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  • 2005-2009
  • 1990-1994
  • 1980-1984  (327)
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  • 1
    ISSN: 1570-7458
    Keywords: Pterostichus melanarius ; Coleoptera ; Carabidae ; pitfall traps ; insecticides ; prey ; hunger ; activity ; Rhopalosiphum padi ; Fenitrothion ; Sumicidin (Fenvalerate) ; spring barley
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Au cours d'essais à grande échelle, effectués en 1981 et 1982, sur orge de printemps, pour évaleur l'effet des insecticides Fenitrothion et Sumicidine (fenvalerate) sur les arthropodes utiles, un accroissement significatif des captures, dans des trappes pièges de Barber, de Pterostichus melanarius (Illiger) a été observé plusierus semaines après le traitement dans les lots traités par rapport aux lots témoins. Significativement plus de femelles de P. melanarius ont été capturées dans les parcelles traitées pendant cette période d'accroissement après traitement. Une diminution correspondante dans les populations de proies a été observée à la suite des traitements. Chaque femelle de P. melanarius des parcelles traitées avait une fraction significativement moins importance de son intestin remplie d'aliments solides (arthropodes) que celles des parcelles non traitées. Des auteurs précédents avaient observé des taux de capture plus rapides dans les trappes et ne plus grande mobilité des carabes affamés. La réduction des populations proies par l'application d'insecticides affamerait les carabes dont l'activité serait par suite plus élevée. Comme le taux de captures dans les trappes est dû à la fois à la taille de la population et à son activité, on en déduit que la capture par trappes seule ne peut donner une image exacte de l'effet des insecticides sur les populations de carabes dans les champs.
    Notes: Abstract During large-scale field experiments in 1981 and 1982, designed to assess the effects of the insecticides Fenitrothion and Sumicidin (Fenvalerate) on beneficial arthropods in spring barley, significant increases in pitfall-trap catches of Pterostichus melanarius (Illiger) were observed in treated plots compared to untreated controls, several weeks after treatment. Significantly more female P. melanarius were caught in treated plots during these post-treatment increases. Corresponding decreases were observed in prey populations following treatments. Individual female P. melanarius from treated plots had significantly fewer of their gut areas full of solid (arthropod) food when compared to those from untreated control plots. Earlier workers observed both faster recapture rates in pitfalls and higher mobility in hungry carabid beetles. The following hypothesis is suggested: reducing prey populations by the application of insecticides results in hungrier carabid beetles with consequently higher activity. Since pitfall-trap catch is determined not only by population size but also activity, it is argued that pitfall-trap catches alone cannot give a true measure of the effects of insecticides on carabid populations in the field.
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  • 2
    ISSN: 1570-7458
    Keywords: Coleoptera ; Curculionidae ; Cylas formicarius elegantulus ; sweetpotato weevil ; sweet potato ; digestion ; enzyme distribution ; trypsin-inhibitors ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'activité endoprotéinase était limitée au liquide de la lumière des régions ventriculaires antérieure et postérieure de l'intestin moyen des larves deCylas formicarius elegantulus Summers. Les aminopeptidases ont été trouvées dans le liquide de la lumière (18%), mais étaient principalement associées avec les fractions insolubles des cellules du ventricule postérieur (82%). Suivant le substrat, l'activité carboxypeptidase était à peu près également répartie entre le liquide de la lumière et les fractions insolubles des cellules du ventricule postérieur. L'amylase, enzyme secrétée, a été observée à la fois dans la lumière antérieure et postérieure. Cinq bandes d'activité amylase ont été révélées sur zymogrammes d'amidon après électrophorèse d'intestins moyens entiers. Trois des bandes d'amylase pouvaient provenir de la plante. Il y avait au moins 2 α-glucosidases, une secrétée et une liée aux cellules du ventricule antérieur. L'activite β-glucosidase était liée aux cellules du ventricule antérieur, fandis que l'activité α-galactosidase était limitée au fluide de la lumière. Les activités β-galactosidase et cellulase ont été trouvées à la fois dans le liquide de la lumière et dans la fraction cellulaire insoluble. Ainsi, la digestion initiale des grosses protéines et des polymères de carbohydrates se produit dans le liquide de la lumière dans les régions ventriculaires antérieure et postérieure. Cependant, l'achèvement de la digestion des oligopeptides se produit principalement dans le ventricule postérieur, tandis que la fin de la digestion des oligosaccharides se produit dans le ventricule antérieur. Les concentrations en inhibiteurs de trypsine de 5 cultivars d'I. batatas L. diffèrent de 1 à 20. Les endoprotéinases deC. formicarius elegantulus ont été inhibées par des extraits de cultivars, mais les cultivars avec des concentrations relativement élevées d'inhibiteur avainent antérieurement montré être susceptibles d'être attaqués par le coléoptère dans des essais en champs.
    Notes: Abstract Endoproteinase activity was confined to luminal fluid from anterior and posterior ventricular regions of midguts of larvae of the sweetpotato weevil,Cylas formicarius elegantulus (Summers). Aminopeptidase was found in luminal fluid (18%) but was primarily associated with insoluble fractions from cells of the posterior ventriculus (82%). Depending on substrate, carboxypeptidase activity was about equally distributed between luminal fluid and insoluble fractions from posterior ventriculus cells. Amylase was found in luminal fluid in both the anterior and posterior ventriculus. Five bands of amylase activity were detected on starch zymograms following electrophoresis of whole midgut samples. Three of the amylase bands may be plant-derived. At least two α-glucosidases were present, one secreted and one bound to anterior ventriculus cells. β-Glucosidase activity was bound to anterior ventriculus cells whereas α-galactosidase activity was confined to luminal fluid. β-Galactosidase and cellulase activities were found in both luminal fluid and the insoluble cell fraction. Thus, initial digestion of large protein and carbohydrate polymers occurs in luminal fluid in both anterior and posterior ventriculus regions. However, terminal digestion of oligopeptides occurs primarily in the posterior ventriculus while terminal digestion of oligosaccharides occurs in the anterior ventriculus. A 20-fold difference in trypsin-inhibitor concentration was found among five sweetpotato cultivars. Endoproteinases from sweetpotato weevil larvae were inhibited by extracts from the cultivars but cultivars with relatively high concentrations of inhibitor were previously shown to be susceptible to weevil attack in field trials.
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  • 3
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    Journal of molecular evolution 18 (1982), S. 310-314 
    ISSN: 1432-1432
    Keywords: Neutral mutation theory ; Natural selection ; Protein evolution ; Levene model ; Environmental variability ; Genetic variability ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary If a phenotypic character is under stabilizing selection, the selective disadvantage of a nonoptimal genotype will decrease exponentially to zero as the proportion of phenotypic variation that is environmental in origin -V e /V p - increases. Under the modified mutation-drift hypothesis of genetic polymorphism, the proportion of mutations that are effectively neutral and average heterozygosity should increase with this ratio. Invertebrates, because of their small size, fast development, and low degree of homeostasis (relative to vertebrates), are expected to show a larger environmental component of phenotypic variation than vertebrates. This may help explain why invertebrates are in general more genetically variable than vertebrates and why, when laboratory populations ofDrosophila are maintained in heterogeneous environments, genetic variability is lost less rapidly than when they are kept in constant conditions.
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  • 4
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    Journal of molecular evolution 20 (1984), S. 251-264 
    ISSN: 1432-1432
    Keywords: Drosophila ; Genome evolution ; 68C Glue gene cluster ; Drosophila melanogaster species subgroup
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 68C puff is a highly transcribed region of theDrosophila melanogaster salivary gland polytene chromosomes. Three different classes of messenger RNA originate in a 5000-bp region in the puff; each class is translated to one of the salivary gland glue proteins sgs-3, sgs-7, or sgs-8. These messenger RNA classes are coordinately controlled, with each RNA appearing in the third larval instar and disappearing at the time of puparium formation. Their disappearance is initiated by the action of the steroid hormone ecdysterone. In the work reported here, we studied evolution of this hormone-regulated gene cluster in themelanogaster species subgroup ofDrosophila. Genome blot hybridization experiments showed that five other species of this subgroup have DNA sequences that hybridize toD. melanogaster 68C sequences, and that these sequences are divided into a highly conserved region, which does not contain the glue genes, and an extraordinarily diverged region, which does. Molecular cloning of this DNA fromD. simulans, D. erecta, D. yakuba, andD. teissieri confirmed the division of the region into a slowly and a rapidly evolving protion, and also showed that the rapidly evolving region of each species codes for third instar larval salivary gland RNAs homologous to theD. melanogaster glue mRNAs. The highly conserved region is at least 13,000 bp long, and is not known to code for any RNAs.
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  • 5
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    Development genes and evolution 193 (1984), S. 267-282 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a search for embryonic lethal mutants on the second chromosome ofDrosophila melanogaster, 5764 balanced lines isogenic for an ethyl methane sulfonate (EMS)-treatedcn bw sp chromosome were established. Of these lines, 4217 carried one or more newly induced lethal mutations corresponding to a total of 7600 lethal hits. Eggs were collected from lethal-bearing lines and unhatched embryos from the lines in which 25% or more of the embryos did not hatch (2843 lines) were dechorionated, fixed, cleared and scored under the compound microscope for abnormalities of the larval cuticle. A total of 272 mutants were isolated with phenotypes unequivocally distinguishable from wild-type embryos on the basis of the cuticular pattern. In complementation tests performed between mutants with similar phenotype, 48 loci were identified by more than one allele, the average being 5.4 alleles per locus. Complementation of all other mutants was shown by 13 mutants. Members of the complementation groups were mapped by recombination analysis. No clustering of loci with similar phenotypes was apparent. From the distribution of the allele frequencies and the rate of discovery of new loci, it was estimated that the 61 loci represent the majority of embryonic lethal loci on the second chromosome yielding phenotypes recognizable in the larval cuticle.
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  • 6
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    Development genes and evolution 193 (1984), S. 90-97 
    ISSN: 1432-041X
    Keywords: Drosophila ; Temperature-sensitive ; Neoplasms ; Differentiation ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary EMS induced temperature-sensitivelethal (2) giant larva, 1(2)gl, alleles were isolated by screening against a knownl(2)gl allele. Analysis of the lethal phase of thel(2)gl ts-deficiency heterozygotes demonstrated: (1) the majority of thel(2)gl tslarvae survive to late third instar, (2) at 29°C the majority of thel(2)gl tslarvae failed to pupate and only rarely did they differentiate adult cuticular structures, (3) at 15°C the majority of the larvae pupated and frequently differentiated adult cuticular structures. Examination of the imaginal discs ofl(2)gl tslarvae reared at 29°C revealed the presence of morphologically abnormal wing, haltere and leg imaginal discs. No morphologically abnormal discs were found in thel(2)gl tslarvae reared at 15°C. Studies on both the histology and the developmental capacity of the morphologically normal and abnormall(2)gl tsdiscs were performed. The morphologically normal discs are histologically normal and produce a full complement of adult cuticular structures. However, the morphologically abnormal discs contained both regions that maintained the normal monolayer epithelium and regions that had lost the normal tissue architecture. The implants obtained when the morphologically abnormal discs are injected into metamorphosing larvae contained only a limited number of the normal complement of adult structures and usually only structures found in the ventral wing hinge region were recovered. In addition, the “metamorphosed” morphologically abnormal discs contained undifferentiated tissue that gave rise to transplantable neoplasms when cultured in adults. The results of the studies on the pathology of thel(2)gl tslarvae are discussed with respect to the role of thel(2)gl tsfunction during normal development, the autonomy of the neoplastic development of thel(2)gl tstissues, and similarities between neoplastic development inDrosophila and mammals.
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  • 7
    ISSN: 1432-041X
    Keywords: Drosophila ; Pole cell transplantation ; Heterospecific combinations ; Gametogenesis ; Chorion morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We transplanted pole cells betweenDrosophila melanogaster, D. mauritiana andD. ananassae to investigate the ability of germ cells to develop in the gonad of a heterospecific host, and to study the interaction between somatic follicle cells and the cells of the germ line in producing the species-specific chorion. FemaleD. mauritiana germ cells in aD. melanogaster ovary produced functional eggs with normal development potential. The same is true for the reciprocal combination. FemaleD. ananassae pole cells in aD. melanogaster host only developed to a very early stage and degenerated afterwards. None of the interspecific combinations of male pole cells led to functional sperm. We could not determine at what stage the transplanted male pole cells were arrested. The cooperation of follicle cells and the oocyte-nurse cell complex in producing the chorion was studied using the germ-line-dependent mutationfs(1) K10 ofD. melanogaster, which causes fused respiratory appendages and an abnormal chorion morphology. Wild-type femaleD. mauritiana germ cells in a mutantfs(1) K10 D. melanogaster ovary led to the production of wild-type eggs withD. melanogaster-specific, short respiratory appendages. On the other hand,D. melanogaster fs(1) K10 germ cells in aD. mauritiana ovary induced the formation of eggs with mutant fused appendages which were, however, typicallyD. mauritiana in length. When.D. mauritiana pole cells developed in aD. melanogaster ovary, the chorion exhibited a new imprint pattern that differs from both species-specific patterns.
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  • 8
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    Development genes and evolution 191 (1982), S. 285-288 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; homoeosis ; Compartments ; Aldehyde oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The aldehyde oxidase staining pattern in wing discs ofDrosophila melanogaster bearing the genotypesap blt /ap blt andap blt andap blt /ap 73n showns changes from the wild-type pattern. Extensive areas of the presumptive dorsal posterior wing blade, which are normally unstained, have enzyme activity in these mutants. In wings of these genotypes, dorsal posterior structures are replaced by dorsal anterior wing structures. A strong correlation has been found between the frequencies of various staining patterns in the discs and the extent of transformation in the cuticular structures of the wing, which is consistent with the idea that aldehyde oxidase activity can be used as an indicator in the wing disc of this transformation. Unlike the homoeotic mutationengrailed, apterous has not been interpreted as a selector gene yet the work reported here shows thatapterous alleles can cause changes resembling those of theengrailed phenotype both in aldehyde oxidase staining behaviour and in the cuticular transformation.
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  • 9
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    Development genes and evolution 191 (1982), S. 264-269 
    ISSN: 1432-041X
    Keywords: Drosophila ; Sexcombless ; Foreleg basitarsus ; Genital disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chromosome which carries the mutationsexcombless (In(1)sx) affects males and females ofD. melanogaster. In the male foreleg basitarsi the number of sexcomb teeth is dramatically reduced from 10 to 0.7 and the number of transverse rows of bristles is increased from 6 to 8. Females homozygous forIn(1)sx show a normal bristle pattern in the foreleg basitarsus. The genital disc derivatives of both male and femaleIn(1)sx flies are strongly affected. While the external genitalia show a duplicated or a reduced bristle pattern, the internal genitalia are mostly absent. However, the sexually dimorphic tergites and sternites of the abdomen remain unaffected. The male-specific effect on the basitarsus and the general effects on the genital disc derivatives are proposed to represent two different phenotypic effects ofIn(1)sx which may derive from mutations at different gene loci in the inverted chromosome.
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  • 10
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    Development genes and evolution 191 (1982), S. 289-291 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Cell competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Imaginal wing discs from late third-instar larvae were gammairradiated to induce clones of rapidly growingMinute − cells in a background of slowly growingMinute cells and culturedin vivo for periods up to 18 days. Clones in discs cultured for 16 to 18 days did not grow significantly larger than clones in uncultured controls, indicating that competition between populations of cells having potentially different mitotic rates does not occur in imaginal discs after their growth is completed.
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  • 11
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    Development genes and evolution 193 (1984), S. 98-107 
    ISSN: 1432-041X
    Keywords: Drosophila ; Neoplasms ; Promotion ; Regeneration ; Temperature-sensitive ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this paper we present an analysis of the behavior ofl(2)gl tsimaginal wing discs during culture in adult hosts. Thel(2)gl tslarvae reared at 29° C contain two types of wing discs, those that are morphologically normal and those that are abnormal. When discs of both types are cultured in adult hosts at 29° C, the restrictive temperature, they give rise to transplantable neoplastic tissue. However, when the 29° C reared discs are cultured at 15° C, the permissive temperature, the morphologically normal discs maintain their morphology, but the morphologically abnormal discs give rise to neoplasms. Thel(2)gl tslarvae reared at 15° C contain only morphologically normal discs. When these discs are cultured in adult hosts at 29° C they give rise to neoplasms, however if the discs are cultured at 15° C they maintain their normal morphology. These results demonstrate: (1) that all wing imaginal discs obtained from 29° C rearedl(2)gl tslarvae are competent to undergo neoplastic development, (2) the morphologically abnormal discs obtained from the 29° C rearedl(2)gl tslarvae are committed to neoplastic development, (3) the neoplastic development of the morphologically normal discs is temperature dependent, (4) once the neoplastic development of thel(2)gl tsdiscs has been initiated the process is not readily reversible. In addition, the ability ofl(2)gl tswing discs to perform epimorphic regulation was tested by amputating morphologically normal permissively rearedl(2)gl tswing discs and culturing both fragiments at the permissive temperature. Fragments of control wild-type discs maintained their morphology during culture at the permissive temperature. However, both fragments of txel(2)gl tsdiscs became neoplastic. This result is discussed with respect to a possible role for thel(2)gl +function in epimorphic regulation and with respect to the phenomena of tumor promotion in vertebrates.
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  • 12
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    Development genes and evolution 191 (1982), S. 103-111 
    ISSN: 1432-041X
    Keywords: Drosophila ; Polytene Chromosomes ; Ecdysteroids ; Fat Body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in polytene chromosome 3 L puffing patterns in the fat body ofDrosophila melanogaster larvae and prepupae are compared to those in the salivary gland. While some general features are common to the two tissues, there are differences which reflect their different developmental roles. In vitro experiments with fat body chromosomes show that they have a distinct response to ecdysteroids which is different from that of salivary gland chromosomes, and which does not,in this culture system, reproduce the changes observed in normal development. In short term culture experiments, the fat body chromosomes appear more sensitive to ecdysteroids than the salivary gland chromosomes and, although 20-OH ecdysone is more active than ecdysone in these assays, the possibility is not excluded that ecdysone has a role in normal development as it appears to alter gene activity at physiological levels in these cells.
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  • 13
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    Development genes and evolution 191 (1982), S. 293-300 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Positional information ; Homology ; Intercalary regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The regulative behavior of fragments of the imaginal discs of the wing and first leg was studied when these fragments were combined with fragments of other thoracic imaginal discs. A fragment of the wing disc which does not normally regenerate when cultured could be stimulated to regenerate by combination with certain fragments of the haltere disc. When combined with a haltere disc fragment thought to be homologous by the criteria of morphology and the pattern of homoeotic transformation, such stimulated intercalary regeneration was not observed. Combinations of first and second leg disc fragments showed that a lateral first leg fragment could be stimulated to regenerate medial structures when combined with a medial second leg disc fragment but not when combined with a lateral second leg disc fragment. Combinations of wing and second leg disc fragments showed that one fragment of the second leg disc is capable of stimulating regeneration from a wing disc fragment while another second leg disc fragment fails to stimulate such regeneration. It is suggested that absence of intercalary regeneration in combinations of fragments of different thoracic imaginal discs is a result of homology or identity of the positional information residing in the cells of the fragments. The pattern of correspondence of positional information revealed by this analysis is consistant with the pattern of homology determined by morphological observation and by analysis of the positional specificity of homoeotic transformation among serially homologous appendages. The implications of the existence of homologous positional information in wing and second leg discs which share a common cell lineage early in development are discussed.
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  • 14
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    Development genes and evolution 191 (1982), S. 335-339 
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Wing disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distribution of gap junctions in mature larvalDrosophila melanogaster wing discs was analyzed by means of quantitative electron microscopy. Gap junctions are non-randomly distributed in the proximal-distal disc axis and in the apical-basal cell axis of the epithelium. In the epithelial cells, the surface density, number and length of gap junctions are greatest in the apical cell region and distal disc region. The average gap junction surface density is 0.0572 μm−1 and 2.77% of the lateral cell surface is composed of gap junctions. In the adepithelial cells, the gap junction surface density is 0.0005 μm−1 and 0.06% of the cell surface is composed of gap junctions. No gap junctions were observed between epithelial cells and adepithelial cells. The absolute area of gap junctions was estimated in a proximal-distal strip of cells in the disc and is considerably less in the folded regions of the epithelium compared to the flat notum and wing pouch regions. The results are discussed with respect to pattern formation and growth control in imaginal discs.
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  • 15
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    Development genes and evolution 191 (1982), S. 28-36 
    ISSN: 1432-041X
    Keywords: Drosophila ; Polarity ; Maternal effect ; Nurse cells ; Embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationdicephalic (dic) affects follicle development and thereby alters the antero-posterior polarity of embryonic patterning. It maps at a single locus (3–46.0±1.0) and can be characterized as a semi-dominant maternal effect mutation with low penetrance. Indic follicles, the 15 nurse cells form two clusters located at opposite poles of the oocyte; the numerical distribution of the nurse cells among the clusters varies from 7:8 to 1:14. Thedic egg shell carries a micropyle (anterior marker) at either pole, but the misshapen respiratory appendages are restricted to one of the two poles in most eggs. The malformed eggs rarely yield larvae and these are always abnormal anteriorly and/or posteriorly. The segment pattern expressed in their cuticle may represent two anterior parts of opposite polarities (double head type), two posterior parts of opposite polarities (double abdomen type, rare) or show uniform polarity. Lability of organization at the cystocyte stage appears as the primary developmental defect of the mutant.
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  • 16
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Imaginal disc ; Pattern formation ; EM Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Developmental changes in the distribution of gap junctions in early, mid and late third larval stage wing discs and in pupariation+6 h and pupariation+24 h stage wing discs fromDrosophila melanogaster were analyzed by quantitative electron microscopy. Gap junctions occur in all 12 intradisc regions examined in each of the five developmental stages. Their distribution is non-random and changes during development which suggests that they are developmentally regulated. The gap junctions are not static structures, rather they grow and regress during development. The changes tend to be gradual ones without sudden increases or decreases. Gap junctions continuously form and grow in size throughout the third larval stage and during the first 6 h following pupariation. Their surface density, number, percent of the lateral plasma membrane area, and absolute area as well as the lateral plasma membrane surface density all increase during this time. Between pupariation+ 6 h and pupariation+24 h all but one of these parameters decrease indicative of gap junctional breakdown. Gap junctions are most numerous and change least during development in the apical cell regions where intercellular contacts are close and stable. They change most in the basal cell regions where intercellular contacts tend to be looser and change during development. The most dramatic change is in the absolute area which increases by a factor of 23 between the early third larval stage and pupariation+24 h. At pupariation the rate of gap junction growth undergoes a transient increase before the phase of disassembly begins. Developmental changes in gap junction surface density are closely coupled with changes in the lateral plasma membrane surface density which suggests that these may be coregulated. Evidence from mutants suggests that when the number and density of gap junctions fail to increase in proportion to lateral plasma membrane growth, wing disc development will be abnormal. Our results support the idea that some minimum gap junction density is required for normal development and that this must increase as development proceeds. The results are consistent with the notion that gap junctions are involved in pattern formation and growth control and are discussed with respect to the acquisition of competence for metamorphosis, disc growth, disc morphogenesis and changes in the hormonal environment.
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  • 17
    ISSN: 1432-041X
    Keywords: Major haemolymph proteins ; Development ; Cuticle ; Immunocytochemistry ; Ceratitis capitata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The developmental profile of the major haemolymph proteins (ceratitins) inCeratitis capitata was studied. Ceratitin concentration in the haemolymph decreases dramatically during the last days of pupal life, while the amounts of ceratitins in whole organism extracts remain unchanged. By electrophoretic, immunological and immunofluorescence techniques it was revealed that ceratitins are reabsorbed by the fat body and a fraction of them is deposited in the cuticle. The possible role of ceratitins is discussed.
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  • 18
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    Development genes and evolution 191 (1982), S. 42-55 
    ISSN: 1432-041X
    Keywords: Clonal analysis ; Growth ; Cell lineage ; Genital disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary InDrosophila, the terminalia (i.e. internal and external analia and genitalia, except the gonads) are formed by the genital disc. Comparative studies suggested that this disc may have evolved through fusion of the imaginal primordia of the last 3 or 4 abdominal segments. The present report describes the clonal relationships within the complex genital disc. Genetically marked cell clones were induced in male and female embryos and larvae heterozygous for cell marker mutations. 1) Frequencies and sizes of clones suggest that the embryonic disc anlage consists of 14–17 precursor cells: 4–6 for the analia, some 7 for the male genitalia, and 3–4 for the female genitalia. These cells grow exponentially during larval development. 2) In both sexes, the clones were confined to either analia or genitalia, suggesting two separate cell lineages already established at blastoderm. 3) Internal and external genitalia remain in the same compartment at least up to 60 h (end of first instar). 4) A clonal restriction appeared around 84 h (mid second instar), separating a dorsal from a ventral part in the male genitalia. The ventral compartment comprises the ventral part of the lateral plate and clasper, hypandrium, and all internal genitalia. No such boundary was detected in the female. 5) In the female, analia and parovaria originate from the same precursors; another cell lineage forms eighth tergites, vaginal plates, oviduct, receptacle, and spermathecae. 6) In female analia, dorsal and ventral plate share common precursors at least up to 84 h. A medio-lateral boundary may appear at 84 h in the ventral anal plate. No clonal restriction was found in the male analia. 7) At all times, clones could cross between left and right sides of the symmetrical terminalia; they consistently did so via ventral structures. 8) The results are discussed in a phylogenetic context, and we propose that the clonal relations reflect the evolution of the complex genital disc.
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    Development genes and evolution 191 (1982), S. 191-201 
    ISSN: 1432-041X
    Keywords: Neurogenic mutants ; Maternal effects ; Drosophila
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    Topics: Biology
    Notes: Summary The size of the neurogenic region ofDrosophila melanogaster is under the control of several genes of zygotic expression. Lack of function from any of those genes produces an increase of the size of the neurogenic region at the expense of the epidermal anlage. However, differences exist in the extent of neuralisation achieved by each of the genetic loci upon mutation. The present results show that in the case ofN andmam phenotype differences are due to different contributions of maternal gene expression. This could be shown by studying the phenotype which appeared in mutant embryos when the oocytes developed from homozygous mutant precursor cells. Clones of mutant cells were induced in the germ line of females heterozygous for the neurogenic mutationin trans over germ line dependent, dominant female sterile mutations. After removing maternal information the phenotype ofN andmam mutants became identical in both cases. Furthermore maternal information fromN + was found to be necessary for viability of the wildtype.
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    Development genes and evolution 191 (1982), S. 211-214 
    ISSN: 1432-041X
    Keywords: Drosophila ; Clonal analysis ; Sex determination
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    Topics: Biology
    Notes: Summary The mutationSxl f , located on the X-chromosome, is a sex-limited recessive lethal that specifically kills 2X; 2A flies while it does not affect X; 2A flies (Cline 1978). We have analyzed the role ofSxl f on sex determination by a clonal analysis of a new spontaneous allele,Sxl fLS . Female embryos and larvae heterozygous forSxl fLS were irradiated at different times of development to generate homozygousSxl fLS clones which were recognized by linked marker mutations. We have studied the phenotype of such clones on sexually dimorphic regions of the fly (foreleg basitarsus, 5th, 6th and 7th tergites, analia and external genitalia). Despite their female (2X; 2A) chromosomal constitution, clones homozygous forSxl fLS differentiated male structures. These results confirm and extend the preliminary report of Cline (1979). They show that the wildtype product ofSxl f is required for female development.
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  • 21
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    Development genes and evolution 193 (1984), S. 296-307 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
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    Topics: Biology
    Notes: Summary In order to identify X-chromosomal genes required inDrosophila for early patterning and morphogenesis, we examined embryos hemizygous for EMS-induced lethal mutations to determine which of those mutations cause gross morphological defects. Embryos from 2711 lethal lines, corresponding to 3255 lethal point mutations were studied. Only 21% caused death during embryogenesis and of these, only one-sixth, or 3% of the total lethals, were associated with defects visible in the final cuticle pattern. Of the 114 point mutants causing visible cuticle defects, 76 could be assigned to 14 complementation groups. An additional 25 mutations mapping to regions of the X-chromosome not covered by male fertile duplications were assigned to six complementation groups based on similarities of map position and phenotype. Thirteen mutations could not be assigned to complementation groups. All mutations allowed normal development through the cellular blastoderm stage, the first defects associated with the earliest acting loci being observed shortly after the onset of gastrulation. The phenotypes of the various loci range from alterations in segment pattern or early morphogenetic movements to defects in final pigmentation and denticle morphology. Cuticle preparations were also examined for 63 deletions spanning in total 74% of the X-chromosome, as well as for 8 deletions and point mutations derived in saturation mutagenesis screens of the fourth chromosome (Hochman 1976). With the exception of defects in head morphology and defects in cuticle differentiation, none of the hemizygous deletions showed phenotypes other than those predicted by point mutations known to lie in those regions. No deletion caused new or unknown alterations in gastrulation, segmentation or cuticle pattern.These results suggest that the number of genes required zygotically for normal embryonic patterning is small and that most, if not all such loci, are represented by point mutations in our collection.
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  • 22
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
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    Topics: Biology
    Notes: Summary The thin region of the peripodial membrane is confined to the area overlying the distal anlagen in thoracic discs. During the early stages of evagination the peripodial membrane is greatly stretched, but does not rupture. The appendage then evaginates through the stalk, probably by means of a contraction of the peripodial membrane. The cells of the peripodial membrane of leg and wing discs persist and differentiate sheets of trichomes characteristic of the ventral and lateral thorax. This is discussed in relation to imaginal disc fate maps.
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  • 23
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    Development genes and evolution 193 (1984), S. 263-265 
    ISSN: 1432-041X
    Keywords: Drosophila ; Biothorax complex ; Prothoracic transformation
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    Topics: Biology
    Notes: Summary If, early in development, theUbx + gene is removed by mitotic recombination from cells of the meso-and metathoracic leg primordia, theseUbx − cells develop as in the posterior prothoracic leg. We show that this transformation, termedpostprothorax, is a discrete genetic function that is independent of other homeotic transformations such asbx, pbx orbxd, which also result from the inactivation of theUbx gene.
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  • 24
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    Development genes and evolution 193 (1984), S. 283-295 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
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    Topics: Biology
    Notes: Summary The present report describes the recovery and genetic characterization of mutant alleles at zygotic loci on the third chromosome ofDrosophila melanogaster which alter the morphology of the larval cuticle. We derived 12600 single lines from ethyl methane sulfonate (EMS)-treatedst e orrucuca chromosomes and assayed them for embryonic lethal mutations by estimating hatch rates of egg collections. About 7100 of these lines yielded at least a quarter of unhatched eggs and were then scored for embryonic phenotypes. Through microscopic examination of unhatched eggs 1772 lines corresponding to 24% of all lethal hits were classified as embryonic lethal. In 198 lines (2.7% of all lethal hits), mutant embryos showed distinct abnormalities of the larval cuticle. These embryonic visible mutants define 45 loci by complementation analysis. For 32 loci, more than one mutant allele was recovered, with an average of 5.8 alleles per locus. Complementation of all other mutants was shown by 13 mutants. The genes were localized on the genetic map by recombination analysis, as well as cytologically by complementation analysis with deficiencies. They appear to be randomly distributed along the chromosome. Allele frequencies and comparisons with deficiency phenotypes indicate that the 45 loci represent most, if not all, zygotic loci on the third chromosome, where lack of function recognizably affects the morphology of the larval cuticle.
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    Development genes and evolution 193 (1984), S. 308-325 
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Pattern of neuroblasts ; Drosophila
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    Topics: Biology
    Notes: Summary This paper deals with morphological aspects of early neurogenesis inDrosophila, in particular with the segregation of neuroblasts from the neurogenic region of the ectoderm and the pattern formed by those wells within both the germ band and the procephalic lobe. The neurogenic ectoderm was found to contain neural precursors intermingled with epidermal precursors, extending from the midline up to the primordia of the tracheal tree along the germ band and laterodorsally in the procephalic lobe. Germ band neuroblasts segregate from the neurogenic ectoderm during a period of several hours according to characteristic spatial and temporal patterns. During the first half of the segregation process the pattern of germ band neuroblasts was found to be the same in different animals in both spatial arrangement and number of cells; this permitted the identification of individual neuroblasts from different embryos. Later in development several difficulties were encountered which precluded an exact description of the neuroblast pattern. The constitution of the neurogenic region is discussed in relation to the phenotype of mutants affecting neurogenesis.
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  • 26
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    Development genes and evolution 193 (1984), S. 388-393 
    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Ring canals ; Oocyte determination ; Polarity
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    Topics: Biology
    Notes: Summary The pattern of intercellular connections between germ line cells has been studied in follicles of the mutantdicephalic (dic), which possess nurse cell clusters at both poles. Staining of follicles with a fluorescent rhodamine conjugate of phalloidin reveals ring canals and cell membranes and thus allows us to reconstruct the spatial organization of the follicle. Each germ line cell can be identified by the pattern of cell-cell connections which reflect the mitotic history of individual cells in the 16-cell cluster. The results indicate that in both wild-type anddicephalic cystocyte clusters one of the two cells with four ring canals normally becomes the pro-oocyte. However, in some follicles (dicephalic and wild-type) oocytes were found with fewer or more than four ring canals. Indic follicles, one or several nurse cells may become disconnected from the other cells during oocyte growth at stage 9–10. Such disconnected cells cannot later on empty their cytoplasm into the oocyte. This, in turn, might be of consequence for the determination of axial polarity of the embryo.
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    Development genes and evolution 193 (1984), S. 406-413 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
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    Topics: Biology
    Notes: Summary The fusion of the eye-antennal discs during culturein vitro has been investigated, and the complex morphogenetic movements which occur during the formation of the head capsule of the insect are described. The initial contact between the eye anlagen is by means of cell processes spanning the gap between the two discs. Subsequently the two epithelia become firmly apposed, and then the integrity of the epithelium in the region of fusion breaks down, cells appearing to move to new positions in order to form an epithelium which unites the two discs. The epithelium eventually secretes a pattern of cuticular structures which is continuous between the derivatives of the two discs. Bristles on either side of the line of fusion are perfectly aligned, and structures such as the median ocellus, which are formed jointly by the cells of the two discs, differentiate normally. This is also found when left and right eye-antennal discs of different genotypes are placed side-by-side, indicating that processes of pattern regulation can occur in culture.
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  • 28
    ISSN: 1432-2048
    Keywords: Immunocytochemistry ; Lectin (localization) ; Phaseolus (lectin) ; Phytohemagglutinin ; Seed (lectin)
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    Topics: Biology
    Notes: Abstract We have examined the properties and subcellular localization of phytohemagglutinin (PHA), the major lectin of the common bean (Phaseolus vulgaris.), in the axis cells of nearly mature and imbibed mature seeds. On a protein basis the axis contained about 15% as much PHA as the cotyledons. Localization of PHA was done with an indirect immunolabeling method (rabbit antibodies against PHA, followed by colloidal gold particles coated with goat antibodies against rabbit immunoglobulins) on ultra-thin cryosections which were embedded in plastic on the grids after the immunolabeling procedure. The embedding greatly improved the visualization of the subcellular structures. The small (4 nm) collodial gold particles, localized with the electron microscope, were found exclusively over small vacuoles or protein bodies in all the cell types examined (cortical parenchyma cells, vascular-bundle cells, epidermal cells). The matrix of these vacuoles-protein bodies appears considerably less dense than that of the protein bodies in the cotyledons, but the results confirm that in all parts of the embryo PHA is localized in similar structures.
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  • 29
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    European journal of clinical pharmacology 21 (1982), S. 287-291 
    ISSN: 1432-1041
    Keywords: tolmesoxide ; hypertension ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Tolmesoxide is a new, direct-acting vasodilator drug for use in the management of both hypertension and cardiac failure. In 6 essential hypertensives inadequately controlled by combined β-blocker and diuretic therapy (average supine blood pressure 178/103 mm Hg) the addition of tolmesoxide (300–900 mg daily) was associated with a significant improvement in blood pressure control (average supine blood pressure 161/89 mmHg). The effect of food on the pharmacokinetics and pharmacodynamics of tolmesoxide have also been studied because, particularly at higher doses, the drug has been associated with upper gastrointestinal upset and it has been empirically recommended that it be taken with food. The blood pressure and heart rate responses were not significantly different when tolmesoxide was taken fasting or with food. Food resulted in a significant reduction in the peak plasma tolmesoxide concentration (2.14 µg/ml compared to 2.97 µg/ml) and a significant increase in the time to reach peak plasma concentration (1.67 h compared to 0.63 h). Although there was no impairment of its hypotensive effect, food significantly altered the pharmacokinetics of tolmesoxide and may therefore be useful in reducing the gastrointestinal disturbance associated with its use. In the treatment of inadequately controlled hypertension, tolmesoxide has a limited role as an alternative vasodilator.
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    European journal of clinical pharmacology 21 (1982), S. 307-310 
    ISSN: 1432-1041
    Keywords: piretanide ; renal failure ; high dose ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of piretanide was studied in patients with renal failure. After oral administration of a high dose of piretanide (96 mg), the pharmacokinetic parameters were: elimination rate constant 0.346±0.072 h−1, half life 2.00±0.35 h, and total plasma clearance 119.55±35.90 ml · min−1. Compared to the values obtained in adults with normal renal function, these results show a decrease in total plasma clearance, but conservation of the metabolic clearance which amounts to 45% of the total clearance in the healthy adult.
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    European journal of clinical pharmacology 21 (1982), S. 397-402 
    ISSN: 1432-1041
    Keywords: ergotamine ; migraine ; radioimmunoassay ; clinical effects ; adverse effects ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The systemic availability of ergotamine after a single therapeutic oral or rectal dose was studied using a radioimmunoassay during the headachefree state in 24 patients suffering from migraine. Plasma concentrations of the drug were compared with anamnestic data about its clinical effects in the same patients. Among 12 patients with a good therapeutic response to medication, the mean plasma ergotamine levels stayed in the range 0.20 to 0.50 ng/ml for 6h. Their mean plasma levels at 30 min (0.33ng/ml) and 1h (0.40ng/ml) were significantly higher than those (0.06 and 0.08ng/ml, respectively) in 9 patients with only a moderate therapeutic response. In 9 patients with a moderate and 3 with a poor therapeutic response, the mean plasma level generally stayed below 0.10ng/ml. The mean peak concentrations in moderate (0.13 ng/ml) and poor (0.11ng/ml) responders appeared later (at 3h) than in good responders (at 1h). Side effects of the medication appeared to be associated with relatively low plasma levels of ergotamine and also with delayed maximum plasma concentrations of the drug. The present results suggest that the time of the maximum plasma drug level is an important determinant of the clinical effects of ergotamine, and that a good therapeutic response may be expected if a plasma ergotamine level of 0.20ng/ml or more is achieved within 1 hour after oral or rectal administration.
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    European journal of clinical pharmacology 21 (1982), S. 343-350 
    ISSN: 1432-1041
    Keywords: orphenadrine ; single dose ; multiple doses ; bioavailability ; pharmacokinetics ; N-demethylorphenadrine ; metabolism ; dog ; man
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma concentrations of orphenadrine were measured by a specific gaschromatographic method in 5 healthy male volunteers after a single oral dose of orphenadrine hydrochloride 100mg. The single dose pharmacokinetic profile of orphenadrine was evaluated from these data. The elimination half-life ranged from 13.2–20.1 h after the commercial tablet formulation. Plasma concentrations, determined in volunteers and patients under different conditions of repeated oral administration of the same formulation of orphenadrine hydrochloride exceeded the theoretical values, predicted from the single dose pharmacokinetics, by a factor 2 to 3. The elimination half-lives after discontinuation of treatment showed a 2 to 3-fold increase over the single dose values. This demonstrates a clear discrepancy between the multiple and single dose pharmacokinetics of orphenadrine. Experiments in dogs suggested competition for biotransformation between orphenadrine and its metabolite N-demethylorphenadrine. Product inhibition of this type could explain the observed discrepancy.
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    European journal of clinical pharmacology 22 (1982), S. 273-279 
    ISSN: 1432-1041
    Keywords: amoxycillin ; i.v. administration ; pharmacokinetics ; two- and three-compartment models
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic characteristics of amoxycillin were studied in healthy volunteers after intravenous injection of 250 mg, 500 mg and 1,000 mg, and infusion of 2 g and 5 g. Serum concentrations were fitted using either bi- and tri- exponentional equations. Comparison of the regression curves obtained revealed that the three-compartment model gave a better fit to the serum concentration versus time curve. It was evident that there was a third, slow, dose dependent phase of disposition. This result has been confirmed by the fact that the terminal half life of amoxycillin on cessation of a continuous infusion is significantly greater than after acute administration.
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  • 34
    ISSN: 1432-1041
    Keywords: indapamide ; bioavailability ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Two formulations of indapamide tablets (2.5 mg) were given as a 5.0 mg dose and the subsequent blood levels were compared to those obtained after administration of a 5.0 mg solution. The study was conducted as a randomized three-way crossover design using healthy male volunteers. The drug was well tolerated by all the subjects involved. The area under the blood concentration versus time curve, extrapolated to infinity was essentially the same for all three formulations (4.2, 4.7, and 4.4 µg-h/ml). Statistical comparison of the blood levels from the two tablets showed that one tablet had a significantly greater maximum blood concentration (263 vs 231 ng/ml) and a significantly shorter time of maximum blood concentration (2.3 vs 3.5 h). Cmax (333 ng/ml) and tmax (0.7 h) values for the solution were significantly higher than either tablet. The average half-life (β-phase) for all three formulations was 15 h, while the average systemic clearance was 20 ml/min. Indapamide has a low clearance rate and there was no evidence that the drug undergoes a first-pass effect.
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    European journal of clinical pharmacology 22 (1982), S. 257-264 
    ISSN: 1432-1041
    Keywords: TRIS buffer ; metabolic acidosis ; pharmacokinetics ; cellular uptake ; renal excretion ; healthy volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To investigate the pharmacokinetics of TRIS, an infusion of the buffer was given to 6 healthy volunteers (121 mg/kg=1 mmol/kg; pH 7.4) and to 20 patients suffering from metabolic acidosis (109–376 mg/kg; pH 10.9). The drug exhibited two-compartment characteristics in volunteers (t0.5,β=5.6 h) and patients with intact renal function (t0.5,β=16.3–45.6 h). The final volume of distribution (Vβ) indicated uptake into tissues, but equilibration between body compartments was slow. Mainly unchanged TRIS was eliminated by the kidney; 82% of the administered dose was recovered from 24 h-urine of healthy subjects. In the patients a linear correlation between creatinine-clearance and TRIS-clearance was observed, the latter always being somewhat greater than the former. Only insignificant amounts of the drug were found in bile and gastric juice. In anuric patients the plasma concentration of TRIS declined monoexponentially, with a half-life between 10 and 58 h. Haemodialysis or haemofiltration did not influence this process. From the data it seems questionable whether cellular uptake of TRIS is an important factor in the therapy of intracellular acidosis, but the possibility of drug accumulation must be borne in mind if repeated doses are given to the same patient.
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    European journal of clinical pharmacology 23 (1982), S. 75-80 
    ISSN: 1432-1041
    Keywords: psoriasis ; 8-methoxypsoralen ; food influence ; suction blister fluid ; serum ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food on the kinetics of 8-methoxypsoralen (8-MOP) in serum and suction blister fluid was evaluated in a cross-over study in 19 psoriatic patients under PUVA treatment. The peak serum concentration of 8-MOP was reached 1.5 h after ingestion on an empty stomach, and in suction blister fluid the maximum concentration was already present in the first sample taken after 2 h, the time when UVA radiation was given. The postprandial kinetics of 8-MOP in serum and suction blister fluid differed, the highest levels being reached, respectively, at 2.4 and 3 h after intake, i.e. in both body fluids after irradiation had started. The side effects of 8-MOP, such as nausea and dizziness, in the two groups were similar. The present results indicate that to optimize the therapeutic effect of PUVA in individual patients, 8-MOP should be given on an empty stomach.
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    European journal of clinical pharmacology 23 (1982), S. 189-195 
    ISSN: 1432-1041
    Keywords: befunolol ; propranolol ; pharmacokinetics ; pharmacodynamic effects ; beta-adrenoceptor blocking agent
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Repeated doses of a new β-adrenoceptor blocking agent, befunolol, were administered orally to adult male volunteers for a cross-over comparison with propranolol. The β-adrenoceptor blocking activity of befunolol was greater than that of propranolol when assessed by the percentage reduction in exercise-induced tachycardia. The elimination half-life of drug was significantly prolonged on repeated administration of propranolol, but not of befunolol. The percentage reduction in exercise-induced tachycardia was highly correlated with the log plasma level of each drug. Both drugs produced a significant reduction in pre-exercise systolic and diastolic blood pressure, and significant attenuation of exercise-induced rise in systolic blood pressure.
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    European journal of clinical pharmacology 23 (1982), S. 235-240 
    ISSN: 1432-1041
    Keywords: ergotamine ; pharmacokinetics ; migraine ; plasma drug levels ; i.v. administration ; i.m. administration ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of ergotamine has been investigated in migrainous patients using a new, specific, sensitive HPLC assay (detection limit 100 pg/ml plasma). 10 patients were given ergotamine tartrate 0.5 mg i.v. and 5 of them received the same dose i.m. 2–3 weeks later. Blood samples were collected for up to 54 h following administration and the plasma concentration were analysed. After intravenous administration the plasma ergotamine declined rapidly, with an initial distribution half-life of 3 min followed by a mean terminal half-life of 1.86 h (range 90–155 min). The mean total plasma clearance was 11.0 ml kg−1 min−1, and the volume of distribution (Vdβ ) was 1847.6 ml kg−1. Individual t1/2β showed a positive linear correlation with the individual Vdβ . The intramuscular absorption of ergotamine was rapid and maximum plasma levels were usually obtained 10 min following administration. The biological availability was incomplete and variable at 46.6% (range 28.3–60.8%).
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    European journal of clinical pharmacology 23 (1982), S. 327-330 
    ISSN: 1432-1041
    Keywords: bendroflumethiazide ; cantharides plasters ; blister fluid ; plasma levels ; pharmacokinetics ; compartmental analysis
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of bendroflumethiazide (BFT) was investigated following the oral administration of 10 mg to 3 healthy volunteers. Each subject participated twice in the study. BFT was determined in plasma and cantharides blister fluid from 1/2 to 30 h post administration. Blister fluid was obtained from blisters 10–22 h old. Plasma levels were fitted to a tri-exponential equation and the concentration of the drug in the peripheral compartment was calculated from the microscopic rate constants. In 5 of 6 cases investigated, cantharides blister fluid levels paralleled the concentration of the drug in the peripheral compartment. The mean blister fluid levels exceeded the calculated concentration in Compartment 2 1.46 fold. In one case, the blister fluid level paralleled the plasma level. This subject clearly differed from the others as more than 10 h were required for blister formation in her. The results suggest that following the administration of BFT, cantharides blister fluid behaves as part of the peripheral compartment. The possible value of studying blister fluid levels in pharmacokinetic investigations is discussed.
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  • 40
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    European journal of clinical pharmacology 23 (1982), S. 343-347 
    ISSN: 1432-1041
    Keywords: valproic acid ; fatty acids ; plasma protein binding ; pharmacokinetics ; drug metabolism
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of physiologic variations of free fatty acid levels on in vivo valproic acid plasma protein binding was studied in 6 healthy adult subjects. 14 blood samples were taken during a 12-h dosing interval at steady state while in a fed condition and also during a 27 h fast. Free fraction and total valproate concentration were determined by equilibrium dialysis and GLC, respectively. Free fatty acid levels were determined from both fresh samples and samples incubated at 37°C for 12 h, the latter in order to simulate equilibrium dialysis conditions. Fasting resulted in increased serum free fatty acid levels in all subjects, ranging from 34–182% (p〈0.01). Incubation also caused free fatty acid levels to rise, more so in fed samples (50–87%,p〈0.01) than in fasting samples (10–50%,p〈0.01). Fasting resulted in a 9% increase in the mean free fraction for all subjects combined (p〈0.01). Regression analysis of 180 sets of values for free fraction, total valproate concentration and free fatty acid level suggested that valproate concentration accounts for 17% and free fatty acid level for 37% of the variation in free fraction. Mean clearance was unchanged by fasting despite an increased free fraction suggesting decreased intrinsic clearance (i.e. decreased metabolism) of valproate under these conditions.
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  • 41
    ISSN: 1432-1041
    Keywords: L-threo-3,4-dihydroxyphenylserine ; familial amyloid polyneuropathy ; pharmacokinetics ; norepinephrine ; pressor response
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of oralL-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) was studied in 7 normal subjects and 7 patients with familial amyloid polyneuropathy. Each person swallowed a single 300 mg dose in the fasting state, andL-threo-DOPS in plasma and urine was determined by high performance liquid chromatography with an electrochemical detector after separation on a boric acid gel column.L-threo-DOPS was slowly absorbed by normal subjects; the maximum plasma concentration occurred 3 h after administration and 20% of the oral dose was recovered unchanged in the urine within 12 h. It induced a substantial elevation of plasma norepinephrine levels, the peak being attained at 5 h, but without any change in blood pressure. In the patients, the absorption and metabolism ofL-threo-DOPS were delayed, and a prolonged pressor response was observed, with a peak after 8 h. It was concluded that the effects on plasma norepinephrine and blood pressure of oralL-threo-DOPS were essentially equal to those of twice as large a dose ofDl-threo-DOPS.
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    European journal of clinical pharmacology 23 (1982), S. 501-504 
    ISSN: 1432-1041
    Keywords: cimetidine ; uraemia ; dosing regimen ; prediction ; computer program ; old age ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Using a recently developed computer program based on a correlation between methods to predict the elimination half-life and apparent volume of distribution of cimetidine and actual data from patients, ideal dosage regimens were generated for patients with renal impairment and for geriatric patients, together with the corresponding maximum and minimum steady state concentrations. Using the ideal dosage regimens, practical regimens with feasible dosing intervals of 6, 8 and 12 h were computed, which should result in therapeutic concentrations of 0.4 to 1.3 µg/ml. For uraemic patients and geriatric patients above the age of 75 years it would be desirable to have an additional oral 100 mg dosage form.
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  • 43
    ISSN: 1432-1041
    Keywords: amitriptyline ; imipramine ; clomipramine ; antidepressant overdose ; clinical effects ; pharmacokinetics ; cardiotoxicity ; maprotiline ; doxepine ; nortriptyline ; opipramol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Twenty-nine cases of self-poisoning with antidepressants (amitriptyline, imipramine, clomipramine, maprotiline, doxepine, nortriptyline, opipramol) were examined by frequent observation of CNS effects, heart rate, blood pressure and standard ECG, 24 h-ECG-monitoring, measurement of systolic time intervals, EEG recordings and frequent measurement of serum levels of antidepressants and primary metabolites. None of the patients died. Maximum total serum antidepressant level (parent compound + desmethyl metabolite) ranged from 20 to 2200 µg/l, with concentrations above 500 µg/l in 11 cases. The serum amitriptyline concentration remained high for 3–4 days in some of the severely intoxicated patients and the decay curves were compatible with partly saturated elimination. A degree of unconsciousness and the occurrence of excitation and hallucinations were generally seen in cases with total serum antidepressant levels above 500 µg/l. Grand mal seizures occurred more frequently at high antidepressant levels, but could not be predicted from the EEG recordings. Increased heart rate and prolonged QRS- and QTc-intervals were significantly correlated with the total serum antidpressant level. 24 h-ECG-monitoring revealed no serious arrhythmias or instances of heart block. Hypotension was only seen initially in few patients. Systolic time interval measurements showed changes suggesting impaired myocardial performance (elevated PEP/LVET ratio) at intermediate (60–500 µg/l) but not high (〉500 µg/l) total serum antidepressant levels. Measurement of serum concentration in antidepressant intoxication is important for identification of patients with high serum levels and the corresponding risk of developing toxic reactions, and to exclude patients with a low concentration who do not require intensive observation.
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  • 44
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    European journal of clinical pharmacology 23 (1982), S. 1-5 
    ISSN: 1432-1041
    Keywords: clonidine ; noradrenaline ; pharmacokinetics ; arterial blood pressure ; plasma concentration
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of clonidine and its relation to blood pressure response and side effects were studied after single oral doses of 75 µg, 150 µg and 250 µg in normotensive subjects. Following oral administration, the drug was absorbed rapidly after an initial lag time of 19–22 min and peak levels were reached between 2.4 and 2.9 h. Sampling over 48 h was necessary for accurate estimation of pharmacokinetic parameters. Post-peak plasma concentration declined in a monoexponential manner and the half-life of the elimination phase ranged from 9.0 to 15.1 h. Maximum plasma concentration (Cmax) and area under curve (AUC) increased proportionally with increasing doses. Clonidine produced significant reductions in the pulse rate and a dose dependent decrease in blood pressure. Clonidine (150 µg) also produced significant reductions in plasma catecholamine levels.
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  • 45
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    European journal of clinical pharmacology 23 (1982), S. 43-47 
    ISSN: 1432-1041
    Keywords: timolol ; pharmacokinetics ; pharmacodynamics ; healthy subjects ; cardiac infarction patients ; i.v. therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Disappearance pharmacokinetics, pharmacodynamics and general tolerance of i.v. timolol were compared in 12 healthy volunteers and 10 patients with a definite or proven acute myocardial infarction. The drug was administered to the patients immediately on arrival at the hospital after a median delay time of 4 h. Tolerance to the injections was good in both volunteers and patients. The study revealed disappearance pharmacokinetics that were similar in volunteers and patients.
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  • 46
    ISSN: 1432-1041
    Keywords: cyclobarbital ; aminopyrine ; liver disease ; 14CO2 breath test ; barbiturate ; pharmacokinetics ; hepatic drug metabolism ; cirrhosis ; alcoholic liver disease ; viral hepatitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The exhalation of 14CO2 derived from an i.v. tracer dose of [dimethylamine-14C]aminopyrine has been investigated in normal controls and patients. They subsequently ingested 200 mg cyclobarbital calcium in the evening and the decline in the plasma drug level over the following 2 days was measured by thin-layer chromatography. The peak specific activity of exhaled 14CO2 occurred 0.5–2 h after 14C-aminopyrine injection in the absence of liver disease and in non-cirrhotic liver disorders. It was delayed in certain patients with cirrhosis. Compared to 8 medically healthy subjects, 10 patients with acute viral hepatitis, 8 with cirrhosis and 10 with fatty liver exhibited a significantly increased half-life of 14CO2 exhalation. Normal mean values were found in 12 patients with non-cirrhotic alcoholic liver disease and in 14 patients with non-hepatic diseases. The cyclobarbital (CB) half-life was prolonged and the clearance reduced in patients with viral hepatitis, cirrhosis, or alcoholic liver damage as compared to data from 17 control subjects. Due to a larger apparent volume of distribution, patients with fatty liver disease had an increased CB half-life, although its clearance was normal. A close negative correlation was detected between the clearance and the logarithm of the CB level measured 36 h after drug ingestion. The oral CB test evaluated from a single blood sample taken about 36 h after drug administration appears to be a useful indicator of human drug metabolising capacity. Discrimination between patients with and without disordered liver function was similar in the two drug elimination tests.
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  • 47
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    European journal of clinical pharmacology 26 (1984), S. 121-124 
    ISSN: 1432-1041
    Keywords: methotrexate ; psoriasis ; pharmacokinetics ; plasma levels ; urinary excretion ; renal clearance ; tubular absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma concentration and urinary excretion of methotrexate were followed in twelve psoriatic patients after intravenous and oral doses of methotrexate ranging from 7.5 to 30 mg. In six of the patients, a nonlinear relation was found between the fractional amount of methotrexate excreted in the urine and the corresponding area under the plasma concentration-time curve. The methotrexate clearance was found to be increased during the initial high plasma concentration, probably due to saturation of the tubular reabsorption of methotrexate. Considerable interindividual variation was found in the apparent saturation point of the active reabsorption, but up to 500–800 ng/ml first order kinetics still applied. At plasma concentrations below saturation, the renal clearance of methotrexate ranged from 52–102 ml/min (mean±SD, 83±19.4 ml/min).
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  • 48
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    European journal of clinical pharmacology 26 (1984), S. 87-93 
    ISSN: 1432-1041
    Keywords: enprofylline ; pharmacokinetics ; renal elimination ; renal insufficiency ; healthy subjects ; creatinine clearance ; side effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Enprofylline, a new bronchodilating drug, was given i.v. at 1.0 mg/kg to 7 healthy subjects and to 14 patients with differing degrees of chronic renal insufficiency. Plasma and urine concentrations of unchanged drug were followed by HPLC. In the patients the plasma half-life was prolonged and the total and renal clearances were reduced in direct proportion to the degree of renal insufficiency as determined by creatinine clearance. The unbound fraction of enprofylline in plasma increased from 55% in the healthy subjects to 66% in the group of patients with the highest degree of renal impairment. The volume of distribution terms, Vβ and Vss, both tended to decrease with decreasing creatinine clearance. When the volume term calculations were based on the unbound drug level in plasma, this tendency was enhanced. Side-effects were noted in 4 subjects, and to some extent were related to the plasma level of the drug.
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  • 49
    ISSN: 1432-1041
    Keywords: sulphapyridine ; sulphasalazine ; pharmacokinetics ; rectal administration ; oral administration ; plasma levels ; ulcerative colitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Rectal administration of sulphasalazine to patients with ulcerative colitis has recently been shown to have similar therapeutic activity but fewer side effects than oral treatment. The present study is a comparison of the pharmacokinetics of sulphasalazine (SASP) and its metabolite sulphapyridine (SP) after rectal and oral administration of SASP to 6 patients with ulcerative colitis. The areas under the concentration-time curves (AUC) and the maximum concentrations (Cmax) of SASP and SP were significantly lower after rectal than oral administration of SASP (p〈0.05). These findings support the view that the lower frequency of side effects after rectal administration of SASP may result from the lower plasma levels of SASP and SP.
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  • 50
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    European journal of clinical pharmacology 26 (1984), S. 309-313 
    ISSN: 1432-1041
    Keywords: clonidine ; hypertension ; therapeutic window ; steady state concentration ; pharmacokinetics ; cardiovascular effects
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Clonidine was given orally as monotherapy in increasing daily doses from 3.1 to 25.7 µg/kg to patients with essential hypertension (n=6). When a steady state concentration in plasma was reached at each dose level, the blood pressure (BP) and heart rate were measured during a dosage interval. Effect time — plasma concentration data were submitted to nonlinear regression analysis, which showed that the observed BP effects could be dissociated into depressor and pressor components. A window for the antihypertensive effect was established. At a plasma clonidine concentration of 0.65±0.07 ng/ml 50% of the maximal depressor effect was found, and it was only separated by a factor of 2 from the half maximal pure pressor concentration in plasma. No relationship between the change in heart rate and the plasma clonidine was observed. The findings strengthen the importance of close monitoring of clonidine therapy.
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  • 51
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    European journal of clinical pharmacology 26 (1984), S. 381-388 
    ISSN: 1432-1041
    Keywords: midazolam ; hypnotic drug ; benzodiazepine ; pharmacokinetics ; aged patients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of midazolam, an imidazo-benzodiazepine derivative, have been studied in 13 subjects over the age of 60 years who received the drug intravenously (0.07 mg kg−1) as an induction agent for endoscopy. Two to three days later, 6 of these subjects received 5 mg of midazolam intramuscularly, and another 6 of the subjects received 10 mg of the drug orally. The plasma concentration-time curves were again studied pharmacokinetically. After intravenous dosing, the mean (± SD) elimination half-life (2.14±1.24 h) showed a statistically significant trend to increase with age in the subjects older than 60 years. While the mean (± SD) clearance value (0.30±0.19 l kg−1h−1) tended to fall with age in the elderly subjects, this trend was not statistically significant. Apparent volume of distribution did not appear to be related to advancing age beyond 60 years, and this parameter (mean ± SD) did not differ to a statistically significant extent between the aged subjects (0.77±0.47 l kg−1) and the young subjects studied previously (1.09±0.58 l kg−1). Atropine premedication did not appear to alter the dispositional parameters of the intravenously administered drug. Intramuscularly administered midazolam was absorbed rapidly. Bioavailability appeared incomplete (F=0.59±0.15, mean ± SD), possibly due to saturable elimination of the drug at the higher plasma levels which were obtained after intravenous midazolam. Oral bioavailability, relative to intravenous, was 0.34±0.17, (mean ± SD), with an appreciable but variable lag time (0.74±0.40 h, mean ± SD). Orally, in the dose used, the drug was an inefficient hypnotic with four of the six subjects failing to attain the plasma drug level of 44–50 µg l−1, which appeared to be the approximate threshold for sleep. It is impossible to know whether this failure represents an age related effect on drug absorption, or is a consequence of the upper alimentary tract abnormalities for which the endoscopies were done.
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  • 52
    ISSN: 1432-1041
    Keywords: cefoxitin ; beta-lactam antibiotics ; pharmacokinetics ; serum concentration ; pleural fluid concentration
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of cefoxitin was studied in 6 healthy volunteers and in 5 patients with a pleural effusion after administration of a single dose of 30 mg/kg i.v. infusion. The serum and pleural fluid concentrations of cefoxitin were determined microbiologically. The elimination half-life of the antibiotic from pleural fluid in all cases was 2–3fold longer than from serum, which shows a difference between the kinetic elimination processes of the antibiotic from the two fluids. The slow elimination of cefoxitin from pleural fluid facilitates its accumulation in this compartment during a multiple dosage regimen.
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  • 53
    ISSN: 1432-1041
    Keywords: cefoperazone ; peritoneal dialysis ; pharmacokinetics ; terminal renal failure ; peritonitis
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of cefoperazone after i.p. and/or i.v. administration were studied in 12 CAPD patients. After i.v. injection, the plasma half-life was 2.65±0.4 h, the total clearance amounting to 70.1±19.2 ml/min. Peritoneal clearance was calculated to be 6.9±1 ml/min. After peritoneal instillation, the bioavailability was 63.9±5%. After repeated i.p. administration, no accumulation of the drug in the body was observed. Thus, cefoperazone can be safely administered for the treatment of peritonitis in CAPD patients.
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  • 54
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    European journal of clinical pharmacology 26 (1984), S. 651-653 
    ISSN: 1432-1041
    Keywords: prednisolone ; prednisone treatment ; pharmacokinetics ; individual variation ; microsomal enzyme induction
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eleven patients on long-term prednisone treatment were studied on two occasions separated by 45 to 325 days. In 10 patients the total body clearance of prednisolone only changed about 10%. In one case a 78.5% decrease was observed after stopping treatment with rifampicin and isoniazide. No association was found between the prednisone dose rate (mg/kg per month), patient age or mean endogenous plasma hydrocortisone level and prednisolone clearance/kg. The results indicate considerable intra-individual consistency of prednisolone kinetics if other conditions are not changed.
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  • 55
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    European journal of clinical pharmacology 26 (1984), S. 749-752 
    ISSN: 1432-1041
    Keywords: dextropropoxyphene ; pharmacokinetics ; half-life ; 3-compartment model ; steady state prediction ; plasma levels
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Data from a previously published single dose study of d-propoxyphene 65 mg given i.v. to 8 healthy subjects have been subjected to non linear regression analysis by a curve-fitting program to test the applicability of a 2- and a 3-compartment open model. Analysis of residuals (difference between observed and computed concentrations) revealed similar systematic deviations in all 8 subjects when the 2-compartment model was used (5–10 h negative residuals, after 13 h positive residuals). In contrast, curve-fit by a 3-compartment model (with two parallel peripheral compartments) was good with no systematic deviations. The data show that a terminal monoexponential decline in d-propoxyphene concentrations cannot be expected until 15–30 h after single dose administration, and that the determination of the corresponding half-life is rather inaccurate. Accordingly, precise steady state level predictions may be difficult to obtain from conventional single dose studies with d-propoxyphene.
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  • 56
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    European journal of clinical pharmacology 27 (1984), S. 105-110 
    ISSN: 1432-1041
    Keywords: phenytoin ; epileptic women ; pharmacokinetics ; bioavailability ; pregnancy
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Five epileptic women needing to commence phenytoin therapy during pregnancy received a single intravenous and a single oral dose of phenytoin several days apart before starting regular intake of the drug. Plasma phenytoin concentration — time data were analysed by three different pharmacokinetic techniques. However assessed, the mean oral bioavailability of the drug proved to be about 90% of the intravenous bioavailability. This finding makes it unlikely that impaired bioavailability accounts for the increase in oral phenytoin dosage necessary in pregnancy to maintain plasma phenytoin concentrations at pre-pregnancy values. Phenytoin clearance in the pregnant subjects was approximately double the published values for phenytoin clearance in nonpregnant persons. This suggests that increased (metabolic) clearance accounts for the increased phenytoin dosage requirement of pregnancy.
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  • 57
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    European journal of clinical pharmacology 27 (1984), S. 159-163 
    ISSN: 1432-1041
    Keywords: endralazine ; renal impairment ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of renal impairment on the pharmacokinetics of endralazine was studied in 12 patients; 4 patients on regular haemodialysis therapy (creatinine clearance less than 5 ml/min) and 8 patients with varying degrees of renal impairment (creatinine clearance 11–52 ml/min). Following an oral dose of 10 mg endralazine the mean terminal elimination half-life (βt1/2) in the dialysis sub-group was prolonged at 7.1 h (range 3.3 to 14 h), compared to 3.6 h in the other renal patients (and compared to 2.3 h in hypertensive patients with normal renal function). After one week's therapy with 10 mg B.D. endralazine in the 8 patients with moderate renal impairment there was a significant increase in βt1/2 to 8.6 h but there was no significant change in the area under the drug concentration-time curve and no evidence of drug accumulation. In this study those patients with the poorest renal function had the longest βt1/2 after acute dosing. There was a significant correlation between creatinine clearance and acute βt1/2 but there was considerable variability in individual patients and, even with severe degrees of renal impairment, major dose adjustments do not appear necessary.
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  • 58
    ISSN: 1432-1041
    Keywords: sotalol ; hydrochlorothiazide ; pharmacokinetics ; moderate renal failure
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Decreased elimination of a combined formulation of Sotalol (160 mg) and hydrochlorothiazide (25 mg) was found in patients with moderate renal insufficiency. Very slight accumulation of sotalol and hydrochlorothiazide was observed, so it appears unnecessary to reduce the dosage in patients with a creatinine clearance of 30 ml/min or more.
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  • 59
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    European journal of clinical pharmacology 27 (1984), S. 583-587 
    ISSN: 1432-1041
    Keywords: propranolol ; pregnancy ; beta-adrenoceptor antagonist ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Propranolol, a beta-adrenoceptor blocking drug, was administered to 6 healthy pregnant volunteers between 32 and 36 weeks gestation and when at least 6 weeks postparum. On both occasions, subjects were given propranolol 120 mg orally or 10 mg intravenously in randomised order with a minimum washout period of 1 week. Propranolol was assayed in plasma by gas-liquid chromatography with electron-capture detection and the pharmacokinetic parameters were investigated. There were no significant alterations in elimination half-life, clearance or apparent volume of distribution per kilogram antenatally compared with postnatally: bioavailability was also unchanged. It is concluded that the disposition of propranolol is not altered during pregnancy.
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  • 60
    ISSN: 1432-1041
    Keywords: Bezitramide ; oral absorption profile ; pharmacokinetics ; male volunteers ; experimental pain ; biliary excretion in rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The oral absorption of bezitramide 5 mg was studied in 7 human volunteers, using a specific radioimmuno-assay which measured both bezitramide and its active metabolite R-4618. A lag time of 0.5–1.0 h and a Cmax of 5.4 ng/ml plasma were found, the latter occurring 2.5–3.5 h after administration. The apparent elimination half-life varied from 11 to 24 h. Less than 0.3% of the dose was excreted unchanged in the urine. High concentrations in the faeces of some individuals indicate incomplete absorption and/or biliary secretion. The analgesic effect, using a standardized superficial electrical stimulation method, reached its maximum between 2.5 and 3.5 h after dosing, in accordance with the absorption phase. The duration of the effect was highly variable. Experiments in rats (n=6,3H-bezitramide 2.5 µg), demonstrated extensive biliary excretion (up to 70% of total radioactivity) and less than 3% of the label was removed by urinary excretion.
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  • 61
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    European journal of clinical pharmacology 21 (1982), S. 293-301 
    ISSN: 1432-1041
    Keywords: metipranolol ; deacetyl metipranolol ; pharmacokinetics ; bioavailability ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic parameters of deacetyl metipranolol were determined after i.v. infusion of increasing doses (6–25 mg) in 17 normal volunteers. In a second cross-over trial, deacetyl metipranolol 10 and 20 mg were infused in a further 10 subjects, and in a third trial another 20 volunteers received metipranolol 40 mg orally. Metipranolol is very rapidly and completely deacetylated in man, so all pharmacokinetic data refer to deacetyl metipranolol, which was assayed by gas chromatography-mass spectrometry. The pharmacokinetic analysis was performed using a recently developed model, using a volume of distribution which is variable with time. The following data were obtained after oral administration: (mean values); lag-time 7.3 min; tmax 50 min, invasion half-life 6.3 min; elimination half-life 3 h; urinary excretion of unchanged drug approximately 4% of the dose. The experiments with infusion of increasing doses, as well as the cross-over study with 10 and 20 mg i.v., showed dose-linearity of the kinetics. The respective mean half-lives of elimination were 2.6, 2.9 and 2.8 h. The mean total, renal and extra-renal clearances amounted to 1237 ml/min, 149 ml/min and 1068 ml/min, respectively. The distribution coefficient was 3.5 l/kg, and protein binding amounted to 70% within the range of therapeutic concentrations. Absolute bioavailability was found to be approximately 50% by several different evaluation procedures. Thus, the pharmacokinetic profile of metipranolol shares features of both the lipophilic and the hydrophilic groups of β-blocking agents.
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  • 62
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    European journal of clinical pharmacology 21 (1982), S. 315-323 
    ISSN: 1432-1041
    Keywords: bendroflumethiazide ; propranolol ; hydralazine ; pharmacokinetics ; thin-layer chromatography ; fluorimetry ; fixed combination product
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Bendroflumethiazide (Bft) was administered to 6 healthy subjects at 3 different dose levels (2.5, 5 and 10 mg) in a cross-over design, either as capsules (2.5 mg) or as tablets (5 mg). Its pharmacokinetics were evaluated then and following administration of a fixed combination of Bft with propranolol and hydralazine to a further 7 volunteers. Plasma and urinary concentrations of Bft were determined by a new fluorimetric — thin-layer chromotography procedure. Peak plasma levels occurred after 2–3 h and averaged 15, 27 and 45 µg/l in the three dose groups. Areas under the plasma concentration — time curves (AUC0→12), which were 75, 147 and 250 µg l−1 h respectively, and cumulative urinary recovery (20%) were independent of the dose administered and the type of formulation. Thus Bft kinetics proved to be linear within the dose range evaluated. The plasma clearance was calculated to be 505 ml/min, renal clearance 108 ml/min and nonrenal clearance 396 ml/min. Bioavailability of Bft was not altered following administration of the fixed combination. The amount of propranolol found in the circulation did not change, whereas that of hydralazine (determined as apparent hydralazine) increased by 59% when the fixed combination was administered.
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    European journal of clinical pharmacology 21 (1982), S. 421-425 
    ISSN: 1432-1041
    Keywords: benzodiazepine ; lormetazepam ; lormetazepam glucuronide ; transfer to milk ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The concentrations of lormetazepam and its glucuronide in plasma and milk were determined during administration of 10 daily doses of lormetazepam 2 mg (2 tablets of NOCTAMID® - 1) to five mothers delivered by Caesarian section. Their babies were breast-fed throughout the study, and the plasma levels of lormetazepam and its glucuronide were determined three times in the babies. At 12 and 24h after administration, the plasma level of lormetazepam was about 3.5 ng/ml and 1.8 ng/ml in mothers, and below 0.09 ng/ml in the children. In milk the lormetazepam concentration was below 0.2 ng/ml. The plasma level of glucuronide varied between 24 ng/ml at 12h and 11 ng/ml 24h after administration. Almost no accumulation of unchanged lormetazepam was observed (factor: 1.3). The ratio of the levels of lormetazepam in milk and plasma was estimated to be below 0.06, and for the glucuronide the ratio was 0.04. The quantity of free and conjugated active ingredient transferred to the children via breast milk was calculated to be at most 100 ng/kg, corresponding to 0.35% of the maternal dose, which is regarded as tolerable.
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  • 64
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    European journal of clinical pharmacology 21 (1982), S. 499-504 
    ISSN: 1432-1041
    Keywords: gentamicin ; malnutrition ; pharmacokinetics ; infant
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of gentamicin was investigated in normal and malnourished infants aged 4–10 months. Neither mean “elimination” nor “distribution half life” show any difference, but the volume of distribution was higher in malnourished babies, probably due to their larger total body water.
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  • 65
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    European journal of clinical pharmacology 22 (1982), S. 423-428 
    ISSN: 1432-1041
    Keywords: pindolol ; renal failure ; metabolism ; pharmacokinetics ; 14C-pindolol ; blood metabolites ; urinary metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Increased metabolism of pindolol in renal impairment has previously been suggested by pharmacokinetic calculations. The present study was a pharmacokinetic and metabolic investigation in 7 patients with severe renal impairment (endogeneous creatinine clearance below 5 ml/min). All the patients received pindolol 5 mg t.d.s. 5 days. On the sixth day, after an overnight fast, 14C-pindolol 5 mg was given orally as a solution to drink. Blood samples were taken for up to 72 h and urine was collected at intervals up to 96 h for measurement of unchanged pindolol by a fluorimetric method and total radioactivity by liquid scintillation counting. Metabolites in blood and urine were analysed after separation by HPLC. It was found that the plasma levels following a single dose of 14C-pindolol were similar to those observed in healthy volunteers, but the elimination half-life was slightly increased up to 11.5 h. The observed steady state plasma concentrations of pindolol were twice as high but they are still in the therapeutic range of 10 to 100 ng/ml. Therefore, the dose of pindolol could have been reduced by a factor 2, but the reduction was not essential. No active metabolite of pindolol was found in plasma or urine, but elimination of the metabolites was decreased. The elimination half-life following multiple doses was prolonged compared to normal and it was quite comparable to that found for the pharmacodynamic half-life in renal patients. The discrepancy between the present findings and the previous results for metabolism and pharmacodynamic half-life was probably due to the sensitivity of the fluorimetric assay of pindolol.
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    European journal of clinical pharmacology 23 (1982), S. 155-160 
    ISSN: 1432-1041
    Keywords: amikacin ; pharmacokinetics ; development ; neonate ; infant ; child
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition kinetics of a single i.v. dose of amikacin was studied in 6 neonates (6–25 days old), 10 infants (4–18 months) and 8 young children (3–11 years). There was a progressive change in the distribution and elimination kinetics during development. The distribution coefficient of the antibiotic averaged of 0.429, 0.320 and 0.210 l/kg in the newborns, infants and young children, respectively and serum half-life (t1/2 β) in these three groups averaged 2.812, 1.803 and 1.196 h, respectively. Significant differences in certain pharmacokinetic parameters were found between the values in paediatric patients and in adults receiving the same dose. A linear relationship was established between the distribution volume of the antibiotic and the weight of the patients, as defined by the following equation: $${\text{Vd}}_{{\text{ss}}} \left( 1 \right) = 0.976 + 1.140 \cdot {\text{TBW}}\left( {{\text{kg}}} \right);r = 0.954$$ The results suggest that a regimen of very frequent administrations should be employed in infants and young children in order to maintain a therapeutic level throughout treatment.
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    European journal of clinical pharmacology 22 (1982), S. 161-169 
    ISSN: 1432-1041
    Keywords: mebendazole ; hydatid disease ; Echinococcus granulosus ; hepatic disease ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma concentrations of mebendazole and its metabolites have been monitored in twelve patients after receiving a 10 mg/kg dose for cystic hydatid disease. The mebendazole plasma concentration-time profiles differed considerably between patients; elimination half-lives ranged from 2.8–9.0 h, time to peak plasma concentration after dosing ranged from 1.5–7.25 h and peak plasma concentrations ranged from 17.5 to 500 ng/ml. The mean peak plasma concentration of mebendazole after an initial dose (69.5 ng/ml) was lower than found in patients during chronic therapy (137.4 ng/ml). The plasma AUCTs for the major metabolites of mebendazole (methyl 5-(α-hydroxybenzyl)-2-benzimidazole carbamate and 2-amino-5 benzoylbenzimidazole) were about five times the plasma AUCT found for mebendazole in patients on chronic therapy. It is suggested that the slower clearance of these polar metabolites relative to mebendazole results from enterohepatic recycling. Since mebendazole is also highly plasma protein bound, caution should be observed in administering mebendazole to patients with liver disease. Concentrations of mebendazole found in the tissue and cyst material collected from two patients during surgery ranged from 59.5 to 206.6 ng/g wet weight.
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  • 68
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    European journal of clinical pharmacology 23 (1982), S. 173-176 
    ISSN: 1432-1041
    Keywords: melperone ; neuroleptic drug ; dose dependent kinetics ; i.m. injection ; i.v. injection ; pharmacokinetics ; oral application
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of melperone (Buronil®, Ferrosan, Sweden) was studied after administration of various parenteral and oral doses to man. After parenteral administration, the data could be fitted to a two-compartment model, but after oral dosing the distribution phase could not be separated from the elimination phase, and so an one-compartment model gave the best fit. The half-lives were about 3–4 h, except after intramuscular injection, when the half-life was about 6 h. The bioavailability of oral doses was about 60% of the intravenous injection. After the highest oral dose of 100 mg, the pharmacokinetics, expressed as AUC or Cmax, showed non-linearity, possibly due to saturation of the hepatic elimination system.
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  • 69
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    European journal of clinical pharmacology 23 (1982), S. 331-333 
    ISSN: 1432-1041
    Keywords: ketoconazole ; vaginal candidosis ; oral antimycotic ; distribution ; pharmacokinetics ; vaginal tissue concentrations
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma samples and biopsies of vaginal tissue were obtained from 23 healthy women undergoing operative sterilization, 1 to 6 h after a single oral dose of ketoconazole 200 mg. Drug concentrations in plasma and tissue, were measured by a specific gas chromatographic method. The vaginal tissue concentration averaged 2.4 times less than the corresponding plasma levels. Equilibrium between tissue, and plasma was established within 1 h after dosing, when vaginal tissue levels exceeded 1 µg/g. Ketoconazole concentrations decayed monoexponentially over the time interval studied (1–6 h), with the similar half-lives of 1.2 and 1.4 h in plasma and tissue, respectively. Following an oral 200 mg dose, a tissue concentration not less than 0.01 µg/ml was maintained over a 12 h period. This concentration has been shown to prevent outgrowth of the invasive (pseudo) mycelial form ofCandida albicans. Hence, a b.i.d. or t.i.d. dosage schedule of ketoconazole in vaginal candidosis would give continuously effective levels at the site of infection. Ketoconazole concentrations in vaginal fluid are thought to be much higher than in the tissue because of ion-trapping. The present data may explain the efficacy of oral ketoconazole in the treatment of vaginal candidosis.
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  • 70
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    European journal of clinical pharmacology 26 (1984), S. 341-346 
    ISSN: 1432-1041
    Keywords: cimetidine ; pharmacokinetics ; critically ill patients ; intravenous administration ; dose individualization
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Cimetidine disposition was studied after rapid (1 min) intravenous infusion in eight critically ill patients aged between 20 years and 77 years; one patient was studied on two occasions. Cimetidine dose was 300 mg in seven patients and 400 mg in the remaining patient. Arterial plasma cimetidine concentrations at the end of the infusion were very high and ranged from approximately 15–35 mg/l. Pharmacokinetic parameters displayed wide interpatient variability (coefficients of variation of 30–50%) and significant relationships emerged between some of these parameters and certain patient characteristics. Most notable, total systemic plasma clearance of cimetidine was directly related to estimated creatinine clearance (p〈0.01). This relationship might prove to be a useful method of individualizing cimetidine dosage in critically ill patients.
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  • 71
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    European journal of clinical pharmacology 26 (1984), S. 591-593 
    ISSN: 1432-1041
    Keywords: cyclophosphamide ; liver failure ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of cyclophosphamide was investigated in 7 patients in severe liver failure. The pharmacokinetic data were compared with those derived from a matched control group of patients with normal liver function. The half-life (t1/2) of cyclophosphamide following intravenous administration in patients with liver failure was 12.5±1.0 h (m±SD), which was significantly longer than in the normal controls in whom it was 7.6±1.4 h (p〈0.001). The mean total body clearance (Clt) was significantly smaller in liver failure at 44.8+8.6l·kg−1 than in the controls in whom it was 63.0±7.6l·kg−1 (p〈0.01). It is concluded that severe liver disease has a significant effect on the disposition of cyclophosphamide, and that it could lead to accumulation of the drug in the body.
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  • 72
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    European journal of clinical pharmacology 26 (1984), S. 647-649 
    ISSN: 1432-1041
    Keywords: tobramycin ; newborn infants ; intrapatient variations ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nineteen newborn infants receiving tobramycin, 2.5 mg/kg every 12 h were studied on two occasions at steady-state during the first week of postnatal age. The two studies were separated by two to four days. Total body clearance of tobramycin averaged 1.15 and 1.14 ml/min/kg (p〉0.05), apparent volume of distribution averaged 0.82 and 0.68 l/kg (p〉0.05), and elimination half-life averaged 8.6 and 7.1 h (p〉0.05), during the first and second study, respectively. When the data were further analyzed based on the birth weight, tobramycin kinetics changed during the second study compared to the first study in very low birth weight infants. In eight infants ⩽1.5 kg birth weight, although total clearance of tobramycin was similar, the average apparent volume of distribution decreased from 1.04 l/kg during the first study to 0.73 l/kg during the second study (p〈0.05) and elimination half-life from 11.1 h during the first study to 8.7 h during the second study (p〈0.05). These data indicate that these infants may require a change in dosing interval with continued tobramycin therapy during the first week of postnatal age. Intrapatient variation in tobramycin kinetics should be considered, in addition to the interpatient variation reported previously, when monitoring the serum concentration to individualize tobramycin therapy in newborn infants ⩽1.5 kg birth weight.
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  • 73
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    European journal of clinical pharmacology 27 (1984), S. 57-59 
    ISSN: 1432-1041
    Keywords: acetaminophen ; pediatric patients ; fever therapy ; accumulation ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Acetaminophen serum concentrations were studied in 21 infants and children with fever. The maximum serum concentrations ranged from 9.96 to 19.6 µg/ml after a single dose of 12–14 mg/kg and 13.9 to 40.1 µg/ml after a single dose of 22–27 mg/kg. Ten patients were restudied at steadystate after repeat doses had been given every 4 or 8 h for 1 to 3 days. Total area under the acetaminophen serum concentration-time curve normalized for dose averaged 0.181 (ml/min/kg)−1 after the first dose and 0.202 (ml/min/kg)−1 at steady-state (p〈0.05). Five patients showed a 13 to 44% increase in the AUC; one had a 10% decrease in the AUC; and four had less than 6% change in the AUC. There was no evidence of hepatotoxicity. These data suggest that acetaminophen may accumulate after repeated therapeutic doses in children with fever.
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  • 74
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    European journal of clinical pharmacology 27 (1984), S. 111-114 
    ISSN: 1432-1041
    Keywords: chlorambucil ; chronic lymphocytic leukaemia ; phenylacetic acid mustard ; food intake ; pharmacokinetics ; bioavailability
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food intake on the pharmacokinetics of chlorambucil (C) and its cytotoxic metabolite, phenylacetic acid mustard (PAM), has been studied in man after oral doses of chlorambucil. The administration of chlorambucil with food resulted in slower absorption than when fasting. However, the area under the plasma concentration-time curve (AUC) was unaffected. The mean ratio AUCPAM/AUCC was 2.8 (range 1.4–7.1) under fasting and 3.3 (range 1.3–7.4) under nonfasting conditions. The metabolite very probably plays an important role in the cytotoxic effects observed after administration of C, since calculations show that a major fraction of the metabolite is eliminated by alkylation reactions.
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  • 75
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    European journal of clinical pharmacology 27 (1984), S. 115-117 
    ISSN: 1432-1041
    Keywords: benzodiazepine antagonist ; Ro 15-1788 ; healthy volunteers ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of the selective benzodiazepine antagonist Ro 15-1788 has been studied in 6 healthy male volunteers following a single intravenous dose of 2.5 mg. The drug was only slightly bound to plasma proteins (40±8%, mean±SD). A negligible amount (〈0.2% of the dose) of unchanged drug was recovered in urine. Hepatic elimination was rapid, as shown by a short t1/2 of 0.9±0.2 h, and high total plasma and blood clearances of 691±216 ml/min and 716±199 ml/min, respectively. The fast decline of plasma levels from about 60 to 2 ng/ml accounts for the short-lasting reversal of benzodiazepine-induced sedation by Ro 15-1788.
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  • 76
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    Keywords: enprofylline ; healthy subjects ; absorption ; pharmacokinetics ; oral- ; duodenal- ; colonic administration
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Enprofylline, a new potent bronchodilator xanthine drug, was given orally as an aqueous solution to 6 healthy subjects in single doses of 2, 4 and 6 mg/kg. The two lower doses produced plasma concentrations in the range 1–4 mg/l, i.e. in the assumed “therapeutic interval” according to previous animal studies. A high 24 h urine recovery of unchanged drug, with mean values for the three dose levels ranging from 85 to 91% of the given dose, indicated good absorption and little metabolism. The dose-corrected area under the plasma concentration-time curve rose with dose as the latter was increased from 2 to 6 mg/kg. This indicates that the elimination of enprofylline is capacity-limited at high doses. Double peaks in the plasma concentration-time curves at the higher dose levels suggested intermittent and delayed gastric emptying as a possible explanation. This hypothesis was confirmed by studies in 6 other healthy subjects, who received the drug solution by three different routes; by mouth, via a catheter in the duodenum, and rectally via a catheter in the colon. The corresponding time to peak values (mean±SEM) were 32.5±8.7, 13.3±2.5, and 157±23 min.
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  • 77
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    Keywords: kelfiprim ; trimethoprim combination ; sulfamethopyrazine combination ; pharmacokinetics ; renal insufficiency
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The combination of trimethoprim (TMP) and sulfamethopyrazine (SMP) has been successfully used to treat chronic urinary tract infections. Since parenchymal involvement associated with renal insufficiency of varying degree is not infrequent in these patients, it was considered important to study the pharmacokinetics of TMP and SMP in a fixed dose combination. Four groups of patients were studied: 1) 4 patients with endogenous creatinine clearance (CLcR) between 80 and 40 ml/min; 2) 3 patients with CLcR between 40 and 10 ml/min; 3) 3 patients on chronic peritoneal dialysis (CAPD); and 4) 3 patients on haemodialysis. A single oral dose of 250 mg TMP and 200 mg SMP was given to each patient. Multiple samples were collected over 9 days and the following pharmacokinetic parameters were calculated: total area under the plasma level curve, slow disposition rate constant β and the corresponding t1/2β, plasma clearance and the apparent volume of distribution. The results show that the two moieties of the TMP-SMP combination behaved differently in uraemic patients as fas as elimination rate was concerned. TMP was eliminated more slowly both in patients with diminished renal function and in those subjected to haemo- or peritoneal dialysis. The reduction in the rate of elimination of TMP was significantly correlated with the degree of renal impairment. The elimination of SMP, however, was not significantly affected by the reduced renal function; indeed a tendency to increase was noted, at least in dialyzed patients. However, as in patients with mild renal insufficiency (CLcR〉40 ml/min) no substantial change in plasma clearance rate need be expected, the TMP-SMP combination could be given to them in the same dose schedule as in people with normal renal function.
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  • 78
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    Keywords: spironolactone ; canrenone ; metabolites ; pharmacokinetics ; single/multiple oral doses ; healthy volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of canrenone and ‘total metabolites’ after base hydrolysis was studied in eight young volunteers following single and multiple dose oral administration of spironolactone. The plasma levels of canrenone and ‘total metabolites’ were fitted to a two-compartment open model with a first-order absorption process. From our eight normal subjects studied, the harmonic mean of the distributive half-life (t1/2α) of canrenone was found to be 1.66 h, and the harmonic mean of the terminal elimination half-life (t1/2β) to be 22.6 h. Harmonic means of the distributive and elimination half-lives of ‘total metabolites’ after base hydrolysis were 2.48 h and 28.8 h respectively. The accumulation ratio of canrenone was 2.53, whereas that of ‘total metabolites’ was 1.89. Despite the fact that spironolactone has been shown to induce hepatic metabolism of other drugs, no evidence of autoinduction was noted in the present study, as plasma levels of canrenone and ‘total metabolites’ were found to obey a linear two-compartment model with reproducible absorption and disposition after single and multiple doses.
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  • 79
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    European journal of clinical pharmacology 27 (1984), S. 429-433 
    ISSN: 1432-1041
    Keywords: mepindolol ; renal failure ; haemodialysis ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Five patients with a creatinine clearance of 14 to 37 ml/min/1.73 m2 were each given an oral dose of 10 mg of the beta-blocker mepindolol sulphate (Corindolan). In addition, two dialysis patients received the same dose either during hemodialysis or on a dialysis-free day. Plasma levels of mepindolol were measured by a sensitive, specific HPLC method. Mepindolol was rapidly absorbed in all the patients. The maximum plasma level of 35±8 ng/ml was reached after 1.4±0.5 h. The half-life of disposition was 4.0±1.5 h. The area under the plasma concentration-time curve was 237±84 ng × h/ml. The data obtained were no different from those found in normal healthy volunteers.
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  • 80
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    European journal of clinical pharmacology 27 (1984), S. 471-475 
    ISSN: 1432-1041
    Keywords: acyclovir ; A515U ; 6-deoxyacyclovir ; pharmacokinetics ; prodrug ; antiviral chemotherapy ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A515U (6-deoxyacyclovir) is an analogue of acyclovir devoid of antiviral activity in vitro but which is well absorbed and undergoes conversion to acyclovir after oral administration to rats. The tolerance and pharmacokinetics of various doses of A515U have been studied in 8 healthy volunteers. Single oral doses of 25, 50, 100, 200 and 400 mg A515U and 400 mg acyclovir for comparison were administered to the volunteers at weekly intervals. Concentrations of the parent drug and acyclovir were determined in plasma and urine. The prodrug was well tolerated and did not cause adverse reactions or changes in haematological or biochemical variables. It was well absorbed and conversion to acyclovir was rapid and extensive at all doses. Plasma concentrations of acyclovir achieved with 50 mg A515U orally were comparable to and less variable than those produced by 400 mg acyclovir. A515U was rapidly cleared with a short plasma elimination half life of approximately 0.5 h. The attainment of high plasma concentrations of acyclovir by oral administration of a prodrug may represent an important advance in antiviral chemotherapy.
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  • 81
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    European journal of clinical pharmacology 27 (1984), S. 619-621 
    ISSN: 1432-1041
    Keywords: biperiden ; pharmacokinetics ; pharmacodynamics ; plasma levels
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of biperiden was studied and compared with pharmacodynamics (pupil size, accomodation, self-rating mood scale) in 6 healthy volunteers. A single-blind cross-over design was employed with placebo and biperiden (4 mg as commercially available tablets). After a lag time of 0.5 h, biperiden was rapidly absorbed with a half-life of 0.3 h, plasma peak levels of 5 ng/ml being reached after 1.5 h. Biperiden showed good tissue penetration (distribution half-life 0.6 h; ratio of total to central distribution volume 9.6), the terminal half-life time of plasma concentration was 18 h, and the oral clearance was 146 l/h. The pharmacodynamic maximum lagged behind the plasma peak concentration by 1 (self-rating) to 4 h (accommodation).
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  • 82
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    European journal of clinical pharmacology 21 (1982), S. 303-306 
    ISSN: 1432-1041
    Keywords: furosemide ; renal failure ; haemodialysis ; pharmacokinetics ; children ; dosage schedule
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Furosemide was measured by gas-liquid chromatography in blood and dialysis fluid from 7 children with chronic renal failure, undergoing regular haemodialysis. It was administered chronically, in two or three daily doses (4.2–9.4 mg/kg). Two children received 1 mg/kg intravenously for determination of the pharmacokinetics. The half-life was longer than in adults and in anephric patients on haemodialysis. Systemic and renal clearance were also much lower. Plasma protein binding in 2 out of 6 cases was reduced as campared to normal adults. The data do not suggest any need to modify the present dosage schedule despite the 4–5 fold increase in the half-life of furosemide. The contribution of haemodialysis to drug clearance was minimal, and accounted for less than 10% of the total clearance.
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  • 83
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    European journal of clinical pharmacology 21 (1982), S. 331-334 
    ISSN: 1432-1041
    Keywords: diclofenac sodium ; rheumatoid disease ; healthy subjects ; serum albumin ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Pharmacokinetic data for diclofenac sodium has been well established in healthy volunteers, whereas in patients with rheumatoid arthritis very little information is available in the literature. A single oral dose of enteric-coated diclofenac sodium was given to 10 patients with active rheumatoid disease, adopting the same procedures used for a group of 10 healthy volunteers in whom pharmacokinetic data was already available. Plasma specimens were collected over a period of 8h following administration and concentrations of diclofenac determined by GLC. Resulting plasma concentration curves were similar to those obtained in the healthy subjects in that areas under curves and terminal half-lives were comparable. However, peak concentrations of diclofenac were significantly reduced in the rheumatoid patients. The lower peak concentrations were correlated with the lower serum albumin levels in the patients which are associated with active rheumatoid disease.
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  • 84
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    European journal of clinical pharmacology 22 (1982), S. 47-52 
    ISSN: 1432-1041
    Keywords: apnoea ; caffeine ; premature infants ; pharmacokinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of caffeine was examined in 13 premature infants (gestational age 25–34 weeks, birth weight 920–2060 g, postnatal age 1–42 days) who received the drug for treatment of opnoea. Caffeine (1% aqueous solution) was given i.v. in single doses; guided by the clinical response infants received between one and seven (mean 2.6) doses of 15 mg/kg. Mean (± SE; range) Clb was extremely slow − 8.5 ml/kg/h (±0.4; 5.8–12.2), t1/2 was prolonged − 65.0 h (±3.7; 48.2–87.5 h) and Vd was 0.781/kg (±0.04; 0.47–1.01). No significant correlation was found between Clb, t1/2 and postnatal age in the whole group or in individual infants. Effective plasma concentrations varied over a wide range (12–36 µg/ml) and overlapped with subtherapeutic concentrations (⩽24 µg/ml). Single doses of 15 mg/kg i.v. or p.o. prevented apnoea in most cases, if necessary followed by additional doses. Monitoring the blood level of caffeine in infants receiving frequent repeated doses is necessary to prevent toxicity.
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  • 85
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    European journal of clinical pharmacology 22 (1982), S. 359-365 
    ISSN: 1432-1041
    Keywords: chlorpheniramine ; pharmacokinetics ; oral absorption ; half-life ; bioavailability ; volume of distribution
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma and urinary levels of chlorpheniramine (CPM) and its 2 demethylated metabolites were measured by HPLC after i.v. and oral dosing. In 5 mg (maleate) i.v. bolus studies in 2 subjects, plasma CPM levels were fitted to triexponential equations with terminal half-lives (t 1/2) of 23 and 22 h and area of 3.6 and 3.21/kg, respectively. Intravenous data predicted hepatic blood extraction ratios for the 2 subjects to be 0.06 and 0.07, respectively. Absolute bioavailability from oral solution (10 mg) was 59 and 34%, and from tablets (8 mg) 44 and 25%, respectively, indicating extensive gut first-pass metabolism. Mean t 1/2 from 7 oral fasting studies in 5 subjects was 28 h (19–43 h). Mean absorption lag time was 0.7 h (0.4–1.3 h), and mean peak time was 2.8 h (2–4 h). In 2 subjects, 6 mg solutions were given every 12 h for 9 doses; good correlation between single and multiple dose kinetics was found. Significant accumulation was demonstrated in simulation studies with frequent daily dosing. Estimated accumulation ratios vary from 4.1 to 9.4 (mean 6.5). The t 1/2 from urinary data (collected for 12 days) was consistent with plasma data. The above results suggest the need to reexamine the current practice of frequent daily dosing and the use of sustained or controlled release dosage forms of this drug. The possible cause of reduced plasma clearance of CPM in renal patients is discussed.
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  • 86
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    European journal of clinical pharmacology 23 (1982), S. 93-97 
    ISSN: 1432-1041
    Keywords: tolmesoxide ; vasodilator ; hypertension ; pharmacokinetics ; haemodynamics ; plasma renin activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The haemodynamic response and pharmacokinetics of single dose oral tolmesoxide were studied at various dose levels in 4 patients with severe hypertension. There was a reproducible fall in mean arterial pressure from baseline of 24.2% and a rise in heart rate of 37.6% following administration of tolmesoxide. The onset of antihypertensive action occurred within 1 h, with a peak effect at 3 h after dosing. The mean duration of action was up to 12.0 h. Tolmesoxide had a mean half-life of 3.0 h. It was rapidly absorbed with a mean peak plasma level occurring at 1.0 h. Plasma levels correlated well with the doses administered. Side-effects included mild nausea, facial flushing and postural symptoms.
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  • 87
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    European journal of clinical pharmacology 23 (1982), S. 37-42 
    ISSN: 1432-1041
    Keywords: metoprolol ; propranolol ; oxprenolol ; pharmacokinetics ; acetubolol ; diacetolol ; oral contraceptive
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma concentrations of metoprolol, propranolol oxprenolol, acebutolol and its metabolite diacetolol were measured after single oral doses in young healthy volunteers. In order to assess the inter-and intra-subject variability the following pharmacokinetic parameters were compared: AUC o 24 , Cmax, tmax and t1/2. The smallest variation in inter-subject variability was seen with oxprenolol and acebutolol: intrasubject variability was more uniform. Female volunteers taking an oral contraceptive generally had higher AUC o 24 and Cmax values than those not. This finding reached statistical significance only for metoprolol AUC o 24 .
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    European journal of clinical pharmacology 23 (1982), S. 49-57 
    ISSN: 1432-1041
    Keywords: verapamil ; norverpamil ; pharmacokinetics ; atrial fibrillation ; oral administration ; i.v. administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic parameters and oral bioavailability of the antiarrhythmic drug verapamil were determined in six patients with atrial fibrillation. Plasma samples were taken following i.v. injection of verapamil 10 mg (Isoptin® 2 ml), and oral verapamil 80 mg (Isoptin® 2 tablets of 40 mg). Verapamil and its N-demethylated metabolite, norverapamil, were analyzed to 1 ng/ml plasma by gas chromatography-mass spectrometry using deuterated standards. Following intravenous injection, the disposition of verapamil followed a biexponential pattern with a fast distribution phase and a slower elimination phase (t1/2β=5.79 h), corresponding to a plasma clearance of 0.26 1/kg/h. After oral administration, only an elimination phase was evident, with the same elimination rate (t1/2β=5.53 h). The oral bioavailability was 10.5%±7.5%. The norverapamil formed after i.v. and oral administration of verapamil had plasma half-lives of 5.86 h and 6.77 h, respectively. The elimination of verapamil in patients with atrial fibrillation was decreased compared to that in healthy young volunteers and the oral bioavailability was lower. Very good correlation between the percentage reduction in heart rate and the log plasma concentration of verapamil was found in every patient during the elimination phase, irrespective of the route of administration. There was also a high correlation when the plasma concentration — effect data from all the patients were pooled (r=0.59,n=71;p〈0.0005).
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    European journal of clinical pharmacology 23 (1982), S. 123-127 
    ISSN: 1432-1041
    Keywords: theophylline ; bronchiolitis ; infants ; pharmacokinetics ; single dose ; multiple doses ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Theophylline pharmacokinetics were studied in 12 infants (age 3 weeks–6.5 months) with bronchiolitis. 9 of the 12 patients received a single dose of aminophylline (5.0–8.5 mg/kg) whereas the remainder were at steady-state receiving multiple doses (2.5–5.0 mg/kg) of aminophylline. The dose was administered IV over 0.5–1.0 h. An HPLC method was used to measure theophylline concentrations in serum and urine. Peak serum concentrations of theophylline measured by HPLC ranged from 8.48–21.6 µg/ml. Total, renal and nonrenal clearance of theophylline ranged from 4.66 to 19.25, 1.07 to 5.76 and 3.59 to 16.83 ml/min/m2, respectively. Mean apparent volume of distribution and elimination half-life were 8.75 l/m2 and 11.38 h, respectively. Although no significant correlation was observed between age and theophylline kinetic parameters, clearance appeared to increase and half-life decrease with age. Our patients had a substantially lower clearance and longer half-life as compared to published data in children 〉1 year of age. A five-fold variation in theophylline clearance demonstrates the need for monitoring theophylline serum concentration to minimize the risk of potential toxicity.
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    European journal of clinical pharmacology 23 (1982), S. 129-134 
    ISSN: 1432-1041
    Keywords: theophylline ; ethinylestradiol ; oral contraceptives ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of chronic oral contraceptive (OC) usage on the disposition of theophylline was examined. Aminophylline solution (4 mg/kg) was given orally to 8 healthy female non-OC users and to 8 healthy women who were chronic (〉6 months) OC users. The OC user group had a significantly lower total plasma clearance of theophylline than women not using OC (35.1±5.6 vs. 53.1±14.5 ml/h/kg). The t1/2 was also significantly prolonged in the OC group (9.79±1.43 vs. 7.34±1.75 h) while the volume of distribution was similar between the 2 groups. The serum ethinylestradiol (EE) concentrations after oral OC administration were measured simultaneously. The apparent clearance of EE was about 30% lower in the OC users. A significant positive correlation was found between the apparent clearance of EE and the plasma clearance of theophylline. The effects of OC are predominantly due to chronic use with decreased elimination of both theophylline and EE.
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  • 91
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    European journal of clinical pharmacology 23 (1982), S. 167-172 
    ISSN: 1432-1041
    Keywords: ticarcillin ; probenecid ; excretion ; pharmacokinetics ; automated chemical assay method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The excretion of radioactivity has been investigated in 3 healthy volunteers following rapid intravenous administration of 5 g of [35S]-ticarcillin. The radioactive dose was rapidly and completely excreted, since within 4 days 98.5% was recovered, 95% in the urine and 3.5% in faeces. All the urine radioactivity was accounted for as ticarcillin and its penicilloic acid. Plasma and urine samples collected from the volunteers at frequent intervals during the first 6 h of the experiment were assayed for penicillin by an automated chemical method and also for radioactivity. The results obtained by the chemical autoanalyser method were in excellent agreement with the plasma levels of radioactivity. From the data it was possible to calculate the renal clearance of the penicillin, a mean value of 104 ml/min was observed in the 3 volunteers. A further three volunteers were dosed intravenously with a 5 g bolus of non-radiolabelled ticarcillin in a cross-over study with and without predosing with probenecid. Serum samples were analysed by the chemical method for penicillin and the data subjected to pharmacokinetic analysis using a two compartment open model. The results indicate a shift of the distribution equilibrium of ticarcillin from the serum into the peripheral compartment after predosing with probenecid. Furthermore, the mean half-life of ticarcillin in the serum of the three volunteers was significantly increased from 1.3 h to 2.1 h by predosing with probenecid.
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  • 92
    ISSN: 1432-1041
    Keywords: dipyridamole ; platelets ; plasma levels ; pharmacokinetics ; adenosine uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Two preparations of dipyridamole have been studied by oral administration to 11 normal volunteers. The plasma levels of dipyridamole and its glucuronide were determined simultaneously by high performance liquid chromatography. The instant form (I.F., 100 mg) was administered four times daily and the slow release preparation (SRP, 200 mg) twice daily, for 3 days. Multiple blood samples were collected on Days 1–4 to provide plasma for assay, and simulteneously, platelet rich plasma was prepared for ex vivo study of the effect of dipyridamole on platelet uptake of adenosine. The pharmacokinetics of absorption and distribution of dipyridamole were described using a two compartment model with lag time and prolonged absorption. Strong inhibition of the platelet adenosine uptake was observed at therapeutic plasma levels. The inhibition of platelet adenosine uptake may be related to some of the pharmacological properties of dipyridamole.
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  • 93
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    European journal of clinical pharmacology 23 (1982), S. 349-351 
    ISSN: 1432-1041
    Keywords: indomethazine ; rheumatoid arthritis ; pharmacokinetics ; tolerance ; side effects ; slow-release tablets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics, efficacy and tolerance of a new formulation of slow-release indomethacin tablet were compared with those of a conventional indomethacin capsule in 30 patients with rheumatoid arthritis. The slow-release tablet was absorbed more slowly than the capsule (tmax 3.7 h and 〈 2 h, respectively) and produced more even serum drug levels in 10 subjects. Side-effects, especially dizziness and diarrhoea, were less frequent after the slow-release tablet than during the capsule period.
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  • 94
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    European journal of clinical pharmacology 21 (1982), S. 335-341 
    ISSN: 1432-1041
    Keywords: phenylephrine ; pharmacokinetics ; bioavailability ; first-pass metabolism ; phenolic conjugates ; m-hydroxymandelic acid ; intravenous ; oral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 7-3H-phenylephrine was given to 15 volunteers by a short-infusionn=4) or p.o. (10 volunteers, 1 patient with porto-caval anastomosis). Analysis of serum for free3H-phenylephrine and fractionation of urinary radioactivity was performed by ion-exchange and thin-layer chromatography. As almost the same3H-activity was excreted in urine after i.v. and p.o. administration, 86% and 80% of the dose respectively, complete enteral absorption can be assumed. A considerable difference was seen in the fraction of free phenylephrine, i.v. 16% of the dose versus p.o. 2.6%, which suggested reduced bioavailability. This was confirmed by comparison of the areas under the serum curve, which showed a bioavailability factor of 0.38. The result for the patient with porto-caval anastomosis was comparable to that in the normal volunteers. The biological half-life of 2 to 3h was comparable to that of structurally related amines, as were the total clearance of 2 1/h, and the volume of distribution of 340l. Metabolism to phenolic conjugates mainly after oral ingestion, and tom-hydroxymandelic acid after i.v. injection, again demonstrated thatm-hydroxylated amines are predominantly conjugated during the “first-pass” metabolism.
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  • 95
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    European journal of clinical pharmacology 22 (1982), S. 315-320 
    ISSN: 1432-1041
    Keywords: furosemide ; cirrhotic patients ; ascitic fluid ; diuretic effect ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of furosemide was studied in 7 patients with diagnosed liver cirrhosis and in 7 healthy subjects. Furosemide in plasma and ascitic fluid was analyzed spectrofluorometrically. After a single intravenous dose, the cirrhotic patients showed lower initial plasma concentrations of furosemide because of the larger volume of distribution. The mean half-life in cirrhotic patients was significantly greater than in healthy volunteers. The longer half-life was associated with a reduction in the serum clearance of furosemide. Ascitic fluid volume in the patients ranged from 4.6 to 7.71. There was no significant amount of furosemide in the fluid. The diuretic interchange between this fluid and plasma was slow, as peak concentrations ranged from 0.3 to 0.5 µg/ml within 3 to 5 h after bolus administration of furosemide. Diuresis and urinary sodium excretion, 5 h after furosemide injection, were similar in both groups; larger potassium excretion was found in the cirrhotic patients.
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  • 96
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    European journal of clinical pharmacology 26 (1984), S. 223-226 
    ISSN: 1432-1041
    Keywords: diazepam ; metoprolol ; drug combination ; pharmacodynamics ; pharmacokinetics ; drug metabolism ; sedation ; interaction study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 6 normotensive, healthy male volunteers the pharmacodynamic responses (blood pressure, heart rate; sedation index, tracking test, reaction time) to metoprolol (100 mg bid orally), diazepam (0.1 mg/kg intravenously) and to their combination were studied. The pharmacokinetics of diazepam were also compared in a cross-over experiment, with and without pretreatment by the β-adrenoceptor antagonist to evaluate the possibility of a drug interaction. The pharmacodynamic and pharmacokinetic investigations indicated that metoprolol only slightly impaired the elimination of diazepam (18% decrease in total clearance, 25% increase in elimination half-life). The pharmacodynamics of metoprolol (17% decrease in heart rate, 17% decrease in diastolic RR) was not significantly altered by the bolus injection of diazepam. The extent of prolongation in choice reaction time (RT2) induced by diazepam was significantly (p=0.001) more pronounced following the co-administration of metoprolol. However, the results of RT1, the tracking test and the sedation index did not indicate any increased effect due to the β-blocking agent. It is concluded that concomitant treatment with metoprolol and diazepam causes only minor and clinically irrelevant changes in drug metabolism and drug response.
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  • 97
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    European journal of clinical pharmacology 26 (1984), S. 113-119 
    ISSN: 1432-1041
    Keywords: estramustine phosphate ; prostatic cancer ; pharmacokinetics ; metabolism ; estramustine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of estramustine phosphate (EMP) was studied in five prostatic cancer patients given single i.v. and oral doses of EMP in a cross-over study. Plasma and urinary concentrations of parent drug, estramustine, estromustine (the estrone analogue), estradiol and estrone were followed for 32 h. The elimination of intravenous EMP from plasma was biphasic. The mean volumes of distribution were small, being 43 and 108 ml/kg for the central and peripheral compartments, respectively. The plasma clearance was 64 ml/kg/h, and the half-lives of the two phases were 0.16 and 1.27 h. Metabolism was the major route of elimination of EMP. It was readily dephosphorylated and oxidized to yield the cytotoxic metabolites estramustine and estromustine. Estromustine was the main metabolite in plasma. When given orally EMP underwent extensive presystemic dephosphorylation, which started in the gastrointestinal tract. The relative bioavailability of estromustine after administration of EMP-capsules was 44%, which reflects incomplete absorption of EMP rather than first-pass metabolism of estromustine. The terminal half-life of estromustine was 10–20 h, which suggests that EMP might be given once or twice a day.
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  • 98
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    European journal of clinical pharmacology 26 (1984), S. 163-169 
    ISSN: 1432-1041
    Keywords: dopamine ; pharmacokinetics ; pharmacodynamics ; adrenaline plasma level ; noradrenaline plasma level ; blood pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and the pharmacodynamic action of dopamine were investigated in 5 healthy subjects. Dopamine was given in different doses (200, 400 and 800 µg/min) by constant intravenous infusion over 90 min. In order to control the influence of the procedure on the measured parameters the subjects also received a similar infusion of saline. Dopamine, noradrenaline and adrenaline levels in plasma were followed for up to 6 h after the infusion, and arterial pressure and heart rate were monitored. Dopamine reached a steady state level within 15 to 30 min after commencement of the infusion; the steady state levels averaged 36.5 µg/l at 200 µg/min, 73.8 µg/l at 400 µg/min and 207 µg/l at 800 µg/min. The corresponding total clearances were 5.8 l/ min, 5.51/min and 3.9 l/min suggesting non-linear kinetics. The kinetics could not be described by compartmental model. Noradrenaline and adrenaline levels were found to be elevated during infusion of dopamine. Noradrenaline had returned to its pretreatment level within 15 to 30 min after cessation of the infusion, whereas the adrenaline level did not return to the pretreatment value within the observation period. Heart rate was increased by the dose of 400 µg/min, and the systolic and mean arterial pressures were elevated, whereas distolic blood pressure remained unchanged. Elevated systolic blood pressure was better correlated with plasma dopamine than with noradrenaline concentration. This finding, in conjunction with the unchanged diastolic blood pressure, indicates that elevation of the systolic blood pressure is a direct rather than an indirect effect of dopamine. The increased heart rate was not correlated with the dopamine level.
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  • 99
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    European journal of clinical pharmacology 26 (1984), S. 261-264 
    ISSN: 1432-1041
    Keywords: indomethacin capsules ; bioequivalence ; volunteers ; pharmacokinetics ; statistical significance ; bioavailability ; comparative bioequivalence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Two, separate 6×6 Latin square cross-over bioequivalence studies were performed in adult male volunteers using 10 different indomethacin capsule preparations marketed in India together with the pure drug powder as the standard. The products were evaluated with respect to plasma level at various times up to 8 h following administration of a 50 mg (2 × 25 mg) dose. Plasma samples were analysed by a fluorimetric method. Various pharmacokinetic parameters were calculated according to a two compartment model. Statistical evaluation of the data employed analysis of variance for a cross-over design (ANOVA) and Duncan's multiple range test to ascertain the significance of differences between the products. Of the 10 products studied, two were found to be bioinequivalent.
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  • 100
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    European journal of clinical pharmacology 26 (1984), S. 485-489 
    ISSN: 1432-1041
    Keywords: theophylline ; erythromycin ; interaction ; metabolism ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 11 healthy volunteers the kinetics of theophylline and the plasma levels and the urinary excretion of its metabolites were studied before and after treatment with erythromycin for 10 days. Theophylline was administered as an intravenous bolus injection (280 mg) followed by a constant intravenous infusion (23.8±4.1 mg/h) for 6 hours. The total clearance of theophylline at steady-state (63.4±9.9 vs 63.8±14.4 ml/min, before vs after erythromycin treatment) and the elimination half-life after cessation of the infusion (6.7±2.6 vs 7.5±1.8 h, before vs after treatment) did not change during the treatment with erythromycin. No difference in the formation of metabolites before and after treatment with erythromycin was detected; the findings in urine were 40.4±5.0 vs 42.1±5.4% 1,3-dimethyluric acid, 29.6±4.6 vs 30.1±5.9% 1-methyluric acid and 13.4±3.5 vs 12.5±2.2% 3-methylxanthine before and after erythromycin treatment, respectively. It is concluded that a clinically relevant interaction between erythromycin and theophylline does not occur.
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