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  • 1
    Electronic Resource
    Electronic Resource
    Inhibition of Sexual Maturation in Male Rats by Melatonin: Evidence Linking the Mechanism of Action to Changes in the Regulation of Hypothalamic Neuropeptide Y (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neuroendocrinology 4 (1992), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Activation of gonadotrophin-releasing hormone (GnRHJ pathways is a pivotal event in the process of sexual maturation, however the regulatory influences that precipitate this change and lead to the onset of puberty remain poorly understood. Recent studies indicate that neuropeptide Y (NPY) may participate in the regulation of luteinizing hormone secretion by modulating the pattern of GnRH secretion and by directly altering the pituitary responsiveness to GnRH stimulation. To determine whether NPY plays a role in puberty-associated changes in hypothalamic function, levels of NPY-like immunoreactivity (NPY-IR) were measured in a fragment of the hypothalamus encompassing the median eminence and medial portion of the arcuate nucleus (ME-AN), and also in the remainder of the hypothalamus from male rats of different ages. To identify changes in hypothaiamic NPY linked to the process of sexual development, the effect of delaying sexual maturation by daily afternoon administration of 100 μg melatonin (MT) from 20 to 40 days was investigated. In the hypothalamus and ME-AN, total NPY content increased progressively with age. Expressed as a concentration (fmol/μg extracted protein), peak values for the ME-AN (55.4 ± 7.0) were observed at 30 days of age followed by a decline to lower levels (30.2 ± 1.9) at 40 days. Daily afternoon administration of MT from 20 days of age resulted in significant increases (P〈0.01) in the levels of NPY-IR in the ME-AN compared to control values at 30 and 40 days of age. MT was without effect on NPY-IR levels in the remainder of the hypothalamus. When MT was administered in the early morning, a procedure which does not delay sexual maturation, NPY-IR values for the ME-AN region were not different from control rats indicating that the MT-induced changes in NPY were related to the effects on sexual maturation. Using pituitary luteinizing hormone content and seminal vesicle weight as indices of sexual development, significant inverse correlation coefficients (P〈0.001) between these parameters and the NPY concentration in the ME-AN were observed (r =−0.79 and −0.70, respectively). From published data it is not possible to conclude whether the main effects of NPY are exerted at the hypothalamic or pituitary level. However, the changes in the NPY content of the ME-AN observed during the onset of puberty, and the influence of MT on these changes, support assertions that NPY is involved in the regulation of sexual maturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2826.1992.tb00337.x
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  • 2
    Electronic Resource
    Electronic Resource
    Complement activation on the nasal mucosal surface - a feature of the immediate allergic reaction in the nose (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 49 (1994), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Complement is a system of functionally linked serum proteins that interact to exert biologic effects in inflammatory and immunologic processes. As part of a larger study with a potential topical antiallergic drug, we measured C3a des Arg and C5a des Arg in 13 patients with seasonal allergic rhinitis and in five nonatopic controls after placebo treatment. After 1 week of placebo treatment, a nasal allergen challenge with increasing doses of pollens was performed in both allergic subjects and controls. A symptom score method was used, and in returned nasal lavage fluid, the activity of C3a des Arg and C5a des Arg was measured. We found that allergen challenge in the allergic subjects induced nasal symptoms concomitantly with increased levels of C3a des Arg and C5a des Arg (P 〈0.05). No increases either in symptoms or in the very low base-line levels of C3a des Arg and C5a des Arg were observed in the nonallergic controls. We conclude that the activation of the complement cascade is one part of the vasculature exudative response during the immediate allergic reaction in the upper airways. Because of their biologic potency, these proteins may be an essential part of the exudative response which perpetuates the ongoing inflammatory reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1398-9995.1994.tb02656.x
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  • 3
    Electronic Resource
    Electronic Resource
    FACILITATING INTIMACY: INTERVENTIONS AND EFFECTS (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of marital and family therapy 20 (1994), S. 0 
    Details
    ISSN: 1752-0606
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Psychology
    Notes: The Present study investigated by effects of two sets of marital interventions taken from Emotionally Focused Therapy (EFT) and Cognitive Marital Therapy (CMT) on level of marital intimacy, dyadic trust, and dyadic adjustment. It was hypothesized that both EFT and CMT would have a positive effect on levels of intimacy, trust, and adjustment as compared to a wait-list control group and that there would be a differential effect in favor of EFT as compared to CMT. Thirty-six couples free of marital distress and seeking to enhance theor intimate relationship were randomaly assigned to EFT, CMT, or a wai-list control group. Therapists' interventions were monitored and found to be faithfully implemented. Groups were equivalent on demographic variables and the quality of the therapeutic alliance. Both EFT and CMT group posttest means were found to be significantly higher than controls on the self-report measures of intimacy, Observational measures of intimacy revealed differential effects in favor of EFT as comopared to CMT at posttest. At a 10-week follow-up, EFT group means were significantly higher than CMT on self-reported intimacy and adjustment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-0606.1994.tb01008.x
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  • 4
    Electronic Resource
    Electronic Resource
    Schlieren diagnostics of the plasma focus using a mode-locked dye laser (1991)
    Springer
    Applied physics 53 (1991), S. 92-96 
    Details
    ISSN: 1432-0649
    Keywords: 42.80 Nw ; 52.55Ez ; 42.60Eb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract By means of schlieren techniques the discharge characteristics of a 1 kJ plasma focus device were investigated. Different inner electrodes were used with diameters ranging from 4 mm to 10 mm and the working gases were hydrogen and neon. A spatial resolution in the μm region and a temporal resolution in the ps region could be achieved using a mode-locked dye laser as schlieren light source. During the run-down and collapse phase of the discharge the spatially and temporally resolved electron density was determined from the schlieren pictures by means of numerical simultations of the beam deflection by the plasma. During the focus phase the temporal development of the plasma could be observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325537
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  • 5
    Electronic Resource
    Electronic Resource
    Leukotriene B4 and platelet-activating factor in human skin (1992)
    Springer
    Archives of dermatological research 284 (1992), S. S12 
    Details
    ISSN: 1432-069X
    Keywords: Leukotriene B4 ; Platelet-activating factor ; Cutaneous inflammation ; Eicosanoids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Acute inflammatory reactions are characterized by leukocyte infiltration associated with increases in vascular permeability and in local blood flow. Leukocyte infiltration can be induced by chemotactic factors such as leukotriene B4 (LTB4) and paf-acether (formely known as platelet-activating factor) that can be generated within inflammatory lesions. Vascular permeability and increase in blood flow are also affected by LTB4 and paf-acether, as well as by several other substances, including histamine and prostaglandins. Derived from arachidonic acid via the 5 lipo-oxygenase pathway, LTB4 is one of the most potent leukocyte chemotactic substances known. Intradermal injections of LTB4 induce dermal neutrophil infiltration in animal models and in humans. Topical application of LTB4 to human skin induces intraepidermal micro-abscesses containing numerous intact neutrophils. LTB4 has been found to be increased in psoriatic lesions, but its synthesis by epidermal cells remains undecided. Like other leukotrienes, LTB4 can stimulate DNA synthesis in cultured human epidermal keratinocytes. However, receptors for LTC4 but not for LTB4 have been found on human keratinocytes in culture. Paf-acether is an ether-linked phospholipid identified as 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine and is considered to be one of the most potent mediators of acute allergic and inflammatory reactions. For instance, intradermal injection of pafacether induces inflammatory events such as neutrophil infiltration and increase in vascular permeability. Recent data suggest that cutaneous cells, such as fibroblasts and keratinocytes, are capable of producing paf and that paf is released during the development of allergic cutaneous reactions. Paf is also increased in psoriatic lesions, and it is tempting to speculate that paf may contribute to the development of various skin disorders with acute and chronic skin inflammation. In the future, LTB4 and paf antagonists might help in providing an answer to the hypothesis that these two mediators may have a key role in many chronic inflammatory skin diseases and may offer new prospects for topical and systemic treatments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00638234
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  • 6
    Electronic Resource
    Electronic Resource
    The ATP synthase (F0−F1) complex in oxidative phosphorylation (1992)
    Springer
    Cellular and molecular life sciences 48 (1992), S. 351-362 
    Details
    ISSN: 1420-9071
    Keywords: ATP synthase ; oxidative phosphorylation ; mitochondrial ATPase ; bacterial ATPase ; F0-F1-ATPase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The transmembrane electrochemical proton gradient generated by the redox systems of the respiratory chain in mitochondria and aerobic bacteria is utilized by proton translocating ATP synthases to catalyze the synthesis of ATP from ADP and Pi. The bacterial and mitochondrial H+-ATP synthases both consist of a membranous sector, F0, which forms a H+-channel, and an extramembranous sector, F1, which is responsible for catalysis. When detached from the membrane, the purified F1 sector functions mainly as an ATPase. In chloroplasts, the synthesis of ATP is also driven by a proton motive force, and the enzyme complex responsible for this synthesis is similar to the mitochondrial and bacterial ATP synthases. The synthesis of ATP by H+-ATP synthases proceeds without the formation of a phosphorylated enzyme intermediate, and involves co-operative interactions between the catalytic subunits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923429
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  • 7
    Electronic Resource
    Electronic Resource
    Weyl's problem for the spectral distribution of Laplacians on P.C.F. self-similar fractals (1993)
    Springer
    Communications in mathematical physics 158 (1993), S. 93-125 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract We establish an analogue of Weyl's classical theorem for the asymptotics of eigenvalues of Laplacians on a finitely ramified (i.e., p.c.f.) self-similar fractalK, such as, for example, the Sierpinski gasket. We consider both Dirichlet and Neumann boundary conditions, as well as Laplacians associated with Bernoulli-type (“multifractal”) measures onK. From a physical point of view, we study the density of states for diffusions or for wave propagation in fractal media. More precisely, let ϱ(x) be the number of eigenvalues less thanx. Then we show that ϱ(x) is of the order ofx d S/2 asx→+∞, where the “spectral exponent”d S is computed in terms of the geometric as well as analytic structures ofK. Further, we give an effective condition that guarantees the existence of the limit ofx −d S/2ϱ(x) asx→+∞; this condition is, in some sense, “generic”. In addition, we define in terms of the above “spectral exponents” and calculate explicitly the “spectral dimension” ofK.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02097233
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  • 8
    Electronic Resource
    Electronic Resource
    Internalization of surface HLA-DR molecules by human epidermal Langerhans cells: analysis by flow cytometry and confocal microscopy (1994)
    Springer
    Cell biology and toxicology 10 (1994), S. 367-373 
    Details
    ISSN: 1573-6822
    Keywords: epidermal Langerhans cells ; flow cytometry ; laser scanning confocal microscopy ; MHC class II molecules ; receptor-mediated endocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Langerhans cells (LC) play a pivotal role in antigen processing and presentation to T cells during delayed-type hypersensitivity reaction in the skin. Antigen presentation involves the interaction between the class II molecules of MHC (HLA-DR) expressed by LC and T receptor of CD4+ T lymphocytes. It is now recognized that class II molecules are internalized into LC and can be associated with processed immunogenic peptides. This process involves receptor-mediated endocytosis. The aim of this study was to investigate the time-course of endocytosis of HLA-DR by freshly isolated human LC. Epidermal cells, obtained from normal skin samples, were labeled by indirect immunofluoresence using anti-HLA-DR monoclonal antibodies (MAb). The cell suspension was incubated at 37°C for different periods (15, 30, 45, 60 and 90 min) and then analyzed by flow cytometry and confocal microscopy. Flow cytometry analysis showed decreased HLA-DR molecule expression by LC after incubation at 37°C. Confocal microscopic analysis showed different strain patterns depending on the incubation time: (1)T=0, continuous peripheral staining; (2)T=15 min, patchy peripheral staining; (3)T=30 min, patches or intracellular vesicular staining; (4)T=45 min, intracellular vesicular staining; (5)T=60 min, diffuse intracellular staining; (6)T=90 min, aggregated staining. In our study model, flow cytometry provides quantitative information for the HLA-DR endocytosis, whereas confocal microscopy provides qualitative results concerning the intracellular distribution of internalized HLA-DR molecules. The use of the two complementary techniques allows us to characterize the spontaneous endocytosis of HLA-DR molecule by freshly isolated LC. Thisin vitro study model might be useful for testing the sensitizing potential of different chemical substances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00755784
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  • 9
    Electronic Resource
    Electronic Resource
    D-E classfiication of the local extensions ofsu 2 current algebras (1992)
    Springer
    Theoretical and mathematical physics 92 (1992), S. 1063-1074 
    Details
    ISSN: 1573-9333
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract A method is developed for constructing single valued rational 4-point functions of primary fields for su2 conformal current algebra satisfying the Knizhnik-Zamolodchikov equation. For integer conformal dimensions Δ these rational solutions are proven to be in one-to-one correspondence with non-diagonal modular invariant partition functions of the D-even and E-even series of the ADE classification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01017084
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