of both drugs, but food intake influenced neither their AUCs nor their rates of absorption and elimination. The peak concentration of chlorpropamide, but not that of tolbutamide, was reduced by food intake. The peak concentrations of serum tolbutamide were approximately doubled by an increase in dose from 0.5 to 1.0 g, and from 1.0 to 2.0 g. At no time did tolbutamide 0.5 g affect the plasma insulin level, neither in the fasting nor in the non-fasting state. However, this dose did reduce the blood glucose level during fasting and the increase in blood glucose in response to the meal. The latter effect was recorded within 30 min, when the serum level of tolbutamide still was close to zero. Plasma insulin concentrations did increase within 30 min after a higher dose of tolbutamide (1.0 g), when the serum concentration of tolbutamide was about 50 µmol/l. Between 2.5 and 8 h after administration of chlorpropamide 250 mg, serum drug concentrations were lower than those following tolbutamide 0.5 g. The blood glucose response was smaller and occurred later, being significant at 2 h, when the serum concentration of the drug was about 70 µmol/l. There was no significant change in plasma insulin. There was no significant pharmacokinetic difference between young and elderly subjects, except that the peak concentration of tolbutamide was higher in the latter. It appears that both for tolbutamide and chlorpropamide there is great interindividual variation in drug disposition, but food intake does not influence the bioavailability of either drug. The effect of any particular drug concentration seems dependent upon the blood glucose level and hence upon the elapsed time since the last meal. Both drugs can reduce blood glucose without an alteration in the peripheral blood concentration of insulin. This may reflect an extrapancreatic effect of the drugs, but it could also be an expression of increased insulin secretion, which is not detected because of enhanced hepatic degradation of the hormone released into the portal circulation. The observations made in young individuals are also probably relevant for elderly subjects.
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  • 69
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    European journal of clinical pharmacology 17 (1980), S. 309-315 
    ISSN: 1432-1041
    Keywords: valproic acid ; sodium valproate ; suppositories ; micro-enemas ; steady-state concentration ; absorption ; bioavailability
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Rectal and oral absorption of valproic acid and its sodium salt by man were compared to explore the possibility of rectal administration of the drug. The plasma concentration of valproic acid was measured by gas chromatography after a single oral dose of sodium valproate 600 mg, and after single rectal doses of sodium valproate 600 mg and valproic acid 520 mg, in a cross-over study in 7 volunteers. The rectal dosage forms included fatty suppositories and aqueous solutions. Compared with oral administration, rectal absorption of sodium valproate from an aqueous micro-enema was fast and complete. The free acid was absorbed more rapidly from fatty suppositories than was the sodium salt. The absorption rate from the rectum increased with the dose of valproic acid. Both findings are consistent with a diffusion — absorption mechanism based on the pH-partition hypothesis. Differences in the chemical composition of the fatty suppository base were not reflected in differences in absorption rate and relative bioavailability. No essential difference in absorption rate was observed if volunteers remained lying or sitting during the experiment. Rectal dosing with valproic acid 520 mg dissolved in 4 ml suppositories, twice a day resulted in steady-state plasma concentrations of 50 to 100 µg · ml−1, within the therapeutic range.
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  • 70
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    European journal of clinical pharmacology 17 (1980), S. 379-384 
    ISSN: 1432-1041
    Keywords: theophylline ; aminophylline ; obstructive lung disease ; microcrystalline ; bioavailability ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Variation in the systemic disposition of theophylline after ingestion of a new microcrystalline product (Theolair®) has been investigated in 7 hospitalized patients with generalized obstructive lung disease. Disposition (absolute bioavailability) was determined by comparing in the same patients the areas under the serum concentration-time curves after a single oral dose of microcrystalline theophylline and after an intravenous infusion of aminophylline. Oral absorption appeared to be fast. The half-life of absorption was 19±9 min (mean±SD). Maximal serum concentrations reached after 100±30 min were found to be in a rather narrow range: 9.8±2.5 mg · 1−1. The absolute bioavailability of the microcrystalline preparation was high and it showed only small variation: 102.7±10.2% of the dose. Relevant pharmacokinetic parameters (half-life of elimination, volume of distribution and total body clearance) were determined after both routes of administration. Individual dosage regimens required to obtain a therapeutic serum concentration were calculated for each individual patient on the basis of the observed pharmacokinetic parameters.
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  • 71
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    European journal of clinical pharmacology 19 (1981), S. 53-55 
    ISSN: 1432-1041
    Keywords: digoxin ; bioavailability ; dose-dependency ; urinary excretion ; healthy volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nine healthy volunteers received single 0.25, 0.5, 1.0, 1.5, and 2.0 mg doses of oral digoxin tablets in random sequence on five occasions separated by at least 4 weeks. Urinary excretion of immunoassayable digoxin was determined from 8 consecutive 24 h urine samples collected after each dose. Mean values of cumulative urinary excretion of digoxin at the 5 doses were: 40.9, 35.6, 36.4, 34.1, and 33.5% of the dose (F=0.64; d. f.=4.32; N. S.). Mean values of urinary excretion half-life were: 2.48, 2.03, 2.20, 2.07, and 1.87 days (F=2.87; d. f.=4.32;p=0.05). Thus, the bioavailability of orally administered digoxin tablets in healthy volunteers is dose-independent over an 8-fold range of doses.
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  • 72
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    European journal of clinical pharmacology 19 (1981), S. 287-292 
    ISSN: 1432-1041
    Keywords: diacetolol ; acebutolol ; bioavailability ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and bioavailability of diacetolol, the principal metabolite of acebutolol, were studied in 6 healthy subjects. Plasma concentrations were determined following a single intravenous injection of diacetolol 100 mg and three oral doses of diacetolol 100, 400 and 800 mg, in random order. The average oral bioavailability of diacetolol was F: 0.302±0.052 (100 mg), 0.363±0.052 (400 mg) and 0.426±0.068 (800 mg); the differences are not significant. The mean plasma half-life of the terminal phase, 7.94±0.26 h after intravenous administration, was significantly higher than after oral administration 12.27±1.00 h (100 mg), 12.82±1.59 h (400 mg) and 13.05±1.22 h (800 mg) (p〈0.02 to 0.05); the mean urine half-lives of the terminal phase were not significantly different. Renal clearance of diacetolol 10.2±0.81·h−1 represented about two-thirds of total body clearance 15.9±1.21·h−1. The results suggest either a first-pass effect or incomplete absorption of diacetolol after oral administration.
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  • 73
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    European journal of clinical pharmacology 19 (1981), S. 305-307 
    ISSN: 1432-1041
    Keywords: ketoprofen ; aluminium phosphate ; bioavailability ; antacid ; pharmacokinetics ; interaction study
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The purpose of this study was to determine whether a concomitant single dose of antacid (aluminium phosphate), or multiple doses of this antacid, administered prior to and with ketoprofen would alter the bioavailability of this non steroidal anti-inflammatory agent. The possible effects of aluminium phosphate were evaluated following administration of ketoprofen alone (Phase I), co-administration of antacid and ketoprofen (Phase II), and antacid for four days before administration of ketoprofen with co-administration on the day of the study (Phase III). There were no significant differences between treatment means for peak plasma concentration, time to peak plasma concentration, and area under the plasma concentration-time curve. The observed differences were due only to individual effects. The results indicate a lack of interaction between ketoprofen and the antacid aluminium phosphate (Phosphalugel)
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  • 74
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    European journal of clinical pharmacology 19 (1981), S. 359-365 
    ISSN: 1432-1041
    Keywords: tolfenamic acid ; anti-inflammatory agent ; human pharmacokinetics ; bioavailability ; intravenous administration
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of tolfenamic acid, a new anti-inflammatory agent was studied in six healthy volunteers after an intravenous dose of 100 mg and oral doses of 100, 200, 400 and 800 mg. The disposition of intravenous tolfenamic acid could be described by two-compartment open model, with a central compartment volume (Vdc) of 5.6±0.31 (mean±SE), volume during β-phase (Vdβ) of 31±21, and a total elimination rate constant (k10) 1.6±0.1 h−1. The terminal elimination half-life was 2.5±0.6 h and the total plasma clearance 155±15 ml/min. The elimination occured principally by extrarenal mechanisms, the recovery of unchanged drug together with is glucuronide in urine averaging only 8.8% of the intravenous dose. The binding of tolfenamic acid to plasma proteins averaged 99.7%. The gastrointestinal absorption had a mean half-life of 1.7±0.1 h. Based on comparison of areas under the plasma concentration time-curves after intravenous and oral administration, the biovailability of tolfenamic acid capsules averaged 60%. The rate and extent of absorption and the rate of elimination of tolfenamic acid were independent of dose.
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  • 75
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    European journal of clinical pharmacology 21 (1982), S. 293-301 
    ISSN: 1432-1041
    Keywords: metipranolol ; deacetyl metipranolol ; pharmacokinetics ; bioavailability ; healthy volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic parameters of deacetyl metipranolol were determined after i.v. infusion of increasing doses (6–25 mg) in 17 normal volunteers. In a second cross-over trial, deacetyl metipranolol 10 and 20 mg were infused in a further 10 subjects, and in a third trial another 20 volunteers received metipranolol 40 mg orally. Metipranolol is very rapidly and completely deacetylated in man, so all pharmacokinetic data refer to deacetyl metipranolol, which was assayed by gas chromatography-mass spectrometry. The pharmacokinetic analysis was performed using a recently developed model, using a volume of distribution which is variable with time. The following data were obtained after oral administration: (mean values); lag-time 7.3 min; tmax 50 min, invasion half-life 6.3 min; elimination half-life 3 h; urinary excretion of unchanged drug approximately 4% of the dose. The experiments with infusion of increasing doses, as well as the cross-over study with 10 and 20 mg i.v., showed dose-linearity of the kinetics. The respective mean half-lives of elimination were 2.6, 2.9 and 2.8 h. The mean total, renal and extra-renal clearances amounted to 1237 ml/min, 149 ml/min and 1068 ml/min, respectively. The distribution coefficient was 3.5 l/kg, and protein binding amounted to 70% within the range of therapeutic concentrations. Absolute bioavailability was found to be approximately 50% by several different evaluation procedures. Thus, the pharmacokinetic profile of metipranolol shares features of both the lipophilic and the hydrophilic groups of β-blocking agents.
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  • 76
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    European journal of clinical pharmacology 21 (1982), S. 403-408 
    ISSN: 1432-1041
    Keywords: glibenclamide ; diabetes ; insulin ; kinetics ; blood glucose ; relationship to meals ; absorption
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In an attempt to assess whether intake of glibenclamide before meals would improve its therapeutic capacity, the present investigation compared the effect of glibenclamide 2.5mg t.i.d. given before and together with meals. In addition, these effects were compared with that of glibenclamide given as a single morning dose of 7.5mg. The subjects studied were six Type 2 diabetics not previously exposed to sulphonylurea drugs. Irrespective of dosage and mode of administration, addition of glibenclamide to a standardized breakfast, lunch and dinner enhanced plasma IRI concentrations and reduced blood glucose concentrations as compared to administration of meals without the drug. The different modes of glibenclamide administration did not differ significantly with respect to IRI responses. However, the blood glucose reduction after breakfast was significantly greater when glibenclaimde 2.5mg had been given before the meal than when 2.5 or 7.5mg were given with the meal; a similar, but non-significant tendency was observed after lunch; no consistent difference was seen after dinner. Food intake did not affect glibenclamide kinetics. It appears that administration of glibenclamide 2.5mg before breakfast improved glucose utilization following the breakfast load, due to earlier attainment of an effective concentration of glibenclamide.
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  • 77
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    European journal of clinical pharmacology 20 (1981), S. 65-72 
    ISSN: 1432-1041
    Keywords: tranexamic acid ; pharmacokinetics ; bioavailability ; oral absorption ; influence of food ; plasma clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Tranexamic acid 1 g was given intravenously to three healthy volunteers. Plasma concentrations decayed in three monoexponential phases. Most elimination took place during the first eight hours, giving an apparent elimination half-life of approximately two hours. Plasma clearance ranged between 110–116 ml/min. The urinary recovery of tranexamic acid exceeded 95% of the dose. Ten healthy volunteers were given tranexamic acid 2 g orally on an empty stomach, and together with a meal. Food had no influence on the absorption of tranexamic acid, as judged by comparison of the peak plasma concentration, the time required to reach the peak, the AUC from zero to six hours, and the urinary excretion data. The oral bioavailability of tranexamic acid, calculated from 24 h urinary excretion after oral and intravenous administration, was 34% of the dose.
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  • 78
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    European journal of clinical pharmacology 22 (1982), S. 171-173 
    ISSN: 1432-1041
    Keywords: theophylline ; neonates ; bioavailability ; food intake ; premature infants
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 16 premature infants suffering from neonatal apnoea received orally an aqueous solution of theophylline 5 mg/kg bodyweight under fasting conditions and immediately before a milk feed. Bioavailability up to 7 h after administration was determined from the serum concentration-time course. The rate of absorption was significantly decreased if the drug was given with food; mean maximum serum concentrations were reached after 4.7 h instead of 1.6 h under fasting conditions. The area under the curve did not differ between the two patient groups which indicates that only the rate but not the amount of absorption was affected by food intake. The influence of feeding on the rate of absorption of theophylline by premature infants, which is more pronounced than in adults, can be related to particular functional factors in the gastrointestinal tract during the neonatal period.
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  • 79
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    European journal of clinical pharmacology 22 (1982), S. 309-314 
    ISSN: 1432-1041
    Keywords: acetylsalicylic acid ; salicylic acid ; dipyridamol ; bioavailability ; kinetics ; rapid- and slow-release formulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Acetylsalicylic acid (ASA) is a strong, irreversible inhibitor of platelet aggregation, but loses this activity following first-pass deacetylation to salicylic acid (SA). In order to compare the bioavailability of unchanged ASA from rapid- and slow-release formulations, the single-dose concentration profiles of ASA and SA were studied in healthy volunteers following intake of two different rapid-release (conventional and effervescent tablets) and three different slow-release (microencapsulated ASA in tablets and in capsules, and enteric-coated tablets) formulations of ASA, and of one slow-release formulation of sodium salicylate. Since anti-platelet therapy with ASA is often combined with dipyridamol, the influence of this drug was also examined. The concentrations of ASA and SA were measured by high-pressure liquid chromatography. While the bioavailability of SA from the 5 ASA formulations was essentially equal and similar to that of the salicylate formulation, the bioavailability and peak concentrations of ASA appeared to be the much greater after rapid-release than after slow-release formulations. Indeed, ASA was only rarely detected in systemic blood following intake of slow-release ASA. Co-administered dipyridamol did not significantly influence the kinetics of ASA or SA. It appears that rapid-release formulations of ASA should be prefered in anti-platelet therapy, either alone or in combination with dipyridamol.
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  • 80
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    European journal of clinical pharmacology 20 (1981), S. 277-282 
    ISSN: 1432-1041
    Keywords: dexamethasone phosphate ; dexamethasone sulphate ; intravenous injection ; bioavailability ; pituitary-adreno-cortical suppression ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The metabolic fate and ACTH-supressant activity of two injectable dexamethasone esters, 21-phosphate and 21-sulphate, were studied in healthy men. After i.v. injection of 20 mg free steroid alcohol, dexamethasone phosphate was efficiently hydrolyzed to free dexamethasone, reaching its peak plasma concentration within 5 min. About 9% of the administered dose appeared in the urine as free dexamethasone. By contrast, virtually no free dexamethasone was found in plasma and urine after injection of dexamethasone sulphate. Pharmacokinetic analysis showed that dexamethasone sulphate had a shorter plasma half-life and a higher metabolic clearance rate than free dexamethasone. A larger fraction (60%) of dexamethasone sulphate was rapidly excreted unmetabolized in urine. The plasma cortisol level was significantly suppressed for more than 24 h after dexamethasone phosphate, while the plasma cortisol profile after dexamethasone sulphate merely showed physiological circadian variations. When the steroid esters were injected after pretreatment with metyrapone, a definite suppression of plasma ACTH was noted after dexamethasone phosphate, but again, dexamethasone sulphate was ineffective. These results cast serious doubt on the clinical value of dexamethasone sulphate as an injectable glucocorticoid, and critical reevaluation of this preparation is needed.
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    European journal of clinical pharmacology 24 (1983), S. 103-108 
    ISSN: 1432-1041
    Keywords: dexamethasone ; bioavailability ; pharmacokinetics ; ‘first-pass’ effect ; pre-systemic elimination
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and oral biovailability of dexamethasone were studied in 6 patients with neurological disease being treated with high dosages of the drug. A specific high performance liquid chromatographic assay was used to measure dexamethasone concentrations. Unlike the previously published mean figure of 0.78 for the oral bioavailability of the drug given in single doses to healthy volunteers, the mean bioavailability of dexamethasone in the patients studied was 0.53±SD 0.40. It appeared more likely that this incomplete bioavailability was due to presystemic elimination than to poor absorption. The intravenous clearance of the drug was relatively high (0.4902±SD 2291 l kg−1, approximately 65% of expected hepatic plasma flow), the oral clearance higher (2.5804±SD 3.2181 l kg−1 h−1) while the absorption rate constant (4.8729±8.4998 h−1), suggested rapid absorption after oral administration. Prior phenytoin and possibly prior dexamethasone therapy is likely to have contributed to the higher clearance values of the drug in these patients than the values reported in healthy volunteers after single dose studies.
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  • 82
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    European journal of clinical pharmacology 24 (1983), S. 41-47 
    ISSN: 1432-1041
    Keywords: quinidine ; digoxin ; interaction ; kinetics ; absorption ; elimination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To evaluate the possible effect of quinidine on digoxin bioavailability, the steady state digoxin kinetics was examined with and without concomitant quinidine therapy, in 7 cardiac patients after simultaneous administration of oral digoxin and intravenous [3H]-digoxin. In the presence of quinidine, the absorption rate constant of digoxin (ka) increased from 2.72±1.04 to 3.53±1.34 h−1 (p〈0.05), whereas lag time and peak time decreased from 0.16±0.10 to 0.05±0.04 h (p〈0.05) and from 0.92±0.27 to 0.69±0.19 h (p〈0.02), respectively. Predose plasma digoxin increased from 0.41±0.25 to 0.70±0.31 ng/ml (p〈0.02), while peak plasma digoxin increased from 0.93±0.34 to 1.63±0.46 ng/ml (p〈0.02). The systemic availability of digoxin increased from 68.48±13.35 to 79.09±14.89% (p〈0.05) in the presence of quinidine. Quinidine had no effect on the biotransformation pattern of digoxin, as assessed by thin layer chromatography. Quinidine increases the rate and extent of digoxin absorption, and this interaction contributes significantly to the elevation in plasma digoxin during both its distribution and elimination phases.
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  • 83
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    European journal of clinical pharmacology 20 (1981), S. 465-471 
    ISSN: 1432-1041
    Keywords: metoclopramide ; pharmacokinetics ; bioavailability ; first-pass effect
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The time courses of plasma metoclopramide concentrations were followed in six subjects after oral and intravenous single dose administration. Plasma concentration-time data following i.v. administration in each subject were found to fit a two compartment model with a mean terminal half-life of 4.55 h±0.80 h and a mean distribution half-time of 0.35 h±0.09 h. Volumes of distribution were high (3.43±1.181 · kg−1), and clearances (0.53±0.191 · kg−1h−1) approached liver plasma flow. This suggests that metoclopramide occurs at higher concentrations in tissues than in plasma, and that its clearance is probably limited by liver blood flow rather than liver metabolic capacity. The post-absorption decline in metoclopramide plasma levels after oral administration was also biexponential in each subject. The terminal half-life was 5.17 h±0.98 h. Mean volume of distribution and mean clearance were similar to intravenous values (after adjustment for bioavailability). Oral absorption was rapid with peak plasma concentrations being reached at a mean time of 0.93 h. A mean bioavailability of 0.77 was calculated for the six subjects, and it was postulated that this incomplete availability is due to a first-pass effect. The inter-individual variation in the degree of ‘first-pass’ was considerable (0.47–1.14).
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  • 84
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    European journal of clinical pharmacology 20 (1981), S. 473-478 
    ISSN: 1432-1041
    Keywords: methadone ; bioavailability ; pharmacokinetics ; single dose ; stable isotope technique ; two compartment model
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition of methadone was studied in eight opiate dependent subjects during detoxification. Plasma concentrations were determined by mass fragmentography for 48 hours after administration of methadone 20 mg as tablets and simultaneous intravenous injection of deuterium-labelled methadone 20 mg. Pharmacokinetic parameters were calculated for the intravenous dose assuming a two compartment open model. Bioavailability was determined by comparing the areas under the plasma concentration versus time curves of unlabelled and labelled methadone. The beta-phase plasma half-lives varied five-fold, with a range from 8.5 to 47 h. The apparent volumes of distribution varied from 2.1 to 5.61/kg. Five patients had a bioavailability exceeding 90%, and three had lower bioavailabilities of between 41 and 76%. The unlabelled and labelled drug appeared to be pharmacokinetically equivalent. The data show that for a majority of these subjects the bioavailability was higher than 45%, the previously reported value. The marked individual variation in methadone pharmacodynamics and kinetics, and the possibilities both of cellular and methabolic tolerance, require an individually optimized dosage regimen.
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  • 85
    ISSN: 1432-1041
    Keywords: oxmetidine ; pharmacokinetics ; bioavailability ; plasma half-life ; clearance ; oral dose ; i.v. dose
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma concentration curves and urinary excretion of oxmetidine after administration of single i.v. (100 mg) and oral (200 mg) doses have been studied in 11 patients with peptic ulcer disease. The mean bioavailability of the drug was 70% (range 53–91%). After intravenous administration, the mean plasmat 1/2β was 3.0 h, the mean apparent volume of distribution 0.7 l/kg, the mean total plasma clearance 12.3 l/h and the mean plasma renal clearance was 0.7 l/h. Following intravenous and oral administration an average of 6% and 3%, respectively, of unchanged drug was found in the urine. The plasma concentration curve after oral administration in most patients exhibited two maxima, with peak concentrations appearing between 45 and 210 min after dosing.
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  • 86
    ISSN: 1432-1041
    Keywords: lorcainide ; oral antiarrhythmic therapy ; nor-lorcainide ; first-pass metabolism ; kinetics ; alternative dosage ; regimens
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The feasibility of giving a supplementary starting dose of the antiarrhythmic drug lorcainide, in order to minimalize the impact of the extensive, but saturable first-pass metabolism, was evaluated. Twenty-five adult patients were given 100 mg lorcainide tablets according to one of 3 different dosage schedules: Eight patients took one tablet at 0, 12 and 24h, 8 took 1 tablet at 0, 1, 12 and 24h and 9 took 1 tablet at 0, 2, 12 and 24h. Levels of lorcainide and its metabolite, nor-lorcainide, during treatment were determined by gas-liquid chromatography. The results show that giving a second tablet 1 or 2h after the first may produce faster saturation of the pre-systemic metabolism of lorcainide in the liver.
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  • 87
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    European journal of clinical pharmacology 24 (1983), S. 801-806 
    ISSN: 1432-1041
    Keywords: acebutolol ; hydrochlorothiazide ; kinetics ; drug combination ; interaction ; diacetolol ; healthy subjects ; renal clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of acebutolol and hydrochlorothiazide (HCT) alone or in combination were studied in 12 healthy subjects in a cross over study. Acebutolol and diacetolol (the main metabolite) in plasma and urine were determined by HPLC and hydrochlorothiazide by GLC. The main pharmacokinetic parameters of acebutolol did not differ significantly: AUC 4492±272 µg l−1 h given alone versus 4118±354 µg l−1 h with HCT, half-life (7,69±0,32 h vs 8,10±0,72 h) and renal clearance (13,1±0,5 lh−1 vs 13,8±0,9 lh−1), respectively. There was no difference in diacetolol pharmacokinetics. HCT values were not significantly different: AUC 784±48 µg l−1 h given alone and 720±42 µg l−1 h with acebutolol, t1/2 (4,79±0,37 h vs 4,73±0,43 h). The renal clearance was slightly higher when HCT was given with acebutolol (26,2±2,6 vs 20,3±2,11 h−1,p〈0,05). This increase, observed during the first four hours, was probably due to competition between the drugs for binding to red blood cells.
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  • 88
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    European journal of clinical pharmacology 22 (1982), S. 85-90 
    ISSN: 1432-1041
    Keywords: lignocaine ; verapamil ; propranolol ; bioavailability ; predictions ; first pass effect ; oral clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary For drugs with a high hepatic clearance, bioavailability is low due to the so-called “first pass effect”. Prediction of the bioavailability for these drugs has been only lossely tested. It is proposed that by plotting the reciprocal of bioavailability versus the oral clearance, a straight line with intercept of unity and slope of reciprocal of hepatic blood flow should ensue. For lignocaine and verapamil, this relationship was found to be strong and gave good predictability, whereas for propranolol this relationship was weak and gave poor predictability. The proposed method may be of value in determining whether the low bioavailability of a drug is due to hepatic first pass metabolism.
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    European journal of clinical pharmacology 25 (1983), S. 689-693 
    ISSN: 1432-1041
    Keywords: amiodarone ; bioavailability ; calculation ; linear pharmacokinetics ; absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Methods for estimating the bioavailability of drugs with long elimination half-lives are examined. Provided both absorption and disposition are linear a simple linear regression method is developed which can be used to calculate bioavailability in situations where only an incomplete estimate of the area under the curve (AUC) is available. The regression method and the traditional method of comparing the AUC following an oral dose to the AUC following an i.v. dose were applied to simulated data. It was found that the AUC ratio method works well as long as absorption is complete within the time over which the AUC is computed. The regression method is less precise than the AUC ratio method but is more accurate for drugs with long absorption half-lives. When applied to published data on a beta blocker the two methods produced comparable results. The bioavailability of amiodarone in three human subjects was calculated to be 0.20, 0.44 and 0.98 using the regression method with similar results from the ratio method. It is not possible to estimate the clearance of amiodarone from single dose data.
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  • 90
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    European journal of clinical pharmacology 23 (1982), S. 261-266 
    ISSN: 1432-1041
    Keywords: mexiletine ; rifampicin ; kinetics ; enzyme induction ; excretion ; antipyrine clearance ; dosage adjustment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To study the effects of enzyme induction on its pharmacokinetics, a single oral dose of the new antiarrhythmic agent mexiletine hydrochloride 400 mg was administered to 8 healthy volunteers before and after treatment with rifampicin 300 mg b.i.d. for ten days. The absorption and distribution of mexiletine were not changed after rifampicin, but its elimination half-life fell from 8.5±0.8 h (mean±SE) to 5.0±0.4 h (p〈0.01), and its nonrenal clearance increased from 435±68 ml/min to 711±101 ml/min (p〈0.01). The mean renal clearance of mexiletine did not change, but it showed an exponential correlation with urinary pH. The amount of unchanged mexiletine excreted in urine over two days decreased from 32±7 to 18±3 mg (p〈0.01). The half-life of antipyrine fell from 11.8±0.4 to 5.5±0.3 h and its clearance increased from 40±3 ml to 74±3 ml/min (p〈0.01). There was a significant (p〈0.05) positive linear correlation between both the half-lives and the clearances of antipyrine and mexiletine. The clearances were positively correlated with serum γ-glutamyl transpeptidase. The results suggest that the dosage of mexiletine should be adjusted when enzyme inducing drugs are started or stopped during therapy with it.
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  • 91
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    European journal of clinical pharmacology 26 (1984), S. 405-407 
    ISSN: 1432-1041
    Keywords: theophylline ; drug absorption ; bioavailability ; food intake ; sustained-release preparations ; Theolin Retard
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of theophylline from a sustained release tablet preparation (Theolin® Retard 300 mg) was studied in 10 subjects both when fasting and immediately after a standardized breakfast. Intravenous aminophylline was used as the reference material. Food did not influence the absorption from Theolin Retard. The bioavailability was complete (93% after 30 h) both with and without food, and no difference was found in the time to peak of the plasma concentration curve (7 h), or the mean residence time (14 h). The absorption characteristics, with predominantly zero order kinetics, did not change with concomitant intake of breakfast.
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  • 92
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    European journal of clinical pharmacology 27 (1984), S. 111-114 
    ISSN: 1432-1041
    Keywords: chlorambucil ; chronic lymphocytic leukaemia ; phenylacetic acid mustard ; food intake ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food intake on the pharmacokinetics of chlorambucil (C) and its cytotoxic metabolite, phenylacetic acid mustard (PAM), has been studied in man after oral doses of chlorambucil. The administration of chlorambucil with food resulted in slower absorption than when fasting. However, the area under the plasma concentration-time curve (AUC) was unaffected. The mean ratio AUCPAM/AUCC was 2.8 (range 1.4–7.1) under fasting and 3.3 (range 1.3–7.4) under nonfasting conditions. The metabolite very probably plays an important role in the cytotoxic effects observed after administration of C, since calculations show that a major fraction of the metabolite is eliminated by alkylation reactions.
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  • 93
    ISSN: 1432-1041
    Keywords: nitroglycerin ; plasma concentration ; transdermal administration ; bioavailability ; pharmacodynamics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 6 healthy volunteers, intravenous infusions of nitroglycerin 4.8 and 10.6 µg/min yielded mean steady-state plasma concentrations of 0.5±0.02 and 0.82±0.04 ng/ml as determined by a gas chromatographic/mass spectrometric method. The plasma concentrations reached in the same subjects 17 h after application of Nitroderm TTS 5 and 10 with in vivo release rates of 3.7 and 5.7 µg/min were 0.28±0.01 and 0.37±0.01 ng/ml, respectively. Thus, 75% of the quantity of nitroglycerin released by the systems passed into the circulation. The inter-individual and intra-individual variations in plasma concentrations were similar for both modes of administration. The nitroglycerin-induced morphological changes in the fingerpulse wave were clearly dose-dependent, but it seems that this pharmacodynamic parameter is determined less by the plasma concentration than by the nitroglycerin content of the vascular wall.
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  • 94
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    European journal of clinical pharmacology 17 (1980), S. 375-378 
    ISSN: 1432-1041
    Keywords: mebendazole ; echinococcosis ; bioavailability ; absorption ; concomitant eating ; plasma level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary High oral doses of mebendazole are used experimentally for the treatment of human alveolar and cystic echinococcosis. In order to assess bioavailability of this drug 1.5 g doses were given to 3 volunteers. Measurable plasma concentrations of 17 to 134 nmol/l were found only if mebendazole was given together with a fatty meal. In a patient with cholestasis plasma concentrations were higher than in the 3 normal subjects. In patients on long term treatment the increase in plasma concentration after administration of a 1 g dose varied between 0 and 500 nmol/l. It is concluded that systemic availability of mebendazole is enhanced by concomitant food intake. In view of the large intra- and interindividual variation in plasma concentration, monitoring plasma levels during long term therapy appears advisable.
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  • 95
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    European journal of clinical pharmacology 17 (1980), S. 465-468 
    ISSN: 1432-1041
    Keywords: paracetamol ; suppository ; tablets ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The relative bioavailability of a new paracetamol suppository (Panodil) and tablets in doses of 0.5 and 1 g was investigated in eight healthy subjects. The tablets were absorbed faster and higher peak plasma concentrations were obtained than after the suppositories. The bioavailability of the suppositories was approximately 80% of that of the tablets at both dose levels. There was no indication of capacity-limited elimination at either the two doses investigated.
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  • 96
    ISSN: 1432-1041
    Keywords: verapamil ; pharmacokinetics ; bioavailability ; hepatic first-pass metabolism ; stable isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Following i. v. administration, the plasma concentration-time curve of verapamil could best be described by either a mono- or biexponential equation. Total plasma clearance (1.26 l/min) approached liver blood flow (1.5 l/min), so it can be concluded that its clearance is liver blood flow-dependent. Although absorption was almost complete after oral administration, absolute bioavailability (20%) was low, due to extensive hepatic first-pass metabolism. The approach using stable isotope-labelled and unlabelled drug permits simultaneous administration by the intravascular and extravascular routes, thus allowing determination of absolute bioavailability in a single experiment.
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  • 97
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    European journal of clinical pharmacology 19 (1981), S. 149-155 
    ISSN: 1432-1041
    Keywords: proxyphylline ; asthma ; pharmacokinetics ; bioavailability ; healthy adults ; theophylline derivative
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Serum concentrations and urinary excretion of proxyphylline have been measured in five healthy adults after intravenous (29 µmol/kg), single oral (21 µmol/kg) and multiple oral (21 µmol/kg three times a day) doses to produce steady state. The mean peak time after oral administration was 29 min. The mean fraction absorbed was 1.09 calculated from serum concentrations, and 1.05 calculated from urinary excretion of the drug. The apparent volume of distribution was 0.61 l/kg (0.53–0.72 l/kg), 26% higher in males than in females. A two-compartment open model was found to describe the decline in the serum concentrations, giving a mean distribution half-life of 6 min. The intersubject ranges of biological half-life were 8.1–12.1 h and 8.3–12.6 h calculated from serum and urine data, respectively. 24% (18–29%) of the dose was excreted unchanged in urine, which agreed with the relationship between the calculated total body clearance and the renal clearance of the drug.
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  • 98
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    European journal of clinical pharmacology 19 (1981), S. 343-347 
    ISSN: 1432-1041
    Keywords: cimetidine ; phenobarbital ; gastro-intestinal absorption ; bioavailability ; renal clearance ; non-renal clearance ; enzyme induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of orally administered cimetidine was studied in 8 healthy subjects before and after 3 weeks of treatment with phenobarbital 100 mg daily, and in a separate study 4 subjects received cimetidine intravenously before and after the administration of phenobarbital. There was no change in the volume of distribution, but total plasma clearance was increased by a mean of 18%, mainly due to a 37% increase in nonrenal clearance. Renal clearance and half-life were not significantly altered. The area under the plasma concentration-time curve after oral administration was significantly (P≪0.05) reduced by a mean of 15% after phenobarbital treatment. The amount of cimetidine excreted in urine and its sulphoxide metabolite were significantly (P〈0.05) reduced, on average by 34% and 26%, respectively by phenobarbital treatment. The data indicate that an apparent 20% reduction in the absorption of cimetidine was due to induction of gastrointestinal metabolism of cimetidine, with some contribution also from hepatic metabolism. Reduced absorption per se could not be totally excluded. Although the magnitude of the change was small, the finding of an 11% decrease in the time to achieve an effective plasma level of cimetidine after phenobarbital treatment may contribute to the ineffectiveness of cimetidine in certain patients.
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  • 99
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    European journal of clinical pharmacology 22 (1982), S. 359-365 
    ISSN: 1432-1041
    Keywords: chlorpheniramine ; pharmacokinetics ; oral absorption ; half-life ; bioavailability ; volume of distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma and urinary levels of chlorpheniramine (CPM) and its 2 demethylated metabolites were measured by HPLC after i.v. and oral dosing. In 5 mg (maleate) i.v. bolus studies in 2 subjects, plasma CPM levels were fitted to triexponential equations with terminal half-lives (t 1/2) of 23 and 22 h and area of 3.6 and 3.21/kg, respectively. Intravenous data predicted hepatic blood extraction ratios for the 2 subjects to be 0.06 and 0.07, respectively. Absolute bioavailability from oral solution (10 mg) was 59 and 34%, and from tablets (8 mg) 44 and 25%, respectively, indicating extensive gut first-pass metabolism. Mean t 1/2 from 7 oral fasting studies in 5 subjects was 28 h (19–43 h). Mean absorption lag time was 0.7 h (0.4–1.3 h), and mean peak time was 2.8 h (2–4 h). In 2 subjects, 6 mg solutions were given every 12 h for 9 doses; good correlation between single and multiple dose kinetics was found. Significant accumulation was demonstrated in simulation studies with frequent daily dosing. Estimated accumulation ratios vary from 4.1 to 9.4 (mean 6.5). The t 1/2 from urinary data (collected for 12 days) was consistent with plasma data. The above results suggest the need to reexamine the current practice of frequent daily dosing and the use of sustained or controlled release dosage forms of this drug. The possible cause of reduced plasma clearance of CPM in renal patients is discussed.
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  • 100
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    European journal of clinical pharmacology 22 (1982), S. 459-462 
    ISSN: 1432-1041
    Keywords: tolbutamide ; diabetes ; food intake ; blood glucose ; blood insulin ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of food on the rate and extent of absorption of tolbutamide in diabetic patients was studied by varying the time of drug administration in relation to the ingestion of a standard meal. Serum levels of tolbutamide, insulin and glucose and related bioavailability parameters were compared following the administration of a single dose of tolbutamide 0.5 g to diabetic patients 30 min prior to and immediately before a standardized meal. A placebo dosage form was also administered to determine baseline glucose and insulin response to the meal. The 700 calorie standard meal was composed of 41% carbohydrate, 18% protein, and 41% fat. Administration of the drug with the meal resulted in a 6% (statistically significant) decrease in the extent of absorption, as determined by measurement of the area under the tolbutamide serum level-time curve from zero to infinity. Serum levels of tolbutamide were also significantly higher 0.5 h after drug administration when the drug was taken with the meal. Except for these two minor effects, no other differences between the drug treatments were observed in any other parameters of tolbutamide absorption or in the postprandial glucose and insulin serum levels. Therefore, the small differences found were judged to be clinically meaningless. These findings demonstrate that administration of tolbutamide 0.5 g tablets 30 min prior to or with a standard meal results in equivalent therapeutic actions.
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