Proceedings of the National Academy of Sciences, 1997
The ultra-long telomeres that have been observed in mice are not in accordance with the concept t... more The ultra-long telomeres that have been observed in mice are not in accordance with the concept that critical telomere shortening is related to aging and immortalization. Here, we have used quantitative fluorescence in situ hybridization to estimate (T 2 AG 3 ) n lengths of individual telomeres in various mouse strains. Telomere lengths were very heterogeneous, but specific chromosomes of bone marrow cells and skin fibroblasts from individual mice had similar telomere lengths. We estimate that the shortest telomeres are around 10 kb in length, indicating that each mouse cell has a few telomeres with (T 2 AG 3 ) n lengths within the range of human telomeres. These short telomeres may be critical in limiting the replicative potential of murine cells.
Positive staining for estrogen receptors is reported in a new case of aggressive angiomyxoma of t... more Positive staining for estrogen receptors is reported in a new case of aggressive angiomyxoma of the vulva. Clinical, light- and electron microscopic features as well as immunohistochemical reactions in this case are compared with the 28 earlier published cases, and the main differential diagnosis, angiomyofibroblastoma of the vulva, is discussed.
ICASSP '84. IEEE International Conference on Acoustics, Speech, and Signal Processing
Ring Laser gyro performance is typically evaluated by measuring the random walk in angle associat... more Ring Laser gyro performance is typically evaluated by measuring the random walk in angle associated with each instrument over a range ot operating and environmental conditions. However, the ring laser gyro, being basically a digital sensor, outputs accumula-ted angle in quantized ...
Physics and Simulation of Optoelectronic Devices III, 1995
The gain dynamics of bulk laser amplifiers is discussed on the basis of simple rate equations, an... more The gain dynamics of bulk laser amplifiers is discussed on the basis of simple rate equations, and comparison is made with experimental pump-and-probe measurements employing ultrashort optical pulses. The rate equation model is derived from semi-classical density matrix equations, and is analyzed in different limiting cases, i.e., an adiabatic limit corresponding to nonlinear gain in laser diodes, a small-signal limit yielding an analytical repsonse function, and a strong-signal regime, where numerical simulations are carried out.
Clonal neurohybridoma NCB-20 cells express a valproate-insensitive succinic semialdehyde reductas... more Clonal neurohybridoma NCB-20 cells express a valproate-insensitive succinic semialdehyde reductase activity that transforms succinic semialdehyde into gamma-hydroxybutyrate. This activity (1.14+/-0.16 nmol/min/mg protein) was similar to the lowest activity existing in adult rat brain. [3H]gamma-Hydroxybutyrate labels a homogeneous population of sites on NCB-20 cell membranes (Kd=250+/-44.4nM, Bmax=180+/-16.2fmol/mg protein) that apparently represents specific gamma-hydroxybutyrate binding sites characterized previously on brain cell membranes. Finally, an Na+-dependent uptake of [3H]gamma-hydroxybutyrate was expressed in NCB-20 cells with a Km of 35+21.1 microM and a Vmax of 80+/-14.2 pmol/min/mg protein. A three-day treatment with 1 mM dibutyryl-cyclic-AMP induced a three-fold increase in the cellular succinic semialdehyde reductase activity. In parallel, a K+-evoked release of [3H]gamma-hydroxybutyrate occurred. This release was Ca2+ dependent and was not present in undifferentiated cells. Cyclic-AMP treatment induced a decrease of [3H]gamma-hydroxybutyrate binding sites, which could be due to spontaneous gamma-hydroxybutyrate release. Patch-clamp experiments carried out on differentiated NCB-20 cells revealed the presence of Ca2+ conductances which were partially inhibited by 50 microM gamma-hydroxybutyrate. This gamma-hydroxybutyrate-induced effect was blocked by the gamma-hydroxybutyrate receptor antagonist NCS-382, but not by the GABA(B) antagonist CGP-55845. These results demonstrate the presence of an active gamma-hydroxybutyratergic system in NCB-20 cells which possesses the ability to release gamma-hydroxybutyrate. These cells express specific gamma-hydroxybutyrate receptors which modulate Ca2+ currents independently of GABA(B) receptors.
Nonlinear gain suppression has a strong influence on the dynamic characteristics of semiconductor... more Nonlinear gain suppression has a strong influence on the dynamic characteristics of semiconductor lasers. Until recently spectral hole burning was believed to be the major cause of nonlinear gain, but experiments on short-pulse amplification in laser amplifiers pointed to the effect of carrier heating.1–3 In this paper we analyze static and dynamic gain suppression in semiconductor lasers, taking into account both spectral hole burning and carrier heating.
The Journal of pharmacology and experimental therapeutics, 1993
The action of agonists or antagonists at the gamma-hydroxybutyrate (GHB) receptor represents a po... more The action of agonists or antagonists at the gamma-hydroxybutyrate (GHB) receptor represents a possibility to modulate dopaminergic activities in brain. In the present study, GHB and six structural analogs were tested for their ability to displace [3H] GHB binding from striatal membranes. All the analogs tested exhibited higher affinity for GHB as compared with GHB itself. Parallel experiments were carried out on striatal slices in order to determine IC50 values for inhibition of dopamine release in the presence of these compounds. All substances inhibited dopamine release with higher potency as compared with GHB itself. These antidopaminergic activities were confirmed in several neuropharmacological tests, usually used to predict neuroleptic activities in vivo. There appears to be a relationship between the affinity for the GHB striatal low-affinity receptor and the inhibition of dopamine release on one hand, and the antidopaminergic activity (as revealed by the in vivo tests) on t...
Proceedings of the National Academy of Sciences, 1997
The ultra-long telomeres that have been observed in mice are not in accordance with the concept t... more The ultra-long telomeres that have been observed in mice are not in accordance with the concept that critical telomere shortening is related to aging and immortalization. Here, we have used quantitative fluorescence in situ hybridization to estimate (T 2 AG 3 ) n lengths of individual telomeres in various mouse strains. Telomere lengths were very heterogeneous, but specific chromosomes of bone marrow cells and skin fibroblasts from individual mice had similar telomere lengths. We estimate that the shortest telomeres are around 10 kb in length, indicating that each mouse cell has a few telomeres with (T 2 AG 3 ) n lengths within the range of human telomeres. These short telomeres may be critical in limiting the replicative potential of murine cells.
Positive staining for estrogen receptors is reported in a new case of aggressive angiomyxoma of t... more Positive staining for estrogen receptors is reported in a new case of aggressive angiomyxoma of the vulva. Clinical, light- and electron microscopic features as well as immunohistochemical reactions in this case are compared with the 28 earlier published cases, and the main differential diagnosis, angiomyofibroblastoma of the vulva, is discussed.
ICASSP '84. IEEE International Conference on Acoustics, Speech, and Signal Processing
Ring Laser gyro performance is typically evaluated by measuring the random walk in angle associat... more Ring Laser gyro performance is typically evaluated by measuring the random walk in angle associated with each instrument over a range ot operating and environmental conditions. However, the ring laser gyro, being basically a digital sensor, outputs accumula-ted angle in quantized ...
Physics and Simulation of Optoelectronic Devices III, 1995
The gain dynamics of bulk laser amplifiers is discussed on the basis of simple rate equations, an... more The gain dynamics of bulk laser amplifiers is discussed on the basis of simple rate equations, and comparison is made with experimental pump-and-probe measurements employing ultrashort optical pulses. The rate equation model is derived from semi-classical density matrix equations, and is analyzed in different limiting cases, i.e., an adiabatic limit corresponding to nonlinear gain in laser diodes, a small-signal limit yielding an analytical repsonse function, and a strong-signal regime, where numerical simulations are carried out.
Clonal neurohybridoma NCB-20 cells express a valproate-insensitive succinic semialdehyde reductas... more Clonal neurohybridoma NCB-20 cells express a valproate-insensitive succinic semialdehyde reductase activity that transforms succinic semialdehyde into gamma-hydroxybutyrate. This activity (1.14+/-0.16 nmol/min/mg protein) was similar to the lowest activity existing in adult rat brain. [3H]gamma-Hydroxybutyrate labels a homogeneous population of sites on NCB-20 cell membranes (Kd=250+/-44.4nM, Bmax=180+/-16.2fmol/mg protein) that apparently represents specific gamma-hydroxybutyrate binding sites characterized previously on brain cell membranes. Finally, an Na+-dependent uptake of [3H]gamma-hydroxybutyrate was expressed in NCB-20 cells with a Km of 35+21.1 microM and a Vmax of 80+/-14.2 pmol/min/mg protein. A three-day treatment with 1 mM dibutyryl-cyclic-AMP induced a three-fold increase in the cellular succinic semialdehyde reductase activity. In parallel, a K+-evoked release of [3H]gamma-hydroxybutyrate occurred. This release was Ca2+ dependent and was not present in undifferentiated cells. Cyclic-AMP treatment induced a decrease of [3H]gamma-hydroxybutyrate binding sites, which could be due to spontaneous gamma-hydroxybutyrate release. Patch-clamp experiments carried out on differentiated NCB-20 cells revealed the presence of Ca2+ conductances which were partially inhibited by 50 microM gamma-hydroxybutyrate. This gamma-hydroxybutyrate-induced effect was blocked by the gamma-hydroxybutyrate receptor antagonist NCS-382, but not by the GABA(B) antagonist CGP-55845. These results demonstrate the presence of an active gamma-hydroxybutyratergic system in NCB-20 cells which possesses the ability to release gamma-hydroxybutyrate. These cells express specific gamma-hydroxybutyrate receptors which modulate Ca2+ currents independently of GABA(B) receptors.
Nonlinear gain suppression has a strong influence on the dynamic characteristics of semiconductor... more Nonlinear gain suppression has a strong influence on the dynamic characteristics of semiconductor lasers. Until recently spectral hole burning was believed to be the major cause of nonlinear gain, but experiments on short-pulse amplification in laser amplifiers pointed to the effect of carrier heating.1–3 In this paper we analyze static and dynamic gain suppression in semiconductor lasers, taking into account both spectral hole burning and carrier heating.
The Journal of pharmacology and experimental therapeutics, 1993
The action of agonists or antagonists at the gamma-hydroxybutyrate (GHB) receptor represents a po... more The action of agonists or antagonists at the gamma-hydroxybutyrate (GHB) receptor represents a possibility to modulate dopaminergic activities in brain. In the present study, GHB and six structural analogs were tested for their ability to displace [3H] GHB binding from striatal membranes. All the analogs tested exhibited higher affinity for GHB as compared with GHB itself. Parallel experiments were carried out on striatal slices in order to determine IC50 values for inhibition of dopamine release in the presence of these compounds. All substances inhibited dopamine release with higher potency as compared with GHB itself. These antidopaminergic activities were confirmed in several neuropharmacological tests, usually used to predict neuroleptic activities in vivo. There appears to be a relationship between the affinity for the GHB striatal low-affinity receptor and the inhibition of dopamine release on one hand, and the antidopaminergic activity (as revealed by the in vivo tests) on t...
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