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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 164-170 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The early morphogenesis of the eye-antennal disc ofDrosophila in response to 20-hydroxy ecdysone involves the curling of the eye anlagen dorsally over the antenna. During this process, the area of the peripodial membrane is substantially reduced. The peripodial membrane is taut at this stage, and if it is cut the curling of the disc cannot continue, and the eye anlagen returns to its original position within one minute of the operation. In contrast, cutting the columnar epithelium between the eye and antennal anlagen does not disrupt curling, but actually facilitates it. During curling, the cells of the peripodial membrane appear healthy, and exhibit basal extensions. We suggest that the curling of the eye is mediated by the conversion of cuboidal peripodial membrane cells into pseudostratified columnar epithelium at the edges of the peripodial membrane. Subsequently, cells of the peripodial membrane secrete first a pupal cuticle, and then an imaginal cuticle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 275-279 
    ISSN: 1432-041X
    Schlagwort(e): Evagination ; Morphogenesis ; Metamorphosis ; Female genital disc ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The morphology of the evaginating female genital disc ofDrosophila melanogaster was examined at different stages of metamorphosis. The observations show that the internal genital organs are derived from the anterior half of the disc and that their morphogenesis is mainly a protrusion of the different primordial areas of the disc epithelium. The external genital and anal derivatives originate from the posterior half of the disc, which undergoes complex rearrangements during metamorphosis. The disc opens along the posterior margin and the dorsal and ventral epithelia evert and thereby completely reverse their anteroposterior orientation. Dramatic elongation has been observed during the formation of the seminal receptacle. The cells of the repressed male genital primordium do not form any recognizable structures and are assumed to be eliminated during metamorphosis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 299-302 
    ISSN: 1432-041X
    Schlagwort(e): Differentiation ; Teratogens ; Drosophila ; 5-Azacytidine ; Methylation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The effects of cytidine and cytidine analogs were studied inDrosophila embryonic cell cultures and two wild-type established cell lines, Oregon-R and Schneider line 2. Primary embryonic cultures have been shown to be an excellent system for the study of embryonic development; a number of cell types undergo normal differentiation in vitro. Treatment of these cultures with putative teratogens resulted in an inhibition of muscle and/or neuron differentiation in our study. Treatment of these cells with cytidine and seven other analogs had no effect on neuron and muscle differentiation. The compound 5-azacytidine, when added to primary cell cultures, inhibited normal differentiation at subtoxic doses while inducing the production of three proteins that comigrate with the heat-shock proteins, hsp 23, 22a and 22b. 5-Azacytidine did not stimulate differentiation in Oregon-R or SchneiderDrosophila cell lines. The in vitro blockage of differentiation by 5-azacytidine suggests that it may act as a teratogen.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 118-122 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Aggregation ; Lectins ; Cell surface ; Embryo-derived cell line
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In this paper we describe the aggregation of cells from embryo-derived cell lines ofDrosophila, measured by examining the ability of single cells to adhere to one another when suspended in culture medium and swirled on a rotary shaker. Using this method we demonstrated the presence of receptors for Concanavalin A, soybean agglutinin, and possibly wheat germ agglutinin on the surface of Schneider's line-2 cells. Our work provides basic descriptive and background information for further studies onDrosophila cells, including those isolated from imaginal discs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 297-300 
    ISSN: 1432-041X
    Schlagwort(e): Myosins ; Drosophila ; muscle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Electrophoresis of myosin extracts from larvae and adult tissues ofDrosophila melanogaster under non-dissociating conditions indicate that two of the bands seen are myosins. They stain for Ca2+ ATPase activity and when cut and re-run under dissociating conditions are found to contain a myosin heavy chain that co-migrates with rabbit skeletal muscle myosin heavy chain. One of the forms of myosin seen is found primarily in extracts from the leg. The other is common to the adult fibrillar flight muscles and the larval body wall muscles. The electrophoretic evidence for two myosin types is strengthened by the histochemical demonstration of two myofibrillar ATPases on the basis of their lability to acid or alkali preincubation. The myofibrillar ATPase in the leg and the Tergal Depressor of the Trochanter (TDT) are shown to be relatively acid labile and alkali stable. The larval body wall muscles and the adult fibrillar flight muscles have an ATPase which is acid stable and alkali labile. This distribution of the two myofibrillar ATPase coincides with that predicted by electrophoresis of extracts from whole tissue and also locates the two myosins to specific muscle types.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 185-190 
    ISSN: 1432-041X
    Schlagwort(e): Wound healing ; Regeneration ; Imaginal discs ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary When complementary fragments of an imaginal disc ofDrosophila are cultured for several days prior to metamorphosis, usually one fragment will regenerate while the other will duplicate. It has been proposed that wound healing plays an important part in disc regulation (French et al. 1976; Reinhardt et al. 1977) by initiating cell proliferation and determining the mode of regulation. We tried to delay the wound healing process by leaving a region of dead cells between the wound edges. In “06” fragments (Bryant 1975a) wound healing has occurred after 1–2 days of culture and the regeneration of missing structures after 2–4 days of culture. We observed that leaving a region of dead cells between the wound edges delays both wound healing and the regeneration of missing structures by 2 days. When disc fragments are cultured in female abdomens and then exposed to3H-thymidine to label replicating cells, then the label is found to be localised around the wound. We observed that delaying wound healing does not delay this localisation of labelled nuclei indicating that wound healing may not be required to initiate DNA replication.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 156-160 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Imaginal discs ; Transdetermination ; Homeosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The transdetermination capacities of leg discs ofDrosophila melanogaster were examined by mechanically disrupting and kneading whole discs from late third instar larvae and by culturing the resulting tissue mass for 10–14 days in adult female abdomens where the cells continued to divide. The grown implants were then dissected from the abdomens and injected into third instar larvae to undergo metamorphosis. After this treatment, prothoracic leg discs ofDrosophila melanogaster transdetermined with a high frequency (59% of all implants) to wing. Mesothoracic leg discs also transdetermined to wing, but at a very low frequency (4%). Metathoracic leg discs exhibited the same low frequency of transdetermination (4%), but in this case the direction of transdetermination was to haltere (Table 1,D. melanogaster). Very similar results were obtained with leg discs ofDrosophila nigromelanica (Table 1,D. nigromelanica), showing that the peculiar behavior of the three leg discs is not unique forDrosophila melanogaster. The homeotic mutation Polycomb (Pc 3) which partially transforms meso- and metathoracic legs into prothoracic legs did not significantly increase the frequencies of transdetermination in these leg dises and had clearly no effect on the direction of transdetermination (Table 1).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 280-284 
    ISSN: 1432-041X
    Schlagwort(e): Evagination ; Morphogenesis ; Metamorphosis ; Intersexual genital disc ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Morphogenetic movements of the intersexual genital disc of thedoublesex-dominant mutant ofDrosophila melanogaster were followed during metamorphosis. Intersexual genital discs contain well developed genital primordia of both sexes as well as an anal primordium, and all of these primordia evaginate simultaneously. The female genital primordium is deflected to the ventral side by the male genital primordium which is located anterior to it. Subsequently the anterior parts of the two genital primordia project their internal appendages in parallel in the anterior direction. The morphogenetic movements closely resemble those of the corresponding parts of normal males and females. The disc opens at the stalk along the posterior edge and the two genital primordia completely evert their posterior parts. These areas undergo complex rearrangements whereby the anlage for the male genital arch as well as that for the 8th tergite evert and move around the lateral side of the disc. They both fuse dorsally after enclosing the anal tube. The formation of the characteristic abnormalities of the intersexual genitalia seems not to result simply from spatial problems of the simultaneous evagination of the genital anlagen but rather to be a direct result of the ambiguous genetic signalling in the intersexual cells of these primordia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 337-346 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Gynandromorphs ; Genital disc ; Compartments ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The genital imaginal disc ofDrosophila differentiates the terminalia, i.e. the genitalia and analia, of both sexes. It represents a composite anlage, containing a female genital primordium, a male genital primordium and an anal primordium. In normal males and females, only one of the two genital primordia differentiates; the other is developmentally repressed. Therefore, cell-lineage relationships between the male and female genital primordia can only be studied in sexual mosaics which differentiate female and male cells. We producedMinute (M)‖non-Minute(M+) gynandromorphs and selected those with sexually mosaic terminalia for a cell-lineage analysis. In these mosaics, either the male (XO) or female (XX) cells wereM + and thus had a growth advantage. The differential growth rates served as a tool to detect clonal restrictions. In control gynandromorphs (M +‖M +), the amount of female genitalia differentiated was largely independent of the amount of male genitalia present. In contrast, male and female anal structures, as a rule, added up to one full set. The same was true for the experimentalM‖M + gynandromorphs, but the contribution ofXX andXO cells to mosaic terminalia changed drastically due toM + cells competing successfully against the more slowly growingM cells. Specific subsamples ofM‖M + gynandromorphs showed thatM cells in a non-mosaic primordium are shielded from cell competition taking place in the neighbouring mosaic primordium. We conclude that the three primordia of the genital disc represent developmental compartments. In the genital primordia, even developmentally repressedM + cells compete successfully against developmentally activeM cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 11-21 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Imaginal discs ; Ecdysteroid ; Lethal mutant ; Morphogenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Imaginal disc development in the non-pupariating lethall(1)npr-1, a mutant that maps to an ecdysone early puff site, is studied in situ, in vitro and in transplanted discs. Disc development is slightly abnormal from the middle of the third instar with severe abnormalities appearing after the rise in 20-hydroxyecdysone that triggers metamorphosis. The mutant discs only partly evaginate and do not undergo any of the detailed morphological changes characteristic of metamorphosis. Treatment of the mutant dises in vitro with colcemid and trypsin facilitates evagination but the appendages remain morphologically abnormal. A number of differentiative processes occur in mutant discs in situ and in discs transplanted into wild type hosts in spite of the absence of normal morphogenesis. Implications of the observations for normal disc development are discussed. Possible modes of action of thel(1)npr-1 gene are also discussed in light of the observation that the mutant gene maps to a locus which is thought to have a regulatory function in development.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 132-138 
    ISSN: 1432-041X
    Schlagwort(e): Maternal effect mutant ; Homeotic-mutants ; Pattern formation ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The temperature sensitive mutationfs(l)h is characterized at the restrictive temperature of 29°C by both a maternal effect responsible for the early embryonic lethality and pupal zygotic lethality. The two phenotypes are inseparable and map at a short deletion in the X chromosome (7Dl, 7D5-6). At semipermissive temperatures, hemizygous mutant females produce adults with morphological defects, such as organ deficiencies and homeotic transformations of haltere to wing and third leg to second leg. These defects depend on the maternal genotype and are governed by an early temperature sensitive period, which covers the end of oogenesis and the first hours of embryogenesis. Furthermore, this maternal effect mutation interacts with some dominant mutations of the bithorax system. These properties suggest thatfs(l)h is somehow involved in segmental determination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 1-10 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Grandchildless ; Pole cells ; ts-mutant ; Cytoplasmic determinant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two temperature-sensitive sex-linkedgrandchildless (gs)-like mutations (gs(1)N26 andgs(1)N441) were induced by ethylmethane sulphonate inDrosophila melanogaster. They complemented each other and mapped at two different loci (1−33.8±0.7 forgs(1)N26 and 1−39.6±1.7 forgs(1)N441), which were not identical to those of any of thegs-like mutants reported in earlier work. Homozygous females of the newly isolated mutants produced eggs that were unable to form pole cells and developed into agametic adults. Competence of the embryos to form pole cells was not restored by wild-type sperm in either mutant; that is, the sterility caused by these mutations is controlled by a maternal effect. Fecundity and fertility ofgs(1)N26 females were low, and their male offspring showed a higher mortality than that of female offspring, causing an abnormal sex ratio. The frequency of agametic progeny was 93.1% and 55.8%, when the female parents were reared at 25° C and 18° C, respectively. In eggs produced by thegs(1)N26 females reared at 25° C, the migration of nuclei to the posterior pole was abnormal, and almost no pole cell formation occurred in these egg. Furthermore, half of these eggs failed to cellularize at the posterior pole. When the females were reared at 18° C, almost all of the eggs underwent complete blastoderm formation, and in half of these blastoderm embryos normal pole cells were formed. In the other mutant,gs(1)N441, the fecundity and fertility of the females were normal. The agametic frequency in the progeny was 70.8% and 18.6% when the female parents were reared at 25° C and 18° C, respectively. In the eggs laid by females reared either at 25° C or at 18° C, the migration of nuclei to the periphery and cellularization proceeded normally; nevertheless, in the majority of the embryos no pole cell formation occured at the stage when nuclei penetrated into the periplasm. When the females were reared at 18° C, some of the embryos from these females formed some round blastoderm cells with cytologically recognizable polar granules and nuclear bodies, which are attributes of pole cells. The temperature sensitive period ofgs(1)N441 was estimated to extend from stage 9 to 13 of King's stages of oogenesis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 308-312 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; ts-Suppressor mutant ; Glue proteins ; Intermolt puffs ; Electrophoresis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The l(1)su(f)ts67g mutation has been shown to suppress the developmentally regulated expression of glue protein genes at 30°C. Transferring mutant larvae to the restrictive temperature before the end of the second larval instar results in the absence or extreme reduction of glue protein synthesis while general protein synthesis is unaffected. At the same time, the three glue protein correlated chromosomal regions 3C, 25B, and 68C continue to show prominent puffs. The results suggest that the mutation may be affecting the processing or translatability of specific mRNAs rather than the translational machinery itself.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 48-50 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Hybrid lethality ; Imaginal discs ; Interspecific transplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Females ofDrosophila melanogaster, crossed with males ofDrosophila mauritiana, produce only female offspring. The male hybrid larvae grow very slowly, fail to pupate and die after prolonged larval life. Imaginal discs from these male hybrids transplanted into Drosophila melanogaster larvae can give rise to adult structures with normal patterns. Differentiation of hybrid imaginal disc tissue is improved by short term culture in non-hybrid larvae prior to metamorphosis, suggesting that the hybrid larval haemolymph is inadequate to sustain normal imaginal disc growth. This may represent the physiological basis of the reproductive isolating mechanism separating the twoDrosophila species
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 270-274 
    ISSN: 1432-041X
    Schlagwort(e): Fate map ; Repressed primordium ; Sex determination ; Genital disc ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The female genital disc ofDrosophila melanogaster was cut into distinct fragments, and the prospective fates of the fragments were determined by putting them through metamorphosis in host larvae. The dorsal epithelium contains the anlagen for the anal plates and parovaria, as well as the repressed male genital primordium. The ventral epithelium gives rise to all of the female genital structures except for the parovaria. The results were compared with published fate maps and observations made in experiments with sex-transforming mutations. This allowed us to establish a detailed three-dimensional fate map of the female genital disc, which shows a well-developed female genital primordium in the ventral epithelium, a repressed male genital primordium in the anterior part of the dorsal epithelium and an anal primordium in the posterior region of the dorsal disc epithelium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 285-294 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Cell degeneration ; Imaginal disc ; Basal lamina ; Blood cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The mutationsvestigial (vg; recessive) andUltravestigial (vg U; dominant) ofDrosophila melanogaster give rise to identical mutant adult phenotypes in which much of the cases this results from cell death in the presumptive wing margin of the wing disc in the third larval instar, but the process of cell degeneration is quite different in the two mutants. Invg cell death occurs continuously throughout the third larval instar, while invg U it occurs only in the early third instar. Cells fragment and some of the fragments condense, becoming electron dense (“apoptosis”). Both condensed and ultrastructurally normal cell fragments are extruded to the basal side of thevg disc epithelium. They accumulate under the basal lamina in the wing pouch area until they are phagocytosed by blood cells entering the wing pouch during the six hours following pupariation. Fragments are not extruded from thevg U epithelium but are apparently phagocytosed by neighboring epithelial cells. The basal lamina undergoes mophological changes following pupariation and is phagocytosed by blood cells in both wild-type andvestigial, but investigial the degenerated cell fragments are also engulfed by the same blood cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 317-326 
    ISSN: 1432-041X
    Schlagwort(e): Neurogenic mutations ; Topological specificity ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Neurogenic mutations have been found to cause the neuralization of certain regions of the ectoderm and yet to permit normal development of the remaining embryonic cells. Thus, it seems that the activity of the wild-type alleles of these genes is dispensable in a considerable fraction of the embryo during wild-type development. This effect might be a consequence of the cells' position within the embryo; alternatively, it might be independent of the position but be due rather to the genetic activity experienced by the cells previous to their commitment. The results described in this paper indicate that genes controlling patterning along the embryonic dorso-ventral perimeter (dorsal and Toll) are epistatic to genes controlling neurogenesis, their activity deciding which ectodermal cells are susceptible to neurogenesis. Using alleles with low expressivity, evidence was obtained showing that the tracheal placodes define the boundary of the territory which has neurogenic abilities at thoracic and abdominal levels.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 301-303 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Geographic strains ; Chorion genes ; Electrophoretic variants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Further IF screening ofDrosophila melanogaster geographic strains has revealed a variant of the s19 major chorion protein. Developmental analysis of F1 hybrids indicates that the source of the variation is found in the structural gene for this protein. The linkage group of the variant gene was determined to be the third, and the gene was localized by several methods of recombination analysis. The s19 gene was found to be tightly linked to thesepia locus, as had been previously found for the s18 gene (Yannoni and Petri 1980). Lack of recombination between the s19 and s18 genes in double heterozygotes suggested that these two genes are within 0.3 map units of each other. Although more precise localization of the s19 gene failed, the s18 gene could be more specifically located to the right ofsepia, betweensepia andhairy. Contrary to our prediction (ibid.), the s19 and s18 genes have been found to be tightly linked in spite of the fact that they display somewhat different developmental stage specificity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 190 (1981), S. 370-373 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Homoeotic mutants ; Ventral cord
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We describe a set of cells in the central nervous system of theDrosophila embryo which are restricted to the thoracic ganglia in the wildtype. Taking these cells as indication of thoracic identity, we find that the ventral cord of embryos homozygous mutant for different bithorax functions and for Polycomb undergoes homoeotic transformations equivalent to those observed in the larval cuticle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 192 (1983), S. 62-74 
    ISSN: 1432-041X
    Schlagwort(e): Early neurogenesis ; Neurogenic mutants ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The central nervous system (CNS) ofDrosophila develops from precursor cells called neuroblasts. Neuroblasts segregate in early embryogenesis from an apparantly undifferentiated ectoderm and move into the embryo, whereas most of the remaining ectodermal cells continue development as epidermal cell precursors. Segregation of neuroblasts occurs within a region called the neurogenic field. We are interested in understanding how the genome ofDrosophila controls the parcelling of the ectoderm into epidermal and neural territories. We describe here mutations belonging to seven complementation groups which effect an abnormal neurogenesis. The phenotypes produced by these mutations are similar. Essential features of these phenotypes are a conspicuous hypertrophy of the CNS accompanied by epidermal defects; the remaining organs and tissues of the mutants are apparently unaffected. The study of mutant phenotype development strongly suggests this phenotype to be due to misrouting into the neural pathway of development of ectodermal cells which in the wildtype would have given rise to epidermal cells, i.e. to an initial enlargement of the neurogenic region at the expense of the epidermogenic region. These observations indicate that the seven genetic loci revealed by the mutations described in this study contribute to control the neurogenic field. The present results suggest that in wildtype development neurogenic genes are supressed within all derivatives of the mesoderm and endoderm and some derivatives of the ectoderm, and conditionally expressed in the remaining ectoderm. The organisation of the neurogenic field in the wildtype is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 19-24 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; guanfacine ; central antihypertensives ; withdrawal ; catecholamines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary 1. Guanfacine (2–6 mg/day) a centrally acting antihypertensive drug, was effective in controlling blood pressure in 5 essential hypertensives and lowered plasma noradrenaline and urinary catecholamine excretion. 2. Withdrawal of guanfacine by blind substitution of identical placebo tablets under observation in hospital led to a gradual recovery of blood pressure over 2–4 days. 3. Salivary flow, which was reduced on guanfacine, returned to pretreatment levels by 2 days after withdrawal and significantly exceeded control for the next two days. 4. Urinary catecholamine excretion returned to pretreatment levels by 3 days but did not exceed control levels during the period of study. 5. Plasma noradrenaline returned gradually to pretreatment levels, and by day 4 significantly exceeded them. 6. No patient experienced symptoms suggesting catecholamine excess although four out of five reported a headache from the second day onwards. 7. Guanfacine, a centrally acting drug which pharmacologically resembles clonidine, has a slow offset of hypotensive effect over 2–3 days. Symptoms or biochemical evidence of catecholamine excess were not encountered within 48 h of withdrawal, possibly reflecting the longer duration of action and plasma half-life of guanfacine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 309-315 
    ISSN: 1432-1041
    Schlagwort(e): guanfacine ; methyldopa ; hypertension ; rebound hypertension ; withdrawal symptoms ; plasma noradrenaline
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Nine patients with essential hypertension completed a clinical trial designed to study the effects and side effects of administration and withdrawal of guanfacine (2 mg tds) and methyldopa (250 mg tds) on blood pressure, heart rate, and plasma noradrenaline. The study was of randomised doubleblind crossover design with two active therapy phases of eight weeks each, preceded by an initial 4 week placebo phase, separated by an intermediate 2 week placebo phase, and followed by a final 2 week placebo phase. Patients took bendrofluazide 5 mgs daily throughout the entire trial, during both active and placebo periods. Each patient was admitted to hospital at the end of the 8 week active treatment phases, so that the effects of drug withdrawal on blood pressure, heart rate, plasma noradrenaline and side reactions, could be closely observed and monitored. The main conclusions from analysis of the results were that: 1. The hypotensive efficacy of guanfacine and methyldopa was very similar in the doses used, each of the two drugs lowering the supine mean arterial pressure by about 15 mm Hg and the supine diastolic pressure by about 10 mm Hg. 2. The frequency of side effects was greater with guanfacine than with methyldopa. 3. There was no signficant early rebound phenomenon after withdrawal of either methyldopa or guanfacine. 4. There was tendency for the blood pressure to rise slowly and marginally above initial placebo values, 2 weeks after cessation of guanfacine treatment though this was not significant. It was however, accompanied by a significant increase in plasma noradrenaline at 2 weeks. This was not seen 2 weeks after cessation of methyldopa. There was no single incidence of worrying rebound hypertension or withdrawal symptoms either early or late in any patient following cessation of methyldopa or guanfacine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 163-168 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; captopril ; cardiac output ; extracellular fluid volume ; renin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effects of captopril 450 mg/day for 4 weeks on blood pressure, heart rate, cardiac output and extracellular fluid volume were compared in severe, often drug-resistant hypertension (n=23), mild to moderate hypertension associated with renal artery stenosis (n=10) and mild to moderate essential hypertension (n=20). Plasma renin in the three groups was 52±19, 58±17 and 20±4 µU/ml (mean ± SEM), respectively. Blood pressure fell by 18±4%, 21±2% and 18±1%. The pressure drop was mainly due to a fall in peripheral vascular resistance. Addition of the diuretic hydrochlorothiazide (25–100 mg/day) caused a further fall in resistance. Despite the vasodilator effect of captopril, reflex cardiostimulation and reactive fluid retention were not observed. In severe hypertension, captopril alone was more effective in lowering blood pressure than combined diuretic-betablocker-vasodilator therapy. Moreover, cardiac output in these patients was higher and resistance was lower after captopril than during combined treatment. Thus, captopril was capable of normalising the abnormal haemodynamic state in patients with essential hypertension, and in hypertension associated with renal artery stenosis. Despite marked differences in pre-treatment plasma renin, the effects of captopril on systemic haemodynamics were similar in all the patients.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    ISSN: 1432-1041
    Schlagwort(e): vasodilator ; hypertension ; haemodynamic effects ; renal plasma flow ; renal tubular function ; plasma renin activity ; aldosterone ; Ro 12-4713
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Selected cardiovascular and endocrine effects of the new oral vasodilator Ro 12-4713 have been evaluated in an acute single dose study. In five patients with essential hypertension, Ro 12-4713 caused a dose-dependent decrease in supine and upright blood pressure and an increase in heart rate. Initial effects occurred one to 2 h after drug ingestion and maximal effects were noted after five hours and persisted for at least 8 h. Blood pressure was normalized, and the antihypertensive and chronotropic effects persisted for 24 h after a dose of about 300 mg/1.73 m2. Plasma and urinary norepinephrine and plasma renin levels tended to be raised, whereas plasma and urinary epinephrine and plasma aldosterone did not change. Changes in supine heart rate were inversely correlated with changes in mean blood pressure (r=−0.60; P〈0.02), and positively with those in plasma norepinephrine (r=0.55; P〈0.05) and renin (r=0.62, P〈0.01); changes in supine plasma renin level were also inversely correlated with those in mean blood pressure (r=−0.65; P〈0.01), and positively with those in plasma norepinephrine (r=0.58; P〈0.05). 24 h-urinary sodium excretion was significantly (P〈0.001) decreased; it was positively correlated with mean blood pressure (r=0.51; P〈0.05) and inversely with supine plasma renin activity (r=−0.63; P〈0.01). In six normal subjects and six patients with essential hypertension, effective renal plasma flow and the renal clearance of sodium, potassium, calcium and uric acid were not significantly altered five hours after a dose of Ro 12-4713 of about 250 mg/1.73 m2; glomerular filtration rate tended to be slightly decreased, and filtration fraction was significantly (P〈0.05) reduced in the hypertensive patients. At the same time blood pressure was decreased and plasma norepinephrine (P〈0.01) and renin (ns) were slightly increased in both groups. Ro 12-4713 in a single oral dose of about 300 mg appeared to be a potent, long acting, hypotensive vasodilator.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 157-161 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; cadralazine ; single dose ; dose response curve ; hypotensive action ; prolonged effect ; side effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Cadralazine (ISF 2469) was administered to 24 hypertensive patients in single oral doses of 7.5, 10, 15, 20 and 30 mg, according to a single-blind, placebo-controlled, within-patient change-over design. The study was done in 2 stages: in the first a range including the upper and lower doses was studied (7.5, 15, 30 mg and placebo), and in the second the range of doses was restricted (10, 15, 20 mg and placebo). The drug produced a significant decrease in blood pressure in the supine and standing positions. The decrease became clinically important starting from the 15 mg dose. Its action was still significant 12 h after administration. A significant increase in heart rate was also observed. All the effects were correlated with the dose. Side effects occurred mainly after the 30 mg dose. Thus, cadralazine, in a single oral dose in man, showed good antihypertensive activity starting from the 15 mg dose, and its effect was dose-related, slow in onset and long-lasting.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 217-220 
    ISSN: 1432-1041
    Schlagwort(e): metoprolol ; pregnancy ; hypertension ; kinetics ; pre-eclampsia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disposition of oral metoprolol was studied in 5 women during the last trimester of pregnancy and 3 to 5 months after delivery. After a single oral dose of 100 mg the individual peak plasma concentration in the pregnant state was only 20–40% of that after pregnancy. The plasma half-lives of metoprolol were about the same during (average 1.3 h) and after pregnancy (average 1.7 h). By contrast, the area under the plasma concentration versus time curve was much smallerduring (mean 262 nmol/l×h) thanafter (mean 1298 nmol/l×h) pregnancy, resulting in an average apparent oral clearance (Clo) of metoprolol that was 4.4times higher during (362 ml×kg−1 body-weight×min−1) than after pregnancy. The increased Clo in pregnancy is assumed to be due to enhanced hepatic metabolism of the drug. The possible clinical consequence of the difference in the disposition of metoprolol is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 307-314 
    ISSN: 1432-1041
    Schlagwort(e): endralazine ; hypertension ; blood pressure ; heart rate ; renal clearance ; plasma renin activity ; plasma aldosterone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effects of endralazine, a new antihypertensive hydrazinopyridazine derivative, on heart rate, mean blood pressure (mBP), glomerular filtration rate (GFR), effective renal plasma flow (CPAH), urine volume (V), the clearance of Na, K, urea (Ur) and uric acid (UA), plasma renin activity (PRA) and plasma aldosterone (PA) were studied in hypertensive patients after a single oral dose of 10–15 mg, and after 8–17 days of treatment with daily doses of 15–90 mg. In the acute experiments, heart rate increased by 27%, mBP decreased on average by 17% and GFR by 33% and CPAH fell by only 5%. Urine volume and electrolyte clearance were also depressed. There was a significant increase in PRA and PA. The fall in GFR correlated directly with mBP, CPAH and the product (mBP×CPAH). The logarithms of the Na clearance and V were correlated with GFR and mBP. The logarithms of the fractional excretion of Na and water also correlated with mBP, suggesting that tubular reabsorption of sodium and water may be affected by change in mBP. The fractional potassium excretion correlated directly with CPAH and ln PA. In contrast, on sustained daily treatment, mBP was less depressed (9%), but GFR increased strikingly by 27% and CPAH by 46%. The body weight increased by 4.5% as a consequence of salt and water retention. GFR was correlated with CPAH, the product (mBP×CPAH) and the increase in body weight. Thus, the improvement in GFR and effective renal plasma flow observed under these conditions may be due, in part, to volume expansion. However, a direct renal vasodilating effect of the drug appears to be the more important determinant.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 579-583 
    ISSN: 1432-1041
    Schlagwort(e): indapamide ; hypertension ; baroreflex ; vascular reactivity ; heart rate ; blood pressure change
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effect of chronic treatment with indapamide on blood pressure (BP), baroreceptor sensitivity (BRS) and vascular reactivity (VR) were investigated in 10 patients with essential hypertension. After 3 months of therapy with indapamide 2.5 mg/d the mean arterial pressure (MAP) had decreased from 135±6 to 112±2 mmHg (p〈0.001); the heart rate (HR) had not changed, VR had decreased from 6.1±1.2 to 4.8±1.8 (pg·min·kg)−1 (p〈0.05), and BRS had increased from 8.3±3.7 to 12.2±5.3 ms/mmHg (p〈0.005), with a leftshift of the relationship between BP and heart period. An inverse correlation was found between the pre-treatment systolic blood pressure and the change in baroreceptor sensitivity after indapamide (r=0.59; p〈0.05). In conclusion, chronic treatment with indapamide enhances BRS and resets the reflex. The resetting may account for the lack of tachycardia at rest observed after treatment with indapamide. The mechanism by which indapamide interferes with the baroreceptor reflex requires further investigations.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 143-144 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; nifedipine ; plasma concentration ; blood pressure response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    ISSN: 1432-1041
    Schlagwort(e): furosemide ; hypertension ; plasma renin activity ; plasma adrenaline ; plasma noradrenaline ; body fluid loss ; diuretic response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary To evaluate the role of adrenergic mechanisms in the acute response of renin to furosemide, plasma renin activity (PRA) and plasma catecholamine concentrations were measured for 3 h after i.v. administration of furosemide 1 mg/kg to 8 patients with mild essential hypertension. Furosemide induced a prompt and long-lasting increase in renin, with PRA more than doubled at all times. The increase in PRA within the first 30 min paralleled the peak increases in urinary water and sodium flow rates, and significant decreases in plasma volume and central venous pressure. There was no change in plasma catecholamine concentrations. Plasma noradrenaline was increased significantly at 60 min and adrenaline at 90 min, once furosemide had induced a marked loss of body-fluid and ∼65% decrease in central venous pressure. Both catecholamines remained elevated until the end of the study, whereas urinary water and sodium flow rates had returned to their pre-treatment values by 150 min. Mean blood pressure was essentially unchanged throughout the study, whereas heart rate increased significantly after 90 min. The findings suggest that in mildly hypertensive patients adrenergic mechanisms are not involved in the initial renin response to furosemide, but they come into play later, probably as a result of reflex sympathetic activation triggered by marked volume depletion.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 307-312 
    ISSN: 1432-1041
    Schlagwort(e): ketanserin ; hypertension ; blood pressure ; plasma noradrenaline ; exercise ; orthostatic reflexes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Ketanserin is a new, specific serotonin receptor blocking agent, which causes vasodilatation, presumably by an action on the vascular wall. The antihypertensive response to ketanserin 40 mg twice daily as monotherapy was assessed in 8 patients with essential hypertension. The investigation was an 8 week, double-blind, cross over study, which also included measurements during isometric (handgrip) and dynamic exercise (bicycle ergometry), as well as determination of plasma catecholamines and ketanserin. Ketanserin caused a reduction of supine and standing systolic and diastolic blood pressure (BP) during rest and a slight bradycardia. Although there was attenuation of the pressor response to handgrip, treatment with ketanserin did not really affect the changes in BP or heart rate during exercise, i.e. the base-line differences remained the same. There was no significant correlation between the effect on BP and the plasma level of ketanserin. The changes in BP produced by ketanserin showed little correlation with the initial levels of plasma catecholamines or with alterations in those levels. Although the results did not indicate direct interference by ketanserin with sympathetic tone, the lack of reflexogenic tachycardia, as well as the lack of increase in plasma noradrenaline during hand grip, indicates at least some modulation of autonomic function. It is concluded that ketanserin lowers BP in essential hypertension without interference with cardiovascular reflexes during standing or exercise, and that the compound may offer an alternative approach in the treatment of hypertension.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 571-575 
    ISSN: 1432-1041
    Schlagwort(e): beta-blocker ; felodipine ; calcium antagonist ; hypertension ; vasodilator ; side effects ; plasma levels ; metoprolol ; propranolol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In a double-blind, cross-over trial, 10 men with primary hypertension, not adequately controlled with a β-blocker alone, were also given felodipine or placebo for periods of one week. Placebo was administered single-blind for 2 weeks and 1 week, respectively, before randomization and between treatments. The dose of felodipine ranged from 6.25 mg to 25 mg. The addition of felodipine resulted in a pronounced (20%), statistically significant reduction in blood pressure (BP) and a small but significant increase in heart rate (HR). The effects were seen within 1–2 h and were maximal after 3–4 h. During steady state treatment the duration of BP reduction was at least 12 h. No orthostatic reaction was seen. There was a significant correlation between the plasma concentration of felodipine and change in BP. The most frequently reported side-effects were headache and ankle oedema, the latter probably being due to pronounced pre-capillary vasodilatation. There was no weight increase and thus no indication of general water retention. No clinically significant change in laboratory variables and no influence on the P-Q time were seen. Thus, felodipine in combination with a β-blocker seems to be a useful addition to the treatment of hypertensive patients whose BP is not adequately controlled with a β-blocker alone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    ISSN: 1432-1041
    Schlagwort(e): prizidilol ; hypertension ; exercise test ; beta-blockade ; vasodilatation ; haemodynamic effects ; vascular tone ; muscle blood flow
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Fourteen men with moderately severe essential hypertension were treated with prizidilol hydrochloride 400–700 mg once daily (mean±S.D. 612±56 mg/day). The study was open and ambulatory, with an initial placebo period followed by dose titration of prizidilol. Prior to treatment and during optimal control of blood pressure cardiovascular adaptation was examined in a submaximal exercise test. Plethysomographic assessment of vascular flow, resistance and tone in the calf musculature during supine rest and during maximal vasodilatation was also performed. A highly significant reduction in systolic (from 164±4.5 to 141±2.7 mmHg; p〈0.001) and diastolic blood pressure (from 105±1.6 to 87±1.3 mmHg; p〈0.001) at supine rest was noted during therapy with prizidilol. There was no significant change in heart rate. Systolic pressure in the standing position was reduced (from 159±4.2 to 139±2.9 mmHg; p〈0.001) and so was the diastolic pressure (from 111±2.5 to 95±1.9 mmHg; p〈0.001). The heart rate in the standing position was significantly increased compared to supine rest in the placebo period and during optimal treatment with prizidilol. The β-adrenoceptor blocking properties of prizidilol were apparent as a reduction in the exercise-induced heart rate response at even the lowest work load. During prizidilol therapy an increase in resting calf muscle blood flow was found from 3.1±1.5 ml/min·100 ml to 4.3±2.1 ml/min·100 ml (p〈0.025). Vascular resistance and vascular tone were significantly reduced. No change regarding blood flow or resistance during maximal vasodilatation was noted. It is considered that prizidilol has a clear antihypertensive effect combining β-receptor blocking and vasodilator properties.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 25-32 
    ISSN: 1432-1041
    Schlagwort(e): clonidine ; hypertension ; baroreceptor reflex ; mode of action ; sympathetic activity ; urinary catecholamines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Acute studies of clonidine suggest that it lowers blood pressure by central enhancement of baroreflex sensitivity coupled with diminished evidence of sympathetic outflow, but longterm clonidine data have not been conclusive. We examined effects of one month of low dose clonidine (0.4 ± 0.15 mg/day) alone in 13 essential hypertensive men, assessing several biochemical indices of sympathetic function, as well as physiologic parameters, including baroreflex sensitivity, the cold pressor test, and the hypotensive response to alpha adrenergic blockade. Clonidine diminished mean arterial pressure (from 104±5 to 84±3 mmHg;p〈0.01), without associated changes in several biochemical parameters of sympathetic outflow (urinary excretion of catecholamines, metanephrines, and vanillylmandelic acid; allp〉0.1). Circulatory baroreflex function was not enhanced by clonidine, during either the amylnitrite test or the phenylephrine test, before or after parasympathetic blockade with atropine. The cold pressor test, an index of efferent sympathetic pressor function, was also unaltered. The enhanced mean arterial pressure response to phentolamine during clonidine therapy (from a fall of 14.8±4.3 to 39.4±5.2 mmHg,p〈0.01), suggested an increase in alpha adrenergic vascular tone, perhaps mediated by clonidine's alpha agonist properties in vascular smooth muscle. The antihypertensive mechanism of longterm low dose clonidine cannot reliably be ascribed either to baroreflex enhancement or to suppression of sympathetic outflow.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 113-118 
    ISSN: 1432-1041
    Schlagwort(e): tolmesoxide ; vasodilators ; hypertension ; side-effects ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics, hypotensive effect and tolerability of a new vasodilator, tolmesoxide (T), have been studied in 6 uncontrolled hypertensive patients receiving atenolol and a diuretic. After a 50 mg oral dose mean (± SD) peak plasma concentration of T was 1.13±0.29 µg/ml−1 and occurred 0.79±0.40 h after the dose; mean peak plasma concentration of its sulphone metabolite (M) was 0.37±0.09 µg/ml−1 at 1.92±1.32 h after the dose. Following peak plasma concentrations there was a monoexponential decline in T and M concentrations with half-lives of 2.78±0.77 h and 10.78±7.85 h respectively. There was a linear increase in plasma concentration of T and M during incremental dosing with 50–200 mg t. i. d. During in-patient administration of 600–900 mg T daily (n=6) there was no significant change in blood pressure, pulse rate or body weight. Out-patient administration of 900 mg T daily (n=4) was associated with a significant fall in mean systolic but not diastolic bp (lying −15/+1 mm Hg. standing −25/−8 mm Hg). A further fall was observed in 2 subjects receiving 1200 mg and 1500 mg daily. Supine pulse rate increased (mean ± SD) significantly from 55±5/min to 66±8/min following 900–1500 mg T in 4 out-patients. Severe nausea and other gastro-intestinal side-effects in all subjects receiving 600–900 mg daily eventually necessitated drug withdrawal. In its present from T is not recommended for the treatment of hypertension.
    Materialart: Digitale Medien
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  • 36
    ISSN: 1432-1041
    Schlagwort(e): carteolol ; hydrochlorthiazide ; amiloride ; hypertension ; double-blind clinical trial
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The antihypertensive effect of carteolol, a new β-blocking agent, added to basal diuretic treatment (hydrochlorthiazide 50 mg and amiloride 5 mg) has been assessed in a controlled trial in 17 patients with mild-to-moderate hypertension. The trial was divided into 4 stages: 1) run-in period with no antihypertensive treatment, 2) diuretic period (the diuretic being continued as basal treatment during the two following periods), 3) carteolol titration period, and 4) double-blind cross-over period comparing carteolol with placebo, which lasted 2 times 4 weeks. Although the diuretic effectively reduced the blood pressure, 17 of the 20 patients originally studied still had an elevated diastolic blood pressure (≧ 95 mmHg) after the diuretic period, thus fulfilling the inclusion criteria for the study. During the titration period carteolol 5 to 20 mg b. i. d. significantly reduced the elevated blood pressure. The blood pressure was reduced to normal in all 17 patients, although in two patients this occurred only during the double-blind period. During the double-blind period, the dose of carteolol was used which had given a satisfactory response during the titration period. The blood pressure in the 14 patients who completed the trial remained low both with carteolol and placebo during the double-blind stage, and was only slightly lower with carteolol than with placebo. This is probably due to a “carry-over” effect. Three patients discontinued the trial due to side effects (1 urticaria, 1 insomnia and 1 nausea) while on carteolol. There was no other difference between carteolol and placebo in the number or severity of side effects.
    Materialart: Digitale Medien
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  • 37
    ISSN: 1432-1041
    Schlagwort(e): vasodilator ; hypertension ; antihypertensive treatment ; catecholamines ; renin ; aldosterone ; blood volume
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The antihypertensive efficacy and endocrine profile of the new antihypertensive agent, Ro 12-4713, were evaluated in 23 patients (17 men and 6 women) with moderate to severe arterial hypertension. Following addition of Ro 12-4713 to pre-existing therapy with diuretics and beta-blockers or sympatholytics, blood pressure in most of the patients was normalized within one month by a daily dose of 60 to 120 mg. Heart rate was only slightly increased. Orthostatic hypotension was not observed. Weight gain or oedema formation occurred in 14 patients within the first four weeks, but could be controlled satisfactorily by intensified diuretic therapy. Increased hair growth occurred in most of the patients. After a mean duration of treatment of 2.8 months, plasma volume and plasma and urine sodium were unaltered, and plasma potassium was slightly decreased. Plasma renin activity was doubled, whereas plasma aldosterone concentrations were unaltered. Plasma norepinephrine levels were high before and increased only slightly during chronic Ro 12-4713 treatment, whereas urinary norepinephrine excretion was unchanged. Plasma and urinary epinephrine were unaltered by Ro 12-4713. Ro 12-4713 appears to be a potent vasodilator for the combination treatment of hypertension in men.
    Materialart: Digitale Medien
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 335-338 
    ISSN: 1432-1041
    Schlagwort(e): atenolol ; atherosclerosis ; hypertension ; serum lipoproteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Serum lipoproteins were determined in 15 patients before and during antihypertensive treatment with atenolol 0.1–0.2 g/day for a mean of 8 months. The mean blood pressure fell from 171/103 to 154/93 mm Hg (p〈0.05). Significant lipoprotein changes were an increase in very low density triglycerides (VLDL-TG) from 1.21±0.95 (SD) to 1.62±1.24 mmol/l (p〈0.01) and in low density (LDL) TG from 0.46±0.12 to 0.51±0.12 mmol/l (p〈0.05). Together, these TG increases resulted in development of hypertriglyceridaemia in 7/15 patients during atenolol treatment. No effect on whole serum cholesterol or on the high density lipoprotein cholesterol concentrations were found. Thus, some patients on long term treatment with atenolol seem to receive the benefit of normotension at the cost of hypertriglyceridaemia. This may have practical implications, since hypertriglyceridaemia constitutes an important risk factor for atherosclerosis.
    Materialart: Digitale Medien
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 347-349 
    ISSN: 1432-1041
    Schlagwort(e): reserpine ; syrosingopine ; prolactin secretion ; hypertension
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In 20 mild hypertensive women, reserpine induced a significant increase in mean plasma PRL, both under basal conditions (from 6.6±0.9 to 17.9±2.9 ng/ml), and on repeated determinations during the day. In contrast to reserpine, the administration of syrosingopine, a synthetic compound derived from reserpine, to the same subjects was not followed by a significant change in prolactin level. Beyond their pharmacological interest, these results are of clinical importance when considering that rauwolfia alkaloids are used for long term treatment, and that an increase in PRL levels is important in pathology, both in relation to the function of the hypophyseogonadal axis and in view of its possible facilitation of the growth and development of mammary cancer.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 15-19 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; mianserin ; clonidine ; methyldopa ; depression ; α2 receptors ; interaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The concurrent administration of tricyclic antidepressants has been shown in man to result in a clinically significant impairment of the antihypertensive effect of clonidine. This interaction is thought to be related to competition for central α2 receptors where clonidine acts as an agonist and the tricyclics act as antagonists. Although it seems to cause less cardiovascular effects than tricyclic antidepressants, the tetracyclic antidepressant, mianserin also has been reported to be an α receptor antagonist and may, therefore, also interfere with the antihypertensive activity of centrally-acting drugs. This study investigates the effects of acute and chronic mianserin administration in patients with essential hypertension established on long term treatment with either clonidine or methyldopa. The first dose of mianserin was not associated with an increase in blood pressure and during a further two weeks of mianserin therapy there were no significant alterations in blood pressure, supine or erect. Similarly, mianserin did not alter heart rate either after acute or after chronic administration. Mianserin itself had a sedative effect but there was no interference with the sedation attributable to clonidine or methyldopa. Mianserin caused no reduction in salivary flow and did not influence the reduced saliva production caused by clonidine. Both clonidine and methyldopa are associated with a reduction in sympathetic outflow but there was no evidence in this study of any further change in plasma noradrenaline or 24 h urinary catecholamine excretion. This study demonstrates that if mianserin is given acutely or chronically, it does not interfere with the effects of the centrally acting antihypertensive drugs, clonidine and methyldopa. Mianserin may therefore be a suitable antidepressant for patients receiving these antihypertensive agents if drug treatment for depression is indicated.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 1-5 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; nifedipine ; calcium antagonists ; beta-blockers ; vasodilators ; diuretics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Nifedipine has been assessed as a possible alternative to other third line drugs in the management of patients with difficult to control hypertension. A group of 20 patients whose blood pressure was unsatisfactory on a 3 drug regimen had their third drug stopped and after a 2 week period nifedipine was added to their beta-blocker plus diuretic therapy. Eleven became normotensive on 30 mg nifedipine daily and a further 6 on 60 mg daily; giving on overall success rate of 85%. This result was achieved with a reduction in side effects and an absence of any haemodynamic or metabolic complications.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 301-305 
    ISSN: 1432-1041
    Schlagwort(e): endralazine ; hypertension ; pindolol ; peripheral vasodilator ; acetylator phenotypes ; antinuclear antibodies ; SLE-syndrome ; side-effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Nineteen out-patients with moderate to severe essential hypertension were treated daily for 3 years, with an average dose of 13 mg endralazine, a new peripheral vasodilator, in free combination with pindolol 3×5 mg. The blood pressure showed a statistically significant reduction from 172/110 mmHg to 154/92 mmHg after treatment for 3 weeks. Tachyphylaxis was not observed during the 3 year period. Oedema was the most frequent side-effect, but it disappeared spontaneously. No difference in efficacy and tolerance between slow and fast acetylators was found. Only 2 patients developed a weak positive antinuclear antibody titre, which disappeared spontaneously from one during continued treatment. No clinical evidence of a systemic lupus erythematosus-like syndrome was noted. It is concluded that the differences between endralazine and hydralazine in dosage and metabolism may explain the lower immunogenic activity of endralazine.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 481-490 
    ISSN: 1432-1041
    Schlagwort(e): propranolol ; pharmacokinetics ; pregnancy ; hypertension ; naphthoxylactic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of propranolol (P) and its major metabolites, propranolol glucuronide (PGLUC), 4-hydroxypropranolol (4OHP), 4-hydroxypropranolol glucuronide (4OHPGLUC) and naphthoxylactic acid (NLA), (Walle et al. 1972) were determined, whenever possible, in the first, second and third trimesters of pregnancy in thirteen patients and also when these patients were at least three months post-partum. No correlations were found between the mean arterial blood pressure (post-therapy) or the fall in blood pressure as a result of the P therapy (p〉 〉0.05) and P dose, peak P plasma concentrations, peak 4-hydroxypropranolol (4OHP) plasma concentrations or peak (P plus 4OHP) plasma concentrations. However, a positive nonlinear relationship was found between the daily P dose (independent variable) and peak P plasma concentrations over the daily dose range 30–160 mg/day. The elimination half-lives of NLA for patients in the third trimester of pregnancy were significantly shorter (p=0.072, df=13) than those when the patients were at least three months post-partum. Also, the areas under the plasma level-time curves of NLA were significantly less (p〈0.05, df=13) for patients in the third trimester of pregnancy than when these patients were at least three months post-partum. The results of this study indicate that the pharmacokinetics of P, PGLUC, 4OHP and 4OHPGLUC are not significantly altered by pregnancy. However, the kinetics of NLA do appear to be altered. The formation of NLA by N-dealkylation of P and further oxidation, appears to be competitively inhibited by unidentified substances, perhaps endogenous steroids, especially in the third trimester when compared to at least three months post-partum.
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  • 44
    ISSN: 1432-1041
    Schlagwort(e): pinacidil ; hypertension ; side effects ; pharmacokinetics ; fluid retention ; retarded release tablet
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In an open study increasing doses of a retarded tablet formulation of pinacidil were given twice daily for four weeks to 9 patients with untreated essential hypertension (WHO I–II). In all patients a decrease in diastolic blood pressure to below 100 mmHg, or a fall exceeding 15 mmHg, was obtained 2 h after tablet intake (p〈0.02), but in only two patients was the effect maintained after 10 hours (n.s.). At a mean serum concentration of 100 ng/ml 2 h after pinacidil 30 mg, the mean blood pressure had decreased by 14 and 12.7 mmHg in the supine and erect positions, respectively (p〈0.05). In contrast, mean blood pressure 10 h after the same dose was unchanged, when the mean serum concentration was 47.5 ng/ml. No change in heart rate was observed. Pharmacokinetic and pharmacodynamic investigations showed a tendency towards a more gradual and longer lasting antihypertensive effect and serum concentration-time curve after the retarded tablet than the previous tablet. Pinacidil 40 mg in the retarded tablet reduced mean blood pressure and increased heart rate for at least 8 h. There was a linear correlation between the serum concentration and the changes in mean blood pressure, and between the changes in mean blood pressure and in heart rate. There was no indication of tachyphylaxis. A serum level of 50 ng/ml of pinacidil appeared to be the minimal effective concentration. The side effect consisted of fluid retention, and the body weight increased by 1.0 kg (p〈0.05); four patients complained of oedema. Therapy was discontinued in one patient after a fainting episode following an increase in the dose. Thus, pinacidil was able to lower blood pressure during monotherapy for 4 weeks provided that an adequate serum concentration was achieved. The present retarded tablet formulation is not suitable for b. d. dosing. The tendency towards fluid-retention suggests that pinacidil should be used in combination with a diuretic.
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  • 45
    ISSN: 1432-1041
    Schlagwort(e): captopril ; propranolol ; sympathetic nervous system ; noradrenaline ; aldosterone ; renin ; angiotensin converting enzyme ; hypertension ; isometric exercise
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effects of captopril and propranolol on blood pressure, heart rate and plasma noradrenaline, renin and aldosterone, and on the responses to changes in posture and to isometric exercise were measured in patients with essential hypertension. During placebo administration blood pressure, heart rate and plasma noradrenaline rose on standing and during isometric exercise. The rise in diastolic blood pressure during isometric exercise correlated significantly with the rise in plasma noradrenaline. During captopril treatment blood pressure was significantly lower than during placebo administration when the patients were lying, standing or sitting, but the reduction during isometric exercise was not significant. Plasma renin increased, but heart rate, plasma noradrenaline and plasma aldosterone remained unchanged. The acute changes in blood pressure, heart rate and plasma noradrenaline produced by standing and isometric exercise during captopril treatment were similar to those during placebo administration. During propranolol treatment diastolic blood pressure was significantly lower than during placebo administration when the patients were lying, standing or sitting and during isometric exercise. Heart rate also fell. Plasma noradrenaline during standing, sitting and isometric exercise was significantly greater than during placebo administration. The changes in plasma noradrenaline measured during propranolol treatment with the patients supine were negatively correlated with noradrenaline values obtained during placebo administration: plasma noradrenaline fell in patients with higher, and increased in those with lower, initial concentrations. The expected acute increase in heart rate on standing and during isometric exercise was blunted by propranolol, but the changes in blood pressure and plasma noradrenaline were unaffected. We conclude that in essential hypertension noradrenaline is involved in the pressor response to isometric exercise. Angiotensin converting enzyme inhibition by captopril did not interfere with the responses of the sympathetic nervous system to postural changes and isometric exercise. During propranolol treatment there was no evidence that reduced sympathetic activity was involved in the hypotensive response.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 145-150 
    ISSN: 1432-1041
    Schlagwort(e): nifedipine ; hypertension ; pharmacokinetics ; tablet formulation ; dose-response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A tablet formulation of nifedipine was given to 8 hospitalized hypertensive men, W.H.O. stage I or II, mean age 45 years. After an initial placebo test, nifedipine 20, 40 or 60 mg was given in random order at 72-h intervals, in a single administration crossover study. The placebo and the active drug were given at 8 a.m. Blood pressure and heart rate were measured twice by the same observer, every 20 min from 7 to 8 a.m., and then hourly until 8 p.m., first in recumbency and again after 1 min of standing upright. Plasma nifedipine was assayed in samples taken hourly from 8 a.m. to noon, every 2 h from noon to 8 p.m., and 24 and 48 h after drug administration. All 3 doses significantly lowered blood pressure; the fall during recumbency was significantly larger (−18%) and lasted longer (12 h) after 60 mg than after 20 mg (−11% and 7 h). All 3 doses caused a similar increase in heart rate (+29 to +38%), which reached its maximum after 2 h and lasted for 5 h. The maximum plasma concentration and the area under the plasma concentration — time curve were dose-dependent despite large inter-subject variation. Absorption, bioavailability and elimination were linear between the 20 and 60 mg doses. Plasma nifedipine levels were strongly correlated with the concomitant decrease in mean arterial blood pressure (r=0.61,p〈0.001). Four patients experienced mild side effects (headaches, flushes, drowsiness or weakness). This tablet form of nifedipine has a potent antihypertensive action which lasts longer than that of the capsule presentation.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 395-401 
    ISSN: 1432-1041
    Schlagwort(e): sotalol ; hydrochlorothiazide ; hypertension ; combination fixed ratio ; serum potassium ; long term treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The combination of sotalol and hydrochlorothiazide in a fixed ratio of 6.4:1 was evaluated in thirty patients with uncomplicated hypertension. In the first part of the study, once daily administration of an optimal dose of the combination was significantly more effective than either hydrochlorothiazide or sotalol alone in lowering both the supine and standing systolic and diastolic blood pressure. Blood pressure was still controlled 24 h after the previous dose. Serum potassium fell by 0.37 mEq/l from the mean pretreatment value after treatment with the combination, but it still remained within the normal range. In the second part of the study the long term effect of the combination on blood pressure, heart rate and biochemical parameters was studied in twenty patients. Supine and standing blood pressure fell by 28.7/15.3 mmHg and 29.5/17.6 mmHg, respectively (p〈0.001). Serum potassium was 3.98±0.07 mEq/l after twelve months of therapy; potassium supplements were not administered. Like serum potassium, the other biochemical parameters remained within the normal range. The combination was well tolerated on long term use, and only one patient withdrew from the study.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 1-8 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; captopril ; angiotensin ; renin ; aldosterone ; catecholamines ; prostaglandins ; kininase II ; hypotensive action
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The acute hypotensive effect of captopril 25 mg was investigated in 26 hypertensive patients (11 with essential and 15 with renal arterial disease). Intra-arterial blood pressure was recorded continuously and arterial blood was sampled for renin, angiotensin I and II, aldosterone, kininase II, catecholamines and prostaglandins. Captopril led to an increase in plasma renin activity, active and total plasma renin concentration and angiotensin I, a decrease in plasma kininase II activity, angiotensin II, aldosterone, prostaglandins E2 and F2* and no change in plasma (nor)adrenaline, dopamine and inactive renin concentration. The hypotensive effect of captopril was related to the changes in plasma angiotensin II level and inversely to the change in prostaglandin E2; the correlation coefficients were low, respectively 0.61 and −0.44. It is likely that the acute hypotensive effect of captopril to some extent is related to changes in plasma angiotensin II and in prostaglandins E2 and F2*. There is no evidence for a role of the adrenergic systems in the hypotensive response.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 399-405 
    ISSN: 1432-1041
    Schlagwort(e): alpha-adrenergic blocker ; hypertension ; blood pressure ; pulse rate ; noradrenaline ; plasma renin activity ; plasma aldosterone ; dopamine-beta-hydroxylase ; E-643
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary To determine whether E-643, a new α-blocking agent, would reduce the blood pressure, regardless of the posture, a 1 mg dose was given 3 times daily for 7 consecutive days, to 8 male and 7 female inpatients, aged 37–73 years, with essential hypertension. Blood pressure and pulse rate were measured daily in the supine, sitting and standing positions. Before and after the treatment with E-643, plasma levels of noradrenaline, adrenaline, dopamine-β-hydroxylase, renin and aldosterone were determined, samples being obtained with the subjects recumbent and after standing upright for 60 min. A significant reduction in the systolic and diastolic blood pressures was evident in the supine (172±31/100±12 → 151±28/89±14 mmHg), sitting (158±22/101±11 → 138±28/89±15 mmHg) and standing (153±32/103±21 → 129±31/89±20 mmHg) positions. The reduction in blood pressure remained unchanged throughout the period of administration of E-643. Pulse rate was not affected when the subjects were supine (67±10 → 69±10 beats/min), but was increased in the sitting (68±10 → 73±9 beats/min) and standing (73±10 → 81±11 beats/min) positions. The increased pulse rate tended to decline during continued administration of E-643. Treatment with E-643 produced no significant change in plasma levels of adrenaline, noradrenaline, dopamine-β-hydroxylase, renin and aldosterone. The antihypertensive effect of treatment was more prominent in the patients with higher levels of plasma catecholamines and dopamine-β-hydroxylase, and was less prominent in those with higher plasma renin and aldosterone. Two patients had temporary bouts of dizziness and visual disturbances, but there were no subjective complaints during treatment.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 407-411 
    ISSN: 1432-1041
    Schlagwort(e): chlorthalidone ; hypertension ; dose response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The dose response curve for 25, 50, 75 and 100 mg doses of chlorthalidone was studied in double blind fashion over an 8 week period in patients who presented with untreated mild hypertension. One hundred and thirty four patients completed this multicentre, family practice study. After 2 week's medication, a decline in blood pressure was noted in all dosage groups and this was maximal by 4 weeks. At 8 weeks all doses of chlorthalidone induced a significant reduction in both systolic and diastolic blood pressures (mean −18 and −10 mmHg respectively). Amongst the 4 dosage groups, no differences in response were noted resulting in a flat dose response curve. During the study, mean blood urea and serum uric acid rose whilst serum potassium fell, the urea and potassium being least affected in the 25 mg dosage group. As the dosage of chlorthalidone increased, so the tendency for abnormal laboratory values increased. Unwanted effects sought during the study were relatively few in number. No clear dose response relationship was evident although the positive responses in the 25 mg dosage group were less than in the higher dosages. These results suggest that 25 mg chlorthalidone is the optimum dosage for initiation of therapy in patients with mild to moderate hypertension. This dosage is associated with less adverse biochemical changes and unwanted effects than the higher dosages studied.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 453-457 
    ISSN: 1432-1041
    Schlagwort(e): diuretics ; trichlormethiazide ; hypertension ; pharmacokinetics ; renal insufficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of trichlormethiazide (TCZ) was studied in twelve patients after a single 4 mg dose. Seven patients had normal renal function with creatinine clearances greater than 90 ml/min. Five patients had compromised renal function with creatinine clearances averaging 48±29 ml/min. The TCZ plasma half life and area under the plasma concentration-time curve (AUC) were significantly greater in patients with impaired function, compared to patients with normal renal function. There were no significant differences between the two patient groups in terms of either rate of drug absorption or total urinary recovery of unchanged drug. Furthermore, there was no correlation between peak drug levels or AUC and renal excretion of water or electrolytes.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 21 (1981), S. 1-8 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; combination therapy ; population survey ; drug treatment ; prescription patterns ; population incidence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In a cross-sectional study, antihypertensive drug treatment was studied in a representative population sample of people aged 30–64 years, using a combination of postal survey, personal interview, clinical assessment and drug prescriptions. 11% of the men and 16% of the women were currently taking antihypertensives; 54% of patients used one, 38% used two, and 8% used three or more preparations. Men used slightly more drugs than women. Diuretics were used by 62% and betablockers by 49% of the sample population. Fixed combinations of thiazides and potassium-sparing agents formed 70% of all diuretic preparations used. Only 12% of the patients used fixed antihypertensive combinations, of which over half were diuretic-reserpine-vasodilator combinations; women and older patients used them most often. The most common freely combined preparations were diuretics and betablockers, which formed almost half of all two-drug combinations, and were also present in 70% of all triple combinations. Adequate control of blood pressure (DBP 〈100 mmHg) was achieved by slightly under 50% of the patients, the BP of women being more adequately controlled than that of men. Differences in BP control were found between the different drugs and combinations. Antihypertensive combination therapy is important in successful treatment, but we still cannot be sure whether fixed combination preparations or, as in this study, free combinations of marketed preparations are better alternatives for treatment.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 21 (1981), S. 87-92 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; metoprolol ; sotalol ; comparison ; plasma levels ; serum uric acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary 28 patients, aged 35–62 years, with uncomplicated hypertension, entered a double-blind, crossover study, in which the effects of single daily doses of sotalol and metoprolol were compared. Both drugs exerted a clinically useful anti-hypertensive effect as monotherapy, or in combination with a thiazide diuretic. No significant difference in hypotensive effects was noted between the two beta-blocking agents, when the dose was titrated to an optimal clinical effect. Treatment with sotalol and metoprolol was associated with a clinically insignificant increase in serum uric acid concentration. The side-effects observed were few, and in only two cases was therapy discontinued. We regard both sotalol and metoprolol as useful anti-hypertensive drugs.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 21 (1981), S. 165-168 
    ISSN: 1432-1041
    Schlagwort(e): frusemide ; saralasin ; hypertension ; reninangiotensin ; sodium ; diet
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The use of tests of the renin-angiotensin system for predicting antihypertensive responses to frusemide combined with dietary sodium deprivation was evaluated in eighteen patients with severe hypertension. No relationship could be shown between changes in blood pressure induced by the angiotensin analogue, saralasin, and the short-term or long-term therapeutic effects of diuretic- and diet-induced sodium depletion. Mean values for saralasin response and initial plasma renin activity in eight patients whose blood pressure was adequately controlled by therapeutic sodium depletion were closely similar to those obtained in the remaining ten patients, who proved refractory to this treatment.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 467-473 
    ISSN: 1432-1041
    Schlagwort(e): hydralazine ; heart failure ; pharmacokinetics ; bioavailability ; metabolism ; hypertension ; dapsone ; acetylator phenotype
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The influence of various disease states, other than hypertension, on the pharmacokinetic behaviour of hydralazine is not completely known. In the present study the pharmacokinetics of oral hydralazine has been evaluated in 7 patients with severe, chronic heart failure, using 8 compensated hypertensives as controls. The pharmacokinetics was evaluated by measuring the plasma concentrations of hydralazine (“apparent” and “real” hydralazine) and hydralazine pyruvate hydrazone, and by assessing acetylator phenotype after a small dose of dapsone. The AUC (area under the plasma concentration curve) following a single, oral 50 mg dose was significantly larger in patients with chronic heart failure NYHA Class III–IV than in patients with essential hypertension without cardiac decompensation. A decreased rate of hepatic elimination of hydralazine is suggested as a major contributory factor to this finding.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 463-466 
    ISSN: 1432-1041
    Schlagwort(e): guanfacine ; hypertension ; phenobarbital ; withdrawal syndrome ; enzyme induction ; pharmacokinetics ; renal insufficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The unusual observation of a withdrawal syndrome due to guanfacine in a hypertensive patient with chronic renal failure led to a study of the kinetics of the drug in this patient. The principal pharmacokinetic parameters of guanfacine were greatly altered, with extended biotransformation and a decrease in the half-life compared to the values observed in other cases of severe renal insufficiency. Associated treatment with phenobarbital had had a considerable effect, as shown by the results of a further kinetic study 2 months after withdrawal of the phenobarbital. The findings then were in good agreement with reference values which strongly suggests a consequence of the enzyme inducing effect of phenobarbital. Advice about the dosage regimen in such cases is given.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 713-715 
    ISSN: 1432-1041
    Schlagwort(e): nifedipine ; hypertension ; calcium antagonist ; plasma renin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Nifedipine, a calcium antagonist with a predominant vasodilator action, was evaluated for the treatment of hypertension. A 20 mg-tablet, with a slower absorption and a more sustained blood-level than provided by the 10 mg-capsule was administered to 20 patients. The duration of the trial was 20 weeks. All patients achieved a significant reduction in both systolic (p〈0.05) and diastolic (p〈0.001) blood-pressure (B.P.), but 10 patients were withdrawn before completion of the trial period. Two patients, although achieving a fall in B.P. which was significant, did not reach to target level (〈160/90) on maximal dosage, one patient suffered a stroke due to a cerebral infarct, and seven patients were withdrawn because of side-effects due mainly to vasodilatation. The remaining 10 patients obtained a satisfactory response. In nine patients, who had achieved a satisfactory result, there was no change in plasma renin activity (P.R.A.) during chronic nifedipine administration.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 835-837 
    ISSN: 1432-1041
    Schlagwort(e): tienilic acid ; hydrochlorothiazide ; amiloride ; blood pressure control ; biochemical effects ; serum uric acid ; serum potassium ; prolonged treatment ; hypertension
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A comparison has been made of arterial pressure and major metabolic parameters during long term treatment with tienilic acid and a hydrochlorothiazide-amiloride combination, using a randomized single-blind study without cross-over. A significant fall in systolic and diastolic blood pressure and no change in most biochemical parameters was observed with both drugs. Serum uric acid concentration was decreased during tienilic acid and was slightly increased whilst subjects took the hydrochlorothiazide-amiloride combination; serum potassium was slightly decreased on tienilic acid. No sign of hepatotoxicity was detected.
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  • 59
    ISSN: 1432-1041
    Schlagwort(e): bufuralol ; hypotensive therapy ; pharmacokinetics ; hypertension ; 1-hydroxybufuralol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The relationship between the plasma concentrations of bufuralol and its major hydroxymetabolite (Ro 3-7410) and β-blocking activity was studied in 10 patients with uncomplicated essential hypertension. Blood samples and haemodynamic data were obtained during rest and after a single-level exercise test on a bicycle cycloergometer, prior to and up to 32 h after administration of a single oral dose of bufuralol 30 mg. Bufuralol was rapidly absorbed, following a first-order process with a lag time. The calculated maximal plasma concentration ranged from 44.6 to 200.3 ng/ml. The half-life of bufuralol was 2.75±1.15 h (mean±SD). Up to 50% of the parent drug was transformed into Ro 3-7410, which showed less interpatient variability in concentration and a fairly constant half-life, which was three times longer than that of the parent drug. In general, the heart rate (HR) was slightly decreased, although 2/10 patients showed an initial increase. The resting HR returned to its pre-treatment level within 6 h, the exercise HR took up to 32 h to return to the pre-treatment level. The drug reduced both resting and exercise blood pressure (BP). The former was reduced from 153.0±14.2/93.5±8.5 to 134.5±14.0/77.0±6.8 mmHg (systolic/diastolic BP; mean±SD) with 6 h after treatment. Similarly, the exercise BP was reduced from 199.0±15.2/98.5±8.8 to 171.0±9.9/88.5±8.5 mmHg at the 6th h post-dosing. The BP values had not returned to their pre-treatment levels even 32 h after treatment. Thus, bufuralol and its metabolite Ro 3-7410 induced a long-lasting antihypertensive effect and inhibited the cardio-acceleratory effect of exercise, and there was a good correlation between the pharmacokinetic and pharmacodynamic behaviour of the drug.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 581-583 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; metoprolol ; hydrochlorothiazide ; drug combination ; adverse reactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In 27 hypertensive patients whose blood pressure could not be adequately controlled with 200 mg metoprolol Durules alone, the effect of a double dose of metoprolol Durules® (400 mg once daily) was compared with a fixed combination of 200 mg metoprolol and 25 mg hydrochlorothiazide (Selokomb®). The study followed a double-blind cross-over schedule in 2 parallel groups. The reduction in diastolic blood pressure (p〈0.01) was comparable in the two groups. A significant fall (p〈0.01) in systolic blood pressure occurred with the metoprolol/hydrochlorothiazide combination. The subsequent change from the double dose of metoprolol Durules to the combination therapy also resulted in a fall in systolic blood pressure (p〈0.05). Mean serum potassium and blood glucose levels did not change after each alteration in therapy. Most of the side-effects mentioned were mild and transient in character.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 157-161 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; captopril ; nifedipine ; plasma renin activity ; aldosterone ; vasopressin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In a single-dose crossover study Captopril (SQ 14225), 1 mg/kg body weight, and Nifedipine (Bay a 1040) 20 mg were administered orally to 12 hospitalized patients with essential hypertension (Stage 1 or 2, W. H. O.). Both drugs significantly reduced blood pressure, but each dose acted differently: the mean maximum arterial pressure reduction was faster and greater with Nifedipine than with Captopril: −23±2% at 37±15 min and −17±1% at 86±25 min, respectively. Captopril inhibited angiotensin II and aldosterone production, but did not accelerate heart rate or stimulate vasopressin release. Nifedipine stimulated vasopressin release and increased heart rate, but the renin angiotensin aldosterone system was not significantly affected. The blood pressure reduction was related to the initial level of activation of the renin angiotensin system only for Captopril. The blood pressure reduction induced by one drug was not related to that produced by the other in the same patient.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 237-240 
    ISSN: 1432-1041
    Schlagwort(e): labetalol ; clonidine ; hypertension ; adverse effects ; plasma catecholamines ; plasma cAMP ; withdrawal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Eleven hypertensive patients in whom clonidine therapy had to be discontinued, were treated prophylactically with labetalol, in order to avoid a possible hypertensive crisis. Most of the known side effects, which are consistent with the withdrawal phenomenon were observed, e.g. tremor, insomnia and apprehension, but headaches and flushing did not occur. Blood pressure levels remained unchanged, despite up to a 20-fold increase in plasma catecholamines. The lack of change in serial measurements of plasma cyclic AMP level appears to indicate that adequate adrenergic blockade was induced by labetalol. Since labetalol is a potent anti-hypertensive drug, and is also effective in avoiding a possible hypertensive crisis due to withdrawal of clonidine, we propose to use it as the drug of choice whenever discontinuation of clonidine therapy is indicated.
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  • 63
    ISSN: 1432-1041
    Schlagwort(e): aldosterone ; hypertension ; propranolol ; blood pressure ; plasma level ; renin ; urine level
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Thirty patients with mild or moderate essential hypertension, and a fixed elevation of diastolic blood pressure, were randomly allocated to three groups and treated with propranolol 40 mg×4 (Group 1), 80 mg×4 (Group 2) and 160 mg×4 (Group 3). Blood pressure (BP), pulse rate (PR), plasma renin activity (PRA), plasma aldosterone concentration (PAC), total plasma propranolol (tPP), free plasma propranolol (fPP), and 24 h urinary propranolol excretion (UP) were determined at the end of four consecutive periods: (A) after four weeks without any treatment; (B) after two to three weeks during which the propranolol dose was gradually increased to the intended level; (C) after four weeks, and (D) after eight weeks of unchanged treatment. The maximum reduction in diastolic BP occurred after period B, and in systolic BP after Period C, for Groups 2 and 3, and for all groups together; for Group 1, however, the maximum diastolic BP reduction was first seen after period C. PR was reduced to the same level in all groups after period B. After period B, PRA and PAC fell in all groups, and remained reduced during C and D in Group 1. After periods C and D, PRA and PAC in Groups 2 and 3 did not differ significantly from the levels after period A; tPP, fPP and UP were significantly correlated with the propranolol dose, and were lowest in Group 1 and highest in Group 3; UP was negatively correlated with systolic but not diastolic BP in Periods B, C and D. In contrast neither fPP nor tPP were correlated with systolic or diastolic BP. There was no significant correlation between PRA, PAC and changes in PRA or PAC on the one hand and tPP, fPP, UP, BP or changes in BP on the other. It was concluded that propranolol effectively reduced BP, but diastolic BP reduction was most rapidly obtained at 320 and 640 mg daily, that the activity of the renin-aldosterone system was initially suppressed in all groups, but for unknown reasons it increased towards the control level after seven to eleven weeks of therapy with 320 and 640 mg/day, and that the reduction in systolic BP increased with higher doses of propranolol and with increasing urinary propranolol excretion.
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  • 64
    ISSN: 1432-1041
    Schlagwort(e): clonidine ; minoxidil ; hypertension ; sympathetic nervous activity ; plasma renin activity ; cardiovascular responses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effect of clonidine and minoxidil on sympathetic nervous activity has been studied in 10 patients with accelerated or resistant hypertension. Clonidine 150 to 900 µg/day caused a significant decrease in blood pressure of 18.6 mm Hg, of heart rate 16.4 beats/min, or plasma renin activity 1.13 ng/ml·h, and of urinary noradrenaline excretion 11.55 µg/day, and a significant lengthening of the pre-ejection period of 12.4 ms. Minoxidil 5 to 22.5 mg/day caused a further significant decrease in blood pressure of 24.2 mm Hg, and significant increases in heart rate 8.2 beats/min, plasma renin activity 1.68 ng/ml·h, and of urinary noradrenaline excretion 5.0 µg/day, and a significant shortening of the pre-ejection period of 20.6 ms. Neither clonidine nor minoxidil altered plasma dopamine β-hydroxylase activity or the cardiovascular responses to treadmill exercise. It is concluded that clonidine is a useful alternative agent to block a minoxidil-induced increase in sympathetic nervous activity.
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 21 (1981), S. 93-96 
    ISSN: 1432-1041
    Schlagwort(e): atenolol ; penbutolol ; hypertension ; beta-blockers ; intrinsic sympathomimetic activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Atenolol 100 mg and penbutolol 40 mg given once a day were both effective in controlling moderate hypertension, as judged by a randomised controlled, double-blind trial in 45 patients treated for six weeks. Both drugs significantly reduced the resting supine and erect blood pressures. No serious adverse effects could be attributed to either drug. Bradycardia occurred more frequently with atenolol than with penbutolol. Penbutolol, which possesses intrinsic sympathomimetic activity, may be useful in the treatment of patients in whom some other beta-blocker has failed to bring about adequate control of the blood pressure, despite marked bradycardia.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 573-577 
    ISSN: 1432-1041
    Schlagwort(e): beta-blockers ; serum lipoproteins ; atenolol ; metoprolol ; hypertension ; VLDL ; HDL ; hypertriglyceridaemia ; hypercholesterolaemia ; side effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Several β-blockers increase VLDL-TG and decrease HDL-cholesterol concentrations. The underlying mechanism ist not yet clear. Some studies have suggested that the effect is less pronounced during treatment with selective β-blockers. The effects of 2 such drugs, metoprolol 200 mg/day and atenolol 50 mg/day, have been compared in 50 hypertensive patients (WHO Stage I–II), mean age 47 years. Serum lipoproteins were determined in 20 patients before treatment and after treatment with either drug for 3 months. Both drugs were equally effective in reducing blood pressure. After atenolol the initial VLDL-cholesterol concentration of 1.04 mmol/l had not changed, but it rose to 1.29 mmol/l after metoprolol (p〈0.05). The HDL-cholesterol concentration 1.42 mmol/l did not fall during atenolol treatment, but during metoprolol there was a small reduction to 1.31 mmol/l (p〈0.05). Hyperlipoproteinaemia is common in hypertensive patients, 40% of the present group had hypertriglyceridaemia and 25% had hypercholesterolaemia. Thus, atenolol 50 mg was found not to affect lipoproteins, whereas metoprolol 200 mg increased the VLDL concentration in 75% of the patients.
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 49-53 
    ISSN: 1432-1041
    Schlagwort(e): felodipine ; hypertension ; cardiac failure ; haemodynamic effects ; non-invasive monitoring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The haemodynamic effects of a new vasodilating drug, felodipine, were studied in eight, healthy, male subjects, aged 22–31 years. The drug was given as an oral solution in the dose of 0.15 mg/kg. Thirty-five minutes later further dose of 0.15 mg/kg was administered. Felodipine induced a pronounced decrease in diastolic blood pressure (maximal effect 15±4 mm Hg) and in the systemic vascular resistance. Cardiac output increased (maximum by 4.2±0.3 l/min), due to an increase both in the stroke volume and the heart rate. The maximal increase in the stroke volume (measured from echo cardiograms) and the heart rate were 33±5 ml and 23±3 beats/min, respectively. Felodipine caused a significant decrease in the pre-ejection period (23±3 ms) and an increase in the left ventricular ejection time (29±3 ms). The quotient PEP/LVET fell from 0.36±0.01 to 0.28±0.01. Significant activity of felodipine could be recorded at a plasma level of about 15 nmol/l. When the maximal haemodynamic effects were recorded the plasma level was about 40 nmol/l. After a cumulative dose of 0.30 mg/kg, there was a twofold variation in the maximal plasma level (from 31 to 61 nmol/l). The results of the present investigation are in agreement with previous haemodynamic studies in animals. It would appear that felodipine is a potent arteriolar vasodilator and it might well be of considerable value in the management of patients with hypertension or congestive cardiac failure.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 191-197 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; beta-blocker ; diuretic ; screening ; naturalistic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A naturalistic study was set up to screen, identify and treat hypertensive patients aged 20–60 years in a rural general practice. 3,222 patients (92%) of a stable population of 3,489 were screened by 2 nurse research assistants and of these 455 patients (14%) were found to be hypertensive or borderline hypertensive. After careful assessment, 192 of these patients were found suitable for treatment and subsequently 138 entered the study. Two well recognised treatment regimes were used and no significant difference between patient response resulted. 84 patients (60.9%) completed the 2 year duration of the study discussed here. The cost of the study is not feasible in an average general practice, but day to day running of such a project, run along clearly defined treatment regimes was managed easily by 2 research assistants: this reduced, therefore, the work load on individual general practitoners.
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 21 (1983), S. 199-211 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; lactate dehydrogenase ; isozymic pattern ; development ; isozymic conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Partially purified lactate dehydrogenase (LDH) from third-instar larvae displays two bands (one major and one minor) on polyacrylamide gels. Analogous preparations from pupae and adults exhibit three LDH-staining bands (one major and two minor) in a similar pattern. The migration of the major band is similar for larvae, pupae, and adults, while the two minor LDH bands of pupae and adults migrate more slowly than the minor larval band. It has been shown that larval LDH incubated with β-nicotinamide adenine dinucleotide exhibits two additional minor bands with an electrophoretic mobility similar to that of the minor bands of both pupae and adults. The intensity of the minor larval LDH band (exhibited also by untreated preparations) is drastically reduced. This fact indicates that the life-cycle stage-dependent LDH isozymic distribution is possibly due to a posttranslational effect(s). Highly purified LDH from larvae, pupae, or adults, obtained by an affinity chromatography procedure, displays just one dispersed band, located in the area between the band 5 and the band 6 exhibited by crude extract preparations. These data, in combination with the lack of difference in catalytic properties among enzymes from larvae, pupae, and adults, suggest that LDH synthesis is controlled by the same single structural gene at all developmental stages.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 567-583 
    ISSN: 1573-4927
    Schlagwort(e): aldehyde oxidase ; Drosophila ; evolution ; gene regulation ; isozymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract At least four enzymes contribute to histochemically, electrophoretically, or spectrophotometrically detectable aldehyde oxidase (AO) activity in Drosophila melanogaster. The one we designate AO-1 contributes the majority of activity measured in extracts of whole flies. Pyridoxal oxidase (PO) is also a broad range AO. It is prominent only in midgut and Malpighian tubules, where it apparently accounts for a substantial fraction of total AO activity. The tissue distributions of these enzymes are clearly disparate despite close linkage of their structural loci and parallel dependence on the mal, lxd, and cin loci. A similarly related enzyme, xanthine dehydrogenase (XDH), is detected as an AO only in electrophoretic gels. A fourth broad range AO, not dependent on mal, lxd, and cin, is confined to the ejaculatory bulb. A similar array of AO isozymes is present in phylogenetically distant Drosophila species.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 21 (1983), S. 199-211 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; lactate dehydrogenase ; isozymic pattern ; development ; isozymic conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Partially purified lactate dehydrogenase (LDH) from third-instar larvae displays two bands (one major and one minor) on polyacrylamide gels. Analogous preparations from pupae and adults exhibit three LDH-staining bands (one major and two minor) in a similar pattern. The migration of the major band is similar for larvae, pupae, and adults, while the two minor LDH bands of pupae and adults migrate more slowly than the minor larval band. It has been shown that larval LDH incubated with β-nicotinamide adenine dinucleotide exhibits two additional minor bands with an electrophoretic mobility similar to that of the minor bands of both pupae and adults. The intensity of the minor larval LDH band (exhibited also by untreated preparations) is drastically reduced. This fact indicates that the life-cycle stage-dependent LDH isozymic distribution is possibly due to a posttranslational effect(s). Highly purified LDH from larvae, pupae, or adults, obtained by an affinity chromatography procedure, displays just one dispersed band, located in the area between the band 5 and the band 6 exhibited by crude extract preparations. These data, in combination with the lack of difference in catalytic properties among enzymes from larvae, pupae, and adults, suggest that LDH synthesis is controlled by the same single structural gene at all developmental stages.
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 21 (1983), S. 1071-1088 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; alcohol dehydrogenase ; enzyme polymorphisms, activity ratios
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Representatives of five allozymic classes of Drosophila alcohol dehydrogenase have been compared with respect to their activity levels on two alcohol substrates, quantities of ADH protein, and stability in crude extracts. Within each allozymic class, strains from widely diverse geographic locations differ in their enzyme activity levels but are identical for a measure known as “activity ratio,” which is obtained by dividing the average activity reading on isopropanol by that obtained with ethanol. They are also similar in the rate at which ADH activity declines in crude extracts held at 25°C. For several of the fast-resistant and fast-moderate strains, differences in ADH activity are associated with differences in the amount of enzyme present. The catalytic efficiencies of the fast-resistant forms are considerably lower than those of the fast-moderate allozymes. The origin and persistence of the rare but ubiquitous fast-resistant allozyme is discussed.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 75-85 
    ISSN: 1573-4927
    Schlagwort(e): dipeptidases ; variation ; allozymes ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Genetic variation at three dipeptidase loci (Dip-A, Dip-B, and Dip-C) in Drosophila simulans was analyzed by starch gel electrophoresis. Dip-A was found to be polymorphic in four populations, while Dip-B and Dip-C were found to be polymorphic in one. The numbers of different alleles found at each respective locus were: Dip-A, two; Dip-B, two; and Dip-C, three. Dip-A was genetically mapped at 57.9 on the second chromosome, and Dip-B and Dip-C at 80.9 and 87.9 on the third chromosome, respectively. Neither Dip-B nor Dip-C has been mapped in D. melanogaster because both loci are apparently monomorphic. Their map positions in D. simulans with respect to flanking markers whose homologous genes have been cytogenetically localized in D. melanogaster suggested that they might be mapped cytogenetically by using available deficiencies in D. melanogaster. Accordingly, by the construction of interspecific hybrids which carried deficiencies of melanogaster and an allele of simulans with a mobility different from that of the fixed melanogaster allele, Dip-B and Dip-C were localized between 87F12-14 and 88C1-3 and between 87B5-6 and 87B8-10, respectively, in the salivary gland chromosomes of D. melanogaster. The similarity between these two species is discussed on the basis of these findings.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 115-127 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; dihydroorotate dehydrogenase ; pyrimidine biosynthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A locus is described that controls levels of mitochondrial dihydroorotate dehydrogenase (EC 1.3.3.1) in Drosophila melanogaster. The effects of alleles of the locus, Dhod, are manifest in preparations from whole organisms as well as in partially purified mitochondrial preparations; however, other mitochondrial functions do not appear to be appreciably affected by Dhod genotypes. The locus maps near p in the proximal portion of the right arm of chromosome 3. Flies trisomic for a chromosome segment including that region display elevated enzyme levels, implying that an enzyme structural gene is in that vicinity. Furthermore, Dhod alleles are semidominant in heterozygotes, suggesting that the dosage-sensitive element detected in the trisomics is actually the Dhod locus. These findings are discussed relative to the role of dihydroorotate dehydrogenase in the de novo pyrimidine biosynthetic pathway and relative to other pathway mutants that have been described in Drosophila.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 311-320 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; thermal stability of enzyme ; α-glycerophosphate dehydrogenase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Thermal stability of α-glycerophosphate dehydrogenase-1 (α-Gpdh-1) in nine Drosophila species was studied at pH's ranging from 6.4 to 8.5. This was done by measuring the changes in the activity of enzymes during the heat denaturation process. In addition to temperature, the rate of denaturation is highly dependent on the pH of the incubation buffer. The results of this study show that the thermal stability of enzyme molecules is different in different species. This holds true also in the species in which the enzymes have been found to be identical by other means. The differences between species of the Drosophila virilis group are discussed.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 321-331 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; embryonic cells ; actin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract In a permanent cell line derived from Drosophila embryos, cytoplasmic actin is produced as an unstable precursor, which is subsequently converted to a stable form. This conversion results in a reduction in isoelectric point, with no apparent change in molecular weight. The conversion involves an enzymatic acetylation, and results in an insensitivity to aminopeptidase digestion, suggesting N-terminal blockage. Both the acetylated and unacetylated actins can participate in the assembly of F-actin, but with different efficiencies.
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 411-419 
    ISSN: 1573-4927
    Schlagwort(e): half life ; Drosophila ; alcohol dehydrogenase ; enzyme stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A rapid and accurate method of measuring the relative in vivo stability of Drosophila alcohol dehydrogenase is presented. The potential of this technique for examining posttranslational control of in vivo enzyme concentrations is discussed.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 421-430 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; alcohol dehydrogenase ; adaptation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The effects of environmental 2-propanol on the in vivo properties of Drosophila alcohol dehydrogenase (E.C. 1.1.1.1.) are presented. Exposed flies were found to exhibit a significant decrease in ADH specific activity with a concomitant increase in the enzyme's relative in vivo stability and concentration. The possible adaptive significance of the observed responses is discussed.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 783-796 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; amylase ; gene regulation ; trans effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Purified amylases from high- and low-activity variants of Drosophila melanogaster showed identical specific activities. Immunoelectrophoresis of crude larval homogenates showed severalfold differences between strains in the amounts of cross-reacting material. Control of amylase activity is “trans”-acting in heterozygotes between high- and low-activity variants. These results suggest the existence of polymorphic regulatory genes affecting the production levels of amylase protein in D. melanogaster.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 19 (1981), S. 947-954 
    ISSN: 1573-4927
    Schlagwort(e): alcohol dehydrogenase ; Drosophila ; cryptic variants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Thirty-five cryptic variant lines were used to examine the mechanisms involved in genetic modulation of alcohol metabolism in Drosophila. Late third-instar larval, preemergence pupal, and adult stages cultured at 18 and 28 C were examined. Spectrophotometric analyses for native alcohol dehydrogenase (ADH) activity and residual ADH activity after treatment with guanidine hydrochloride and heat were performed. Differential response of cryptic variants to treatment with the denaturants during development suggested that this variation may have an adaptive significance.
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  • 81
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; molybdoenzymes ; sulfite oxidase ; tungstate feeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Sulfite oxidase (sulfite: ferricytochrome c oxidoreductase; EC 1.8.2.1) has been detected in Drosophila melanogaster and some of its properties have been studied. In most respects this enzyme resembles the mammalian sulfite oxidases except for its molecular weight (148,000), which is somewhat higher than that of rat sulfite oxidase (116,000). Cytochrome c, potassium-ferricyanide, and oxygen can serve as electron acceptors in the oxidation of sulfite by the enzyme. Although definite evidence can be obtained only through the analysis of the pure enzyme, experiments involving tungstate feeding suggest that Drosophila sulfite oxidase is most probably a molybdoenzyme. Extracts of mal flies show normal levels of sulfite oxidase, whereas lxd flies have only 5–10% of the activity of wild type, and in cin flies the enzyme is apparently absent. While it is possible that the lxd and cin mutations are at some level responsible for the defective synthesis of a molybdenum-containing cofactor (supposed to be present in most molybdoenzymes), the evidence accumulated so far by several authors and the results of the present investigation argue against the involvement of a Mo cofactor in the multiple enzyme deficiencies observed in mal flies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 21 (1983), S. 703-711 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; glucose-6-phosphate dehydrogenase ; polymorphism ; sequential electrophoresis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Studies were undertaken to investigate two critical aspects of the glucose-6-phosphate dehydrogenase polymorphism in Drosophila melanogaster. The first investigation unequivocally maps the genetic site of the G6PD locus to the X chromosome. The second study subjects a set of isochromosomal lines to sequential electrophoresis in an attempt to uncover common molecular heterogeneity within the global polymorphism, assuming that this variation may have gone undetected under conventional electrophoretic conditions. The genetic site was mapped following the segregation of the two common electrophoretic alleles, a so-called null allele, and two rare electrophoretic variants. From the pooled results, the Zw locus mapped to 62.9 on the X chromosome relative to the flanking markers car (at 62.5) and sw (at 64.7). A set of 126 iso-X chromosomal lines of diverse geographic origin was subjected to sequential electrophoresis under three different acrylamide conditions in addition to the conventional starch electrophoretic system. No additional variation beyond the common diallele polymorphism was seen.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 13 (1983), S. 17-27 
    ISSN: 1573-3297
    Schlagwort(e): pupation site ; pupation height ; artificial selection ; Drosophila ; density-dependent behavior ; genotype-environment interaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Selection for increased pupation height was carried out for 17 generations in two lines ofDrosophila simulans derived from a genetically heterogeneous base population. The realized heritability for mean pupation height in each line, calculated over the 17 generations, did not differ significantly from zero. Both selected lines tended to pupate away from the center of the culture medium to a greater extent than the control in the latter generations of the experiment but not in earlier generations. Pupation height may have been refractory to artificial selection because of an adaptation of this species to pupate on the larval food source. In a subsequent experiment, each line was tested at three larval densities in an apparatus different from the one used for selection. Each successively higher density showed a corresponding increase in pupation height. Both selected lines had higher mean pupation heights than the control line. The differences between lines became more pronounced as the larval density increased.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 11 (1981), S. 557-563 
    ISSN: 1573-3297
    Schlagwort(e): Drosophila ; photobehavior ; pupation site selection ; sibling species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Drosophila melanogaster prefers to pupate in the dark, while its sibling species,D. simulans, prefers the light when the species are tested in isolation and when cultured and tested together. Reciprocal interspecific hybridizations were carried out and the F 1 individuals were tested. Progeny from the cross ofD. melanogaster females withD. simulans males chose pupations sites exactly intermediate between those of the two parental species, while the reciprocal-cross offspring preferred light pupation sites. The pupation site preferences (PSPs) of the hybrids are compatible with a sex-linked locus or loci influencing light-dependent PSP in this pair of species. Examination of light preferences of larvae prior to the late third instar demonstrates that these preference are highly specific, being restricted to the time just before pupation. During the first two larval instarsD. melanogaster is quite photopositive whileD. simulans is comparatively photoneutral. These differences in light-dependent behavior could aid in reducing competition between the two species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 21 (1983), S. 365-374 
    ISSN: 1573-4927
    Schlagwort(e): alcohol dehydrogenase ; NAD+ levels ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Previous studies carried out in mammalian systems indicated that an organism's NAD+/NADH balance is carefully regulated but can be destabilized by dietary stresses. Since Drosophila alcohol dehydrogenase (ADH) uses NAD+ to remove a hydrogen from ethanol in the first step of alcohol catabolism, it is possible that under alcohol stress conditions the in vivo NAD+ levels in Drosophila may decrease. In this study genetically homozygous flies were stressed with maximally sublethal concentrations of ethanol (10%) for periods of up to 24 hr. The results indicate that NAD+ levels do in fact drop by at least 20% in response to ethanol stress. Evidence is presented that suggests that this decrease is the direct result of ADH-mediated catabolism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 65 (1983), S. 173-180 
    ISSN: 1432-2242
    Schlagwort(e): Disruptive selection ; Linkage disequilibrium ; Genetic variance ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Theoretical predictions of changes in variance with disruptive selection have used models of infinitely many genes so the increase in variance was necessarily due to linkage disequilibrium. With small numbers of loci, the disequilibrium is shown still to comprise the major part of the changes in variance. In a replicated experiment with Drosophila melanogaster, disruptive selection was practised for three generations, and this was followed by 5 or 7 generations of random mating. The heritability, as estimated from regression of progeny on parent, rose from 37% to 68% on selection, and subsequently declined to 45% on random mating. Changes of variance can be interpreted invoking the build up of linkage disequilibrium during selection followed by its breakdown upon relaxation. The results agree well with those obtained from Monte Carlo simulation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 87
    ISSN: 1432-2242
    Schlagwort(e): Drosophila ; Enzyme polymorphisms ; Latitudinal clines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The octanol dehydrogenase (Odh) and acid phosphatase (Acph) loci of Drosophila melanogaster are each polymorphic for two electrophoretically detectable alleles. The frequencies of the Odh and Acph alleles have been analysed in populations sampled from up to a 40 ° latitudinal range in each of Australasia, North America and Europe/Asia. Odh S frequency is found to be significantly negatively associated with distance from the equator in all three zones. The relationship of Acph S frequency to distance from the equator is significant and negative in Australasia but neither significant nor consistent in sign in North America and Europe/Asia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 59 (1981), S. 23-24 
    ISSN: 1432-2242
    Schlagwort(e): Genetic sexing ; Alcohol dehydrogenase ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary By incorporating ethanol (4% v/v) into the larval rearing medium of a specially constructed Drosophila melanogaster strain it was possible to produce only male adults; the female larvae died. In this strain, the male determining chromosome was linked with a positive Alcohol dehydrogenase (ADH) allele by a translocation. The females were homozygous for the null allele and hence sensitive to ethanol. This genetic sexing method is discussed in relation to its use in the genetic control of insects.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Bulletin of experimental biology and medicine 92 (1981), S. 1606-1609 
    ISSN: 1573-8221
    Schlagwort(e): mesenteric microcriculation ; cardiac output ; Cardiogreen dilution method ; celiac ganglion ; hypertension
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Bulletin of experimental biology and medicine 95 (1983), S. 412-414 
    ISSN: 1573-8221
    Schlagwort(e): brain ; blood-brain barrier ; hypertension ; angiotensin ; noradrenalin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Bulletin of experimental biology and medicine 96 (1983), S. 1631-1633 
    ISSN: 1573-8221
    Schlagwort(e): smooth muscles ; calcium ; intracellular vesicles ; hypertension
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Bulletin of experimental biology and medicine 91 (1981), S. 18-21 
    ISSN: 1573-8221
    Schlagwort(e): arterial pressure ; hypertension ; capillary circulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 11 (1981), S. 127-133 
    ISSN: 1573-3297
    Schlagwort(e): sexual isolation ; Drosophila ; isofemale strains ; isolation index ; mating propensity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Eight isofemale strains of the cosmopolitan speciesDrosophila immigrans derived from a single location in Melbourne, Australia, were crossed in all combinations to test for sexual isolation. Statistically significant sexual isolation occurred in 12 of 28 crosses, with one strain showing significant isolation from the other seven. There were significantly unequal male mating propensities (relative rates of mating) in 7 of the 28 crosses.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular neurobiology 3 (1983), S. 143-149 
    ISSN: 1573-6830
    Schlagwort(e): electroretinogram ; visual mutants ; visual sensitization ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. Mutations at thestoned locus ofDrosophila melanogaster produce a reversible temperature-sensitive debilitation. At permissive temperatures they also exhibit an unusual jump response to a light-off stimulus. 2. An increase in the amplitude of the off-transient of the electroretinogram (ERG) is associated with this abnormal jump. Both the jump response and the increased amplitude of the off-transient are shown to be dependent on the duration of the light pulse prior to the light-off stimulus. 3. Instoned flies which are light adapted, the jump response, as measured by recording from the indirect flight muscles, is seen to habituate with increasing light-off frequency. This habituation corresponds to the decrease in the amplitude of the off-transient that also occurs with high-frequency stimulation. 4. Another visual mutanttan, removes the off and on-transients of the ERG. 5. The combining of thestoned mutation withtan in thetan, stoned double mutant results in the loss of the jump behavior as well as the partial restoration of the off-transient to an otherwisetan-like ERG. The relationship between the increase in the amplitude of the off-transient instoned flies and the eliciting of the jump response is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular neurobiology 3 (1983), S. 127-141 
    ISSN: 1573-6830
    Schlagwort(e): cyclic adenosine monophosphate ; calmodulin ; phosphorylation ; visual mutants ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. Protein IV from synaptosomal fractions ofDrosophila heads is phosphorylatedin vitro by an endogenous cyclic adenosine monophosphate (cAMP)-dependent protein kinase. Thein vivo phosphorylation of this protein is affected by light. 2. Two visual mutants,tan andstoned, exhibit altered levels ofin vivo phosphorylation of protein IV. Thetan strain shows depressedin vivo levels of phosphorylation of protein IV, whereasstoned shows an increase in thein vivo level of phosphorylation of this same protein. 3. Protein D is phosphorylatedin vitro by an endogenous Ca2+/calmodulindependent protein kinase and has a molecular weight identical to that of protein IV. Thestoned mutant strain shows an increase in thein vivo level of phosphorylation of protein D. 4. The data presented here suggest that the phosphorylation of protein IV, and perhaps D, may play a role in the early processing of visual information in the fly.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 228 (1983), S. 497-509 
    ISSN: 1432-0878
    Schlagwort(e): Drosophila ; Larval salivary glands ; Nuclear “oval bodies” ; Annulate lamellae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Morphological data are presented concerning the single-membrane-bound vesicles (“oval bodies”) associated with the nuclear envelopes of larval salivary gland cells of Drosophila. Data are also presented concerning the existence of cytoplasmic annulate lamellae in these same cells. The mode of formation of these structures, as well as the relationships between them and with other cytoplasmic organelles are described. The possible functional significance of these phenomena is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 233 (1983), S. 305-317 
    ISSN: 1432-0878
    Schlagwort(e): Freeze fracture ; HVEM ; Retina ; Optic neuropile ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The developmental mutant of Drosophila (ora JK84) is characterized by nonfunctional photoreceptor cells (R1–6), while the R7/R8 cells are normal. A fundamental question is: Does the near absence of photosensitive membranes inhibit development of the Rl-6 axons and their synapses at the other end of the cell? The retina and first optic neuropile (lamina ganglionaris) were examined with freeze-fracture technique and high voltage electron microscopy. R1–6 have reduced rhabdomere caps; rhabdomeric microvilli have about 50% of the normal diameter and 20% of the normal length. Affected cells exhibit prominent vacuoles which appear to communicate with some highly convoluted microvillar membranes. Almost no P-face particles (putative rhodopsin molecules) are present in the R1–6 rhabdomeres, and particle densities are lower in R7 than previously reported. Near the rhabdomere caps, microvilli of R1–6 are fairly normal, but at more proximal levels they are greatly diminished in length and changed in orientation, while at still more proximal levels they are lost. R1–6, R7, and R8 axons from each ommatidium are bundled into normal pseudocartridges beneath the basement membrane. No abnormalities are found in the lamina ganglionaris, and all synaptic associations as well as the presumed “virgin” synapses (of R1–6) appear normal. No glial anomalies are present, and R7/R8 axons project through the lamina in the usual fashion. These fine structural findings are correlated with known electrophysiological, biochemical, and behavioral correlates of both sets of photoreceptors (R1–6, and R7/R8).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    ISSN: 1432-0878
    Schlagwort(e): Drosophila ; Oogenesis ; Colchicine ; Microtubules ; Sterility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Adult female fruitflies exposed to colchicine admixed to the culture medium show a series of dosage-related abnormalities that affect oogenesis and may induce sterility. Among the effects observed were decreased fecundity and hatchability of laid eggs, formation of oocytes lacking chorionic appendages, abnormal distribution and diminution in number of yolk spheres, inhibition of oocyte growth and abnormally located oocyte nuclei. Potentially the most significant effect was the development of egg chambers which contained the normal complement of 16 cells but in which all the cells had the nuclear morphology of nurse cells. The approach provides for the first time an experimental means to divert a potential oocyte into the developmental pathway of the nurse cell in a wild-type fly, and hence should be helpful in the elucidation of factors which control oocyte and nurse cell differentiation. In addition, the results serve to expand the usefulness of oogenesis in Drosophila as a model system for the evaluation of drug-induced metabolic-morphologic abnormalities.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 220 (1981), S. 251-262 
    ISSN: 1432-0878
    Schlagwort(e): Meiosis ; Spermiogenesis ; Organ culture ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In vitro spermatogenesis of isolated single spermatocyte cysts of Drosophila hydei was studied by microscopic observations and time-lapse cinematography. Cysts of spermatocytes isolated during diplotene develop as far as the coiling stage of spermatid differentiation. The existence of an interphase between meiosis I and meiosis II is, for the first time, documented. Meiosis, Nebenkern formation, and elongation of spermatids occur just as in D. melanogaster; however, an individualization cone, as described for D. melanogaster, can not be detected.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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