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  • Scolytidae
  • bioavailability
  • healthy volunteers
  • Springer  (23)
  • American Association of Petroleum Geologists (AAPG)
  • Nature Publishing Group
  • 1995-1999  (23)
Sammlung
Verlag/Herausgeber
  • Springer  (23)
  • American Association of Petroleum Geologists (AAPG)
  • Nature Publishing Group
Erscheinungszeitraum
Jahr
  • 1
    ISSN: 1573-1561
    Schlagwort(e): Ips pini ; Ips integer ; Coleoptera ; Scolytidae ; aggregation pheromone ; lanierone ; ipsdienol ; geographic variation ; synergism ; Enoclerus lecontei ; Cleridae ; kairomone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Lanierone strongly synergized the attraction of male and female Ips pini (Say) to ipsdienol in New York and Wisconsin. Synergy was only weakly significant in Montana and British Columbia and not significant in California. Catches of I. pini in ipsdienol-baited traps were increased 0% ( i.e., nonsignificant) to 9942% by lanierone, with the highest increases in eastern North America. Lanierone had the least effect in California. The effects of lanierone on sex ratios of I. pini in trap catches varied significantly between regions. The addition of lanierone to ipsdienol-baited traps resulted in a general increase in male representation at nine of 12 sites. Ips integer (Eichhoff) was attracted to lanierone alone. Ipsdienol reduced the response of I. integer to lanierone. Enoclerus lecontei (Wolcott) (Cleridae) preferred traps baited with the combination of ipsdienol and lanierone. (R)-(–)-Ipsdienol was attractive to E. sphegeus (F.), Thanasimus undatulus (Say) (Cleridae), and Temnochila chlorodia (Mannerheim) (Trogositidae), while racemic ipsdienol was attractive to E. nigrifrons var. gerhardi Wolc. and Thanasimus dubius (F.). Lanierone had no effect on these species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1573-5036
    Schlagwort(e): bioavailability ; cadmium ; chicory ; chromium ; Cichorium intybus ; contamination ; ecological risk assessment ; Erigeron canadensis ; Eupatorium capillifolium ; horseweed ; index plants ; index species ; metals ; nickel ; soil ; vanadium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Uncultivated plants growing on disturbed sites may be useful for assessing the bioavailability of some metals in soils, and thus the potential for metal mobilization up the terrestrial food chain, an important element in ecological risk assessment. A planted chicory cultivar (Cichorium intybus L. var. foliosum Hegi.) and the uncultivated plants horseweed (Canada fleabane) (Erigeron canadensis L.) and dogfennel (Eupatorium capillifolium (Lam.) Small) were evaluated for their ability to act as index plant species for soil Cd, Cr, Ni, and V at two field sites where these metals had been applied five yr previously to two highly weathered sandy Ultisols. Soil Cd was available to all analyzed plant tissues of all three plant species at both sites, particularly on the sandier Blanton soil. Chicory was an effective index plant for Cd on the finer textured Orangeburg soil but functioned as an indicator plant (toxicity symptoms were observed) on the sandier Blanton soil. Horseweed and dogfennel were effective index plants for Cd in both contaminated soils. Soil Cr, Ni, and V were less bioavailable than soil Cd and plant metal uptake was more sensitive to residual soil Cr, Ni, and V than was soil extraction with double acid. Horseweed and chicory may have potential as index plants for soil Cr. Chicory may have potential as a Ni index plant. Chicory and dogfennel may have potential as V index plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1436-6215
    Schlagwort(e): Strontium ; oraler Strontium-Test ; Calcium ; Absorption ; gesunde Probanden ; Strontium ; oral strontium test ; calcium ; absorption ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Intestinal strontium absorption has been discussed recently as an indirect measure for calcium uptake. Prerequisite for the clinical use of an oral strontium test is the availability of a reliable procedure including controlled strontium supply, sample pretreatment and analysis as well as the assessment of normal values. In the present study, a group of young females (n=33; 24.0 ± 2.7 y; BMI 21.5 ± 1.9) received an oral dose of 2.27 mmol strontium in a standardized breakfast that contained 0.625 mmol calcium. Before and 220 min after the bolus serum strontium concentrations were determined by means of atomic absorption spectrophotometry (coefficient of variation: within day 4.8 %, n=10; day-to-day 9.5 %, n=8). The error of the method was 2.7 %. Calculation of the fractional strontium absorption rate considered the respective distribution volume (extracellular fluid; either estimated using body weight or determined by means of bioimpedance analysis [BIA]). Average absorption rates were 13.3 ± 3.1 % and, considering BIA measurement 13.6 ± 2.6 %, respectively. Smoking, exercise and, use of oral contraceptives showed no effects. Our oral strontium test is characterized by excellent reliability, easy handling and low costs and, thus, is suitable for routine use.
    Notizen: Zusammenfassung Die Erfassung der Strontiumabsorption wird heute als indirektes Verfahren zur Beurteilung der intestinalen Calciumabsorption diskutiert. Voraussetzung für die klinische Anwendung ist ein vertrauenswürdiges Testverfahren inclusive kontrollierter Strontiumgabe, Probenaufarbeitung und -analyse sowie die Erfassung von Normalwerten. Für unsere Studien wurde ein Kollektiv junger Frauen (n=33, 24,0 ± 2,7 Jahre; BMI 21,5 ± 1,9) herangezogen. Die Probandinnen erhielten eine Bolusgabe von 2,27 mmol Strontium zusammen mit einem Standardfrühstück (ca. 0,625 mmol Calcium). Vor und 220 min nach der Bolusgabe erfolgte die Bestimmung des Serum-Strontiumgehaltes mittels Atomabsorptionsspektrometrie. Der Variationskoeffizient der Methode lag innerhalb eines Tages bei 4,8 % (n=10) und von Tag zu Tag 9,5 % (n=8). Der Fehler der Methode betrug 2,7 %. Die Berechnung der fraktionellen Strontiumabsorptionsrate erfolgte unter Berücksichtigung des entsprechenden Verteilungsraumes (Extrazellulärflüssigkeit; Schätzverfahren über Körpergewicht bzw. Bioimpedanz-Analyse [BIA]). Die Strontiumabsorptionsrate lag im Mittel bei 13,3 ± 3,1 %, unter Berücksichtigung der BIA-Werte bei 13,6 ± 2,6 %. Rauchen, sportliche Aktivität bzw. Einnahme oraler Kontrazeptiva zeigten keinen Einfluß. Das hier vorgestellte Testverfahren ist aufgrund seiner hohen Vertrauenswürdigkeit und relativ einfacher Handhabung für Routine-untersuchungen geeignet.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1572-8773
    Schlagwort(e): aluminium citrate ; aluminium hydroxide ; bioavailability ; ingestion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A study was undertaken to determine the fraction of ingested aluminium taken up by two male volunteers, following their ingestion of either aluminium citrate or aluminium hydroxide. In addition, the effects of simultaneous citrate ingestion on the gastrointestinal absorption of aluminium from its hydroxide was studied. Volunteers received three oral doses of26Al-labelled aluminium compound in water. The doses were administered directly into the stomach using a paediatric feeding tube. Blood samples were collected from the volunteers at 1, 4 and 24 h after administration, and their daily output of urine and faeces was collected for 6 days. These samples were analysed for their26Al content using either coincidence gamma-counting or accelerator mass spectrometry. The uptake of aluminium was greatest following its administration in the citrate form and was least following intake as the aluminium hydroxide suspension. The co-administration of citrate, with the aluminium hydroxide suspension, was found to enhance the levels of26Al uptake in both volunteers. Using a urinary excretion factor based on the results of previous studies, the fractional aluminium uptake from each of the species was calculated: aluminium citrate, 5.23 × 10−3; aluminium hydroxide, 1.04 × 10−4; aluminium hydroxide with citrate, 1.36 × 10−3.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Biodegradation 8 (1997), S. 287-296 
    ISSN: 1572-9729
    Schlagwort(e): asphaltene ; bioavailability ; biodegradation ; crude oil ; diffusivity ; modeling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Energietechnik , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Crude oil is a complex mixture ofseveral different structural classes of compoundsincluding alkanes, aromatics, heterocyclic polarcompounds, and asphaltenes. The rate and extent ofmicrobial degradation of crude oil depends on theinteraction between the physical and biochemicalproperties of the biodegradable compounds and theirinteractions with the non-biodegradable fraction. Inthis study we have systematically altered theconcentration of non-biodegradable material in thecrude oil and analyzed its impact on transport of thebiodegradable components of crude oil to themicroorganisms. We have also developed a mathematicalmodel that explains and accounts for the dependence ofbiodegradation of crude oil through a putativebioavailability parameter. Experimental resultsindicate that as the asphaltene concentration in oilincreases, the maximum oxygen uptake in respirometersdecreases. The mathematically fitted bioavailabilityparameter of degradable components of oil alsodecreases as the asphaltene concentration increases.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 102 (1995), S. 17-23 
    ISSN: 1432-1939
    Schlagwort(e): Kairomones ; Predation ; Coevolution ; Scolytidae ; Pheromones
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Predators that exploit prey pheromones may select for relatively subtle chemical changes that confer partial escape yet retain intraspecific functionality. Parallel experiments conducted with a transcontinentally distributed bark beetle, Ips pini, demonstrated that the most abundant predators in California and Wisconsin were more attracted to prey from distant sources than to those from local sources. Conversely, local I. pini populations were most attractive to local conspecifics. Any benefits to prey are probably only partial and temporary, however, because all predators showed some attraction to both I. pini populations. Responses by other insects exploiting I. pini communication systems varied with ecological guild. A parasitic wasp that attacks adult hosts was more attracted to local than to distant I. pini populations. Secondary subcortically feeding herbivores that cannot colonize living trees but rather breed in trees killed by I. pini were highly attracted to infested logs but did not consistently prefer either I. pini population source. Some possible underlying mechanisms, implications for natural enemy-prey coevolution, and suggested strategies for biological control are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1432-1041
    Schlagwort(e): Piroxicam ; β-Cyclodextrin ; pharmacokinetics ; healthy volunteers ; multiple dose ; adverse event
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract CHF1194 is an inclusion complex of β-cyclodextrin with the nonsteroidal anti-inflammatory drug piroxicam. In man, β-cyclodextrin acts as a carrier of piroxicam. As the inclusion complex of piroxicam-β-cyclodextrin is wettable and more water soluble, the absorption rate of the drug is increased whilst its other pharmacokinetic characteristics remain unchanged. The aim of the present study in 12 healthy subjects was to compare the oral bioavailability of 20 mg piroxicam in a CHF1194 tablet and a plain piroxicam capsule after a single dose and after two weeks of once daily administration, and also to assess the plasma levels and urinary excretion of β-cyclodextrin after CHF1194 administration. The two treatments were administered in cross-over fashion, separated by a wash-out period of three weeks. Piroxicam, 5′-hydroxypiroxicam and β-cyclodextrin were monitored in plasma and urine for 120 h after the first and last doses. Clinical tolerance was excellent and no adverse event occurred during either phase of the study. The extent of absorption of piroxicam from the CHF1194 tablet after the single dose was equivalent to that after the plain piroxicam capsule, within confidence limits of less than 80–125%. After repeated dosing, CHF1194 yielded the same steady-state systemic concentrations of piroxicam and 5′-hydroxypiroxicam as the reference capsule, and similar excretion pattern of the metabolite. After both single and multiple dosing, piroxicam was absorbed more rapidly after CHF1194, an expected consequence of the complexation of piroxicam with β-cyclodextrin. This may be of therapeutic interest as it might accelerate the onset of pain relief. The pharmacokinetics of piroxicam was linear after the doses used here, suggesting that long term treatment with CHF1194 should not require any change in dosing regimen. Even after 14 days of repeated administration of CHF1194, β-cyclodextrin could not be detected in plasma or urine, suggesting that in man the unchanged oligosaccharide was absorbed to a very small extent.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 48 (1995), S. 203-208 
    ISSN: 1432-1041
    Schlagwort(e): Moxonidine ; Renal haemodynamics ; imidazoline receptors ; natriuresis ; blood pressure ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract Moxonidine and related compounds have been recently introduced into antihypertensive therapy. It is thought that these drugs exert their blood pressure lowering effect through interaction with nonadrenergic receptors in the central nervous system, i.e. imidazoline receptors, although the contribution of specific interaction with α2-receptors is still under debate. Imidazoline receptors have recently been documented in the renal proximal tubule. In experimental studies, interaction of imidazolines with these receptors decreased the activity of the Na+/H+ antiporter and induced natriuresis. To quantitate the effect of the imidazoline receptor agonist moxonidine on renal sodium handling and renal haemodynamics in man, we examined ten healthy normotensive males (aged 25 ± 4 years) in a double blind placebo-controlled study using a crossover design. Subjects were studied on a standardized salt intake (50 mmol per day). On the 7th and 10th study day they were randomly allocated to receive either i.v. placebo or i.v. 0.2 mg moxonidine. Urinary electrolyte excretion, lithium clearance (as an index of proximal tubular sodium handling), glomerular filtration rate (GFR), effective renal plasma flow (ERPF), renal vascular resistance (RVR), mean arterial blood pressure (MAP), plasma renin activity (PRA) and plasma noradrenaline (NA) levels were assessed. Injection of moxonidine did not increase fractional sodium excretion or lithium clearance. Specifically, antinatriuresis was not observed after injection of moxonidine despite a significant decrease in MAP from 91 to 85 mmHg and a significant increase in PRA. MAP and PRA did not change with administration of placebo. Injection of moxonidine did not affect GFR and RVR; ERPF decreased slightly but not significantly. Acute administration of 0.2 mg i.v. moxonidine decreased blood pressure in healthy volunteers on standardized salt intake, but did not affect natriuresis, proximal tubular sodium reabsorption or glomerular filtration rate. The absence of an antinatriuretic response despite a decrease in blood pressure suggests a direct facilitation of natriuresis by moxonidine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 49 (1995), S. 45-49 
    ISSN: 1432-1041
    Schlagwort(e): Atropine ; M2-cholinoceptors ; effect kinetics ; radioreceptor assay ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract The effects of an oral dose of atropine (0.03 mg/kg body weight) and an IM (0.02 mg/kg) dose on the heart rate and salivary flow in seven healthy adult volunteers were compared to see whether the oral dose was sufficient to inhibit vagal reflexes of the heart. Atropine concentrations in plasma were determined by an M2-selective radioreceptor assay, and the in vitro occupancy of porcine cardiac M2-cholinoceptors was measured in parallel. In ligand-binding studies, atropine has been shown to have a comparable affinity for human and porcine cardiac M2-cholinoceptors (Ki 4.0 and 5.9, respectively). Slight changes in heart rate after oral administration were not significant. After IM administration, however, the heart rate increased significantly, by a maximum of 22 beats·min−1 after 45 min. The slight increase in heart rate after the oral dose corresponded to a receptor occupancy in vitro near the lower limit of detection, whereas the significant increase in heart rate after the IM dose corresponded to a receptor occupancy of up to 47%. The maximum reduction in salivary flow was similar after the oral and IM doses (84.3 and 87.5%, respectively). The almost complete inhibition of salivary flow could be explained by the lower vagal tone in the salivary glands compared with to the heart. The difference in the effect on heart rate was probably due to lower absorption of the oral dose. Thus, an oral dose greater than 0.03 mg atropine/kilogram body weight is required to compensate for low gastrointestinal absorption and to overcome the high vagal tone of the heart.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 47 (1995), S. 417-421 
    ISSN: 1432-1041
    Schlagwort(e): Phase I trials ; Alanine amino transferase ; healthy volunteers ; adverse experience ; normal range ; liver function test
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract In Phase I clinical studies, the maximum tolerated dose has to be determined by a case by case analysis sometimes using a laboratory adverse effect, e.g. an increase in alanine amino transferase (ALT). For this reason a threshold to discriminate between significant or non significant adverse changes in ALT is required particularly in Phase I studies, in order to deal with the very common “close to the limit values”. Previous methods (limit of normal range or normal range plus an arbitrary margin) do not solve this problem. The authors propose a new method taking into account the threshold used as inclusion criteria for ALT (R) and the range of spontaneous variations measured under identical Phase I study conditions (V). The (R) and (V) thresholds, respectively, are defined as 50 IU·1−1 and a 50% increase, from baseline. Thus an ALT value is recognized as a “significant adverse experience” if it exceeds 50 IU·1−1 above an increase from baseline exceeding 50% of the baseline value. To highlight the value of the method, it was implemented in a one year period including 8 studies and 134 subjects. The sensitivity, specificity and positive predictive value of various methods were compared. The results showed the following: Six out of 134 subjects had significant adverse changes in ALT (4%); and all these 6 subjects were detected by the proposed new method without error. Eight subjects including two false positives, were detected by an use of the normal range limit, and only 4 were detected using, the 10% margin. Thus, use of the new method showed 1. keeping the normal range limit as the detection threshold led to preserved sensitivity; 2. it reduced the background noise of false positive results related to chance variation around the upper limit, mainly in subjects with a baseline value close to the limit; 3. it allowed better judgment of the significance of a value which lay just beyond the limit when variation from the baseline exceeding the normal range. The new method produced the best combination of sensitivity, specificity and positive predictive value. Given the small number of subjects in the study, further evaluation with a larger population is required. Finally, the proposed new method seems to be a tool easy to use determining the significance of adverse changes in ALT when the values are close to the limit that is common in Phase I studies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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