Rapid eye movement (REM) sleep deprivation leads to an induction of galanin gene expression in the rat brain, especially in the hypothalamus. Galanin affects neuroendocrine systems that are involved in sleep regulation, i.e. the growth hormone-releasing hormone-dependent system of the hypothalamus and the locus coeruleus. In the study reported here we investigated the effects of 4 x 50 microg galanin (n = 10) and of 4 x 150 microg galanin (n = 8) administered hourly between 22.00 and 01.00 h as intravenous boluses on the sleep EEG and nocturnal hormone secretion in healthy young men. Galanin administration significantly increased REM sleep in the third sleep cycle with no difference between the two doses. Spectral analysis revealed a significant increase in the EEG power in the delta and theta frequency range for the total night after the lower dose of galanin, but not after the higher dose. The secretion of growth hormone, cortisol and prolactin remained unchanged during sleep in both cases. Our data are consistent with the assumption of a functional resemblance between the effect of galanin and that of REM sleep deprivation, which is known to have antidepressive efficacy.

Adult↗

PubMedDate not supplied

On-line monitoring of adhesion and proliferation of cultured hepatoma cells using optical waveguide lightmode spectroscopy (OWLS).

Monitoring of cell adhesion, cell spreading, and cell proliferation opens attractive perspectives in the on-line control of monolayer cell cultures in toxicity tests, in bioreactors as used for the serial production of skin grafts, or in extracorporeal liver devices. In this study the hepatoma Hep G2 cell adhesion and proliferation was monitored using an integrated optical method, optical waveguide lightmode spectroscopy (OWLS). This method is based upon refractive index measurements within a 100-nm thin layer above a Si(Ti)O(2) surface on which the cells were cultured and exposed to cytotoxic and cytostatic agents. The OWLS signal was proportional to cell density during the spreading period (4 h), and in long-term experiments (46 h) the OWLS signal correlated on a logarithmic scale with cell density. After administration of the protein synthesis inhibitor cycloheximide (4 microg/mL) to fully spread hepatoma cells, cell growth was arrested and change of the OWLS signal became noticeable within 6 h after drug administration. For exposure to increasing concentrations of the anticancer drug cyclophosphamide (2.5-20 mM) a concentration-dependent reduction of the OWLS signal was found. For cycloheximide and cyclophospamide the OWLS signal was also confirmed by cell viability measurements using the neutral red assay, the thiazolylblue tetrazoliumbromide assay, total protein measurements, and cell morphology. It was demonstrated that the OWLS signal detects minor changes in cell adhesion, which serve as indicators of metabolic state and growth behavior. OWLS is thus a quantitative tool to characterize impaired cell growth mediated by culture medium, by extracellular matrix, or after exposure to a toxin.

Bioreactors↗

PubMedDate not supplied

Possible occupational hazards associated with the preparation/administration of antineoplastic agents.

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Antineoplastic Agents↗