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  • 1
    Electronic Resource
    Electronic Resource
    Effects of 17β-estradiol on glucose transporter 1 expression and endothelial cell survival following focal ischemia in the rats (1997)
    Springer
    Experimental brain research 117 (1997), S. 200-206 
    Details
    ISSN: 1432-1106
    Keywords: Key words Estrogen ; Middle cerebral artery occlusion ; Glucose transporter ; Cerebral endothelium ; Glucose metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Estrogen replacement therapy in postmenopausal women is associated with a decreased mortality and morbidity from stroke. The present study was undertaken to investigate the effects of estrogen on endothelial cell glucose transporter 1 (GLUT 1) and on the cell viability during focal ischemia in a rat model. Female rats were ovariectomized (OVX) and 2 weeks later 17β-estradiol (E2) was injected subcutaneously at a dose of 100 μg/kg 2 h before unilateral middle cerebral artery (MCA) occlusion. Ischemic lesion size was quantified using 2,3,5-triphenyl tetrazolium chloride (TTC) staining and GLUT 1 protein was analyzed by Western blotting. E2 treatment decreased ischemic lesion size in slices taken at 9 and 11 mm posterior from the olfactory bulb by 46.3% and 44.1%, respectively (P 〈 0.05). GLUT 1 protein decreased in both OVX and E2 groups by 24.6% and 22.7% respectively (P 〈 0.05) compared with the non-lesioned side in the core ischemic region, including the basal ganglia. GLUT 1 protein was increased in the E2-treated group compared with the control group (23.3%, P 〈 0.05) in the penumbral ischemic region of the cortex. Primary rat brain capillary endothelial cell (BCEC) cultures were established as an in vitro model for ischemic effects on endothelial cells. Estrogen reduced BCEC loss by 35.9%, 28.4% and 23.5% (P 〈 0.05) when glucose in the culture medium was reduced to 50%, 20% and 10%, respectively; and by 28.4% and 18.4% (P 〈 0.05) following 1 or 4 h of anoxia, respectively. This study demonstrates that estrogen treatment increases GLUT 1 transporters and protects BCEC loss which may in turn reduce focal ischemic brain damage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050216
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  • 2
    Electronic Resource
    Electronic Resource
    Automated outgassing facility with inductive heating (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 276-279 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The use of graphite for both first walls and limiters in fusion experiments has increased during recent years. However, graphite contains large amounts of gaseous contaminants that affect the plasma adversely. To study the vacuum characteristics of various candidate graphites and to evaluate conditioning techniques for these materials, we have built an outgassing facility, which is described in this paper. Induction heating is used to heat the sample to 2000 °C. This heating technique was chosen to avoid heating other components in the vacuum chamber. Since the walls are heated by radiation from the sample at the higher temperatures, they are kept at a constant elevated temperature of 100 °C by thermostatically controlled heaters throughout the experiment. The entire system is automated. Some results that compare POCO and pyrolytic graphites are shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140240
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  • 3
    Electronic Resource
    Electronic Resource
    Estradiol protects against ATP depletion, mitochondrial membrane potential decline and the generation of reactive oxygen species induced by 3-nitroproprionic acid in SK-N-SH human neuroblastoma cells (2001)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 77 (2001), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Mitochondria are recognized as modulators of neuronal viability during ischemia, hypoxia and toxic chemical exposure, wherein mitochondria dysfunction leading to ATP depletion may be a common pathway of cell death. Estrogens have been reported to be neuroprotective and proposed to play a role in the modulation of cerebral energy/glucose metabolism. To address the involvement of 17β-estradiol preservation of mitochondrial function, we examined various markers of mitochondrial activity in human SK-N-SH neuroblastoma cells exposed to 3-nitroproprionic acid (3-NPA), a succinate dehydrogenase inhibitor which uncouples oxidative phosphorylation. 3-NPA (10 mm) significantly increased ATP levels at 2 h then caused a 40% and a 50% decrease in ATP levels from baseline when treated for 12 h and 24 h, respectively. 3-NPA also induced significant increases in levels of cellular hydrogen peroxide and peroxynitrite at 2 h and a 60% decrease in mitochondrial membrane potential (MMP) at 12 h exposure. 17β-Estradiol (17β-E2) pretreatment restored the ATP level back to 80% at 12 h of that in control cells treated with 3-NPA but without E2, blunted the effect of 3-NPA on MMP and reactive oxygen species levels. The present study indicates that 17β-E2 can preserve mitochondrial function in the face of inhibition of oxidative phosphorylation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2001.00271.x
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  • 4
    Electronic Resource
    Electronic Resource
    Modulation of Aβ peptides by estrogen in mouse models (2002)
    Oxford, UK : Blackwell Science, Ltd
    Journal of neurochemistry 80 (2002), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Clinical studies have shown that estrogen deprivation through menopause is a risk factor in both the initiation and progression of Alzheimer's disease (AD) and that estrogen replacement therapy may be protective. One of the major pathological features in the human AD brain is the senile plaque, a proteinaceous structure composed mainly of heterogeneous peptides collectively known as A-beta (Aβ). In vitro studies have linked estrogen with Aβ modulation, suggesting that one-way that estrogen depletion at menopause may exacerbate the features of AD is through Aβ accumulation. To test this, two studies were performed on transgenic models of amyloidosis. Firstly, transgenic mice without detectable amyloid aggregates were subjected to ovariectomy and estradiol supplementation, and Aβ levels were assessed. Secondly, the effects of estrogen modulation were assessed in mice at an age when plaques would be forming initially. Overall, Aβ levels were higher in estrogen-deprived mice than intact mice, and this effect could be reversed through the administration of estradiol. These data suggest that, in vivo, estrogen depletion leads to the accumulation of Aβ in the CNS, which can be reversed through replacement of estradiol. These results provide evidence that post-menopausal estrogen depletion may be linked to an increased risk of AD through Aβ modulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.0022-3042.2001.00690.x
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  • 5
    Electronic Resource
    Electronic Resource
    Long pulse experiments on the Advanced Toroidal Facility (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 2435-2439 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Advanced Toroidal Facility (ATF) [Fusion Technol. 10, 179 (1986)] is the world's largest stellarator. It was designed and built to demonstrate high beta, steady-state operation in a toroidal confinement system. During its final operating period ATF achieved pulse lengths of over one hour (4667 s). The objectives of these experiments were (1) investigation of plasma performance at times that are long compared to the plasma/wall equilibrium time; (2) determination of plasma control and wall conditioning techniques; and (3) adaptation of plasma diagnostic and data acquisition systems to long-pulse operation. Other experiments have also extended earlier studies of dimensionless-parameter plasma confinement scaling. By employing two discrete electron cyclotron heating (ECH) frequencies (28 and 35 GHz), and by simultaneously modulating the ECH power, magnetic field, and plasma density, it has been possible to maintain fixed plasma beta and collisionality while modulating the normalized gyroradius. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871267
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  • 6
    Electronic Resource
    Electronic Resource
    Application of modern optical fiber technology to the study of plasmas of closed divertors and pump limiters in reactor-relevant conditions : Eighth topical conference on high—temperature plasma diagnostics (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 2943-2945 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Modern optical fibers, through control of the purity of the materials and the tolerances of the core and clad diameters, provide very good light transmission in the visible and near-ultraviolet regions of the spectrum. This makes it possible to use them in place of traditional optical systems without large losses in light intensity at the detectors. In addition, the same control of the quality of the fiber materials, coupled with novel jacket materials, makes it possible to use the fibers inside vacuum chambers and at elevated temperatures. A fiber-optic bundle recently installed in the TEXTOR tokamak is an example of the use of modern fiber technology. The bundle was made of 80 100-μm fibers held together with a polyimide organic material that has good outgassing specifications up to 400 °C. This fiber bundle has been used for recent measurements of the recycling in the throat region of one of the blades of the Advanced Limiter Test-II (ALT-II) belt pump limiter. Another system presently under design and testing employs individual fibers that are gold plated. These fibers are fed through holes in a vacuum blank flange and silver soldered to the flange. This system is designed to transmit the light from the strike point inside the closed divertor of the DIII-D tokamak out to a spectrometer. There, the spectral profile of the Hα line is analyzed to determine the energy distribution of the recycling particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141784
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  • 7
    Electronic Resource
    Electronic Resource
    Anxiolytic activity of a brain delivery system for GABA (1987)
    Springer
    Psychopharmacology 92 (1987), S. 157-163 
    Details
    ISSN: 1432-2072
    Keywords: GABA delivery system ; Brain ; Anxiolysis ; CNS inhibitory neurotransmitter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We evaluated the anxiolytic property of a brain-specific gamma-aminobutyric acid delivery system (GABA-CDS) in male rats by means of a drink-foot shock conflict procedure. Brain-specific delivery of the active compound was achieved by combination of GABA benzyl ester with an interconvertible dihydropyridine⇌pyridinium salt carrier, which is “locked in” to the brain upon its oxidation. Pharmacokinetic studies revealed that the hydrophilic pyridinium salt form (G-Q+) of the GABA-CDS formed in situ remained in the brain for 12 h but was cleared from the blood and other peripheral tissues by 0.5–4 h. While the lipophilic form (G-DH) of the GABA-CDS caused a marked and sustained anxiolytic response when administered systemically, GABA and the charged pyridinium salt (G-Q+ form) of the GABA-CDS were ineffective. G-DH was injected at either 0, 4, 10 or 25 mg/kg IV in DMSO after rats were water and food deprived. After either 0.5, 2, 4, 8 or 24 h, rats were permitted 10 s of shock-free drinking of 10% sucrose, then given a 35 mA (DC) current through the drinking tube. Drinking time was recorded for 3 min. All doses of G-DH caused a significant increase in anxiolysis over control levels through 8 h. An increase (4 to 7-fold) in anxiolytic activity was observed through the 10 mg/kg dose with the 25 mg/kg dose causing no additional increase. No sedation or analgesia was observed at 2 h with any anxiolytic-producing dose of G-DH. These results suggest that G-DH elicits anxiolysis with minimal sedation, through the local brain action the G-Q+ or subsequent to the release of GABA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00177908
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  • 8
    Electronic Resource
    Electronic Resource
    Glucose modulation of skin temperature responses during morphine withdrawal in the rat (1990)
    Springer
    Psychopharmacology 102 (1990), S. 213-220 
    Details
    ISSN: 1432-2072
    Keywords: Glucose ; Morphine ; Opiates ; Withdrawal ; Temperature regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Studies were undertaken to determine the effects of acute alterations in plasma glucose levels on the tail skin temperature (TST) response of morphine-dependent rats to naloxone-precipitated withdrawal. In morphine-dependent rats, treatment with dextrose at doses of 0.5 or 2.5 g/kg did not alter the normal 6.0±0.3° C TST response to naloxone. However, treatment with 5, 10 or 20 g dextrose/kg, which increased plasma glucose to 250 mg/dl or greater, blocked the TST response during morphine withdrawal. In contrast, an IV injection of 2.5 IU insulin (Na-porcine)/kg, which reduced plasma glucose for 2 h, caused a delayed TST response of 4.7±0.4° C in control rats and exaggerated the TST response normally observed in morphine-dependent rats treated with naloxone. Collectively, these data indicate that acute hyperglycemia can attenuate and hypoglycemia can enhance the skin vasodilation which accompanies precipitated morphine withdrawal. In view of our observation that naloxone-precipitated morphine withdrawal caused a marked increasee in blood glucose, the sympathetic activation associated with opiate withdrawal may be intended to elevate blood glucose and thereby limit the manifestation of the withdrawal response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245924
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