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  • bioavailability  (74)
  • morphology
  • Springer  (132)
  • Berlin-Brandenburgische Akademie der Wissenschaften
  • Cell Press
  • Förderverein Akademie 2. Lebenshälfte im Land Brandenburg
  • 2000-2004  (64)
  • 1975-1979  (68)
Collection
Keywords
Publisher
  • Springer  (132)
  • Berlin-Brandenburgische Akademie der Wissenschaften
  • Cell Press
  • Förderverein Akademie 2. Lebenshälfte im Land Brandenburg
  • Wiley-Blackwell  (1)
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Absorption of iron in rats with experimental enteritis* (2000)
    Springer
    BioMetals 13 (2000), S. 29-35 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009205505217
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  • 2
    Electronic Resource
    Electronic Resource
    Submersible observations of Equatorial Atlantic mantle: The St. Paul Fracture Zone region (2000)
    Springer
    Marine geophysical researches 21 (2000), S. 529-560 
    Details
    ISSN: 1573-0581
    Keywords: Structure ; morphology ; petrology ; peridotite-basalt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The St. Paul F.Z. is a large structural domain made up of multiple transform faults interrupted by several Intra-Transform Ridge (ITR) spreading segments. Two regions were studied in details by submersible: (1) The ITR short (〈20 km in length) segment near 0° 37′N–25° 27′W and 1° N–27° 42′W and (2) The St. Peter and St. Paul's Rocks (SPPR) massif located at 29° 25′W (¡3700 m depth). (1) The short ITR segments consist of a magma starved rift valley with recent volcanic activities at 4700 m depth. A geological profile made along the rift valley wall showed localized volcanics (basalts and dykes) which are believed to overlay and intrude the ultramafics. The geological setting and the high ultramafic/volcanic ratio suggest an extremely low magmatic supply and crustal-mantle uplift during lithospheric stretching and denudation. (2) The St. Peter and St. Paul's Rocks (SPPR) massif consists of a sigmoidal ridge within the active transform zone. The SPPR is divided into two different geological domains called the North and the South Ridges. The North Ridge consists of strongly tectonized fault scarps composed of banded and mylonitized peridotite, sporadic gabbros (3900–2500 m) and metabasalts (2700–1700 m). The South Ridge is less tectonized with undeformed, serpentinized spinel lherzolite (2000–1400 m) and basalts. Extensional motion and denudation accompanied by diapirism affected the South Ridge within a transform domain. Instead, the North Ridge was formed during an important strike-slip and faulting motion resulting in the uplifted portion of the St. Paul F.Z. transverse ridge. There is a regional compositional variation of the volcanics where E-MORBs and alkali basalts are produced on the SPPR massif and are comparable to the adjacent northern segments of the Mid-Atlantic Ridge. On the other hand, N and T- MORBs collected from the eastern part of the St. Paul F.Z. (25° 27′ W IRT) are similar to the volcanics from the southern segments of the MAR. The peridotites exposed in these provinces (SPPR and ITR) are similar in their REE and trace element distribution. Different degrees (3–15%) of partial melting of a mixed composite mantle consisting of spinel and amphibole bearing lherzolite veined with 5–40% clinopyroxenite gave rise to the observed MORBs and alkali basalts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004819701870
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  • 3
    Electronic Resource
    Electronic Resource
    T.H. Huxley's Criticism of German Cell Theory: An Epigenetic and Physiological Interpretation of Cell Structure (2000)
    Springer
    Journal of the history of biology 33 (2000), S. 247-289 
    Details
    ISSN: 1573-0387
    Keywords: cell theory ; morphology ; Thomas Henry Huxley ; physiology ; Schleiden-Schwann cell theory ; Romantic biology ; scientific zoology ; cytology ; preformationism ; natural history ; epigenesis ; Kernmonopol ; histology ; Albert von Kölliker ; embryology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , History
    Notes: Abstract In 1853, the young Thomas Henry Huxley published a long review of German cell theory in which he roundly criticized the basic tenets of the Schleiden-Schwann model of the cell. Although historians of cytology have dismissed Huxley’s criticism as based on an erroneous interpretation of cell physiology, the review is better understood as a contribution to embryology. “The Cell-theory” presents Huxley’s “epigenetic” interpretation of histological organization emerging from changes in the protoplasm to replace the “preformationist” cell theory of Schleiden and Schwann (as modified by Albert vonKölliker), which posited the nucleus as the seat of organic vitality. Huxley’s views influenced a number of British biologists, who continued to oppose German cell theory well into the twentieth century. Yet Huxley was pivotal in introducing the new German program of “scientific zoology” to Britain in the early 1850s,championing its empiricist methodology as a means to enact broad disciplinary and institutional reforms in British natural history.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004881730937
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  • 4
    Electronic Resource
    Electronic Resource
    TMDSC and Atomic Force Microscopy Studies of Morphology and Recrystallization in Polyesters Including Oriented Films (2000)
    Springer
    Journal of thermal analysis and calorimetry 59 (2000), S. 227-243 
    Details
    ISSN: 1572-8943
    Keywords: atomic force microscopy (AFM) ; morphology ; polyester ; recrystallization ; TMDSC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermal and crystal morphological properties of poly[ethylene teraphthalate] (PET) and poly(ethylene-2,6-naphthalenedicarboxylate) (PEN) biaxially oriented films were compared to amorphous and other isotropic semi-crystalline samples. Crystal melting as a function of temperature was characterized by temperature modulated DSC (TMDSC) and found to begin just above the glass transition for both oriented films. About 75°C above the glass transitions, substantial exothermic recrystallization begins and continues through the final melting region in oriented films. The maximum in the non-reversing TMDSC signal for the oriented films signifies the maximum recrystallization exothermic activity with peaks at 248°C and 258°C for PET and PEN, respectively. The final melting endotherm detected was 260°C and 270°C for PET and PEN, and is shown by the TMDSC data and by independent rapid heating rate melting point determinations to be due to the melting of species recrystallized during the heating scan. The results are compared with TMDSC data for initially amorphous and melt crystallized samples. The volume fraction of rigid species (Frigid=total crystal fraction plus ‘rigid amorphous or non-crystalline species’) were measured by TMDSC glass transition data, and contrasted with the area fraction of rigid species at the oriented film surface characterized with very high resolution atomic force microscopy (AFM) phase data. The data suggest that the 11 nm wide hard domains in PET, and 21 nm wide domains in PEN film detected by AFM consist of both crystal and high stiffness interphase species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010148331705
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  • 5
    Electronic Resource
    Electronic Resource
    Polypropylene Crystallization in an Ethylene-propylene-diene Rubber Matrix (2000)
    Springer
    Journal of thermal analysis and calorimetry 61 (2000), S. 437-450 
    Details
    ISSN: 1572-8943
    Keywords: crystallization ; EPDM ; kinetics ; morphology ; PP ; rubber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effect of the incorporation of an amorphous immiscible polymer (ethylene-propylene-diene- terpolymer) on the PP crystallization kinetics and thermodynamics is investigated by thermal analysis. The results of the investigation have shown that EPDM acts as a nucleant agent. A marked decrease of the half time of PP crystallization, τ1/2 , as well as a sensible increase of the overall crystallization rate, K n , has been observed in the presence of EPDM. Moreover, at any crystallization temperature, a minimum of τ1/2 , is obtained at 25% EPDM content in the blend. The Avrami model has been successfully applied to describe the crystallization kinetics of the blend. The kinetic curves obtained under non-isothermal conditions confirm the results obtained under isothermal conditions and demonstrate the nucleant action of the EPDM phase on the PP crystallization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010165317028
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanical Properties of Natural Fibre Mat Reinforced Thermoplastic (2000)
    Springer
    Applied composite materials 7 (2000), S. 403-414 
    Details
    ISSN: 1573-4897
    Keywords: flax fibres ; natural fibres ; thermoplastics ; tensile properties ; impact properties ; anisotropy ; electron microscopy ; morphology ; compression moulding ; processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The use of natural fibres instead of man made fibres, as reinforcements in thermoplastics, gives interesting alternatives for production of low cost and ecologically friendly composites. In this work different commercially available semi-finished natural fibre mat reinforced thermoplastics (NMT) composites have been studied. Mechanical properties and microstructure of different NMT composites were investigated and compared to conventional GMT (glass fibre mat reinforced thermoplastic) composites and pure polypropylene (PP). The study included also NMT composites manufacturing processing parameters as processing temperatures and pressure during compression moulding. The results showed that NMT composites have a high stiffness compared to pure polymer and the NMT with a high fibre content (50% by weight) showed even better stiffness than the GMT. The GMT composites had superior strength and impact properties compared to the NMT which might be due to the relatively low strength of the natural fibres but also to poor adhesion to the PP matrix. The NMT materials showed a large dependence on direction and are therefore believed to have more fibres oriented in one direction. The stronger direction (0°) of the NMT was in some cases as much as 45% better than the 90° direction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026546426764
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  • 7
    Electronic Resource
    Electronic Resource
    MoSx Thin Films by Thermolysis of a Single-Source Precursor (2000)
    Springer
    Journal of sol gel science and technology 19 (2000), S. 821-824 
    Details
    ISSN: 1573-4846
    Keywords: MoS x ; thin film ; liquid film coating ; thermolysis ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Thin films of MoS x have been prepared on silicon substrates by spin coating and thermolysis of 0.5 M solutions of alkyldiammonium tetrathiomolybdates in 1,2-ethanediamine (EDA) and 1,2-propanediamine (12PDA). The films have been heat treated in air at temperatures between 80 and 250°C and under N2 atmosphere at temperatures between 300 and 800°C. X-ray diffraction shows a restricted crystallisation and amorphous residues in both kind of films. EDA-based films exhibit a high tendency to crystallise whereas 12PDA-based films form associated structures with the solvent preventing precursor crystallisation. An insight into the processes occurring in film formation is gained by infrared spectroscopy which indicates a beginning of the decomposition of the 12PDA-based film at temperatures as low as 80°C with incorporation of the diamine solvent. In contrast, the EDA-based films show first signs of a decomposition at 150°C. The decomposition of the intermediate MoS3 in both cases starts between 250 and 300°C. By means of SNMS depth profiles carbon contents up to 21 and 32 atom-% were found in EDA- and 12PDA-based films, respectively. The films show a significant deficit of sulphur which is compensated by the carbon. Near the surface of the coatings a loss of carbon is observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008728604305
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  • 8
    Electronic Resource
    Electronic Resource
    Influence of the Layer Morphology on the Electrical Properties of Sol Gel Transparent Conducting Oxide Coatings (2000)
    Springer
    Journal of sol gel science and technology 19 (2000), S. 435-439 
    Details
    ISSN: 1573-4846
    Keywords: morphology ; electrical properties ; transparent conductive coatings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Tranparent conducting coatings have been prepared by sol gel methods either by a conventional sol-gel process (Antimony doped Tin Oxide—ATO, Aluminium doped Zinc Oxide—AZO) or a new wet chemical process using fully dispersed crystalline nanoparticles (ATO, Indium Tin Oxide—ITO). The dip coating technique has been used as deposition technique with single coating thickness varying from a few nanometer to ca. 400 nm. The layers have been fired in a furnace. Structural properties have been determined by x-ray diffraction and TEM analysis and the electrical properties by the van der Pauw/Hall measurement. Three different coating procedures have been used to investigate the effect on the structure, morphology and the electrical properties of the coatings. It is shown that the individual layer thickness in multilayer coatings influences dramatically the mentioned properties. Very thin individual layers favour a heterogeneous nucleation with dense columnar growth of the crystallites leading to low electrical resistivity (ρ ≈ 10−3Ω cm), while thick individual layers result in a porous morphology made of small crystallites leading to resistivities in the 10−2Ω cm range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008747429862
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  • 9
    Electronic Resource
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    Chemical and Biological Parameters as Tools to Evaluate and Improve Heavy Metal Phytoremediation (2000)
    Springer
    Bioscience reports 20 (2000), S. 239-258 
    Details
    ISSN: 1573-4935
    Keywords: heavy metals ; phytoremediation ; bioremediation ; bioavailability ; chemical availability ; soil microorganisms ; plant-microbe interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In this review, chemical and biological parameters are discussed thatstrongly influence the speciation of heavy metals, their availability tobiological systems and, consequently, the possibilities to usebioremediation as a cleanup tool for heavy metal polluted sites. In orderto assess heavy metal availability, a need exists for rapid, cost-effectivesystems that reliably predict this parameter and, based on this, thefeasibility of using biological remediation techniques for site managementand restoration. Special attention is paid to phytoremediation as anemerging technology for stabilization and remediation of heavy metalpollution. In order to improve phytoremediation of heavy metal pollutedsites, several important points relevant to the process have to beelucidated. These include the speciation and bioavailability of the heavymetals in the soil determined by many chemical and biological parameters,the role of plant-associated soil microorganisms and fungi inphytoremediation, and the plants. Several options are described how plant-associated soil microorganisms canbe used to improve heavy metal phytoremediation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026436806319
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  • 10
    Electronic Resource
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    The First Finding of the Actinia Synandwakia hozawai in the Sea of Okhotsk (2000)
    Springer
    Russian journal of marine biology 26 (2000), S. 445-449 
    Details
    ISSN: 1608-3377
    Keywords: actinia ; Synandwakia hozawai ; Sea of Okhotsk ; morphology ; nematocysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The finding of the actinia Synandwakia hozawai in the coastal waters of northern Sakhalin (Sea of Okhotsk) suggests a wider range of this species, which was previously only known to inhabit the coastal waters of eastern Japan. Data are presented on the morphology of the S. hozawai specimen from the Sea of Okhotsk and the types of its nematocysts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009455007047
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  • 11
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    A newLeptographium species associated withTomicus piniperda in south-western China (2000)
    Springer
    Mycoscience 41 (2000), S. 573-578 
    Details
    ISSN: 1618-2545
    Keywords: China ; Leptographium ; morphology ; taxonomy ; Tomicus piniperda
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tomicus species (Coleoptera: Scolytidae) are serious pests of pines with a wide distribution in Europe, Asia and America. In Yunnan, south-western China,T. piniperda has destroyed more than 0.5 million ha ofPinus yunnanensis in the past 15 years. A blue stain fungus belonging to the genusLeptographium is associated with both the shoot-feeding and trunk-attacking stages of the beetle's life cycle. The fungus is morphologically similar to the anamorph ofOphiostoma crassivaginatum and toL. pyrinum, which are both characterised by short robust conidiophores and hyphae covered by a granular layer. Both these species have been isolated from conifers and are associated with insects. After comparing the fungus fromT. piniperda with similarLeptographium species, using light and scanning electron microscopy, we concluded that it represents a new taxon, which is described here asL. yunnanense sp. nov.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02460923
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  • 12
    Electronic Resource
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    Phylogeny ofCyclamen L. (Primulaceae): Evidence from morphology and sequence data from the internal transcribed spacers of nuclear ribosomal DNA (2000)
    Springer
    Plant systematics and evolution 220 (2000), S. 147-160 
    Details
    ISSN: 1615-6110
    Keywords: Primulaceae ; Cyclamen ; phylogeny ; rDNA sequences ; ITS ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A molecular phylogenetic study of the genusCyclamen L. (Primulaceae) has been undertaken, based on sequence data from the 5.8S gene in the ribosomal nuclear DNA and its flanking internal transcribed spacers ITS1 and ITS2. Sequence data from 15 species ofCyclamen and seven outgroup taxa selected from Primulaceae and Myrsinaceae were analyzed phylogenetically. A second analysis based on a combined morphological and molecular dataset was performed to evaluate earlier hypotheses of character evolution in the genus. The results indicate that four monophyletic subgroups may be recognized in the genus, viz.Cyclamen, Psilanthum Schwarz,Eucosme Schwarz andGyrophoebe Schwarz. Each of the four subgenera is diagnosed by distinct basic chromosome number, as well as by morphological and molecular characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00985043
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  • 13
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    Quantitative morphological variation inTetramolopium (Asteraceae) in Hawaii and the Cook Islands (2000)
    Springer
    Plant systematics and evolution 221 (2000), S. 1-13 
    Details
    ISSN: 1615-6110
    Keywords: Asteraceae ; Tetramolopium ; morphology ; systematics ; Hawaii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Multivariate analyses of quantitative characters were undertaken to examine the pattern of variation resulting from adaptive radiation ofTetramolopium in Hawaii and to investigate the systematics of an undescribed species in the Cook Islands and a group of populations of uncertain affinity on Kalaupapa Peninsula in Hawaii. Taxa differentiated on quantitative characters in the absence of qualitative characters. Differentiation was observed in multiple characters which could be organized into a few principal components. The analyses supported the species rank of the Cook Islands plants. The relationship of the Kalaupapa Peninsula populations to the rest of the taxa needs further study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01086376
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  • 14
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    A search for the phylogenetic position of the seven-son flower (Heptacodium, Dipsacales): Combining molecular and morphological evidence (2000)
    Springer
    Plant systematics and evolution 225 (2000), S. 185-199 
    Details
    ISSN: 1615-6110
    Keywords: Cladistic analyses ; Dipsacales ; Heptacodium ; morphology ; ndhF ; phylogeny ; rbcL
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A first report on the problematic phylogenetic position ofHeptacodium (2 spp.; China) using molecular data from chloroplast DNA is presented. Amplification of ORF2280 homolog region was executed in a number of representative taxa in order to determine ifHeptacodium shows similar structural rearrangements as other Dipsacales. DNA sequences ofndhF were generated to clarify the phylogenetic position ofHeptacodium among Caprifoliaceae (s.l.). Six outgroup taxa and fifteen representatives of Dipsacales were sampled and more than 2100 basepairs ofndhF sequence were used in a cladistic analysis. Parsimony analysis produced two shortest trees and showedHeptacodium as sister to all members of Caprifoliaceae (s.str.), although weakly supported. Additionally, trees were constructed withndhF data supplemented with availablerbcL sequences and a morphological data set. Results of all analyses support an unresolved basal position forHeptacodium among Caprifoliaceae (s.l.), which in part explains the difficulty experienced previously in classifying the genus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00985467
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  • 15
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    Raman Light Scattering in System of Oriented Wires in Porous Silicon (2000)
    Springer
    Journal of porous materials 7 (2000), S. 275-278 
    Details
    ISSN: 1573-4854
    Keywords: porous silicon ; Raman spectroscopy ; morphology
    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 Raman-light scattering in porous silicon samples with oriented quantum wires was studied. It was shown, that the experimental data depends on the type of organization of wire system. The explanation of observed effect is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009632114501
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  • 16
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    Towards the Morphology Control of Stain Etched Porous Silicon (2000)
    Springer
    Journal of porous materials 7 (2000), S. 407-410 
    Details
    ISSN: 1573-4854
    Keywords: porous silicon ; stain etching ; morphology ; HREM ; reflectance spectrometry
    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 Porous silicon films, nearly 100 nm thick, were produced by stain etching of n+-type silicon substrates. The films were studied by a non-destructive technique: dielectric function profiles were deduced by spectral reflectance via a finite difference model, and porosity was computed by the Effective Medium Approximation. The obtained information, combined with High Resolution Electron Microscopy observations,provided a deeper insight on the relations among technological process, morphology and reflective properties. Our preliminary results outline the possibility to control the porosity profile as well the reflectance of the porous films via the oxidising species concentration in the stain etching solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009607725830
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  • 17
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    Location of genes involved in ear compactness in wheat (Triticum aestivum) by means of molecular markers (2000)
    Springer
    Molecular breeding 6 (2000), S. 247-255 
    Details
    ISSN: 1572-9788
    Keywords: mapping ; morphology ; QTL ; RFLP ; spike density ; Triticeae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Quantitative trait loci (QTLs) for three traits related to ear morphology (spike length, number of spikelets, and compactness as the ratio between number of spikelets and spike length) in wheat (Triticum aestivum L.) were mapped in a doubled-haploid (DH) population derived from the cross between the cultivars Courtot and Chinese Spring. A molecular marker linkage map of this cross that had previously been constructed based on 187 DH lines and 380 markers was used for QTL mapping. The genome was well covered (85%) except chromosomes 1D and 4D and a set of anchor loci regularly spaced (one marker each 15.5 cM) were chosen for marker regression analysis. The presence of a QTL was declared at a significance threshold α = 0.001. The population was grown in one location under field conditions during three years (1994, 1995 and 1998). For each trait, 4 to 6 QTLs were identified with individual effects ranging between 6.9% and 21.8% of total phenotypic variation. Several QTLs were detected that affected more than one trait. Of the QTLs 50% were detected in more than one year and two of them (number of spikelets on chromosome 2B, and compactness on chromosome 2D) emerged from the data from the three years. Only one QTL co-segregated with the gene Q known to be involved in ear morphology, namely the speltoid phenotype. However, this chromosome region explained only a minor part of the variation (7.5–11%). Other regions had a stronger effect, especially two previously unidentified regions located on chromosomes 1A and 2B. The region on the long arm of chromosome 1A was close to the locus XksuG34-1A and explained 12% of variation in spike length and 10% for compactness. On chromosome 2B, the QTL was detected for the three traits near the locus Xfbb121-2B. This QTL explained 9% to 22% of variation for the traits and was located in the same region as the gene involved in photoperiod response (Ppd2). Other regions were located at homoeologous positions on chromosomes 2A and 2D.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009688011563
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  • 18
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    Morphological and Biomechanical Studies of Pedicle Screw Fixation for the Lower Cervical Spine (2000)
    Springer
    Journal of systems integration 10 (2000), S. 55-66 
    Details
    ISSN: 1573-8787
    Keywords: biomechanics ; morphology ; cervical spine ; pedicle screw fixation ; finite element analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Based on eight specimens removedfrom fresh cadavers, the morphology of the pedicles of the C3–7cervical vertebrae was determined. Three preliminary designsof pedicle screw and finite element models of the screw withcervical vertebra were developed. The feasibility of pediclescrew fixation for the lower cervical spine is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026559301696
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  • 19
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    Nonaqueous Phase Liquid Dissolution in Porous Media: Current State of Knowledge and Research Needs (2000)
    Springer
    Transport in porous media 38 (2000), S. 3-28 
    Details
    ISSN: 1573-1634
    Keywords: NAPL ; dissolution ; mass transfer ; morphology ; multicomponent ; up‐scaling ; inverse modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Our understanding of nonaqueous phase liquid (NAPL) dissolution in the subsurface environment has been increasing rapidly over the past decade. This knowledge has provided the basis for recent developments in the area of NAPL recovery, including cosolvent and surfactant flushing. Despite these advances toward feasible remediation technologies, there remain a number of unresolved issues to motivate environmental researchers in this area. For example, the lack of an effective NAPL‐location methodology precludes effective deployment of NAPL recovery technologies. The objectives of this paper are to critically review the state of knowledge in the area of stationary NAPL dissolution in porous media and to identify specific research needs. The review first compares NAPL dissolution‐based mass transfer correlations reported for environmental systems with more fundamental results from the literature involving model systems. This comparison suggests that our current understanding of NAPL dissolution in small‐scale (on the order of cm) systems is reasonably consistent with fundamental mass transfer theory. The discussion then expands to encompass several issues currently under investigation in NAPL dissolution research, including: characterizing NAPL morphology (i.e. effective size and surface area); multicomponent mixtures; scale-related issues (dispersion, flow by-passing); locating NAPL in the subsurface and enhanced NAPL recovery. Research needs and potential approaches are discussed throughout the paper. This review supports the following conclusions: (1) Our knowledge related to local dissolution and remediation issues is maturing, but should be brought to closure with respect to the link between NAPL emplacement theory (as it impacts NAPL morphology) and NAPL dissolution; (2) The role of nonideal NAPL mixtures, and intra-NAPL mass transfer processes must be clarified; (3) Valid models for quantifying and designing NAPL recovery schemes with chemical additives need to be refined with respect to chemical equilibria, mass transfer and chemical delivery issues; (4) Computational and large-scale experimental studies should begin to address parameter up-scaling issues in support of model application at the field scale; and (5) Inverse modeling efforts aimed at exploiting the previous developments should be expanded to support field-scale characterization of NAPL location and strength as a dissolving source.
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    URL: http://dx.doi.org/10.1023/A:1006667318234
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    Intraspecific Variation in the Vocalizations and Hand Pad Morphology of Southern Lesser Bush Babies (Galago moholi): A Comparison with G. senegalensis (2000)
    Springer
    International journal of primatology 21 (2000), S. 537-555 
    Details
    ISSN: 1573-8604
    Keywords: galago ; taxonomy ; vocalization ; morphology ; zoogeography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have shown the taxonomic value of vocal repertoires and hand (volar) pad characteristics in the classification of cryptic nocturnal primates such as bush babies. However, no study included quantitative comparisons within the geographical range of any one species. We investigated levels of intraspecific variation in calls and hand pad characteristics of the southern lesser bush baby (Galago moholi), using the northern lesser bush baby (Galago senegalensis) for interspecific comparisons. Examination of calls recorded from different regions along a transect of 1500 km across southern Africa revealed low levels of intraspecific variation in Galago moholi, whereas comparisons with homologous call-types in G. senegalensis revealed them to be significantly different. Volar pad measurements across the ranges of both species also showed low levels of intraspecific variation and relatively high interspecific variation. These findings demonstrate that vocal and volar pad characteristics can be used as consistent measures of difference between species that look almost identical. These methods provide a practical means of distinguishing between cryptic species, whether in the field, in captivity, or, in the case of volar pads, of preserved specimens.
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    URL: http://dx.doi.org/10.1023/A:1005400205038
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    Penile Morphology and Classification of Bush Babies (Subfamily Galagoninae) (2000)
    Springer
    International journal of primatology 21 (2000), S. 815-836 
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    ISSN: 1573-8604
    Keywords: Galago ; bush baby ; classification ; penis ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The penile morphologies of nocturnal prosimians are complex and vary considerably between genera and species. Accordingly, comparative morphology can be useful in taxonomic studies, particularly when assessing the status of newly discovered species. I measured features of penile morphology—surface area of the glans penis; shape and size of the keratinized spines on the glans—for populations representing 14 species within the subfamily Galagoninae. Intraspecific variations in penile morphology were relatively minor. By contrast, there are significant differences in several morphological features among closely related, sympatric species, e.g., in the greater bush babies (Otolemur crassicaudatus and O. garnettii) and lesser bush babies (Galago senegalensis and Galago moholi). Assessment of glans area resulted in the recognition of a second needle-clawed form: Euoticus pallidus. Similar divisions exist in the dwarf and greater bush babies with respect to proportional spiny area and characteristics of spine size. I constructed a key based on the presence/absence of certain features—penile spines, dermal markings on the glans, penile lappets—as well as the shape of the baculum and possession of different spinal morphotypes. This key may be used to identify all 14 species of bush babies. Penile morphologies provide a useful guide to specific identity in the Galagoninae, which may be true also for other groups of nocturnal mammals.
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    URL: http://dx.doi.org/10.1023/A:1005542609002
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    Increasing the efficiency of reed plantations on stressed lake and river shores by using special clones of Phragmites australis (2000)
    Springer
    Wetlands ecology and management 8 (2000), S. 415-424 
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    ISSN: 1572-9834
    Keywords: expansion ; morphology ; nitrogen content ; Phragmites australis ; planting design ; shore restoration ; stand structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In an investigation aimed at comparing the variationin growth and expansion of different reed clones, 10reed clones were planted in spring of 1995 on sixexperimental fields on the River Dahme and the RiverHavel in Berlin. Their sites of origin differed innutrient supply, substrate quality and shoreexposition. The main aim of this large-scaleexperiment was to search for reed clones that would beable to colonize lake shores rapidly and to expandinto deeper water. Two years after planting thedeveloping reed stands differed significantly inmorphology and stand structure, both among clones andamong sites. This indicates that the development ofreed stands depended on the environment as well as onthe genotype. The differences in development impliedthat some of the clones would be more suited thanothers for restoration purposes, so that successfulrestoration of a degraded river or lake shores mightdepend on the selection of the best suited clones.The nitrogen contents in the aboveground biomass oftwo clones differing in nitrogen dynamics at theiroriginal sites (described as `assimilation' and`translocation' types in the literature) did notdiffer in this experiment, even though the two clonesdid differ in some morphological traits. These resultsmight be influenced by the fact that stands were stilldeveloping and that possibly clones had reached adifferent degree of maturity. Nevertheless, theysuggest that nitrogen content depends more on siteconditions, with only little genetically determineddifference, and that morphological variation isdetermined by factors other than variation in nitrogenuptake.
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    In Vivo Absorption Properties of Orally Administered Recombinant Human Interleukin-11 (2000)
    Springer
    Pharmaceutical research 17 (2000), S. 482-485 
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    ISSN: 1573-904X
    Keywords: pharmacokinetics ; recombinant human interleukin-11 ; absorption ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1023/A:1007545524408
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    Apparent Lack of Effect of P-Glycoprotein on the Gastrointestinal Absorption of a Substrate, Tacrolimus, in Normal Mice (2000)
    Springer
    Pharmaceutical research 17 (2000), S. 205-208 
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    ISSN: 1573-904X
    Keywords: tacrolimus ; P-glycoprotein ; bioavailability ; drug absorption ; mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To study the contribution of P-glycoprotein (P-gp) to the oralabsorption of a substrate, tacrolimus, by comparing the extent and rateof bioavailability in normal and mdr1a knockout mice. Methods. Intravenous and oral (2 mg/kg) blood concentration data oftacrolimus in normal and knockout mice were obtained from a studyby K. Yokogawa et al. in Pharm. Res. 16:1213-1218 (1999). Meanbioavailability (F), mean hepatic first-pass extraction ratio (Fh), meanbioavailability rates, mean oral clearance, and mean total hepaticintrinsic clearance were calculated using standard pharmacokinetic methods. Results. The mean F of tacrolimus (an apparently highly permeablecompound) was increased from 0.22 in normal mice to 0.72 in knockoutmice. These values were consistent with mean predicted Eh (based onintravenous data) of 0.77 and 0.27 in normal and knockout mice,respectively. Great similarity in the relative bioavailability profile (suchas short Tmax) between normal and knockout mice was also found. Meanoral clearance and mean total or unbound hepatic intrinsic clearance oftacrolimus in knockout mice were found to be about 10 times lowercompared to those in normal mice. Conclusions. The above results suggest an apparent lack of effect ofP-gp on the gastrointestinal absorption of tacrolimus in normal miceunder the study condition. It is postulated that the effect of P-gp onthe rate and extent of oral absorption should be more pronounced forthose more slowly or incompletely absorbed drugs (i.e., drugs withrelatively low permeabilities) as illustrated by talinolol in humans. Theclearance data also suggest a very dominant role of P-glycoprotein incontrolling the rate of hepatic metabolism of tacrolimus in normalmice, and P-glycoprotein may serve as an effective efflux pump fordirect transport of metabolites formed in hepatocytes into the bloodcirculation.
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    Crystallization of Lactose from Carbopol Gels (2000)
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    Pharmaceutical research 17 (2000), S. 879-886 
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    ISSN: 1573-904X
    Keywords: lactose ; crystallization ; Carbopol gels ; morphology ; crystal form ; crystal habit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To crystallize lactose under static conditions with a view topreparing crystals of well-defined morphology. Methods. α-Lactose monohydrate was crystallized from neutralizedCarbopol 934 gels. When the majority of crystals had grown to maturity,the gels were acidified using diluted hydrochloric acid and the crystalswere harvested by filtration or centrifugation and washed with ethanol-watermixtures. Results. Crystals prepared from the gel had a consistently narrowersize distribution than control crystals, prepared from solution underconstant stirring. If crystallization was effected in the gel withoutsedimentation of the crystals, then the resultant crystals had smoothsurfaces without visually detectable surface roughness or asperitiesviewed by optical microscopy. The crystals from Carbopol gels alsoexhibited the uniform shape of an elongated tomahawk regardless of thecrystallization conditions, in contrast to crystallization under constantstirring, where the crystal shape of lactose changed with crystallizationconditions especially as a function of the initial concentration of lactose.All batches of lactose crystals prepared from Carbopol gels existedas α-lactose monohydrate, which showed better flowability than thecontrols of a similar particle size. Conclusions. Crystallization from Carbopol gel produces lactose crystalsof uniform size, regular shape, smooth surface, and improvedflowability.
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    Phylogeny of the tribe Antirrhineae (Scrophulariaceae) based on morphological andndhF sequence data (2000)
    Springer
    Plant systematics and evolution 220 (2000), S. 223-239 
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    ISSN: 1615-6110
    Keywords: Scrophulariaceae ; Antirrhineae ; morphology ; ndhF ; phylogeny ; pollination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phylogenetic relationships within the tribe Antirrhineae (Scrophulariaceae) are analysed and discussed on the basis of parsimony analyses of morphological andndhF gene sequence data. The results indicate that the tribe Antirrhineae consists of four major groups of genera, theAnarrhinum clade, theGambelia clade, theMaurandya clade, and theAntirrhinum clade. TheAnarrhinum clade, consisting of the Old World bee-pollinated generaAnarrhinum andKickxia, is sister to the rest of the tribe. TheGambelia clade consists of the New World generaGambelia andGalvezia, which are very closely related and pollinated by hummingbirds. TheMaurandya clade consists of one subclade includingMaurandya and a number of related bee- or hummingbird-pollinated New World genera and another subclade with the Old World bee-pollinated generaAsarina andCymbalaria. TheAntirrhinum clade consists mainly of bee-pollinated Old World genera, such asAntirrhinum, Linaria, Chaenorhinum, and their segregates, but also includes the New World generaMohavea andHowelliella, of which the latter is known to be partly pollinated by hummingbirds. It is concluded that hummingbirdpollination has evolved independently within Antirrhineae at least three times from bee-pollinated ancestors.
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    URL: http://dx.doi.org/10.1007/BF00985047
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    Implications of morphological phylogenetics for the placement of the generaAdenocaulon andEriachaenium (Asteraceae) (2000)
    Springer
    Plant systematics and evolution 223 (2000), S. 229-250 
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    ISSN: 1615-6110
    Keywords: Asteraceae ; Cichorioideae ; Adenocaulon ; Eriachaenium ; problematic genera ; morphology ; phylogenetic analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adenocaulon andEriachaenium are two problematic genera because their tribal and subfamilial placement in Asteraceae is uncertain. Previous cladistic analyses based on molecular data undertaken to analyze the relationships within Asteraceae, placeAdenocaulon in the tribe Mutisieae (Cichorioideae). This paper investigates cladistic relationships amongAdenocaulon andEriachaenium and tribes of subfamilies Cichorioideae and Asteroideae using morphological data. Thirty-eight characters were scored across 52 genera selected as exemplar taxa to represent the current classification system. In the analysis (one tree, length = 86, c.i. = 0.55, r.i. = 0.64)Adenocaulon andEriachaenium are sister taxa and appear as an isolated clade nested in Cichorioideae. A new, tentative position among the tribes of the paraphyletic Cichorioideae is proposed for these two isolated genera.
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    URL: http://dx.doi.org/10.1007/BF00985282
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    Software dependent phenetic relationships of non-nodulating African species ofAcacia (2000)
    Springer
    Plant systematics and evolution 220 (2000), S. 139-146 
    Details
    ISSN: 1615-6110
    Keywords: Acacia ; classification ; Leguminosae ; morphology ; phenetics ; RAPD ; software ; taxonomy ; UPGMA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phenetic analysis of non-nodulatingAcacia species by Harrier et al. (1997) was repeated to illustrate how different computer programs may generate alternative UPGMA trees for the very same data, even in the absence of data input order effects (ties). For example, all Harrier et al.'s UPGMA dendrograms produced by software from the Scottish Agricultural Statistics Service differed from those obtained by the packages NTSYS and MVSP87. Particularly, the positions ofA. albida, A. rovumae, andA. pentagona, as well as the relationships betweenDiacanthae andTriacanthae were affected by this phenomenon. Hence, whenever clustering techniques are used, care should be taken to consider possible software-dependent caveats and artefacts. Nevertheless, all programs provided clusterings that largely coincided with the subgeneric and sectional groupings proposed by Vassal (1972) although the positions of some species varied depending on whether morphological or molecular data were considered (e.g.A. albida andA. rovumae).
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    Phylogenetic signal common to three data sets: Combining data which initially appear heterogeneous (2000)
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    Plant systematics and evolution 221 (2000), S. 179-198 
    Details
    ISSN: 1615-6110
    Keywords: Gesneriaceae ; congruence ; morphology ; ndhF ; rbcL ; phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study makes use of three sources of data, morphology and two chloroplast DNA sequences,ndhF andrbcL, to resolve relationships in Gesneriaceae. Cladograms from each of the three data sets separately are not topologically congruent. Statistical indices suggest that each data set is congruent with thendhF data althoughrbcL and morphology are themselves incongruent. Consensus methods provide no resolution of taxonomic relationships when trees from the different data sets are combined. Combining data sets generally results in cladograms that are more fully resolved than each of the data sets analyzed separately and support for the clades increases based on higher decay index and bootstrap values. These results indicate that there is a phylogenetic signal common to each of the data sets, however, the noise (errors due to homoplasy, mis-scoring, etc.) unique to each data source masks this signal. In combining the data, the evidence for the common evolutionary history in each data set overcomes the noise and is apparent in the resulting trees.
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    URL: http://dx.doi.org/10.1007/BF01089293
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    Mycelium of Arbuscular Mycorrhizal fungi (AMF) from different genera: form, function and detection (2000)
    Springer
    Plant and soil 226 (2000), S. 131-151 
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    ISSN: 1573-5036
    Keywords: arbuscular mycorrhizas ; ecological function ; isozymes ; morphology ; mycelium architecture ; molecular probes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract It is often assumed that all species of arbuscular mycorrhizal fungi (AMF) have the same function because of the ubiquity of the arbuscular mycorrhizal symbiosis and the fact that all AMF occupy the same plant/soil niche. Despite apparent differences in the timing of evolutionary divergence and the morphological characteristics of AMF from the different genera, the majority of studies on these fungi use only species of Glomus. There is increasing evidence, however, that the mechanisms involved in the establishment of a mycorrhiza may differ for species and genera of AMF and influence their subsequent function. The aim of this paper is to highlight the diversity in the form and function of AMF from different genera, knowledge of which is vital in understanding their ecological roles. Potential use of biochemical and molecular approaches to detect AMF in planta and ex planta is also discussed.
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    URL: http://dx.doi.org/10.1023/A:1026574828169
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    Morphological relationships among 15 species of Trifolium occurring in Poland (2000)
    Springer
    Genetic resources and crop evolution 47 (2000), S. 267-272 
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    ISSN: 1573-5109
    Keywords: morphology ; numerical taxonomy ; phenetics ; Trifolium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Populations of 15 Trifolium species were morphologically assayed to elucidate species relationships and taxonomic arrangements in the genus. Twenty-one characters were scored and analyzed by numerical methods. All species proved to be heterogenous. The levels of dissimilarity among populations of the same species ranged from around 0.05 to around 0.6. Cluster analysis divided all taxa into two major groups of species which were joined at D (Euclidean Distance) around 0.9. Within the first group three major sub-groups were revealed, comprising T. hybridum L., T. repens L., T. strepens Cr., T. dubium Sibth., T. campestre Schreb., T. patens Schreb. and T. fragiferum L. The second major group consisted of T. pannonicum L., T. arvense L., T. montanum L., T. incarnatum L., T. alpestre L., T. rubens L., T. pratense L. and T. medium L. The present results proved that the genus is very heterogenous, and support the hypothesis that the section Lotoidea was probably the stock from which other sections derived. Morphological relationships among 15 Trifolium species support their taxonomic arrangements proposed by Zohary & Heller (1984), with some exceptions. Sectional positions of T. montanum and T. strepens should be reexamined. Conspecific ranks for three species of section Chronosemum – T. dubium, T. campestre and T. patens – should be considered.
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    Diversity of the Sheanut tree (Vitellaria paradoxa C.F. Gaertn.) in Ghana (2000)
    Springer
    Genetic resources and crop evolution 47 (2000), S. 293-304 
    Details
    ISSN: 1573-5109
    Keywords: clinal trends ; isozymes ; morphology ; population variance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Sheanut tree (Vitellaria paradoxa C.F. Gaertn.) is highly valued for oil obtained from its seeds and frequently maintained in the semi-arid parklands of sub-Saharan Africa from Senegal to Uganda. Although variation has been noted for V. paradoxa subsp. paradoxa, few studies have been undertaken on patterns of phenotypic or genotypic diversity. Results are presented from 294 accessions collected in Ghana, using easily quantifiable morphological parameters. Productive mature trees varied from shrubby multi-stemmed individuals (height 〈5 m) to 30-m straight-boled trees with high compact canopies. The leaf lamina (tree mean ±% coefficient of variation of total mean) varied from 9.2 to 22.5 cm (±15.0%); seed length from 1.74 to 3.74 cm (±11.7%); and fat content from 29.1 to 61.9% of dry kernel weight (±9.4%). Clinal trends significantly correlated with location parameters that in turn related to environmental variation. Population variation of seed characteristics increased to the Northeast, perpendicular to the annual movement of the inter-tropical convergence zone. It is proposed that this is a consequence of past climatic changes, coupled with a lack of methodical selection for seed type when trees are maintained on agricultural land. Isozyme analysis revealed moderate to high levels of heterozygosity (He 0.2142) and high geneflow (Fst = 0.0124, Nm = 19.9), supporting results obtained from morphological studies. Isozyme and multivariate morphology analyses showed similar but weak geographical separation patterns.
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    A phenetic analysis of morphological variation in Citrullus lanatus in Namibia (2000)
    Springer
    Genetic resources and crop evolution 47 (2000), S. 385-393 
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    ISSN: 1573-5109
    Keywords: Citrullus lanatus ; cluster analysis ; evolution ; morphology ; watermelon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Morphological data recorded from field trials using Citrullus lanatus germplasm collected in Namibia were used to analyse and compare the various morphotypes of this species. The experiment comprised wild types and local landraces as well as commercial cultivars. Cluster analysis supported the indigenous classification system used in Namibia, in which Citrullus types are distinguished based on gross morphology, ecology and usage and grouped into seed, cooking and fresh-eating (watermelon) types. Commercial watermelon cultivars formed a distinct cluster. Wide variation was found within the local types whereas the genetic basis of the commercial type appears to be narrow. The commercial cultivars were most closely related to local watermelon types and more distantly related to the wild types, whereas the cooking melons form an intermediate group.
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    The ontogeny of the cypridid ostracod Eucypris virens (Jurine, 1820) (Crustacea, Ostracoda) (2000)
    Springer
    Hydrobiologia 419 (2000), S. 31-63 
    Details
    ISSN: 1573-5117
    Keywords: morphology ; ontogeny ; Ostracoda ; evolution ; fifth limb ; crustacean phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chaetotaxy (shape, structure and distribution of setae) of appendages and valve allometry during the post embryonic ontogeny of the cyprididine ostracod Eucypris virens are described. It is shown that the basic ontogenetic development of E. virens is very similar to that of other species of the family Cyprididae. During ontogeny, the chaetotaxy shows continual development on all podomeres of the limbs with the exception of the last podomere on the antennulae. The long setae on the exopodite and protopodite of the antennae have a natatory function until the actual natatory setae develop in later instars. Aesthetascs (presumed chemoreceptors) ya and y3 are the first to develop and may have an important function in the first instars. Cyprididae require a pediform limb in the posterior of the body presumably to help them to attach to substrates and this is reflected by the pediform nature of one limb at all times throughout all instars. This study has also shown that the fifth limb is most probably of thoracic origin and hence ostracods have only one pair of maxillae.
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    Differences in the apportionment of molecular and morphological variation in North American strawberry and the consequences for genetic resource management (2000)
    Springer
    Genetic resources and crop evolution 47 (2000), S. 647-657 
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    ISSN: 1573-5109
    Keywords: Fragaria chiloensis ; Fragaria virginiana ; genetic resources ; morphology ; RAPD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Variation for 24 morphological traits measured in a greenhouse environment and 36 randomly amplified polymorphic DNA (RAPD) markers was assessed among 318 wild octoploid strawberry (Fragariaspp.) genotypes from diverse habitats across the northern USA. RAPD marker frequencies and certain leaf and flower morphology traits (petiole color, leaf mass/area ratio, leaflet length and width, flower and receptacle diameter, petal width, flowers/inflorescence) were significantly different between the F. chiloensis-platypetala and F. virginiana-glauca species complexes. The proportion of variation accounted for by provenance effects was lower for the RAPD markers than for most morphological traits, especially in the F. virginiana-glauca species complex. Morphological traits of potential adaptive importance group the collection into provenances within each species-complex, and reflect the significant habitat and geographic differences across the region from which the germplasm was collected. Variation among populations within provenances was low for the molecular and most morphological traits, with a much larger amount of variability among plants within populations. Most of the variation for the presumably more selectively-neutral RAPD data was among plants within populations and populations within provenances rather than among the provenances that were recognized based on morphological traits, especially in the F. virginiana-glauca complex. Patterns of diversity for morphological traits must be considered, along with more selectively-neutral molecular characters such as RAPDs, to formulate effective sampling strategies and to properly estimate the quantity and apportionment of diversity within this germplasm.
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    Preface: Ostracoda and the four pillars of evolutionary wisdom (2000)
    Springer
    Hydrobiologia 419 (2000), S. 7-11 
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    ISSN: 1573-5117
    Keywords: morphology ; palaeontology ; ecology ; genetics ; Ostracoda ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Morphology, palaeontology, genetics and ecology are the main scientific domains contributing theories, concepts and new data to evolutionary biology. Ostracods are potentially very good model organisms for evolutionary studies because they combine an excellent fossil record with a wide extant distribution and, therefore, allow studies on both patterns and processes leading to extant diversity. This preface provides an overview of the 15 contributions to the present volume and concludes that this set of papers supports the claim that ostracod studies are situated in all main evolutionary domains.
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    Redescription and assignment of the chydorid Indialona ganapati Petkovski, 1966 (Branchiopoda: Anomopoda: Aloninae) to Indialonini, new tribus (2000)
    Springer
    Hydrobiologia 439 (2000), S. 161-178 
    Details
    ISSN: 1573-5117
    Keywords: Cladocera ; Anomopoda ; Chydoridae ; Indialona ; morphology ; systematics ; Indialonini n. trib. ; evolutionary relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chydorid Indialona ganapati Petkovski, 1966 is redescribed based on material from the sublittoral plankton of Ajwa Reservoir, Ahmedabad, India, and a neotype is selected. Lateral head pores are recorded, and all thoracic limbs are studied in detail. Gamogenetic specimens are described for the first time. Evolutionarily relationships of Indialona and other Aloninae are discussed. A new tribe Indialonini n. trib. is proposed for the sole genus Indialona, while all other genera of Aloninae, as far as is known, compose the tribe Alonini s. str. A diagnosis of both tribes and a key for their discrimination is proposed. Sharp differences between these tribes are found in some characters of the thoracic limbs. The limbs of the Indialonini are more oligomerized than those of the Alonini, and a strong oligomerization is characteristic of limbs I–II.
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    Phylogenetic implications of the Crustacean nauplius (2000)
    Springer
    Hydrobiologia 417 (2000), S. 91-99 
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    ISSN: 1573-5117
    Keywords: evolution ; phylogeny ; larval characters ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The plesiomorphic mode of crustacean development is widely accepted to be via a larva called the nauplius. Extant taxa like the Cephalocarida, Branchiopoda, Ostracoda, Mystacocarida, Copepoda, Cirripedia, Ascothoracida, Facetotecta, Euphausiacea and Penaeidea hatch from an egg as a free-living nauplius. Other crustaceans show an embryonic phase of development suggestive of a naupliar organization. Several features of the nauplius larva have been proposed as diagnostic characters for the Crustacea: a median (nauplius) eye; at least three pairs of head appendages (antennules, antennae, mandibles); a posteriorly directed fold (the labrum) extending over the mouth and a cephalic (nauplius) shield. The relationship between trilobite protaspis with at least four appendages and the crustacean nauplius remains unclear, but reports of a copepod orthonauplius with four appendages are rejected. Swimming is suggested to represent the underived mode of locomotion for the crustacean nauplius, and that naupliar swimming directly results in naupliar feeding which also is underived.
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    URL: http://dx.doi.org/10.1023/A:1003886818724
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    The dinoflagellate genus Prorocentrum along the coasts of the Mexican Pacific (2000)
    Springer
    Hydrobiologia 418 (2000), S. 111-121 
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    ISSN: 1573-5117
    Keywords: dinoflagellates ; Prorocentrum ; morphology ; taxonomy ; Mexican Pacific ; red tides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We surveyed the dinoflagellate genus Prorocentrum Ehrenberg in Mexican Pacific waters, where it is rather common and sometimes causes red tides in coastal areas or shrimp farms. Material collected from Baja California and the Gulf of California was analyzed. Thirteen species were identified, all of them planktonic (although P. mexicanum is also epiphytic). All species are described by light microscopy, and most are also described by scanning electron microscopy; comments on morphology, taxonomy and distribution are made. Red tides were caused by P. dentatum, P. minimum and P. triestinum. Prorocentrum mexicanum and P. minimum were suspected of being toxic. Four species, previously reported in the Gulf of California, were not found. A total of 18 species, including the new records P. dactylum and P. lebourae have been to date reported from the Mexican Pacific.
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    URL: http://dx.doi.org/10.1023/A:1003806719515
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    Redescription of Diaphanosoma dubium Manuilova, 1964 (Branchiopoda: Ctenopoda: Sididae), and description of a new, related species (2000)
    Springer
    Hydrobiologia 441 (2000), S. 73-92 
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    ISSN: 1573-5117
    Keywords: Diaphanosoma dubium ; D. pseudodubium sp.nov. ; morphology ; taxonomy ; geographical distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The poorly known D. dubium Manuilova is redescribed on extensive material from more than 80 populations from the Russian Far East, Central Asia, Mongolia, China, Japan, Vietnam, the Philippines, Thailand, Malaysia, Bangladesh, India and Sri Lanka. Its morphological variability and geographical distribution are analysed and supplemented by notes on biology. The conspecificity of morphologically different distant populations is discussed. In the northern part of its range, D. dubium was long confused with D. brachyurum or D. leuchtenbergianum, and in the south with D. modigliani. It seems that the recent appearance of D. dubium in fish ponds of Uzbekistan and Kazakhstan was an introduction, together with Far Eastern fish. D. pseudodubium sp.nov., close to but markedly different, is described from two lakes in the lower Amur river system. D. dubium, D. pseudodubium, D. tropicum and D. modigliani s. str. form a group of related species, widely distributed in Eastern and Southern Asia.
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    URL: http://dx.doi.org/10.1023/A:1017574921558
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    A new Ceratium species (Dinophyceae) from Lake Doïrani, Macedonia, Greece (2000)
    Springer
    Hydrobiologia 424 (2000), S. 101-108 
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    ISSN: 1573-5117
    Keywords: Ceratium ; freshwater ; ecology ; morphology ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new taxon of Ceratium is described from Lake Doïrani, Greece. It is proposed as a new species and named Ceratium monoceras. It differs morphologically from known species of Ceratium by having only one horn, the apical horn. Accordingly, the vegetative cells form cysts that have only one spine. Details of its ecology and occurence are given.
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    Redescription of Ilyocryptus tuberculatus Brehm, 1913 (Anomopoda, Branchiopoda) (2000)
    Springer
    Hydrobiologia 428 (2000), S. 115-128 
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    ISSN: 1573-5117
    Keywords: `Cladocera' ; Anomopoda ; Ilyocryptus tuberculatus ; morphology ; redescription ; Africa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology of Ilyocryptus tuberculatus Brehm, 1913 is redescribed, based on material from the Niger basin, Africa. The species name was given by Brehm erroneously, because under an optical microscope he mistook internal structures (the columns between the outer and inner walls of the valves) for the tubercules on the valve surface. But this species is undoubtedly valid, and `incorrect' species names must be conserved. Differences between I. tuberculatus and the most similar I. agilis (probably absent from the majority of African waters), I. spinifer (common in Africa), and some other species are discussed. Currently, I. tuberculatus is known for the Central African Republic, Mali and Niger.
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    Lithoglyptes cornutus, new species (Cirripedia: Acrothoracica), a boring barnacle from the Seychelles, with some data on its ultrastructure (2000)
    Springer
    Hydrobiologia 438 (2000), S. 185-191 
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    ISSN: 1573-5117
    Keywords: systematics ; morphology ; organ ; relationship ; SEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species of the Lithoglyptes from the Seychelles is described. The external morphology of the mantle sac and the body were examined under SEM. The position of a new species within Lithoglyptes and the ultrastructural characters of different species of this genus are discussed.
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    External morphology of the burrowing barnacle shape Lithoglyptes bicornis (Crustacea: Cirripedia: Acrothoracica) (2000)
    Springer
    Hydrobiologia 438 (2000), S. 193-203 
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    ISSN: 1573-5117
    Keywords: Cirripedia ; Acrothoracica ; morphology ; organs ; trophi ; SEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The external morphology of female and male Lithoglyptes bicornis was examined under SEM. The structure of the mantle, the thorax and, especially, the trophi were thoroughly examined. The data on the mantle and the thorax structures were compared with the previous data on the acrothoracican ultrastructure. The data on the structure and the character of trophi setation allow to speculate about a relationship with other cirripede taxa.
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    Morphological characterization of new populations of the copepod Eurytemora velox (Lilljeborg, 1853) (Calanoida, Temoridae) found in Austria and Hungary (2000)
    Springer
    Hydrobiologia 438 (2000), S. 205-216 
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    ISSN: 1573-5117
    Keywords: Eurytemora velox ; morphology ; distribution ; Austria ; Hungary ; Danube River
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The calanoid copepod Eurytemora velox (Lilljeborg, 1853) was found in the backwater system of the Danube River upstream of Vienna (km 1948) in 1994. Since that time, the species has invaded the side arms of the river between kms 1897 and 1988, as confirmed by findings from 10 different localities. In Hungary, the species has been known since 1992. In the present article, we report 15 new sites in the westernmost part of this country. A brief diagnosis of the morphology of male and female of the Austrian specimens is presented, including detailed illustrations of the structures used in this paper for taxonomic analysis. Females show morphological variability mainly on the structure of the fifth leg pair. Right and left legs frequently have a different spinulation pattern. Males show less morphological variability, particularly in the structure of the basis and the distal section of exopod 2 of the fifth left leg. Morphological variation within E. veloxwas determined by comparing specimens from Austria, Hungary and Rumania. The geographic distribution of the species in the Palearctic region, Austria and Hungary is presented.
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    Absorption of glucose, amino acids, and dipeptides by the intestines of Atlantic salmon (Salmo salar L.) (2000)
    Springer
    Fish physiology and biochemistry 22 (2000), S. 33-44 
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    ISSN: 1573-5168
    Keywords: diffusion ; everted sleeve method ; morphology ; nutrients ; pyloric ceca ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of glucose, amino acid and dipeptide absorption by the intestine of Atlantic salmon (Salmo salar L.) were measured in vitro at 10 °C as functions of concentration and region using intact tissues (everted sleeve method). Salmon (weight range 300–1300 g) fed a commercial, extruded salmon feed, were kept at 12–13 °C in freshwater. Maximum rates (V max) of glucose and dipeptide transport were low compared to most amino acid V max values. There was a declining proximal-to-distal gradient of absorption along the post-gastric intestinal tract. A saturable component of absorption was not evident for proline and glycyl-proline in the distal intestine, and glycyl-sarcosine in any region. `Apparent diffusion', which may include low affinity, high capacity carrier systems and carrier-independent influx, appears to account for the majority of total uptake at higher concentrations of amino acids and dipeptides. There was competition between the dipeptides for transporter sites in the pyloric ceca and mid intestine, suggesting a common carrier. There was also indication of hydrolysis of these dipeptides by brush border membrane enzymes.
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    Tight Junctions of the Blood–Brain Barrier (2000)
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    Cellular and molecular neurobiology 20 (2000), S. 57-76 
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    ISSN: 1573-6830
    Keywords: tight junction ; blood–brain barrier ; morphology ; freeze–fracture ; cadherins ; catenins ; occludin ; cytoskeleton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. The blood–brain barrier is essential for the maintainance and regulation of the neural microenvironment. The blood–brain barrier endothelial cells comprise an extremely low rate of transcytotic vesicles and a restrictive paracellular diffusion barrier. The latter is realized by the tight junctions between the endothelial cells of the brain microvasculature, which are subject of this review. Morphologically, blood–brain barrier-tight junctions are more similar to epithelial tight junctions than to endothelial tight junctions in peripheral blood vessels. 2. Although blood–brain barrier-tight junctions share many characteristics with epithelial tight junctions, there are also essential differences. However, in contrast to tight junctions in epithelial systems, structural and functional characteristics of tight junctions in endothelial cells are highly sensitive to ambient factors. 3. Many ubiquitous molecular constituents of tight junctions have been identified and characterized including claudins, occludin, ZO-1, ZO-2, ZO-3, cingulin, and 7H6. Signaling pathways involved in tight junction regulation comprise, among others, G-proteins, serine, threonine, and tyrosine kinases, extra- and intracellular calcium levels, cAMP levels, proteases, and TNFα. Common to most of these pathways is the modulation of cytoskeletal elements which may define blood–brain barrier characteristics. Additionally, cross-talk between components of the tight junction– and the cadherin–catenin system suggests a close functional interdependence of the two cell–cell contact systems. 4. Recent studies were able to elucidate crucial aspects of the molecular basis of tight junction regulation. An integration of new results into previous morphological work is the central intention of this review.
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    Morphological and biochemical characterization of the exocellular investments of polysaccharide-producing Nostoc strains from the Pasteur Culture Collection (2000)
    Springer
    World journal of microbiology and biotechnology 16 (2000), S. 655-661 
    Details
    ISSN: 1573-0972
    Keywords: Exocellular investments ; exopolysaccharide ; morphology ; Nostoc ; Pasteur Culture Collection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A total of 40 Nostoc strains, belonging to the Pasteur Culture Collection and originally isolated from different habitats, were photoautotrophically grown in liquid cultures and tested for the presence of exocellular polysaccharidic investments surrounding the trichomes. However, 25 of them showed a significant presence of these structures, coupled with the release of polysaccharidic material (RPS) into the medium. A rather large number of different morphological forms was observed in the cultures during growth, but at the time of harvesting the predominant morphological form was, in most cases, the vegetative trichome. With regard to the exocellular mucilaginous investments, three main types of morphologies were observed: (i) capsules surrounded by an external pellicle, (ii) capsules with sharp outlines but without an external pellicle, (iii) slimy investments that either loosely surrounded the trichomes without following their shape or were organized in large globular lumps. Among the twenty-five strains that released polysaccharides into the culture medium, three showed mean daily productivities ranging from 30 to 50 mg (RPS) l−1 d−1, values comparable with those of the most productive cyanobacterial strains so far described. The morphological characteristics of the polysaccharidic investments produced by the Nostoc strains seem not to be related to their original habitats. Furthermore, the differences in RPS productivities observed among the strains seem not to be related to the shape of the mucilaginous exocellular investments. Chemical analysis of purified samples of the polysaccharides demonstrated that all the polymers possess an acidic nature, due to the presence of uronic acids, and that they are characterized by the presence of a peptidic moiety and of amino sugars.
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    Photosynthetic acclimation of shade-grown red pine (Pinus resinosa Ait.) seedlings to a high light environment (2000)
    Springer
    New forests 19 (2000), S. 1-11 
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    ISSN: 1573-5095
    Keywords: chlorophyll fluorescence ; competition ; morphology ; photosynthesis ; red pine ; stomatal conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Photosynthetic light acclimation in red pine (Pinus resinosa Ait.) seedlings was examined in a greenhouse study to better understand the physiological response of this species to increased light intensity following release from competition. Seedlings grown in a high (HL), medium (ML) or low (LL) light environment for 12 weeks were transferred to high light. Gas exchange and chlorophyll fluorescence of ML and LL seedlings were measured prior to and following transfer and compared with the HL control treatment. Photosynthetic characteristics were related to initial light treatment and time after transfer. Acclimation of gas exchange features to high light in shade formed ML and LL foliage was relatively rapid, with similar values among light treatments within 57 days of transfer. Acclimation of net photosynthetic rate was similar in ML and LL seedlings, and was associated primarily with increased mesophyll conductance to CO2. The ratio of variable to maximal chlorophyll fluorescence (Fv/Fm) decreased initially after transfer, especially in LL seedlings, but recovered to normal values after 57 days. Red pine seedlings appear to be well adapted for photosynthetic acclimation to high light intensity, consistent with that reported for other early successional tree species.
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    Ilyocryptus spinifer Herrick 1882 (Anomopoda, Branchiopoda): a redescription based on North American material and designation of a neotype from Minnesota (2000)
    Springer
    Hydrobiologia 428 (2000), S. 67-84 
    Details
    ISSN: 1573-5117
    Keywords: Anomopoda ; Ilyocryptidae ; Ilyocryptus spinifer ; morphology ; North America ; neotype ; redescription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology of Ilyocryptus spinifer Herrick, 1882 is redescribed based on material from USA and Canada with special attention to features, regarded now as important for Ilyocryptidae taxonomy. Morphological variability is analysed, and a neotype of this species is designated from Lake Alice Bog, MN, USA. Scanning electron microscopy is used to illustrate fine morphological details. Males, ephippial females and ephippia are described for the first time for North American populations. Historical descriptions of well-known previous North American authors are critically discussed. Only a single species from I. spinifer s. lat. species group is present in USA and Canada, Ilyocryptus longiremis Sars 1888 is a junior synonym of I. spinifer.
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    Analysis of the Ilyocryptus spinifer-species group (Anomopoda, Branchiopoda), with description of a new species (2000)
    Springer
    Hydrobiologia 428 (2000), S. 85-113 
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    ISSN: 1573-5117
    Keywords: Anomopoda ; `Cladocera' ; Ilyocryptus ; morphology ; variability ; systematics ; world fauna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied the morphology and variability of Ilyocryptus spinifer Herrick, 1882 from different parts of the world using optical microscopy and SEM, re-examining type material wherever possible. Morphometric analysis failed to reveal significant regional differences between populations. The following species names for members of Ilyocryptus spinifer group, I. halyi Brady, 1886; I. longiremis Sars, 1888; I. immundus F. Mueller in Ihering, 1895; I. verrucosus Daday, 1905; and I. tetraspinatus Berganim, 1939, are junior synonyms of I. spinifer. A new species from this group is described from Queensland, Australia. Ilyocryptus timmsi n. sp. shows unique morphological characters in the armature of the lateral swimming setae of the antennal endopod, its apical segment and the postabdominal claws.
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    Taxonomic re-evaluation of Aphanizomenon flos-aquae NH-5 based on morphology and 16S rRNA gene sequences (2000)
    Springer
    Hydrobiologia 438 (2000), S. 99-105 
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    ISSN: 1573-5117
    Keywords: Aphanizomenon ; Cyanobacteria ; 16S rRNA ; morphology ; sequences ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The taxonomy of Aphanizomenon flos-aquae strain NH-5, a producer of cyanotoxins, was re-evaluated by comparison with six other Aphanizomenon strains using morphological characteristics and 16S rRNA gene sequences. Strain NH-5 was concluded to be improperly identified as Aph. flos-aquae based upon (1) lack of bundle formation in the trichomes, (2) location of akinetes next to heterocytes, (3) lower similarities (less than 97.5%) in the 16S rRNA gene sequences relative to Aph. flos-aquae strains, and (4) comparison within a phylogenetic tree constructed from 16S rRNA gene sequences. The Aphanizomenon strains investigated in this study are classified to four morphological groups as described by the classical taxonomy of Komárek & Kovácik (1989). This classification was supported from the phylogenetic results of 16S rRNA gene sequences. This study also discusses the generic boundaries between Aphanizomenon and Anabaena.
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    Taxonomic studies of planktic species of Anabaena based on morphological characteristics in cultured strains (2000)
    Springer
    Hydrobiologia 438 (2000), S. 117-138 
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    ISSN: 1573-5117
    Keywords: Anabaena ; cyanobacteria ; identification ; morphology ; planktic ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fifty (50) strains of planktic species of Anabaena (cyanobacteria), including collections from Japan and China and from different culture collections, were induced to form akinetes at low temperature (15 °C). Their morphologies were then observed and described. Fourty seven strains successfully formed akinetes and these were classified into 20 species comprising seven with straight trichomes and 13 with coiled trichomes. Three strains, which did not form akinetes, were separated into two taxonomic groups, but could not be identified to any described species. In addition, a key to the planktic species of Anabaena described in the study is presented.
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    A eukaryotic alga from picoplankton of Lake Baikal: morphology, ultrastructure and rDNA sequence data (2000)
    Springer
    Hydrobiologia 435 (2000), S. 83-90 
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    ISSN: 1573-5117
    Keywords: Lake Baikal ; picoplankton ; Choricystis minor ; morphology ; ultrastructure ; rDNA sequence data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An eukaryotic alga (strain BAC 9708) from the picoplankton of Lake Baikal (Eastern Siberia) has been cultivated in order to investigate its morphology, ultrastructure, growth requirements, pigment composition and nuclear-encoded 18S and chloroplast-encoded 16S rDNA sequences. Cells of strain BAC 9708 contain a nucleus, a single chloroplast without a pyrenoid, one mitochondrion, a poorly visible dictyosome, a large vacuole and a cell wall with an outer sporopollenin-containing layer. Ellipsoidal cells, 1.5–2.0 × 1.0–1.5 μm in size, propagate usually by two, or infrequently by four autospores. Sequence analysis of nuclear-encoded rDNA showed that all 581 nucleotides of the 5′-end of the 18S rDNA were identical to that of Choricystis minor (Skuja) Fott (Chlorococcales, Chlorophyta) obtained earlier (Krienitz et al., 1996). The chloroplast-encoded rDNA sequence of this strain showed identity with one of three chloroplast sequences, selected by PCR-amplification with 16S rDNA specific primers from total picoplanktonic DNA, obtained previously.
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    Apoptosis evaluation in epithelial cells exposed to different chemicals: relevance of floating cells (2000)
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    Cell biology and toxicology 16 (2000), S. 53-62 
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    ISSN: 1573-6822
    Keywords: apoptosis ; cell adhesion ; cytotoxicity tests ; epithelial cells ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The recent increase in understanding of cell death has promoted new approaches in toxicological studies, mainly those dealing within vitro systems where the evaluation of cell death has been the most widely adopted end-point in measuring the effects of chemical toxicants. The aim of this study was to investigate the possibility of improving the traditional cytotoxicity test protocols in order to produce more specific information on the type of cell death induced by exposure to toxicants. In particular, we characterized the mode of cell death in an established epithelial cell line, HEp-2 cells, which is frequently used in cytotoxicity testing owing to its easy handling and standardization of culture conditions. Reference chemicals for apoptosis and necrosis were selected as controls, together with other molecules that have been shown, in preliminary studies, to induce various morphological and structural modifications in relation to cell death. The results obtained show that: (a) the floating fraction of treated cells gives the clearest picture of the necrotic/apoptotic distribution; (b) morphological analysis is crucial for characterization of apoptosis; (c) more than one cytotoxic end-point is necessary to clearly identify the type of cell death.
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    Joint Toxicity of Copper and Zinc to a Terrestrial Nematode Community in an Acid Sandy Soil (2000)
    Springer
    Ecotoxicology 9 (2000), S. 219-228 
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    ISSN: 1573-3017
    Keywords: nematodes ; copper ; zinc ; joint toxicity ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Heavy metal toxicity to an indigenous nematode community was examined following the addition of Cu and Zn, alone or in combination, to agricultural soil. The dissolved Cu or Zn concentrations measured after equilibrating soil samples with a 0.01 M solution of CaCl2 showed that the metal concentrations found in soils with combined metal additions were not significantly different from those with single metal additions. After an exposure period of six months, many nematode community parameters and individual nematode taxa were significantly affected by increasing concentrations of Cu and Zn up to 200 mg kg−1. Some nematode taxa, such as Thonus, Alaimus and Aporcelaimellus were very sensitive and disappeared at Cu and Zn concentrations exceeding 50 mg kg−1. For several nematode community parameters and nematode taxa, EC50 values for single metal exposures were used to calculate TU50 values for the joint toxicity of Cu and Zn. Based on these calculations, it is concluded that the effects of a combined exposure to Cu and Zn were additive or less than additive. Before this conclusion can be generalised, however, more data are needed on other types of soil, other pH values and other combinations of pollutants.
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    URL: http://dx.doi.org/10.1023/A:1008950905983
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    Effect of Humic Acid on the Bioavailability of γ-Hexachlorocyclohexane in Marsilea Minuta (L.) (2000)
    Springer
    Environmental monitoring and assessment 61 (2000), S. 231-237 
    Details
    ISSN: 1573-2959
    Keywords: bioavailability ; γ-HCH ; humic acid ; photoperiods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Effect of various concentrations of humic acid (0.2 to 1%) on thebioavailability of γ-HCH in vegetative clones of theaquatic fern Marsilea minuta was studied in a staticexperimental bioassay system on different photoperiods. Additionof humic acid showed the reduction in the bioavailability ofγ-HCH in all the photoperiods (72 hr light to 144 hrlight) at the interval of 16 hr light (L) and 8 hr dark (D) inboth aerial and submerged portion as compared to controlindicating its protective role in toxicity.
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    URL: http://dx.doi.org/10.1023/A:1006171206492
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    The Oral Route for the Administration of Cytotoxic Drugs: Strategies to Increase the Efficiency and Consistency of Drug Delivery (2000)
    Springer
    Investigational new drugs 18 (2000), S. 231-241 
    Details
    ISSN: 1573-0646
    Keywords: cytotoxic drugs ; oral administration ; bioavailability ; variability ; P-glycoprotein ; CYP3A
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract There is an increasing interest to administer cytotoxic drugs topatients by the oral route. Quality of life issues, treatmentadvantages and pharmaco-economics are major arguments in favorof oral therapy. However, low or moderate bioavailability incombination with considerable interpatient variability arefrequently observed which may reduce the feasibility of the oralroute for this class of drugs with a generally narrow therapeuticwindow. Until recently, investigators focused on absorptionenhancers which slightly damage the intestinal surface such assalicylates, methylxantines and surfactants to improve the oralbioavailability of drugs. To date, a shift can be seen towardsmore subtle mechanisms to enhance the absorption. This reviewarticle focuses on two important mechanisms that determine theoral bioavailability of cytotoxic drugs. These include thepresence of drug transporters in the intestinal epitheliumpumping drugs into the intestinal lumen, such as MDR1 typeP-glycoproteins, and first-pass elimination by cytochrome P450isoenzymes (e.g. 3A4 and 3A5) or other enzymes in the intestinesand/or liver. Currently preclinical and clinical studies arebeing performed to explore the feasibility of blocking thesetransporters/enzymes in order to achieve higher and less variablesystemic drug levels after oral dosing. This review gives anupdate of the results of these studies. It is concluded however,that further research to unravel the processes involved in oraldrug uptake is warranted to make the oral route a more efficientand consistent way of drug administration.
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    URL: http://dx.doi.org/10.1023/A:1006469621561
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    Investigation of Morphology of Porous Silicon Formed on N+ Type Silicon (2000)
    Springer
    Journal of porous materials 7 (2000), S. 23-26 
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    ISSN: 1573-4854
    Keywords: porous silicon ; morphology ; mechanism of growth
    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 properties of porous silicon (PS) are closely connected to its morphology, much investigation has been done in order to correlate the morphological characteristics of PS with the anodisation parameters. In this paper the results of morphological analysis of PS formed on N+type substrates of 〈1 0 0〉 and 〈1 1 1〉 orientation are presented. The dependences of the porosity, thickness of PS, density of pores and of the effective surface on the current density are obtained. Interpretation of these results in terms of diffusion layer and energy levels is given, with special attention given to the low current density case.
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    URL: http://dx.doi.org/10.1023/A:1009627412800
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    The taxonomic relationships within the genus Excoecaria L. (Euphorbiaceae) based on leaf morphology and rDNA sequence data (2000)
    Springer
    Wetlands ecology and management 8 (2000), S. 19-28 
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    ISSN: 1572-9834
    Keywords: Excoecaria ; ITS sequence ; morphology ; phylogeny ; rDNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The tropical Indo-Pacific genus Excoecaria L. (Euphorbiaceae) has several closely related species in Australia whose taxonomic relationships are unclear. The most widely reported species in Australia is the mangrove species Excoecaria agallocha L. (type species), whose taxonomic and geographic limits are difficult to define from its closely related species or sub-species. Two additional taxa have also been described but not clearly differentiated from the type species: Excoecaria dallachyana Baillon and Excoecaria ovalis Endl. This project aimed to determine the taxonomic relationships of the Australian Excoecaria species using both leaf morphological data and DNA sequence data from the internal transcribed spacer (ITS) region of ribosomal genes. The nucleotide differences in the examined ITS1 region show that E. agallocha from eastern Australia and E. ovalis from Western Australia respectively, are genetically uniform within species but differ from each other consistently, thus supporting species status. The leaf morphological data also support this view: single factor analysis of variance consistently separated E. ovalis from E. agallocha on the basis of leaf width, leaf length and length of petiole. In contrast, E. ovalis from the Gulf of Carpentaria differs only slightly from E. ovalis in Western Australia, but no evidence was found to suggest any leaf morphological differentiation within this species. The analysis also suggests that E. dallachyana is not closely related to either mangrove species E. agallocha or E. ovalis, despite superficial morphological similarities.
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    URL: http://dx.doi.org/10.1023/A:1008407009397
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    Bioavailability of Heavy Metals in Sewage Sludge-Amended Thai Soils (2000)
    Springer
    Water, air & soil pollution 122 (2000), S. 163-182 
    Details
    ISSN: 1573-2932
    Keywords: bioavailability ; heavy metal ; laboratory experiment ; sewagesludge ; tropical soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Plough and subsoil layers of two majoragricultural soil series, Rangsit and Thonburi, foundin Bangkok area of Thailand were studied fordetermining the bioavailability and solubilitybehavior of heavy metals (Cd, Cu, Zn, Mn, and Fe)following application of sewage sludge from awastewater treatment plant and a series of laboratoryexperiments. The soils contained low indigenous heavymetals while the sludge contained higher amounts ofheavy metals but in an acceptable range forapplication as plant nutrient source in agriculturalsoil. Applications of sewage sludge increased pH ofthe acid soil and available plant nutrients to thesoils. The heavy metal concentration levels in thesoils also increased. Most partitioned into easilymobile pools and later into sparingly mobile poolsfollowing 12 weeks of incubation time. Bioavailabilityforms of Cd in soil solution were low but that of Cu,Zn, and Mn remained elevated even at 12 weeks of thereaction time. Applied inorganic Zn depressed Cdsorption capacity of two soils studied but it had noeffect on Cd desorption.
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    URL: http://dx.doi.org/10.1023/A:1005247427037
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    Characteristics of Pestalotiopsis Associated with Hardy Ornamental Plants in the UK (2000)
    Springer
    European journal of plant pathology 106 (2000), S. 77-85 
    Details
    ISSN: 1573-8469
    Keywords: Pestalotiopsis sydowiana ; morphology ; pathogenicity ; ericaceous plants ; conifers ; temperature ; pH ; water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Pestalotiopsis isolates obtained from the foliage, stem-base and roots of hardy ornamentals grown on commercial nurseries in the UK were identified and characterised according to pathogenicity and colony morphology. All 18 isolates were identified as Pestalotiopsis sydowiana on the basis of conidia morphology, and confirmation of identification was made by experts at CABI Bioscience. Isolates were pathogenic on the host from which originally isolated. Typical symptoms included foliar browning of foliage and stems, and the presence of black or greenish-black acervuli on diseased tissue. Isolates were not host specific and infected other species of hardy ornamentals. Three colony types on potato dextrose agar were distinguished according to colour and production of acervuli by individual isolates. Three selected isolates of P. sydowiana were characterised by examining the effects of growth media, temperature, pH, and water potential on hyphal extension. Isolates grew well on commonly used growth media, including PDA, Sabouraud dextrose agar (SDA), V8 juice agar (V8), malt extract agar (MEA) and Czapek Dox agar (CDA). The optimum temperature for growth on PDA was in the range 20–25°C, with little or no growth occurring below 5°C or above 30°C. Hyphal extension occurred over a pH range between 2.6–8.6, with optimum values occurring at pH 5.5. In general, decreases in osmotic and matric potential caused a reduction in growth. Hyphal extension on media adjusted osmotically as NaCl ceased between −9.9 and −10.5 MPa. Isolates were more tolerant of osmotic than matric potential, with no growth occurring at −6.5 MPa on media adjusted with polyethylene glycol.
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    URL: http://dx.doi.org/10.1023/A:1008776611306
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    Water velocity shapes juvenile salmonids (2000)
    Springer
    Evolutionary ecology 14 (2000), S. 721-730 
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    ISSN: 1573-8477
    Keywords: Atlantic salmon ; brown trout ; environmental effect ; morphology ; phenotypic plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phenotypic plasticity in morphology is often considered adaptive. Stream-living fish encounter considerable spatial and temporal environmental variation in their native habitats, and the ability to adapt to this variation is of utmost importance. We studied experimentally whether water velocity affects the body shape of juvenile Atlantic salmon (Salmo salar m. sebago Girard) and brown trout (Salmo trutta m. lacustris L.). The fish were reared in slow and fast water flow, and their morphology was studied by measuring a number of morphometric characters. We studied which characters differed between the environments in each species, and found that water velocity caused morphological differentiation in both salmon and brown trout. The differences occurred especially in body height as well as in fin sizes, characters that are very likely to be of functional importance for life in the stream environment. Salmon in fast flow became more robust, whereas brown trout in fast flow became slightly more streamlined. The observed variation in body morphology of salmon and brown trout indicates phenotypic plasticity, but the species differed in their response to environmental variation, which may be due to different energetics and cost reduction strategies. Morphological differentiation caused by water flow occurred very rapidly, within 1-month exposure to the different water flows.
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    URL: http://dx.doi.org/10.1023/A:1011691810801
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    Biokinetics of Transdermal Therapeutic Medicinal Form of Phenazepam (2000)
    Springer
    Bulletin of experimental biology and medicine 130 (2000), S. 1153-1155 
    Details
    ISSN: 1573-8221
    Keywords: transdermal therapeutic system ; phenazepam ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We studied the rate of phenazepam absorption into the blood and its transport to the brain from a transdermal therapeutic system and bioavailability of the drug in this system. Hydrogel matrix consisting of polyvinyl alcohol and 1,2-propylene glycol was used for application. Transdermal application of 0.1-0.4 mg phenazepam in a dose of 14 mg/kg provided a stable level of this drug during application interval (1-48 h), while its bioavailability for blood plasma and brain was 0.63 and 0.2, respectively (determined for 0.4 mg phenazepam). The rate of drug penetration into the blood and brain was 46 and 60 ng/ml/h, respectively.
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    URL: http://dx.doi.org/10.1023/A:1017519731950
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    Influence of milk products on fluoride bioavailability in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 211-215 
    Details
    ISSN: 1432-1041
    Keywords: fluoride ; bioavailability ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of milk products on the gastrointestinal absorption of fluoride from sodium fluoride tablets was studied in five healthy subjects. Two different diets were tested: (1) 250 ml standardized milk (3% fat) and (2) 500 ml of milk, 3 pieces of white bread with cheese and 150 ml of yoghurt. The 100% bioavailability of sodium fluoride tablets during fasting was greatly decreased by coadministration of milk products: with Diet 1 the absolute bioavailability calculated from combined plasma and urine data was in the range 50–79% and with Diet 2 it ranged from 50–71%. It is suggested that the decreased bioavailability produced by dairy products should be taken into account when establishing fluoride dosage regimens for prophylaxis of caries.
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    Comparative bioavailability of a microcrystalline theophylline tablet and uncoated aminophylline tablets (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 417-421 
    Details
    ISSN: 1432-1041
    Keywords: theophylline ; aminophylline ; bioavailability ; rapidly dissolving tablet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability of a rapidly dissolving tablet of theophylline and three brands of standard aminophylline tablets was estimated in a four way cross-over study involving 8 healthy adult volunteers. The relative extent of bioavailability as assessed by the measurement of the total area under the plasma concentration time curves showed no difference between the products (P〉0.05). Computed estimates of the rate of drug absorption were similar for all 4 products tested. The results indicate that the rapidly dissolving tablet offers no advantage in respect to rate and extent of absorption over conventional aminophylline tablets.
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    URL: http://dx.doi.org/10.1007/BF00568203
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    Absolute bioavailability of chlorthalidone in man: A cross-over study after intravenous and oral administration (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 35-50 
    Details
    ISSN: 1432-1041
    Keywords: chlorthalidone ; pharmacokinetics ; oral and i.v. doses ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Seven normal human volunteers each received a constant-rate infusion of chlorthalidone for 2 h, and the same (commonly 50 mg) single oral dose on separate occasions. The concentration of unchanged chlorthalidone was analyzed over a 100 to 220 h period in plasma, red blood cells, urine and faeces after both dosage forms. A three compartment model was required to describe the intravenous plasma concentrations in five of the subjects. A two compartment model sufficed to account for the decay of the oral plasma concentrations in all seven subjects. The mean plasma t1/2 after i.v. dosing was 36.5 h (±10.5 SD), and the mean plasma t1/2 after oral doses was 44.1 h (±9.6 SD). The mean red blood cell concentration t1/2 after i.v. doses was 46.4 h (±9.9 SD), and the mean red blood cell t1/2 after the oral doses was 52.7 h (±9.0 SD). The shorter i.v. half-live was not equally manifest in all subjects, being mainly apparent in three of them. In all cases the urinary excretion rate plots were parallel to the plasma concentration curves. As the faster decay after i.v. administration was not accompanied by increased renal clearance, the difference must have been due to non-renal mechanism. The mean total of 65.4 (±8.6 SD) % of the intravenous dose was excreted in urine over infinite time, whereas the mean total excretion after the oral dose was 43.8 (±8.5 SD) %. Faecal excretion ranged from 1.3–8.5% of dose in the i.v. study to 17.5–31.2% of dose in the oral study. The sum of the amounts present in urine plus faeces pointed strongly to an important metabolic route of elimination of chlorthalidone. Bioavailability estimates (F) from three sets of data were — a mean F of 0.61 from plasma concentrations, 0.67 from urinary excretion measurements and 0.72 from the erythrocyte concentrations. Simulations with a non-linear model indicated lesser validity of the estimate from erythrocyte concentrations. It was concluded that the average of plasma and urine data, F=0.64, yielded the best estimate of the oral availability of chlorthalidone 50 mg in man.
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    Disposition pharmacokinetics of bezafibrate in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 31-38 
    Details
    ISSN: 1432-1041
    Keywords: bezafibrate ; hyperlipoproteinemia ; bioavailability ; pharmacokinetics ; GC-MS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition kinetics of bezafibrate, a newly developed drug of great lipid-lowering potency, were investigated in normal male subjects. Five male volunteers received14C-labelled bezafibrate orally in solution, and a further 10 were given the same dose (300 mg) of un-labelled drug as tablets. The concentration of bezafibrate in serum and urine from the latter was determined by GC, and in the former total radioactivity in serum, urine and feces was followed for 48 h, and urinary excretion products were analysed by TLC and GC-MS. Rapid absorption from the gastrointestinal tract led to peak serum levels 30 min and 2 h after administration of solution and tablets, respectively. Since approximately 95% of the administered14C-bezafibrate was excreted in urine within 48 h, and almost all the remainder was detected in feces, absorption can be regarded as complete after administration in solution. The relative optimal bioavailability from the tablets was also complete, since in both cases approximately 50% of the administered dose was detected as unchanged bezafibrate in urine within 24 h by GC in the tablet study, and by TLC in the solution study. Of the decomposition products, more than 20% of the dose was present as glucuronides and the remainder consisted of several more polar compounds, one of which was identified as a hydroxyderivative of bezafibrate. Since the apparent halflife of bezafibrate in serum was 2.1 h, this new drug possesses favourable pharmacokinetic features: rapid and complete absorption, even from tablets, combined with a conveniently short half-life, and clearance which is half renal (56 ml/min) and half metabolic (43 ml/min), giving a total clearance of 99 ml/min.
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    Pharmacokinetic, bioavailability and pharmacodynamic study of indobufen (K 3920), an inhibitor of platelet aggregation, after a single dose in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 323-327 
    Details
    ISSN: 1432-1041
    Keywords: indobufen ; platelet aggregation ; single dose ; bioavailability ; pharmacodynamics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Six healthy volunteers received single iv and oral doses of 2-[p-(1-oxo-2-isoindolinyl)phenyl] butyric acid 100 mg (indobufen; K 3920), an inhibitor of platelet aggregation. Plasma levels and urinary excretion of the drug were determined by GLC. Collagen-induced platelet aggregation was assessed turbidimetrically at various intervals after administration. The plasma half-life of the drug was 7–8 h and more than 70% of the administered dose was recovered within 48 h in urine, as unchanged drug and as the glucuronide of indobufen. After oral administration of tablets of two different formulations, the drug was completely absorbed, but one formulation showed faster absorption. The maximal inhibitory effect on platelet aggregation was observed 1 to 4 h after iv administration, and it had decreased by 8 h. After tablets, peak effect and the time of the peak were similar, but activity was significantly prolonged, in accordance with the higher plasma levels found at 8 h. The data suggest that the effect of indobufen on platelets is reversible, and that for this drug platelets behave as a compartment that slowly equilibrates with plasma.
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    Absolute bioavailability of quinidine in two sustained release preparations (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 45-48 
    Details
    ISSN: 1432-1041
    Keywords: quinidine ; slow release formulation ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability of quinidine in two sustained release preparations A and B has been compared in three females and three males with i.v. administration of quinidine. The initial rate of oral absorption did not differ between the two drug preparations; the peak concentration was observed after 4 h both for A and B, but was significantly higher after B. A slower decrease in plasma concentration was observed after preparation A than B. Absolute bioavailability did not differ significantly between A (median value 78.4%) and B (median 87.1%). Drug absorption in vivo was in good agreement with the results of in vitro dissolution tests on both preparations. The slower decrease in plasma concentration found for the new sustained release form of quinidine should be of clinical advantage.
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    Bioavailability and pharmacokinetics of cimetidine (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 335-340 
    Details
    ISSN: 1432-1041
    Keywords: cimetidine ; enterohepatic circulation ; irregular absorption ; bioavailability ; pharmacokinetics ; volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability and pharmacokinetics of cimetidine have been studied in healthy volunteers after administration of single intravenous (100 mg) and oral doses (100, 400 and 800 mg). After i.v. administration, the kinetics of cimetidine could be described by a linear, two compartment open model. Substantial variation in half-life was observed between subjects, with a mean value of 2.1 h (range 0.9–4.7). Cimetidine had a low hepatic extraction ratio and a high total plasma clearance, due to extensive urinary excretion of unchanged drug. After oral administration, the plasma concentration vs time curves in most subjects exhibited two marked peaks, an observation that seemed to be constant within individuals and was independent of dose. Bioavailability, estimated as the area under the plasma concentration vs time curves (AUC), after oral doses as compared to the intravenous dose, in most cases exceeded 100%. There was no correlation between bioavailability estimated as AUC and as urinary excretion of unchanged drug. These observations may indicate an enterohepatic circulatory mechanism, predominantly after oral administration. Both unchanged drug and its sulphoxide metabolite appear to be excreted in bile. The latter was shown in vitro to be reduced to cimetidine by fecal bacteria.
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    Influence of food on the absorption of phenytoin in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 269-274 
    Details
    ISSN: 1432-1041
    Keywords: phenytoin ; food-intake ; bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food intake on the absorption of phenytoin was examined in eight healthy volunteers, by study of single-dose kinetics following ingestion of phenytoin 300 mg either with a standardized breakfast or on an empty stomach. Blood samples were collected at regular intervals from 0 to 48 h, and serum concentrations of unmetabolized phenytoin were determined by gas chromatography. Serum concentrations of the major metabolite of phenytoin, 4-hydroxyphenytoin, were measured by mass fragmentography. Concurrent intake of food and phenytoin appeared to accelerate absorption of the drug from the formulation used, and the peak concentrations were significantly higher (mean increase 40%) in the postprandial than in the preprandial state. As reflected by the AUC (area under the curve), the amount of drug absorbed was increased during postprandial conditions, although the difference only reached borderline significance. It is suggested that phenytoin should always be taken in a defined relation to meals.
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    Absorption of quinidine from an enteric-coated preparation (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 107-112 
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    ISSN: 1432-1041
    Keywords: quinidine ; enteric-coated tablets ; bioavailability ; gastric emptying ; pH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of quinidine from single and multiple doses of an enteric-coated preparation (Systodin®) was studied in seven healthy subjects, and was compared with the pharmacokinetics of intravenously administered quinidine and the results of in vitro dissolution tests of the tablets. Absorption of quinidine began after a variable delay, 2–8 h (mean 4.8) after fasting and 3–10 h (mean 6.1) after food. The rate of absorption varied both in and between individuals. It appeared to be lower when the drug was administered after food. Multiple doses after food gave a pattern of plasma concentration-time curves similar to that found on administration of single doses after food. The delay prior to absorption was prolonged at night. The ratio between the maximum and minimum concentration of quinidine during a dose interval varied from 1.3 to 3.2 (mean 2.0). Bioavailability of quinidine in fasting subjects ranged from 69 to 95% (mean 83); variation was greater when doses were administered after food. The release of quinidine from the enteric-coated preparation was pH dependent and was sustained at low pHs as may be found in the intestines. The results indicate that the absorption of quinidine from the enteric-coated formulation was dependent on the highly variable rate of gastric emptying and the pH of intestinal fluid, and it varied greatly both within and between individuals.
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    Pharmacokinetics of prazepam in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 141-147 
    Details
    ISSN: 1432-1041
    Keywords: prazepam ; N-desmethyldiazepam ; bioavailability ; pharmokinetics ; electron-capture gasliquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary An original electron-capture gas chromatographic assay was developed for simultaneous measurement of plasma levels of the benzodiazepine derivative prazepam and of its principal unconjugated metabolite, N-desmethyldiazepam. The assay was used to study the pharmacokinetics of the drug and its comparative bioavailability from tablets and from a specially prepared solution. Nine healthy adult volunteers were studied. Each volunteer on one occasion took 30 mg of the drug in tablet form, and on another occasion 30 mg of the drug in solution. In all subjects, N-desmethyldiazepam appeared in plasma shortly after prazepam appeared and reached a peak within four hours of prazepam ingestion. Thereafter plasma N-desmethyldiazepam levels were much higher than plasma prazepam levels throughout. Prazepam became undetectable within six hours of intake, whereas its metabolite could still be measured in plasma fourteen days after dosage. Thus much of the pharmacological action of prazepam may be mediated through its metabolite, N-desmethyldiazepam. In five of the nine subjects, areas under the plasma level curves for the metabolite were not markedly different for the tablet and solution formulations studied. In the other four subjects the area under the curve for the tablets was 50% to 80% of the area under the curve for the solution. The time to reach peak plasma level for the metabolite was shorter after the solution formulation (mean 2.0±SD 1.2 h) than after the tablet formulation (mean 4.2±SD 1.7 h).
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    URL: http://dx.doi.org/10.1007/BF00563121
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    Systemic availability of ergotamine tartrate after three successive doses and during continuous medication (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 355-360 
    Details
    ISSN: 1432-1041
    Keywords: ergotamine ; migraine ; bioavailability ; radioimmunoassay ; plasma level ; CSF level ; continuous dosing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma ergotamine concentrations were determined by radioimmunoassay in 10 healthy subjects after a 2 mg oral dose of ergotamine, administered at 24 h intervals on three consecutive days. After the first dose the mean peak plasma level of 0.35±0.05 (SEM) ng/ml was found 1–2 h after administration. In the samples obtained 2 h after the second and third doses, plasma ergotamine levels did not exceed the first peak value. On the other hand, after the third and last dose the plasma ergotamine began to rise slowly, reaching maximum of 0.70± 0.10 ng/ml on the 6th day after administration. This supports the concept of accumulation of the drug or of immunoreactive metabolites. CSF ergotamine was determined in 4 patients, who underwent lumbar puncture for other diagnostic purposes, 1 to 2 h after the 2 mg oral dose. A concentration of 0.40± 0.03 ng/ml was observed. In seven out of 18 migraine patients who were taking ergotamine preparations daily (mean 11.7 mg/week), ergotamine could not be detected in plasma 1 h after administration of the dose. In the remaining migraine patients, the pattern of plasma ergotamine after both the daily and the test doses was similar to that of the 10 healthy subjects. The results in volunteers and migraine patients suggest notable variation in bioavailability of the drug. It seems that in most subjects there is accumulation or tissue redistribution of ergotamine or its immunoreactive metabolites, although in a significant number of migraine patients who use the drug daily, ergotamine does not appear to be biologically available.
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    URL: http://dx.doi.org/10.1007/BF00605636
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    The pharmacokinetics of diclofenac sodium following intravenous and oral administration (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 405-410 
    Details
    ISSN: 1432-1041
    Keywords: diclofenac ; plasma levels ; intravenous bolus administration ; oral administration ; enteric coating ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of diclofenac were examined following single rapid intravenous injection and also following single oral doses to healthy female volunteers. After intravenous injection plasma levels of diclofenac fell rapidly and were below the limits of detection at 5.5 h postdosing. Individual drug profiles were described by a triexponential function and mean half-lives of the three exponential phases were 0.05, 0.26 and 1.1 h. After oral doses of enteric-coated tablets, the lag time between dosing and the appearance of drug in plasma varied between 1.0 and 4.5 h. However once drug absorption had commenced similar plasma drug profiles were obtained in different individuals. Peak plasma diclofenac levels ranged from 1.4 to 3.0 µg · ml−1. The mean terminal drug half-life in plasma was 1.8 h after oral doses. This value was not significantly greater than the value of 1.1 h following intravenous doses. Fifty percent of orally dosed diclofenac did not reach the systemic circulation due, predominantly, to first-pass metabolism.
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    URL: http://dx.doi.org/10.1007/BF00568201
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    Divergence in pharmacokinetic parameters of quinidine obtained by specific and nonspecific assay methods (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 303-311 
    Details
    ISSN: 1573-8744
    Keywords: quinidine ; pharmacokinetic parameters ; assay methods ; assay specificity ; area under the plasma concentration-time curve ; bioavailability ; clearance ; therapeutic window
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Previously published estimates of pharmacokinetic characteristics of quinidine can be shown to be dependent on whether the investigators have used analytical methods which are specific for quinidine. Areas under the plasma concentration-time curve and peak plasma concentrations after administration of the drug were higher and clearance values consequently lower in studies utilizing nonspecific assays unable to distinguish quinidine from its metabolites. The error introduced is larger after oral administration as a result of marked first-pass metabolism of quinidine. The absolute oral bioavailabilities from pharmaceutical preparations might therefore be estimated higher in studies with assays including metabolites in the determination. Although the pharmacodynamic response to quinidine is related to the plasma concentration, the therapeutic window of drug concentrations has been defined only using nonspecific assays. In light of the availability of newly developed specific assays, redefinition of the range of therapeutic plasma concentrations is opportune.
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    URL: http://dx.doi.org/10.1007/BF01060020
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    Pharmacokinetics of ampicillin and its prodrugs bacampicillin and pivampicillin in man (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 429-451 
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    ISSN: 1573-8744
    Keywords: ampicillin ; bacampicillin ; pivampicillin ; prodrug ; bioavailability ; zero-order absorption ; two-compartment model ; renal clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Five healthy fasting male subjects were each given single doses of intravenous ampicillin (471 mg), oral ampicillin tablets (495 mg), oral bacampicillin hydrochloride tablets (562 mg ampicillin equivalent), and oral pivampicillin hydrochloride capsules (491 mg ampicillin equivalent) in a crossover experiment. The resulting concentrations of ampicillin were determined in plasma and urine. The pharmacokinetic analysis was made according to a two-compartment open model. The total distribution volume of unbound ampicillin during the disposition phase was 0.247 ± 0.045 (sd) liter/kg, which is only slightly more than the extracellular fluid, suggesting that tissue binding and intracellular distribution of ampicillin are limited. The bioavailability of the esters bacampicillin (86 ± 11%) and pivampicillin (92± 18%) was significantly greater than that of ampicillin (62 ± 17%); however, the difference between the esters was not statistically significant. The absorption for all drugs given orally proceeded at a constant rate, suggesting zero-order release rates from the products. The absorption rate was highest for bacampicillin (0.89 ± 0.39% of dose absorbed per minute), followed by pivampicillin (0.64 ± 0.19) and ampicillin (0.58 ± 0.16). Bacampicillin also had the shortest lag time for the start of absorption (7.0 ± 0.9 min) under the present conditions. Thus, in comparison with ampicillin, the esters have a higher bioavailability, which, in fact, is close to the theoretically highest possible value by clearance concepts. The higher bioavailability in connection with higher absorption rates may be clinically important in ampicillin treatment by the oral route.
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    URL: http://dx.doi.org/10.1007/BF01062386
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    Pharmacokinetics/pharmacodynamics of furosemide in man: A review (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 1-27 
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    ISSN: 1573-8744
    Keywords: furosemide ; renal failure ; congestive heart failure ; bioavailability ; diuretic effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetics of furosemide and the attempt to correlate biological fluid measurements with diuretic response have been the subject of a large number of studies since the original reports of HajdÚ, Rupp, and coworkers in the mid-1960s. This article attempts to critically review these studies under seven different sections: furosemide pharmacokinetics in normal volunteers, furosemide pharmacokinetics in patients with decreased renal function, furosemide pharmacokinetics in patients with congestive heart failure, furosemide metabolism and assay methods, furosemide bioavailability, dose-response relationships, and the role of inhibitors and mediators on furosemide effects. The literature is reviewed through August 1978.
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    URL: http://dx.doi.org/10.1007/BF01059438
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    Bioavailability of imipramine tablets relative to a stable isotope-labeled internal standard: Increasing the power of bioavailability tests (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 233-248 
    Details
    ISSN: 1573-8744
    Keywords: bioavailability ; confidence intervals ; hypothesis testing ; imipramine ; internal standard ; mass spectrometry ; power ; relative bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new methodology for comparative bioavailability testing is described in which each drug formulation is compared with a stable isotope-labeled variant of the drug that is consumed orally in solution at the same time the tested formulation is ingested. The methodology is used to determine the comparative bioavailabilities of two commercially available brands of imipramine hydrochloride. The power of the new methodology to detect differences between drug formulations, when, in fact, such differences exist, is shown to be superior to that of conventional bioavailability tests.
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    URL: http://dx.doi.org/10.1007/BF01060015
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    Bioavailability of p-chlorophenoxyisobutyric acid (clofibrinic acid) after repeated doses of its calcium salt to humans (1978)
    Springer
    European journal of clinical pharmacology 13 (1978), S. 49-53 
    Details
    ISSN: 1432-1041
    Keywords: p-Chlorophenoxyisobutyric acid ; clofibrate ; steady-state plasma concentrations ; bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma concentrations and bioavailability of clofibrinic acid have been estimated under conditions approaching the steady-state during a ten-day period of administration as clofibrate or as a calcium clofibrinate-carbonate combination (1:1 w/w) at a dosage interval of 12 h. Formulation — related differences in bioavailability were not significant, and the 95% confidence limits of these differences were within −2% to +8% of the mean for the reference formulation of clofibrate. The mean steadystate plasma concentrations of clofibrinic acid measured on the tenth day of dosing were 116 µg/ml±22 S.D. and 119 µg/ml±23 S.D. after administration of 885 mg as clofibrate and the calcium clofibrinate-carbonate combination respectively. The peaks of mean plasma concentrations were 70 µg/ml±15 S.D., 119 µg/ml±32 S.D. and 131 µg/ml±26 S.D. on the first, fifth and tenth day of dosing with clofibrate, and 62 µg/ml±13 S.D., 127 µg/ml±S.D. and 143 µg/ml±25 S.D. on the corresponding days of dosing with the calcium clofibrinate-carbonate combination. After the last dose on the tenth day of dosing, the mean apparent half-lives of elimination of clofibrinic acid from plasma were 24.2 h±4.4 S.D. and 25.5 h±3.2 S.D. after administration of clofibrate and the calcium clofibrinate-carbonate combination respectively.
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    URL: http://dx.doi.org/10.1007/BF00606682
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    Gastrointestinal absorption of hydrochlorothiazide enhanced by concomitant intake of food (1978)
    Springer
    European journal of clinical pharmacology 13 (1978), S. 125-128 
    Details
    ISSN: 1432-1041
    Keywords: bioavailability ; diuretics ; gastrointestinal absorption ; hydrochlorothiazide ; thiazides ; food effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Hydrochlorothiazide (hct) 75 mg was administered orally to eight healthy volunteers without (Study I) or together with a standardized meal (Study II), and plasma and urine concentrations of hct were analyzed by GLC. The plasma levels of hct were higher initially when the tablets were taken on an empty stomach, but after 5 h they were higher in Study II. There was no difference between the two studies in the area under plasma concentration time curves. The urinary recovery of hct totalled 55.6±4.9 mg when the drug was given with food and 47.4±6.0 when it was taken on an empty stomach. The difference is significant (p〈0.01). As the urinary recovery represents the uptake of hct, it appears that the gastrointestinal absorption of hct is enhanced when the drug is given with food.
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    URL: http://dx.doi.org/10.1007/BF00609756
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    Dose tolerance and pharmacokinetic studies of L (+) pseudoephedrine capsules in man (1978)
    Springer
    European journal of clinical pharmacology 14 (1978), S. 253-259 
    Details
    ISSN: 1432-1041
    Keywords: Pseudoephedrine ; side effects ; bioavailability ; multiple oral dosing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Dose tolerance and pharmacokinetic studies of pseudoephedrine sustained action capsules were performed in thirty-three adult male subjects who received either 120 mg or 150 mg capsules every twelve hours for seven consecutive days in a double-blind parallel design study. Although only one subject in the 150 mg group was discontinued prematurely from this study, a large number of side effects typical of CNS stimulation were seen. A placebo effect might account for a portion of these complaints, however symtoms evaluated as being due to drug were significantly more severe and persistent in the 150 mg group. Pulse rates showed a persistent and significant increase while systolic and diastolic blood pressure fell from the baseline values in both groups. A pharmacokinetic analysis of the pseudoephedrine plasma concentration-time data provided estimates of half-life and the volume of distribution/availability ratio. The values obtained were in good agreement with values reported by others. Half-life was not influenced by urine pH probably as a result of the narrow range of urine pHs observed in the subjects. Calculations of relative bioavailability suggest that the 120 mg capsule formulation has a 30% greater bioavailability compared to the 150 mg capsule.
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    URL: http://dx.doi.org/10.1007/BF00560458
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    Absorption of oral and intramuscular chlordiazepoxide (1978)
    Springer
    European journal of clinical pharmacology 13 (1978), S. 267-274 
    Details
    ISSN: 1432-1041
    Keywords: Chlordiazepoxide ; benzodiazepines ; pharmacokinetics ; bioavailability ; intramuscular injection ; alcohol withdrawal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of oral and intramuscular (i. m.) chlordiazepoxide hydrochloride (CDX · HCl) was compared in two pharmacokinetic studies. In Study One, single 50-mg doses of CDX · HCl were administered orally and by i. m. injection to 14 healthy volunteers using a crossover design. Whole-blood concentrations of chlordiazepoxide (CDX) and its first active metabolite, desmethylchlordiazepoxide (DMCDX), were determined in multiple samples drawn after the dose. Mean pharmacokinetic variables for CDX following oral and i. m. administration, respectively, were: highest measured blood concentration, 1.65 vs 0.87 µg/ml (p〈0.001); time of highest concentration, 2.3 vs 7.6 h after dosing (p〈0.001); apparent absorption half-life, 0.71 vs 3.39 h (p〈0.001). Biphasic absorption after i. m. injection, consistent with precipitation at the injection site, was observed in 9 of 14 subjects. Based upon comparison with previous intravenous data, the completeness of absorption was 100% for oral vs 86% for i. m. CDX · HCl (p〈0.1). In Study Two, 28 male chronic alcoholics with clinical manifestations of the acute alcohol withdrawal syndrome were randomly assigned to one of four treatment conditions: 50 or 100 mg doses of CDX · HCl, by mouth or by i. m. injection. Concentrations of CDX and DMCDX, determined in plasma samples drawn every 20 min for 5 h following the dose, were significantly higher after oral administration of a given dose than at corresponding points in time after i.m. injection after the same dose. Thus absorption of oral CDX is reasonably rapid and complete, whereas the absorption rate of i. m. CDX is slow.
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    Bioavailability of norethindrone in human subjects (1978)
    Springer
    European journal of clinical pharmacology 13 (1978), S. 35-39 
    Details
    ISSN: 1432-1041
    Keywords: Norethindrone ; bioavailability ; man ; competitive protein binding ; sex differences ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A competitive protein binding assay for norethindrone was developed to measure plasma levels in human subjects. The plasma levels were considerably higher in women than in men, especially at low dose levels. The plasma levels were directly related to the dose in men; but greater variations in the plasma levels were observed in women. The plasma half-life was about 5 h in both sexes with single oral doses of 5 to 20 mg. A comparative bioavailability study with norethindrone from 2 different manufacturers, formulated in the same manner, showed no significant differences in absorption characteristics and provided sufficient data for pharmacokinetic analysis.
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    URL: http://dx.doi.org/10.1007/BF00606680
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    The pharmacokinetics of slow-release procainamide (1978)
    Springer
    European journal of clinical pharmacology 14 (1978), S. 261-265 
    Details
    ISSN: 1432-1041
    Keywords: Procainamide ; slow release formulations ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Procainamide was given to 20 patients with normal renal function as an i.v. bolus of 500 mg followed by 1.0 or 1.5 g eight-hourly by mouth in the form of a slow release preparation (Durules). 97.6±27.1 (SD)% of the oral procainamide was absorbed, the absorption half life being 1.54 h. The elimination half life following the oral formulation was 6.0±0.8 h, compared to a mean of 3.4±0.4 h following i.v. administration. Elimination half life following i.v. administration was slightly related to acetylator status, being 2.75±0.9 h in fast acetylators, and 4.4±2.4 h in slow acetylators. This dependence on acetylator status was not seen in half life following oral administration. Total body clearance, steady state plasma procainamide and N-acetylprocainamide were not significantly dependent on acetylator status, although a few patients who are slow acetylators had unexpectedly low clearance and high steady state procainamide concentrations when given the higher dose.
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    The comparative bioavailability of Lanoxin tablets and Lanoxicaps with and without sorbitol (1978)
    Springer
    European journal of clinical pharmacology 14 (1978), S. 357-360 
    Details
    ISSN: 1432-1041
    Keywords: Lanoxin tablets ; Lanoxicaps ; sorbitol ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary (1) The mean cumulative urinary digoxin excretion over 8 days was compared in 8 healthy volunteers after single doses of digoxin administered as 3 Lanoxin tablets of 0.25 mg, 3 digoxin tablets of 0.2 mg, 12 Lanoxicaps without sorbitol of 0.05 mg, 6 Lanoxicaps without sorbitol of 0.1 mg digoxin, 3 Lanoxicaps without sorbitol of 0.2 mg and 3 Lanoxicaps with sorbitol of 0.2 mg. (2) There was no significant difference between the 8 day cumulative urinary excretion for any of the Lanoxicaps treatments. (3) Cumulative urinary excretion after 3 digoxin tablets of 0.2 mg was significantly (P〈0.05) lower than after all other treatments. (4) Cumulative urinary excretion after 3 Lanoxin tablets of 0.25 mg was not significantly different from that after any of the Lanoxicaps treatments except 0.1 mg Lanoxicaps without sorbitol, it was significantly (P〈0.05) lower after the latter. (5) Mean urinary excretion of digoxin was 60% of ingested dose for all Lanoxicaps treatments and was significantly (P〈0.05) higher than the mean value of 50% for both tablet treatments. (6) Enhanced absorption of digoxin from Lanoxicaps was confirmed and shown to be unrelated to the sorbitol content of the capsule shell.
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    Linear systems analysis in pharmacokinetics (1978)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 265-282 
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    ISSN: 1573-8744
    Keywords: pharmacokinetics ; linear systems analysis ; in vivo dissolution rates ; absorption rates ; metabolic rates ; bioavailability ; numerical desconvolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The application of certain aspects of linear systems analysis to pharmacokinetic-problems is described. Topics covered include the evaluation of in vivodissolution rates, absorption rates, and metabolic rates, and the use of pharmacological data. Relevant numerical procedures are also discussed.
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    URL: http://dx.doi.org/10.1007/BF01312266
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    Dose-dependent bioavailability of tetracycline in man (1978)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 99-110 
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    ISSN: 1573-8744
    Keywords: bioavailability ; tetracycline HCl capsules ; dose dependency ; brand dependency ; water ingestion ; urinary excretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Seven healthy male volunteers were administered, on different occasions, one, two, and three capsules of two commercially available brands (A and B) each containing 250 mg tetracycline HCl. Urinary excretion rates and cumulative amounts of drug excreted in the urine in 4 days were used to assess the bioavailability of the two brands at the different doses studied. The rate constants of absorption and elimination of tetracyline were similar at all dose levels. However, the extent of absorption (F)appears to be dependent on the brand, dose, and volume of water ingested with the drug. Fof Brand B was not significantly different than that of brand A at the 250-mg dose but was decreased by 23.3% (p〈0.01)at the 500-mg dose and by 19.7% (p 〈0.05) at the 750-mg dose. With respect to dose, Fof each brand at the 500-mg dose was not significantly different than its value at the 250-mg dose. However, Fof brand A at the 750-mg dose was reduced by 14.8% (p 〈0.05) and that of brand B by 21.1% (p 〈0.05) relative to their respective values at the single dose. Surprisingly, when the 750-mg dose of brand A was ingested with a small volume of water, Fwas increased by 18.9% (p 〈0.05) compared to the ingestion of the identical dose of the same brand under waterloading conditions.
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    Statistical moments in pharmacokinetics (1978)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 547-558 
    Details
    ISSN: 1573-8744
    Keywords: statistical moments ; network theory ; pharmacokinetics ; bioavailability ; deconvolution ; plasma concentration-time curve ; urinary excretion rate-time curve ; compartment models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Statistical moments are parameters that describe the characteristics of the time courses of plasma concentration (area, mean residence time, and variance of residence time) and of the urinary excretion rate that follow administration of a single dose of a drug. The relationship between the moments of a time-course curve and pharmacokinetic profiles of drug disposition, i.e., absorption, distribution, metabolism, and excretion, is described. The moments are related to the extent and rate of bioavailability, and it is shown that they can be effectively applied to the deconvolution operation.
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    Critical evaluation of the potential error in pharmacokinetic studies of using the linear trapezoidal rule method for the calculation of the area under the plasma level-time curve (1978)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 539-546 
    Details
    ISSN: 1573-8744
    Keywords: trapezoidal rule ; area under the curve ; pharmacokinetics ; clearance ; bioavailability ; integration method ; sulfisoxazole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The linear trapezoidal rule method is commonly used for the estimation of the area under the plasma level-time curve. Error analyses are performed when the method is used in first-order absorption and first-order elimination kinetics in the one-compartment system. It is found that significant underestimations and overestimations in area during the absorption phase and postabsorption phase, respectively, can occur when the method is improperly used. During the exponential postabsorption phase the relative error is only a function of the ratio (n)of the time interval over the half-life of the two plasma data points in the interval. The error from the linear trapezoidal rule method at n=0.5 is about 1%. The error increases to 15.5% and 57.1 % when nis increased to 2 and 4, respectively. It is recommended that for most absorption studies the linear trapezoidal method be used for prepeak and plateau plasma data and the logarithmic trapezoidal method for postpeak plasma data.
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    Absorption of oral tetracycline in patients with Billroth-II gastrectomy (1978)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 295-303 
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    ISSN: 1573-8744
    Keywords: tetracycline ; antibiotics ; Billroth-II gastrectomy ; gastrectomy ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The bioavailability of a single 250-mg oral dose of tetracycline hydroghloride was studied in seven patients following Billroth-II gastrectomy in comparison with seven control subjects matched for age and body weight. There were no significant differences between control subjects and gastrectomized patients in the apparent lag time prior to the start of absorption (23.6 vs. 22.8 min), peak serum tetracycline concentration (1.72 vs. 1.75 μg/ml), the time of attainment of peak concentrations (3.35 vs. 3.42 hr), the apparent first-order absorption half-life (1.8 vs. 1.4hr), or the apparent first-order elimination half-life (8.0 vs. 8.7hr). Completeness of tetracycline absorption, as judged by area under the 24-hr serum concentration curve, did not differ significantly between the two groups, nor did 24-hr urinary excretion of tetracycline. Thus the abnormalities of gastrointestinal structure and function produced by Billroth -II gastrectomy do not result in impairment of the rate and completeness of tetracycline absorption.
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    URL: http://dx.doi.org/10.1007/BF01060093
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    Effect of lidocaine on the absorption, disposition and tolerance of intramuscularly administered cefoxitin (1977)
    Springer
    European journal of clinical pharmacology 12 (1977), S. 273-279 
    Details
    ISSN: 1432-1041
    Keywords: Cefoxitin ; lidocaine ; intramuscular ; bioavailability ; pain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The use of lidocaine HCl solution at concentrations of 0.5 and 1.0% to reconstitute sodium cefoxitin relieves the pain associated with intramuscular injections of the antibiotic. Cefoxitin absorption by the intramuscular route is initially rapid and is virtually complete. Peak serum concentrations, corresponding to about one-half those of a comparable intravenous infusion, are achieved in 30 min. Continuing absorption tends to maintain higher serum concentrations for longer times. Renal clearance and serum half-life of cefoxitin do not appear to be affected by lidocaine at its effective anaesthetic concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00607426
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  • 94
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    Bioavailability of metronidazole in fasting and non-fasting healthy subjects and in patients with Crohn's disease (1977)
    Springer
    European journal of clinical pharmacology 12 (1977), S. 69-72 
    Details
    ISSN: 1432-1041
    Keywords: Metronidazole ; serum concentration ; bioavailability ; food intake ; healthy subjects ; Crohn's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The possible influence of food intake on the bioavailability of metronidazole was examined in ten healthy volunteers by administration of a single dose of metronidazole on an empty stomach, and with a standardized breakfast. Food intake did not significantly alter the bioavailability of metronidazole. The interindividual variation in bioavailability appeared to be slight. In nine patients with Crohn's disease, the absorption of metronidazole appeared to be reduced and to be more variable than in healthy subjects. In both groups there was a clear relationship between the amount absorbed and dose/kg body weight. Thus, from the pharmacokinetic point of view, metronidazole can safely be given either with or between meals. The dose should be related to body weight.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561408
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  • 95
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    Bioavailability of three phenytoin preparations in healthy subjects and in epileptics (1977)
    Springer
    European journal of clinical pharmacology 12 (1977), S. 285-290 
    Details
    ISSN: 1432-1041
    Keywords: Phenytoin acid ; phenytoin calcium ; bioavailability ; inequivalence of generics ; normal subjects ; volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Serum phenytoin concentrations have been studied in epileptic patients and healthy subjects taking tablets of phenytoin calcium (Desitin), A, phenytoin acid (Desitin), B, and phenytoin acid (Nordmark), C. Retrospective data and prospective investigation of hospitalized patients on long-term phenytoin treatment showed that significantly higher serum concentrations of phenytoin were produced by the phenytoin acid preparations B and C than by the phenytoin calcium preparation A. In a cross over study six volunteers received 200 mg/day of preparations A, B, and C for three weeks. In this study, too, higher phenytoin serum concentrations were produced by B and C than by A, although the differences were not statistically significant. The reasons for the discrepancies between the studies in healthy and epileptic subjects are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00607428
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  • 96
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    Human pharmacokinetics and bioavailability of temazepam administered in soft gelatin capsules (1977)
    Springer
    European journal of clinical pharmacology 12 (1977), S. 383-386 
    Details
    ISSN: 1432-1041
    Keywords: Benzodiazepine ; temazepam ; pharmacokinetics ; bioavailability ; hard and soft gelatine capsules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma levels of temazepam were determined in healthy subjects after single oral administration of soft and hard gelatin capsules, and after 7 consecutive night-time doses in soft capsules. Absorption from soft gelatin capsules was significantly faster and produced earlier and higher peak plasma levels. The two pharmaceutical forms did not show any significant difference in relative availability. The apparent half-life of temazepam after night-time administration was significantly shorter than after morning administration, but no change in half-life was observed between the first and seventh night-time doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562455
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  • 97
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    Proscillaridin activity in portal and peripheral venous blood after oral administration to man (1977)
    Springer
    European journal of clinical pharmacology 11 (1977), S. 277-281 
    Details
    ISSN: 1432-1041
    Keywords: Proscillaridin ; oral administration ; portal venous sample ; porto-peripheral concentration difference ; bioavailability ; 86Rb-uptake inhibition assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of proscillaridin A was studied in four patients undergoing catheterization of the portal vein for diagnostic purposes. Proscillaridin 1.5 mg was given as a single oral dose and plasma glycoside activity was analyzed by the86Rb-uptake inhibition technique. Proscillaridin appeared rapidly in the portal blood, peak activity being found after 15 min in three and after 30 min in one patient. In peripheral blood the peak activity occurred after approximately 35 min. Despite rapid passage across the gut wall, porto-peripheral differences in glycoside activity were small; they were zero after 4 h. The mean amount absorbed as active proscillaridin during the first 4 h after the dose was calculated to be only 7.1% of the given amount. Late porto-peripheral differences, probably due to enterohepatic recycling, appeared after 6 h in three patients. The results suggest that proscillaridin undergoes first pass inactivation in the gut wall. Enterohepatic recirculation may contribute to the amounts of active glycoside that reach the systemic circulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00607677
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  • 98
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    Electronic Resource
    Plasma concentrations, bioavailability and dissolution of chlorpropamide (1977)
    Springer
    European journal of clinical pharmacology 11 (1977), S. 207-212 
    Details
    ISSN: 1432-1041
    Keywords: Chlorpropamide ; hypoglycaemic agent ; bioavailability ; plasma concentrations ; bioequivalence ; dissolution tests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability of chlorpropamide from two new formulations (Melitase® tablets) has been compared to that from a reference formulation which is currently in clinical use as a hypoglycaemic agent. In both rate and extent of bioavailability, all three formulations may be considered equivalent, providing allowances are made for differences in drug content. With 95% confidence, the mean bioavailability of chlorpropamide from the new formulations was within about 16% of the mean from the reference formulation, and formulation-related differences were not statistically significant. Although all three formulations were shown to have similar dissolution profiles, dissolution of chlorpropamide was pH-dependent in vitro. Dissolution was almost complete during 30 min at pH 7.2, but only 40%–60% had dissolved during 90 min at pH 2.0. A peak mean concentration of 22.7 µg/ml was reached 3 h after administration of 2×100 mg tablets of the new formulation and peak mean concentrations of 26.8 µg/ml and 27.4 µg/ml were reached 3 h and 4 hours after administration of one 250 mg tablet of the new formulation and one 250 mg tablet of the reference formulation respectively. Formulation-related differences of mean plasma concentrations (after scaling for equal doses of 250 mg) were not significant and each formulation provided similar plasma concentrations at corresponding times after administration. Statistically significant subject-related differences in all the parameters of bioavailability were shown by analyses of variance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606412
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  • 99
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    Electronic Resource
    First pass hydroxylation of nortriptyline: Concentrations of parent drug and major metabolites in plasma (1977)
    Springer
    European journal of clinical pharmacology 11 (1977), S. 219-224 
    Details
    ISSN: 1432-1041
    Keywords: Nortriptyline ; 10-OH-nortriptyline ; bioavailability ; plasma metabolites ; first pass metabolism ; oral dose ; intramuscular dose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nortriptyline was given orally and intramuscularly to six depressed patients. Plasma concentrations of parent drug and the unconjugated and conjugated principal metabolite, 10-hydroxynortriptyline, were determined by mass fragmentography. There was a significant decrease in the area under the nortriptyline plasma concentration — time curve after the oral route of administration, whilst the elimination rate was unchanged. With the oral dose, plasma concentrations of the metabolites were higher and peaked earlier than after intramuscular administration, whilst the opposite was true for the parent compound. This proves that the difference in bioavailability between the two routes of administration was due to first pass metabolism. As determined from the ratio between corresponding areas, the relative bioavailability of the oral dose was 66±21 S.D. per cent. This fraction is higher than that reported previously when intravenous nortriptyline was used as the reference dosage form.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606414
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  • 100
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    Influence of nutritional status on plasma levels and relative bioavailability of tetracycline (1977)
    Springer
    European journal of clinical pharmacology 12 (1977), S. 281-284 
    Details
    ISSN: 1432-1041
    Keywords: Tetracycline ; bioavailability ; plasma levels ; nutritional state ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Relative bioavailability after oral administration of a single dose and Cmin levels of tetracycline in plasma after multiple doses were determined in groups of well-nourished and undernourished subjects. The relative bioavailability of tetracycline, assessed by the area under serum concentration time-curves, did not differ in undernourished and well-nourished patients. The plasma levels were not different in the two groups after the conventional dose of tetracycline HCl 250 mg at 6 hour intervals. However, in these studies undernourished subjects received a higher dose per kg body weight, which could have compensated for any effect of a shortened half life of the drug. When the dose per kg body weight was reduced, the Cmin levels were lower. On the other hand, with the same dose per kg body weight at more frequent intervals, the plasma concentrations were similar to those in well-nourished subjects. These studies indicate that the dosage regimen should be based both on body weight and on the nutritional status of the individual.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00607427
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