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  • 2000-2004
  • 1995-1999  (4)
  • 1990-1994  (5)
  • 1905-1909
  • Cell & Developmental Biology  (5)
  • Human  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Differential effects of diazepam and lorazepam on repetition priming in healthy volunteers (1992)
    Springer
    Psychopharmacology 108 (1992), S. 371-379 
    Details
    ISSN: 1432-2072
    Keywords: Benzodiazepines ; Diazepam ; Human ; Lorazepam ; Memory ; Repetition priming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of two benzodiazepines, diazepam (15 or 20 mg orally) and lorazepam (1.75 or 2.5 mg orally), and a placebo on explicit memory, lexical priming and perceptual priming were assessed using a freerecall, a word-completion and a picture-completion test. The picture-completion test included two different study conditions intended to manipulate the magnitude of the priming effect. Sixty healthy volunteers took part in this double-blind study. Free-recall performances were altered by both drugs. Lorazepam impaired word-completion and picture-completion performance, whereas diazepam only exhibited a deleterious effect on the more sensitive of the two measures of the picture-completion test. These results indicate that the two benzodiazepines have differential amnestic effects. It is suggested that these differential effects could be accounted for by a different cortical distribution of the two benzodiazepines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245126
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  • 2
    Electronic Resource
    Electronic Resource
    Lorazepam impairs perceptual integration of visual forms: a central effect (1996)
    Springer
    Psychopharmacology 126 (1996), S. 260-270 
    Details
    ISSN: 1432-2072
    Keywords: Benzodiazepine ; Lorazepam ; Human ; Visual perception ; Oculomotor balance ; Integration processes ; Symmetry perception
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies have shown a lorazepam effect on visual perception. We tested whether this impairment resulted from a peripheral effect induced by benzodiazepines. A first experiment showed that a single dose of lorazepam induces an oculomotor imbalance without impairing visual acuity or accommodation. In a second experiment, we tested whether the impairment induced by lorazepam on visual perception still occurred in monocular vision. Subjects matched incomplete forms controlled on the spacing and alignment of their local contour elements. A reference object was first displayed and followed by two laterally displayed objects, a target and a distractor. The distractor was the mirror-reversed version of the target. Performance was impaired in the lorazepam group when the reference was an incomplete form with a spacing of 10.8' or 22.2' of arc. These results were not correlated with sedation. They confirm that lorazepam has a central deleterious effect on visual perception. A posthoc analysis also suggested that lorazepam-treated subjects used asymmetry in the stimuli as a compensatory strategy. This result is discussed in relation to previous hypotheses about the physiological mechanisms that determine the effects of lorazepam on visual perception.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246456
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Lorazepam and diazepam effects on memory acquisition in priming tasks (1994)
    Springer
    Psychopharmacology 115 (1994), S. 397-406 
    Details
    ISSN: 1432-2072
    Keywords: Benzodiazepine ; Diazepam ; Human ; Lorazepam ; Memory ; Perceptual priming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Unlike diazepam, lorazepam has repeatedly been shown to impair perceptual priming as well as explicit memory. To determine whether this deleterious effect was due to an impairment in acquisition of information, 60 healthy volunteers were randomly assigned to five treatment groups (placebo, lorazepam 0.026 or 0.038 mg/kg, diazepam 0.2 or 0.3 mg/kg) and successively performed perceptual priming tasks and a free-recall task. Priming performance on information learned before or 2 h after drug administration, i.e. at the peak concentration of lorazepam, was assessed under the influence of the drugs, using a picture-fragment and a word-stem completion task. Free-recall performance was altered by both drugs. Lorazepam decreased priming performance when information was acquired after, but not before, drug administration, indicating that the drug alters the acquisition of information. Lorazepam also impaired the ability to identify fragmented pictures, but there was no evidence that this perceptual effect accounts for the priming impairment. Surprisingly, diazepam also decreased priming when information was acquired after drug administration, suggesting that, at least in certain circumstances, the two benzodiazepines may exert similar effects on priming measures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245083
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of haloperidol and amisulpride on motor and cognitive skill learning in healthy volunteers (1997)
    Springer
    Psychopharmacology 131 (1997), S. 329-338 
    Details
    ISSN: 1432-2072
    Keywords: Key words Haloperidol ; Amisulpride ; Human ; Cognitive ; Motor ; Skill learning ; Memory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of a typical neuroleptic, haloperidol (1 and 2 mg orally), of an atypical neuroleptic, amisulpride (50 and 100 mg) and of a placebo on motor and cognitive skill learning were assessed in 60 healthy volunteers using repeated testing on the Tower of Toronto puzzle. Subjects were asked to solve three blocks of eight trials and, at distance from drug administration, a fourth block. The puzzle was connected to a computer in order to obtain a precise timing of individual moves. Two components of cognitive skill learning were assessed, the ability to learn to solve the puzzle and the acquisition of a problem-solving routine. Subjective feelings of effort and automatisation of the task were assessed using a questionnaire. Like placebo-treated subjects, neuroleptic-treated subjects were able to acquire a motor skill, to learn to solve the puzzle and to acquire a routine. However, haloperidol 2 mg-treated subjects needed significantly more moves to solve the puzzle in blocks 3 and 4, some of them having routinised a non-optimal solution. A significant cognitive slowing was observed in the haloperidol 1mg group in block 4. The performance pattern and verbal reports suggested that haloperidol impaired the higher cognitive functions such as the ability to shift from one strategy to another and/or to assess one’s performance accurately, possibly leading to the development of compensatory strategies. The only deleterious amisulpride effect was a cognitive slowing in block 4, which was observed in the lower dose group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050300
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    A complex composed of at least two HeLa nuclear proteins protects preferentially one DNA strand of the simple (gt)n(ga)m containing region of intron 2 in HLA-DRB-genes (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 56 (1994), S. 74-85 
    Details
    ISSN: 0730-2312
    Keywords: DNA/protein interaction ; simple repetitive DNA ; binding domain ; conformation changes ; intron 2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Electrophoretic mobility shift assays reveal that HeLa neuclear proteins bind fast and with measurable affinity to target DNAs containing mixed simple repetitive (gt)n(ga)m stretches. Preincubation of the proteins at elevated temperature prevents the formation of the major DNA/protein complex in favour of several distinct assemblies. A similar pattern of retarded bands was observed employing higher salt concentrations in binding reaction. Thus conformational changes of different proteins appear to influence the complex rather than alternating DNA structures. Separation of the total nuclear extract into a water soluble and an insoluble protein fraction leads to a complete loss of target DNA bindinlg capability of the fractions. The binding capacity is restored by combining the two fractions suggesting that at least two protein components are necessary to form a complex with the target sequence. The proteins can be differentiated into head sensitive, water soluble and temporary stable, water insoluble, respectively. Furthermore, specifically binding polypeptides are not detectable by Southwestern analyses, probably because the essential components are separated during electrophoresis. DNase 1 footpoint analyses yield four different protein binding regions only on the (gt)n(ga)m harbouring strand. The footprints cover larger portions of the mixed simple repeat in addition to a portion 5′ of the (gt)n part. Hence at lealst two nuclear protein components of unknown biological function have to be present simultaneously to protect preferentially the (gt)n(ga)m-containing strand intron 2 in HLA-DRB genes
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240560112
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of chromatin-condensing proteins during spermiogenesis in a neogastropod mollusc (Murex brandaris) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 440-452 
    Details
    ISSN: 1040-452X
    Keywords: Spermiogenesis ; Nuclear condensation ; Chromatin ; Protamines ; Protein-precursors ; Neogastropod mollusc ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: During the process of chromatin cndensation in the spermiogenesis of the neogastropod mollusc Murex brandaris, the nuclear protein complement undergoes a complex series of changes. These changes lead to the appearance of three small protamines in the ripe sperm nuclei. We have characterized this system electrophoretically and at the compositions with antibodies elicited against a specific spermatozoan protamine. Our results indicate that the complex pattern of chromatin condensation during spermiogenesis in this species (M. brandaris) may be modulated by a series of post-translational (and intranuclear) modifications of DNA-interacting proteins, such as precursors to the sperm protamines. The amino acid composition of each sperm protamine is remarkably simple (lys + arg + gly ≥96 mol%). This system of spermiogenic/spermatozoal proteins in the neogastropod M. brandaris clearly differs from that in patellogastropods and archaeogastropods, and it may be helpful in understanding evolutionary changes in the chromatin condensation pattern during the spermiogenesis of gastropod molluscs. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380412
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  • 7
    Electronic Resource
    Electronic Resource
    Immunoelectron microscopical distribution of histones H2B and H3 and protamines in the course of mouse spermiogenesis (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 259-267 
    Details
    ISSN: 1059-910X
    Keywords: Ultrastructure ; Immunocytochemistry ; Chromatin structure ; Nuclear proteins ; Testis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have followed the fine structural distribution of two nucleosomal core histones, H2B and H3, and of protamines in the course of mouse spermiogenesis by means of specific antibodies and ultrastructural immunocytochemistry.Our results demonstrate that the nuclear labeling density of histone H2B decreases during steps 6-8 and then increases again in step 9-10 spermatids, while the labeling for histone H3 is constant throughout this period. In step 12 spermatids, the anti-H2B antibody labels mainly the central area of the nucleus. The first signs of protamine labeling are present in step 12 spermatids, where the gold grains can be found over the periphery of the nucleus. Later on, protamine labeling constantly increases and, by the end of spermiogenesis, the whole nucleus is labeled.We suggest that the morphological and structural differences between the central area and the periphery of mouse spermatids are, at least partly, due to a difference in the protein moiety associated with DNA. The central area, which is peculiar to the mouse and has been previously considered as a focus of chromatin condensation, represents, however, the last nuclear region containing histones and consequently the last area where the substitution of histones by protamines takes place.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070200305
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  • 8
    Electronic Resource
    Electronic Resource
    P-glycoprotein stability is affected by serum deprivation and high cell density in multidrug-resistant cells (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 163 (1995), S. 538-544 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The control of P-glycoprotein (Pgp) expression in multidrug-resistant cells (MDR) is complex and may be regulated at different levels. We have investigated Pgp stability in four different human and hamster MDR cell lines. Using a pulse-chase procedure we show that Pgp half-life is between 14 and 17 h in all these cell lines when they are growing exponentially. However, in the presence of a low level of serum, Pgp half-life is increased four to sixfold. A similar effect is observed when the cell cultures are maintained in high cell density. The increased Pgp stability appears to be differently regulated as serum deprivation results in a general enhanced degradation of total cytoplasmic and membrane proteins. Moreover, the observed serum effect suggests the involvement of growth factors in the control of Pgp stability. These findings suggest that protein stability may be an important factor in the regulation of Pgp expression. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041630314
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  • 9
    Electronic Resource
    Electronic Resource
    Ubiquitin in homeostasis, development and disease (1995)
    New York, NY : Wiley-Blackwell
    BioEssays 17 (1995), S. 677-684 
    Details
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ubiquitin is the most phylogenetically conserved protein known. This 8,500 Da polypeptide can be covalently attached to cellular proteins as a posttranslational modification. In most cases, the addition of multiple ubiquitin adducts to a protein targets it for rapid degradation by a multisubunit protease known as the 26S proteasome. While the ubiquitin/26S proteasome pathway is responsible for the degradation of the bulk of cellular proteins during homeostasis, it may also be responsible for the rapid loss of protein during the programmed death of certain cells, such as skeletal muscle during insect metamorphosis. In addition, alterations in the expression and regulation of ubiquitin may play significant roles in pathological disorders. For example, dramatic increases in ubiquitin and ubiquitin-protein conjugates are observed in a wide variety of neurodegenerative disorders, including Alzheimer's disease. Patients suffering from the autoimmune disease systemic lupus erythematosus generate antibodies reacting with ubiquitin and ubiquitinated histones. At present, it is not known whether these changes in ubiquitin expression and regulation initiate pathological changes in these diseases or if they are altered as a consequence of these disorders.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bies.950170804
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