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  • 1
    Electronic Resource
    Electronic Resource
    A linear combination of Gaussian-type orbitals (LCGTO) Xα study of ferrocene: The metal-to-ring distance and ionization potentials (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 5967-5968 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The metal-to-ring distance of ferrocene, Fe(C5H5)2, has been optimized using the LCGTO-Xα method. The resulting distance is 0.047 A(ring) shorter than the experimental value of 1.65 A(ring). The corresponding symmetric stretching frequency of 331 cm−1 shows good agreement with experiment (303 cm−1). The two lowest (Fe 3d derived) ionization potentials are calculated almost degenerate but in reverse order compared to experiment (2A'1 below 2E2). The errors of all these results are discussed in the light of known inadequacies of the local density approximation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450854
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  • 2
    Electronic Resource
    Electronic Resource
    Clock gene mRNA and protein rhythms in the pineal gland of mice (2004)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 19 (2004), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In vertebrates, the rhythmic transcription of clock genes, regulated by their own gene products, provides the basis for self-sustaining circadian clockworks. These endogenous clocks are lost in most mammalian tissues, but not in the central pacemaker of the hypothalamic suprachiasmatic nucleus (SCN). An interesting model system to understand this phylogenetic shift in function of clock gene products is the rodent pineal gland, as its intrinsic clockwork was replaced during evolution by an input-dependent oscillator. By means of immunohistochemistry, immunoblotting and real time PCR, we investigated the day/night expression profiles of all major clock genes and their products in the pineal gland of one melatonin-proficient and one melatonin-deficient mouse strain. All clockwork elements known to be indispensable for a sustained rhythm generation in the SCN were also found in the pineal organ of both mouse strains. Only mPer1 mRNA and PER1 protein accumulation coincides with timecourses of many other pineal genes and their products, which are cyclicAMP inducible. Here, presented data together with the known mechanisms for regulation of the mPer1 gene in the rodent pineal gland forward the idea that in this tissue PER1 may have a trigger function for initiating the cycles of the clockwork's transcriptional/translational feedback loops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0953-816X.2004.03444.x
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  • 3
    Electronic Resource
    Electronic Resource
    Rhythms in clock proteins in the mouse pars tuberalis depend on MT1 melatonin receptor signalling (2005)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 22 (2005), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Melatonin provides a rhythmic neuroendocrine output, driven by a central circadian clock that encodes information about phase and length of the night. In the hypophyseal pars tuberalis (PT), melatonin is crucial for rhythmic expression of the clock genes mPer1 and mCry1, and melatonin acting in the PT influences prolactin secretion from the pars distalis. To examine further the possibility of a circadian clockwork functioning in the PT, and the impact of melatonin on this tissue, we assessed circadian clock proteins by immunohistochemistry and compared the diurnal expression in the PT of wild type (WT), and MT1 melatonin receptor-deficient (MT1–/–) mice. While in the PT of WT mice mPER1, mPER2, and mCRY1 showed a pronounced rhythm, mCRY2, CLOCK, and BMAL1 were constitutively present. Despite reported differences in maximal levels and timing of mCry1, mPer1, and mPer2 RNAs, the corresponding protein levels peaked simultaneously during late day, suggesting a codependency for their stabilization and/or nuclear entry. MT1–/– mice had reduced levels of mPER1, mCRY1, CLOCK and BMAL1, consistent with the earlier reported reduction in mRNA expression of these clock genes. Surprisingly, mPER2-immunoreaction was constitutively low, although mPer2 was rhythmically expressed in the PT of MT1–/– mice. This suggests that mPER2 is degraded due to the reduced levels of its stabilizing interaction partners mPER1 and mCRY1. The results show that melatonin, acting through the MT1, determines availability of the circadian proteins mPER1, mPER2 and mCRY1 and thus plays a crucial role in regulating rhythmicity in PT cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2005.04485.x
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  • 4
    Electronic Resource
    Electronic Resource
    Analysis of cell signalling in the rodent pineal gland deciphers regulators of dynamic transcription in neural/endocrine cells (2001)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 14 (2001), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In neurons, a temporally restricted expression of cAMP-inducible genes is part of many developmental and adaptive processes. To understand such dynamics, the neuroendocrine rodent pineal gland provides an excellent model system as it has a clearly defined input, the neurotransmitter norepinephrine, and a measurable output, the hormone melatonin. In this system, a regulatory scenario has been deciphered, wherein cAMP-inducible genes are rapidly activated via the transcription factor phosphoCREB to induce transcriptional events necessary for an increase in hormone synthesis. However, among the activated genes is also the inhibitory transcription factor ICER. The increasing amount in ICER protein leads ultimately to the termination of mRNA accumulation of cAMP-inducible genes, including the gene for the Aa-nat that controls melatonin production. This shift in ratio of phosphoCREB and ICER levels that depends on the duration of stimulation can be interpreted as a self-restriction of cellular responses in neurons and has also been demonstrated to interfere with cellular plasticity in many non-neuronal systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.0953-816x.2001.01627.x
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  • 5
    Electronic Resource
    Electronic Resource
    Rhythmic variation in β1-adrenergic receptor mRNA levels in the rat pineal gland: circadian and developmental regulation (1998)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 10 (1998), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In the rat pineal gland noradrenaline is released in large quantities from sympathetic nerve endings at the onset of darkness, thereby driving rhythmic melatonin synthesis with elevated levels at night-time. Upon release, noradrenaline interacts with postsynaptic β1-adrenergic receptors to activate the cyclic AMP signalling pathway. Well characterized third messengers of this signalling cascade affect cyclic AMP-inducible genes that are crucially involved in initiation, maintenance and termination of hormone production. Among these third messengers are CREB (cyclic AMP responsive element binding protein) as an activating and ICER (inducible cyclic AMP early repressor) as an inhibitory transcription factor. Because a cyclic AMP-inducible promoter element is present on the β1-adrenergic receptor gene, the expression of the receptor itself may be under control of the cyclic AMP-signalling pathway. By in situ hybridization, Northern blot analysis and RT-PCR we demonstrate a day/night rhythm in β1-adrenergic receptor mRNA in the rat pineal gland with elevated levels during the dark period. As this rhythm persists, under constant darkness but is abolished upon removal of the sympathetic innervation, it is truly circadian. A marked day/night difference in the levels of β1-adrenergic receptor mRNA becomes evident only after postnatal day 10, coinciding with the appearance of a functional cyclic AMP signalling pathway in the rat pineal gland. Furthermore, targeting ICER expression by transfection of pinealocytes with an antisense ICER construct, clearly indicates that the levels of the β1-adrenergic receptor mRNA are regulated by the cyclic AMP-signalling pathway in a feedback mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1998.00309.x
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  • 6
    Electronic Resource
    Electronic Resource
    Transcription factor dynamics and neuroendocrine signalling in the mouse pineal gland: a comparative analysis of melatonin-deficient C57BL mice and melatonin-proficient C3H mice (2000)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 12 (2000), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In rodents, the nocturnal rise and fall of arylalkylamine N-acetyltransferase (AANAT) activity controls the rhythmic synthesis of melatonin, the hormone of the pineal gland. This rhythm involves the transcriptional regulation of the AANAT by two norepinephrine (NE)-inducible transcription factors, e.g. the activator pCREB (phosphorylated Ca2+/cAMP-response element binding protein) and the inhibitor ICER (inducible cAMP early repressor). Most inbred mouse strains do not produce melatonin under standard laboratory light/dark conditions. As melatonin-deficient mice are often the founders for transgenic animals used for chronobiological experimentations, molecular components of neuroendocrine signalling in the pineal gland as an integral part of clock entrainment mechanisms have to be deciphered. We therefore compared calcium signalling, transcriptional events and melatonin synthesis in the melatonin-deficient C57BL mouse and the melatonin-proficient C3H mouse. Pineal glands and primary pinealocytes were cultured and stimulated with NE or were collected at various times of the light/dark (LD) cycle. Changes in intracellular calcium concentrations, the phosphorylation of CREB, and ICER protein levels follow similar dynamics in the pineal glands of both mouse strains. pCREB levels are high during the early night and ICER protein shows elevated levels during the late night. In the C57BL pineal gland, a low but significant increase in melatonin synthesis could be observed upon NE stimulation, and, notably, also when animals were exposed to long nights. We conclude that the commonly used C57BL mouse is not completely melatonin-deficient and that this melatonin-deficiency does not affect molecular details involved in regulating transcriptional events of melatonin synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2000.00990.x
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  • 7
    Electronic Resource
    Electronic Resource
    Nucleofection: a new, highly efficient transfection method for primary human keratinocytes (2005)
    Oxford, UK; Malden, USA : Munksgaard International Publishers
    Experimental dermatology 14 (2005), S. 0 
    Details
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  Transfection is an essential tool for numerous in vitro applications including studies of gene expression, promoter analysis, and intracellular signaling pathways and also for therapeutic strategies such as tissue engineering and gene therapy. However, transfection of primary cells including keratinocytes with common methods such as calcium phosphate, DEAE-dextran, liposome-mediated transfer, electroporation or viral vectors is problematic because of low transfection efficiency and the induction of terminal differentiation. Here we analyzed the use of nucleofection, a new, electroporation-based transfection method that enables the DNA to enter directly the nucleus, for the transfection of keratinocytes. Several different conditions were tested and optimized, resulting in a final transfection efficiency of 56% in primary human epidermal keratinocytes. This efficiency is superior to all non-viral transfection methods reported so far. The number of non-viable keratinocytes after nucleofection was low, varying between 14 and 16%. In contrast to other transfection protocols, nucleofection did not induce terminal differentiation in the transfected keratinocytes. In addition, nucleofection is a fast method, because the results can be analyzed within 7 h. In summary, nucleofection is a fast, easy and highly effective alternative for the transfection of primary human keratinocytes, which offers new opportunities for various research applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0906-6705.2005.00276.x
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  • 8
    Electronic Resource
    Electronic Resource
    Dephosphorylation of pCREB by protein serine/threonine phosphatases is involved in inactivation of Aanat gene transcription in rat pineal gland (2003)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 85 (2003), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The rat pineal gland is a suitable model to investigate neurotransmitter-controlled gene expression, because it is well established that the stimulation of melatonin biosynthesis by norepinephrine (NE) depends on the activation of the gene that encodes arylalkylamine N-acetyltransferase (AANAT), the melatonin rhythm enzyme. The mechanisms responsible for downregulation of Aanat transcription are less clear. In this in vitro study we investigated the role of pCREB dephosphorylation for termination of Aanat gene transcription. Immunosignals for pCREB, strongly induced after NE stimulation, rapidly decreased after withdrawal of NE. The immunoreactivity of the inhibitory transcription factor ICER increased twofold after NE treatment for 6 h, but did not change within 30 min after removal of the stimulus. Application of protein serine/threonine phosphatase (PSP) inhibitors prevented pCREB dephosphorylation and blocked the decreases in Aanat mRNA levels, AANAT protein amount and melatonin biosynthesis all of which occurred rapidly after NE withdrawal. PSPs in the rat pineal gland were characterized by immunocytochemistry and immunoblotting. NE-stimulation for 8 h induced accumulation of PSP1-catalytic subunit (CSU) in pinealocyte nuclei, but did not affect the distribution of PSP2A-CSU. The results identify dephosphorylation of pCREB by PSPs as an essential mechanism for downregulation of Aanat transcription in the rat pineal gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2003.01651.x
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  • 9
    Electronic Resource
    Electronic Resource
    Antisense experiments reveal molecular details on mechanisms of ICER suppressing cAMP-inducible genes in rat pinealocytes (2000)
    Copenhagen : Munksgaard
    Journal of pineal research 29 (2000), S. 0 
    Details
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In the rat pineal gland neuronal signals determine the rhythmic synthesis of the hormone melatonin. Norepinephrine (NE) is the principal neurotransmitter that drives hormone synthesis by activating the cAMP signaling pathway. This activation depends on transcriptional and posttranscriptional regulatory mechanisms. The cAMP-dependent transcriptional regulation of the rate-limiting enzyme of melatonin synthesis, arylalkylamine-N-acetyltransferase (AA-NAT) involves the activating transcription factor (TF) CREB and the inhibitory TF ICER. By silencing elements of this cAMP-dependent neuroendocrine transduction cascade we wished to gain further insight into the role of ICER in the regulation of gene expression in rat pineal gland. Inhibition of specific kinases in primary pinealocyte cultures showed that ICER induction depends pivotally on the activation of cAMP-dependent protein kinase II. Eliminating ICER's impact by transfecting antisense constructs into pinealocytes revealed a predominant β-adrenergic mechanism in regulating a cotransfected CRE-inducible reporter gene and notably, also the endogenous AA-NAT gene. Deciphering molecular details of the cAMP-dependent gene expression in mammalian pinealocytes provides a basis for understanding the general architecture of this signaling pathway that serves adaptive processes ubiquitously in the organism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-079X.2000.290104.x
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  • 10
    Electronic Resource
    Electronic Resource
    Deep lamellar keratoplasty with the guided trephine system for transplanting fullthickness donor tissue (1998)
    Springer
    Der Ophthalmologe 95 (1998), S. 748-754 
    Details
    ISSN: 1433-0423
    Keywords: Key words Deep lamellar keratoplasty • Penetrating keratoplasty • Guided trephine system • Microkeratome ; Schlüsselwörter Tiefe lamelläre Keratoplastik • Perforierende Keratoplastik • Geführtes Trepan-System • Mikrokeratom
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Fragestellung: Obwohl die tiefe lamelläre Keratoplastik (TLKP) im Vergleich zur perforierenden Keratoplastik (PKP) weniger invasiv ist, ist diese Technik kaum verbreitet. Wir untersuchten, ob die von uns durchgeführte Technik der TLKP eine stabile Visusverbesserung ermöglicht. Patienten und Methode: Bei 33 Augen mit superfizieller Hornhautpathologie oder fortgeschrittenem Keratokonus wurde eine 8,0 mm TLKP durchgeführt. Das Spendergewebe war geeignet für eine PKP. Die Spenderscheibe wurde auf der Vorderkammerbank des geführten Trepan-Systems (GTS) gewonnen. Die Empfängerhornhaut wurde auf eine Tiefe von 680 μm vortrepaniert und das Empfängerbett wurde manuell präpariert. Nach Entfernung des Endothels wurde das Transplantat in ganzer Dicke übertragen und mit einer 10 × 0 doppelten anti-torque-Naht eingenäht. Postoperativ wurden Kortison-Antibiotika-Augentropfen gegeben. Ergebnisse: Der postoperative Verlauf war in der gesamten Serie ohne Komplikationen. Der mittlere bestkorrigierte Brillenvisus (BSCVA) lag präoperativ bei 0,29 ( ± 0,21), 0,1 ( ± 0,11) nach 1 Woche, 0,33 ( ± 0,14) nach einem Monat, 0,5 ( ± 0,13) nach 6 Monaten, 0,61 ( ± 0,16) nach einem Jahr und 0,63 ( ± 0,16) nach 2 Jahren. Es wurden 2 Untergruppen beobachtet: in einer Gruppe (87 %) verbesserte sich der BSCVA auf einen durchschnittlichen Wert von 0,67 ( ± 0.07) nach 6 Monaten. In der zweiten Gruppe (BSCVA ≤ 0,25 nach 6 Monaten) verblieb der mittlere BSCVA auf 0,2 ( ± 0.04) nach einem Jahr. Der mittlere Astigmatismus betrug präoperativ 2,93 ( ± 1,62) Dpt, 2,69 ( ± 1,18) dpt nach 1 Monat, 2,09 ( ± 1,07) dpt nach 1 Jahr und 2,22 ( ± 1,11) dpt nach 2 Jahren. Es traten keine Abstoßungsreaktionen auf. Schlußfolgerung: Die hier vorgestellte Technik gewährleistet eine optimale Paßform von Spenderscheibe und Transplantatbett. Die Trennung von Empfänger- und Spenderstroma verhindert eine Heilung im Interface. Die TLKP ist ein sicheres Verfahren und eröffnet bei superfizieller Hornhautpathologie eine echte Alternative zur PKP.
    Notes: Background: Despite the fact that deep lamellar keratoplasty (DLKP) is less invasive than to penetrating keratoplasty (PKP), this procedure is rarely performed. We therefore investigated whether or not the DLKP technique we employed can achieve stable improvement of visual acuity. Materials and methods: Thirty-three eyes underwent TLKP for treatment of superficial corneal pathology. The donor tissue transplanted was suitable for PKP. The donor lenticule was obtained on the artificial chamber of the guided trephine system (GTS). The recipient cornea was trephined with the same trephine to a depth of 680 μm. Manual dissection was performed with a bevel-up blade. The donor lenticule with the endothelium peeled off was then sutured in with a 10 × 0 nylon double-running antitorque suture. Cortisone-antibiotic eye drops were administered postoperatively. Results: Throughout the series no complications occurred. The mean best corrected visual acuity (BSCVA) over glasses was 0.29 ( ± 0.21) preoperatively, 0.1 ( ± 0.11) at 1 week, 0.33 ( ± 0.14) at 1 month, 0.5 ( ± 0.13) at 6 months, 0.61 ( ± 0.16) at 1 year and 0.63 ( ± 0.15) at 2 years. Clinically, we observed two subpopulations. In the first group of 87 % of the cases, mean BSCVA was 0.67 ( ± 0.07) at 6 months. The remaining cases (BSCVA ≤ 0.25 at 6 months) achieved a mean BSCVA of only 0.2 ( ± 0.04) at 1 year. Mean corneal astigmatism measured 2.93 D ( ± 1.62) preoperatively, 2.69 D ( ± 1.18) at 1 month, 2.09 D ( ± 1.07) at 1 year, and 2.22 D ( ± 1.11) at 2 years. We did not observe any graft rejection. Conclusion: The technique reported for DLKP provides excellent matching of donor lenticule and recipient bed. Separation of donor and recipient stroma prevents interface healing. DLKP appears to be a safe procedure for the surgical treatment of superficial corneal pathology and may offer a clinically applicable alternative to PKP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003470050347
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