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  • 1
    Electronic Resource
    Electronic Resource
    Circadian Rhythm of Melatonin Release From the Photoreceptive Pineal Organ of a Teleost, Ayu (Plecoglossus altivelis) in Flow-Thorough Culture (2004)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 16 (2004), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In the present study, we tested whether the pineal organ of ayu (Plecoglossus altivelis), an osmerid teleost close relative of salmonids, harbours a circadian oscillator regulating rhythmic melatonin release using flow-through culture. The pineal organ maintained under light/dark cycles released melatonin in a rhythmic fashion with high levels during the dark phase. A circadian rhythm of melatonin release persisted in constant darkness for at least four cycles. Characteristics of the circadian rhythm (free-running period, phase and amplitude) exhibited small variations among cultures when the data was normalized, indicating that this system is sufficient for the analysis of the circadian rhythm both at qualitative and quantitative levels. Six-hour extension of the light phase from the normal onset time of the dark phase or exposure to constant light for 36 or 48 h before transfer to constant darkness significantly inhibited melatonin release. Phase shifts in the circadian rhythm of melatonin release were also observed. Thus, the ayu pineal organ contains all the three essential components of the circadian system (a circadian clock, the photoreceptor responsible for photic entrainment of the clock, and melatonin generating system as an output pathway). This system should provide a useful model for analysing the physiological and molecular basis of the vertebrate circadian system. In addition, further comparative studies using salmonids and related species including ayu will provide some insight into the evolution of the roles of the pineal organ in the vertebrate circadian system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2826.2004.01132.x
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  • 2
    Electronic Resource
    Electronic Resource
    Circadian rhythms of melatonin secretion from superfused goldfish (Carassius auratus) pineal glands in vitro
    Amsterdam : Elsevier
    General and Comparative Endocrinology 83 (1991), S. 152-158 
    Details
    ISSN: 0016-6480
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0016-6480(91)90115-M
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  • 3
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of 1-alkylcarbamoyl-5-fluorouracils in plasma and ascites fluid after oral administration in mice (1980)
    Springer
    Cancer chemotherapy and pharmacology 4 (1980), S. 189-193 
    Details
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pharmacokinetics of 1-alkylcarbamoyl-5-fluorouracils was examined in mice bearing sarcoma 180. The alkylcarbamoyl derivatives were absorbed rapidly as intact form through the gastrointestinal tract and distributed into ascites fluid. Concentration-x-time (C-x-t) values of 5-fluorouracil formed in plasma and ascites fluid decreased in order by extension of the carbon chain of the alkyl moiety. C-x-t value of 5-fluorouracil formed in ascites fluid after hexylcarbamoyl derivative was higher than that in plasma. Antitumor activity of the compounds was correlated with both maximum concentration (Cmax) and C-x-t values of 5-fluorouracil formed and Cmax of total (intact form plus 5-fluorouracil formed) in ascites fluid (P〈0.01), and with C-x-t values in ascites fluid and Cmax and C-x-t values of 5-fluorouracil formed in plasma (P〈0.05). Alkylcarbamoyl structure was valuable for rapid absorption through the gastrointestinal tract and blood-ascites barrier and for maintenance of 5-fluorouracil level in plasma and ascites fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254017
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  • 4
    Electronic Resource
    Electronic Resource
    Antitumor activity of 1-alkylcarbamoyl derivatives of 5-fluorouracil in a variety of mouse tumors (1978)
    Springer
    Cancer chemotherapy and pharmacology 1 (1978), S. 203-208 
    Details
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The antitumor properties of 1-alkylcarbamoyl derivatives of 5-fluorouracil were examined in various mouse tumor systems to select promising compounds for clinical use. Almost all alkylcarbamoyl derivatives were active against various tumors when given by oral administration. Among them, 1-methyl, 1-ethyl, 1-isopropyl, 1-hexyl and 1-octyl carbamoyl derivatives of 5-fluorouracil were moderately or markedly active in six mouse tumor systems tested. However, 1-methyl, 1-ethyl, and 1-isopropyl carbamoyl derivatives were toxic to mice, though not lethal. As a result, 1-hexyl and 1-octyl carbamoyl derivatives were selected as the best candidates for antitumor agents in further study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257150
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  • 5
    Electronic Resource
    Electronic Resource
    Markedly induced asialoGM1+CD8+ T cell production and enhancement of antimetastatic activity by interferon β with folic or folinic acid (1997)
    Springer
    Cancer immunology immunotherapy 44 (1997), S. 65-69 
    Details
    ISSN: 1432-0851
    Keywords: Key words Colon carcinoma 26 ; Antimetastatic activity ; Interferon ; Folinic acid ; AsialoGM1+CD8+ T cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Either folic or folinic acid enhanced the antimetastatic activity of recombinant murine interferon β (rMuIFNβ) toward highly metastatic colon carcinoma 26 (Co 26Lu). Folinic acid administered with rMuIFNβ markedly increased asialoGM1+CD4+ and asialoGM1+CD8+ T cell production in the peritoneal cavity but not in the thymus and spleen. Peritoneal cells expressed killing activity toward Co 26Lu cells in vitro. In athymic nude mice, the above combination produced many asialoGM1+CD4+ and few asialoGM1+CD8+ T cells in the peritoneal cavity, but did not decrease lung metastatic colonies. AsialoGM1+CD4+ T cells would thus appear to have no or only very weak killing activity toward these tumor cells. The antimetastatic activity of folinic acid with rMuIFNβ was significantly decreased with anti-asialoGM1 and anti-CD8 antibodies. Inactivated CD8+ and asialoGM1+ cells cease to have killing activity toward Co 26Lu cells as shown by Winn’s assay. AsialoGM1+CD8+ cell production was markedly induced in the peritoneal cavity by treatment with rMuIFNβ and folinic acid. AsialoGM1+CD8+ T cells may be inhibiting lung metastasis of Co 26Lu. Folinic acid and interferon are used in combination therapy with 5-fluorouracil for biochemical modulation. Folinic acid with interferon, as adjuvant therapy, may promote the induction of CD8+ T cell production with consequent prevention of metastasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002620050356
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  • 6
    Electronic Resource
    Electronic Resource
    Potentiation of the chemotherapeutic action of tegafur against solid adenocarcinoma 755 by combination with l-cystine (1986)
    Springer
    Journal of cancer research and clinical oncology 111 (1986), S. 187-190 
    Details
    ISSN: 1432-1335
    Keywords: Tegafur ; l-Cysteine ; l-Cystine ; Combination chemotherapy ; Antitumor activity ; Potentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The chemotherapeutic action of tegafur (FT) against adenocarcinoma 755 in mice was markedly potentiated by oral administration of l-cysteine and l-cystine without increasing its toxicity. In particular, the combination of FT at 200 mg/kg per day (maximum dose) and 1000 mg/kg per day of l-cystine markedly inhibited tumor growth. The dose ratio of l-cysteine or l-cystine to FT needs 5 by weight to potentiate the antitumor activity of FT. The antitumor activity of 5-fluorouracil (FU) was slightly, but not significantly, increased by l-cysteine. The total concentration of FT in the plasma and the tumor when it was given in combination with l-cystine was significantly increased when compared with FT alone 1 h after oral administration. The FU level in the plasma after administration of the combination of FT and l-cystine was three times higher than that after FT alone, and the FU level in the tumor after treatment with the combination of FT and l-cystine was also higher (about 20%) than that after FT alone. This significant increase in FT and FU levels in the plasma and the tumor may be related to the potentiation of the antitumor activity of FT by l-cystine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389232
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  • 7
    Electronic Resource
    Electronic Resource
    Daily cycles in plasma and ocular melatonin in demand-fed sea bass, Dicentrarchus labrax L. (1997)
    Springer
    Journal of comparative physiology 167 (1997), S. 409-415 
    Details
    ISSN: 1432-136X
    Keywords: Key words Melatonin ; Pineal ; Eye ; Feeding behaviour ; Daily rhythms ; Dual phasing ; Sea bass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Melatonin is regarded as an internal zeitgeber, involved in the synchronization to light of the daily and seasonal rhythms of vertebrates. To date, plasma and ocular melatonin in fish have been extensively surveyed almost solely in freshwater species – with the exception of some migrating species of salmonids. In the present paper, melatonin levels of a marine species (sea bass, Dicentrarchus labrax L) were examined. In addition, the daily rhythms of the demand-feeding activity of sea bass, a fish species characterized by a dual phasing capacity (i.e. the ability to switch between diurnal and nocturnal behaviour), were investigated before sampling. Sea bass, distributed in 12 groups of four fish and kept under constant water temperature and salinity, were exposed to a 12 h light:12 h dark cycle (200:0 lx, lights on at 0800 hours). After 4 weeks recording, the animals were killed at 0900, 1200, 1400, 1600, 1900, 2100, 2400, 0200, 0400, 0700 and 0900 hours. Actograms of demand-feeding records revealed a nocturnal feeding behaviour, with some cases of spontaneous inversions in phasing. Melatonin levels in plasma peaked in the middle of the dark phase, dropping after lights on. Melatonin in the eye, on the contrary, exhibited an inverse profile, with high levels during daytime and low levels at night. These results suggest that melatonin in the plasma and the eye may act independently on the flexible circadian system of sea bass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050090
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