Seizure induction and magnetic brain stimulation after stroke.
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Cerebrovascular Disorders↗
Biomedical subjects
C Fauth
Publications and source records attributed to C Fauth.
Transport of organic cations by kidney epithelial cell line LLC-PK1.
Transport of two organic cations, N1-methylnicotinamide (NMN) and tetraethylammonium (TEA), was investigated in LLC-PK1 cells grown on Transwell collagen coated Nuclepore filters. Two min NMN or TEA unidirectional transepithelial flux and simultaneous cellular uptake were measured. Transport of NMN and TEA from basolateral to apical side was temperature-dependent, saturable and competitively inhibited by each other or by mepiperphenidol. NMN and TEA transport from the apical to the basolateral side was very slow, only slightly faster than that of mannitol. Apparent kinetic parameters of basolateral to apical transcellular flux were measured. For NMN apparent Km = 133.6 +/- 35.4 microM, Vmax = 48.3 +/- 5.6 pmol/cm2.2 min. For TEA apparent Km = 11.4 +/- 2.2 microM, Vmax = 42.1 +/- 1.8 pmol/cm2.2 min. Kinetic parameters of cellular uptake were also estimated. For NMN apparent Km = 436.9 +/- 139.8 microM, Vmax = 143.7 +/- 30.5 pmol/micrograms DNA. For TEA apparent Km = 50.3 +/- 7.2 microM, Vmax = 26.5 +/- 2.5 pmol/micrograms DNA. It is concluded that LLC-PK1 cells transport NMN and TEA from the basolateral to the apical side; this flux corresponds to the secretory transport of the renal proximal tubule. NMN and TEA share the same transport system, but NMN has a lower affinity.
Biological Transport↗
Transport of tetraethylammonium by a kidney epithelial cell line (LLC-PK1).
We investigated whether the LLC-PK1 epithelial cell line (which shows many characteristics of proximal tubular cells) also is capable of transporting an organic ion. Suspended LLC-PK1 cells accumulated tetraethylammonium (TEA). The uptake showed characteristics of a facilitated mechanism; TEA uptake was saturable and temperature-dependent and was inhibited by other organic cations. Quinine and mepiperphenidol were the most potent inhibitors, whereas N1-methylnicotinamide and morphine inhibited the transport system only slightly at doses of 10(-3) M. Basolateral-to-apical TEA flux through LLC-PK1 monolayers was five to six times larger than that of mannitol, a nontransported compound, whereas apical-to-basolateral TEA and mannitol fluxes were equal. Only the basolateral-to-apical TEA flux was inhibited by quinine. Under similar experimental conditions, no transport of p-aminohippuric acid was observed. It is concluded that LLC-PK1 cells are able to transport TEA, as do cells of the proximal tubule.
Animals↗
Establishment of renal cell lines derived from S2 segments of the proximal tubule.
The aim of this study was to establish epithelial cell lines derived from defined nephron segments. Primary cultures were prepared from dissected proximal S2 segments of the rabbit kidney, and grown in monolayers. Immortalization was observed after nuclear microinjection of the cells with simian virus 40 DNA and resulted in the development of cell lines of epithelial morphology. These cell lines were maintained in culture for at least 24 passages, then cells were frozen. One of the cell lines, the RKPC-2, was selected and further characterized. RKPC-2 cells formed domes on impermeable supports, indicating fluid and solute transport. RKPC-2 cells formed continuous monolayers of low transepithelial resistance on collagen-coated filters. They were able to accumulate tetraethylammonium, an organic cation; however, no significant transcellular transport could be measured. We conclude that this cell line which shows characteristics of epithelial cells has maintained certain properties of intact proximal tubules, in particular the capacity to accumulate organic cations.
Animals↗