Search results for "ATS"
showing 10 items of 6881 documents
PARTICIPATION OF RAT LIVER NUCLEI IN MOVEMENTS OF SODIUM.
1964
In vitro investigations of movements of sodium with muscular tissue seem to have shown that the non-extracellular sodium belongs to more than one phase1. The existence of either a membranous and a cellular phase2 or of two cellular phases with different degrees of order3 has been discussed. We wish to present some experimental findings which may well contribute to the interpretation of sodium transfer processes in animal tissue.
Time-related changes in size of nuclei of pinealocytes in rats
1981
In a study of 96 adult male Sprague-Dawley rats, da- and time-related changes of the mean nuclear volume of pinealocytes were determined with the aim of testing the reproducibility of the karyometric findings described by Quay and Renzoni (1966). It is shown (i) that statistically significant differences exist between the central and peripheral mean volumes of pinealocyte nuclei/group of animals and time point (p less than 0.001), (ii) that the day and time related differences are statistically different in both regions (p less than 0.001), (iii) that in the center and periphery of the pineal body different diurnal patterns exist, and (iv) that the diurnal patterns are not parallel in the t…
Live cell imaging of duplex siRNA intracellular trafficking.
2015
Intracellular distribution of siRNA after in vitro transfection typically depends on lipopolyplexes, which must release the siRNA into the cytosol. Here, the fate of siRNAs was monitored by FRET-based live cell imaging. Subsequent to in situ observation of uptake and release processes, this approach allowed the observation of a number of hitherto uncharacterized intracellular distribution and degradation processes, commencing with a burst of endosomal releases, followed, in some cases, by fast siRNA influx into the nucleus. The continued observation of intact siRNA against a background of free fluorophores resulting from advanced degradation was possible by a specifically developed imaging …
The selection of serum-independent PC12 cells for a more-reliable manganese cytotoxicity test.
2007
A major issue concerning the protocols of heavy metal cytotoxicity tests with PC12 cells was the hypothesis that serum in the culture medium might sequester the metal, thus altering the results obtained. However, serum withdrawal impairs the viability of PC12 cells themselves, thus impeding cytotoxicity testing in the absence of serum. In this study, we repeatedly selected undifferentiated, totally non-adherent PC12 cells in Petri dishes. Surprisingly, we discovered that these cells could survive and proliferate in serum-free medium. Moreover, features such as NGF-responsiveness, resazurin reduction potential, doubling rate, protein content, and basal caspase-3 enzyme activity, were equiva…
Central nicotinic receptors, neurotrophic factors and neuroprotection
2000
The multiple combinations of nAChR subunits identified in central nervous structures possess distinct pharmacological and physiological properties. A growing number of data have shown that compounds interacting with neuronal nAChRs have, both in vivo and in vitro, the potential to be neuroprotective and that treatment with nAChR agonists elicit long-lasting improving of cognitive performance in a variety of behavioural tests in rats, monkeys and humans. Epidemiological and clinical studies suggested also a potential neuroprotective/trophic role of (-)-nicotine in neurodegenerative disease, such as Alzheimer's and Parkinson's disease. Taken together experimental and clinical data largely ind…
Uridine enhances the cytotoxic effect of D-glucosamine in rat C6 glioma cells.
1986
This paper studies the influence of uridine on the effects exerted by D-glucosamine in rat C6 glioma cells. 2 mM uridine increased markedly both the cytotoxic effect of the aminosugar and the inhibition of thymidine incorporation into acid-insoluble fraction. Furthermore the complete resumption of the capacity to incorporate either 3H-thymidine or 3H-mannose which was observed after the removal of the aminosugar, was impeded when the cells were treated contemporaneously with D-glucosamine and uridine. An exposure for 4 hr to 20 mM glucosamine alone enhanced about 15-fold the cellular pool of UDP-N-acetylhexosamines; the addition of 2 mM uridine intensified the expansion of this pool, which …
Membrane protein oxidation determines neuronal degeneration
2015
Oxidative stress is an early hallmark in neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. However, the critical biochemical effector mechanisms of oxidative neurotoxicity have remained surprisingly elusive. In screening various peroxides and potential substrates of oxidation for their effect on neuronal survival, we observed that intramembrane compounds were significantly more active than aqueous or amphiphilic compounds. To better understand this result, we synthesized a series of competitive and site-specific membrane protein oxidation inhibitors termed aminoacyllipids, whose structures were designed on the basis of amino acids frequently found at the protein-lipi…
Galantamine modulates nicotinic receptor and blocks Aβ-enhanced glutamate toxicity
2004
Galantamine is a plant alkaloid that is used in the treatment of Alzheimer's disease. We have studied the effects of galantamine on beta-amyloid-enhanced glutamate toxicity using primary rat cultured cortical neurons. Nicotine and galantamine alone, and in combination, protected neurons against this neurotoxicity. The protection was not blocked by alpha4beta2 nicotinic acetylcholine receptor (nAChR) antagonists, but was partially blocked by alpha7 nAChR antagonists. Galantamine induced phosphorylation of Akt, an effector of phosphatidylinositol 3-kinase (PI3K), while PI3K inhibitors blocked the protective effect and Akt phosphorylation. The antibody FK1, which selectively blocks the alloste…
Differential regulation of apoptosis-associated genes by estrogen receptor alpha in human neuroblastoma cells
2012
Purpose: The neuroendocrinology of female sex hormones is of great interest for a variety of neuropsychiatric disorders. In fact, estrogens and estrogen receptors (ERs) exert neuromodulatory and neuroprotective functions. Here we investigated potential targets of the ER subtype alpha that may mediate neuroprotection and focused on direct modulators and downstream executors of apoptosis. Methods: We employed subclones of human neuroblastoma cells (SK-N-MC) stably transfected with one of the ER subtypes, ERalpha or ERbeta. Differences between the cell lines regarding the mRNA expression levels were examined by qPCR, changes on protein levels were examined by Western Blot and immunocytochemist…
Geographical mapping of metabolites in biological tissue with quantitative bioluminescence and single photon imaging
1993
This article features a novel technique for measuring the spatial distribution of metabolites, such as ATP, glucose, and lactate, in rapidly frozen tissue. Concentration values are obtained in absolute terms and with a spatial resolution of single-cell dimension. The method is based on enzymatic reactions that link the metabolite of interest to luciferase with subsequent light emission. Using a specific array, cryosections are brought into contact with the enzymes in a well-defined, reproducible way inducing a distribution of light across the section with an intensity that is proportional to the metabolite concentration. The emitted light can be visualized through a microscope and an imagin…