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  • 1
    Electronic Resource
    Electronic Resource
    Synapse-like contacts between axons of the pineal tract and the subcommissural organ in Rana perezi (Anra) and their absence in Carassius auratus (Teleostei): ultrastructural tracer studies (1993)
    Springer
    Cell & tissue research 273 (1993), S. 317-325 
    Details
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Pineal organ ; Innervation ; Horseradish peroxidase (HRP) ; Synaptoid contacts ; Carassius auratus (Teleostei) ; Rana perezi (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The present study was designed to investigate the controversial subject of the existence of a neural input from the pineal organ via the pineal tract to the subcommissural organ (SCO) in teleosts and anurans. Horseradish peroxidase was injected into the pineal organ and pineal tract of Carassius auratus and Rana perezi. Within the pinealofugal fibers the tracer was visualized at the light-and electron-microscopic levels either by immunocytochemistry using an anti-peroxidase serum, or by revealing the enzymatic activity of peroxidase. In both species, labeled myelinated and unmyelinated fibers of the pineal tract were readily traced by means of electron microscopy. In R. perezi, numerous terminals contacting the SCO cells in a synapse-like (synaptoid, hemisynaptic) manner bore the label, whereas a different population of endings was devoid of the tracer, indicating that in this species the SCO receives a dual neural input, one of pineal origin, the other of unknown source and nature. In the SCO of C. auratus, neither labeled nor unlabeled synapse-like contacts were found. Thus, in this latter species, a direct neural input to the SCO is missing. It is concluded that the secretory activity of the SCO can be controlled by different mechanisms in different species, and that more than one neural input mechanism may operate in the same species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312834
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  • 2
    Electronic Resource
    Electronic Resource
    The spatio-temporal pattern of photoreceptor degeneration in the aged rd/rd mouse retina (1996)
    Springer
    Cell & tissue research 284 (1996), S. 193-202 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Retinal degeneration ; Cone photoreceptors ; Rod photoreceptors ; Circadian photoreceptors ; Homozygous rd/rd mice (C57BL/6J strain)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Photoreceptor degeneration in the retina of the rd/rd (retinal degeneration) mice has been studied using immunocytochemistry with antisera against cone- and rod-opsin. The rd/rd mice exhibited different regional specific rates of degeneration for rods and cones. As early as postnatal day 25, cells labelled with the rod-opsin and cone-opsin antisera disappeared preferently from the central retina. Whereas in the inferior half of the retina, degeneration subsequently proceeded towards the periphery, this did not occur in the dorsal hemisphere. By the age of 100 days, many cells immunoreactive for the cone-opsin antiserum and a few cells immunoreactive for the rod-opsin antiserum were located in an area of the dorsal retina. The ventral retina lacked labelled elements at this age. Finally, rd/rd mice at one year or 600 days of age contained a similar number of cone-opsin immunopositive cells (approximately 2000–2800 cells), occupying almost the same area in the retina as that found at 100 days of age. A photoreceptor candidate for the entrainment of non-visual photoreception probably remains in the cone population in aged rd/rd mice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050579
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  • 3
    Electronic Resource
    Electronic Resource
    An immunocytochemical study of encephalic photoreceptors in three species of lamprey (1997)
    Springer
    Cell & tissue research 288 (1997), S. 267-278 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Arrestin ; CSF-contacting neurons ; Deep brain photoreceptors ; Extraretinal photoreceptors ; Opsin ; Parapineal ; Pineal ; Photoreceptors ; S-antigen ; Transducin ; Petromyzon marinus ; Lampetra fluviatilis ; Ichthymyzon uricuspis (Lyclostomata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The extraretinal and extrapineal photoreceptors of three species of adult lamprey, sea lamprey (Petromyzon marinus), river lamprey (Lampetra fluviatilis) and silver lamprey (Ichthyomyzon unicuspis) were studied using antibodies raised against photoreceptor rod and cone opsins, α-transducin and arrestin. In all three species cells in the pineal organ (P), parapineal organ (PP), nucleus preopticus (T5), nucleus commissurae postopticae (D8), nucleus ventralis hypothalami (D10) and nucleus dorsalis hypothalami (D11) were labelled by one or more of the anti-opsin antibodies. In addition, anti-arrestin antibodies labelled cells within the D8 and anti-α-transducin antibodies labelled cells within the pineal complex and hypothalamus (primarily D8 and/or D10). A more variable and species dependent pattern of opsin, arrestin and α-transducin labelling was observed within the nucleus commissurae postinfundibularis (D12) in an area comprising the nucleus dorsalis thalami pars subhabenularis (D4sh) and nucleus dorsalis thalami pars caudalis/nucleus commissurae posterioris (D4c/M1), and in the proximity of the second Müller cells in the ventrocaudal diencephalon (2.MZ/M6). The majority of the neurons labelled within the pineal and parapineal organs and hypothalamus were periventricular with clear cerebrospinal fluid contacts (CSF-contacting neurons). Labelled neurons in the epithalamic (D4sh and D4c/M1) and caudal diencephalon (2.MZ/M6) had no obvious ventricular contacts. We speculate that the ”primitive” vertebrate brain of lampreys represents an ancestral condition in which different populations of encephalic photoreceptors are associated with different behavioural and physiological responses. Image-forming vision needs an eye, but irradiance detection does not require a specialised organ. Rather the photoreceptors could be closely associated with their effector systems within the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050812
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  • 4
    Electronic Resource
    Electronic Resource
    New functionals for correlation energy deduced in the framework of the correlation factor approach (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 61 (1997), S. 313-323 
    Details
    ISSN: 0020-7608
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The general characteristics of two-body density functionals (TBDF) are explored and two new correlation energy functionals are derived using the correlation factor approach. The optimization of the parameters entering the above functionals requires exact and accurate atomic correlation energies (ACE). We revised the ACE values in the literature and obtained a new set of “exact” ACE for atoms with 2 ≤ Z ≤ 10. Unfortunately, there exist some inaccuracies in the ACE values of the second-row atoms, which make unsuitable the inclusion of them in the optimization. The ACE calculated for the first period with the above functionals, using the optimized sets of parameters, are in excellent agreement with the exact ones, while the corresponding values calculated for the second-row atoms are between the precision margins estimated by us for the exact values. © 1997 John Wiley & Sons, Inc.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
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