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  • 1
    Electronic Resource
    Electronic Resource
    Dielectrophoretic ratchets (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Chaos 8 (1998), S. 650-656 
    Details
    ISSN: 1089-7682
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have experimentally applied some concepts of "force-free" motion to micron size particles (latex beads). The coupling of dissipation and local spatial asymmetry of the potential experienced by the beads can put them into motion. The potentials used in these experiments are of dielectrophoretic nature. To that end, electrodes of particular shapes were used in order to submit the considered suspensions to inhomogeneous ac electric fields. Two regimes were explored: i—the Brownian ratchet case in which a Brownian particle is successively trapped in a factory roof-like potential and left free to diffuse. ii—the shifted ratchets case in which two potentials exhibiting similar characteristics are applied successively, one of them being shifted by a fraction of their common period relatively to the other. In both cases, a good agreement with the theoretical predictions was observed. In particular, particles of different sizes were characterized by different macroscopic velocities leading to the prospect of promising separation techniques. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.166347
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  • 2
    Electronic Resource
    Electronic Resource
    Intravaginal amputation of the uterine cervix with frozen section examination of the endocervical margin: a review of 414 consecutive patients (1996)
    Suite 500, 5th Floor, 238 Main Street, Cambridge, Massachusetts 02142, USA : Blackwell Science Inc.
    International journal of gynecological cancer 6 (1996), S. 0 
    Details
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We report our institutional experience with the accuracy and usefulness of cervical amputations with frozen section evaluation of the endocervical margin in the management of preinvasive squamous epithelial lesions. Four hundred and fourteen consecutive patients, who underwent amputation of the cervix because of a preinvasive epithelial lesion, or discrepancy between cytologic and biopsy findings especially when colposcopic evaluation was unsatisfactory, had frozen section evaluation of the endocervical margin. Medical records were reviewed and pathologic findings were compared with those obtained on paraffin embedded sections. Frozen section analysis of the upper endocervical margin led to the diagnosis of a residual lesion in 90 (21.7%) cases. In 59 (14.2%) of these cases a further excision was performed during the same operative procedure leading to complete resection in 34 (8.2%) cases. In 403 (97.3%) cases the diagnosis based on the frozen section was corroborated by the permanent sections. For the diagnosis of insufficient cervical resection, the sensitivity and specificity of frozen sections were 93.8% and 99.7% respectively. We conclude that frozen section evaluation of the upper endocervical margin at the time of cervical amputation is a reliable procedure that increases the rate of complete resection. The risks associated with additional anesthesia are then reduced, as are inconvenience to the patients and costs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1525-1438.1996.06060452.x
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  • 3
    Electronic Resource
    Electronic Resource
    Dopaminergic Receptors Linked to Adenylate Cyclase in Human Cerebromicrovascular Endothelium (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 57 (1991), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: : Cultured endothelium derived from three fractions of human cerebral microvessels was used to characterize dopamine (DA) receptors linked to adenylate cyclase activity. DA or D1 agonist, (±)-SKF-82958 hydrobromide, stimulated endothelial cyclic AMP formation in a dose-dependent manner. The selective D, antagonist, (±)SCH-23390, inhibited in a dose-dependent manner the production of cyclic AMP induced by DA. The affinity for the D1 receptor appeared to be greater in endothelium derived from large and small microvessels than from capillaries. Cholera toxin ADP-ribosylation of Gs proteins abolished the DA stimulatory effect on endothelial adenylate cyclase, whereas pertussis toxin ADP-ribosylation enhanced the DA-inducible formation, indicating the presence of both D1 and D2 receptors. Agonists of α1-adrenergic receptors (phenylephrine, 6-fluoronorepinephrine) or serotonin (5-HT), which stimulated the production of cyclic AMP, had no additive effect on DA-stimulated cyclic AMP formation. Incubation of these agents with DA produced the same or lower levels of cyclic AMP as compared to that formed by DA alone. The effect of α1-adrenergic agonists or 5-HT on DA production of cyclic AMP was partially prevented by the D2 antagonist, S(-)-sulpiride, or ketanserin (5-HT2 〉 α1 〉 H1 antagonists), respectively. These findings represent the first demonstration of D1-(stimulatory) and D2-(inhibitory) receptors linked to adenylate cyclase in microvascular endothelium derived from human brain. The data also indicate that dopaminergic receptors can interact with either α1adrenergic or 5-HT receptors in endothelium on the adenylate cyclase level. These results provide strong support for the previously contemplated existence of a central dopaminergic mechanism in cerebral vessels, a notion that is clinically important.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1991.tb06380.x
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  • 4
    Electronic Resource
    Electronic Resource
    Endothelin 1 Stimulates Na+,K+-ATPase and Na+-K+-Cl− Cotransport Through ETA Receptors and Protein Kinase C-Dependent Pathway in Cerebral Capillary Endothelium (1995)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 65 (1995), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effect of endothelins (ET-1 and ET-3) on 86Rb+ uptake as a measure of K+ uptake was investigated in cultured rat brain capillary endothelium. ET-1 or ET-3 dose-dependently enhanced K+ uptake (EC50 = 0.60 ± 0.15 and 21.5 ± 4.1 nM, respectively), which was inhibited by the selective ETA receptor antagonist BQ 123 (cyclo-d-Trp-d-Asp-Pro-d-Val-Leu). Neither the selective ETB agonists IRL 1620 [N-succinyl-(Glu9,-Ala11,15)-ET-1] and sarafotoxin S6c, nor the ETB receptor antagonist IRL 1038 [(Cys11,Cys15)-ET-1] had any effect on K+ uptake. Ouabain (inhibitor of Na+,K+-ATPase) and bumetanide (inhibitor of Na+-K+-Cl− cotransport) reduced (up to 40% and up to 70%, respectively) the ET-1-stimulated K+ uptake. Complete inhibition was seen with both agents. Phorbol 12-myristate 13-acetate (PMA), activator of protein kinase C (PKC), stimulated Na+,K+-ATPase and Na+-K+-Cl− cotransport. ET-1-but not PMA-stimulated K+ uptake was inhibited by 5-(N-ethyl-N-isopropyl)amiloride (inhibitor of Na+/H+ exchange system), suggesting a linkage of Na+/H+ exchange with ET-1-stimulated Na+,K+-ATPase and Na+-K+-Cl− cotransport activity that is not mediated by PKC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1995.65041588.x
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of Cerebral Ischemia on Regional Dopamine Release and D1 and D2 Receptors (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 60 (1993), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: To expand on the nature of regional cerebral vulnerability to ischemia, the release of dopamine (DA) and dopaminergic (D1 and D2) receptors were investigated in Mongolian gerbils subjected to bilateral carotid artery occlusion (15 min) alone or with reflow (1–2 h). Extracellular cortical and striatal content of DA and its metabolites was measured by microdialysis using HPLC with electrochemical detection. The kinetic properties of D1 and/or D2 receptor binding sites were determined in cortical and striatal membranes with the use of radiolabeled ligands (125I-SCH23982 and [3H]YM-09151-2, respectively). The ischemic release of DA from the striatum was greater (400-fold over preischemic level) than that from the cortex (12-fold over preischemic content). The affinity for the D1-receptor ligand was lower (KD= 1.248 ± 0.047 nM) after ischemia than that for sham controls (KD= 0.928 ± 0.032 nM, p 〈 0.001). The number of binding sites for D2 receptors decreased in striatum (Bmax= 428 ± 18.4 fmol/mg of protein) after ischemia compared with sham controls (Bmax= 510 ± 25.2 fmol/mg of protein, p 〈 0.05). D1 or D2 binding sites were not changed either in the ischemic cortex or postischemic striatum and cortex. The findings strongly suggest that the ischemic release of DA from striatum is associated with early transient changes in D1- and D2-mediated DA neurotransmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1993.tb03311.x
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  • 6
    Electronic Resource
    Electronic Resource
    Ischemic Modification of Cerebrocortical Membranes: 5-Hydroxytryptamine Receptors, Fluidity, and Inducible In Vitro Lipid Peroxidation (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 53 (1989), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effect of ischemia on the properties of 5-hydroxytryptamine1A+B (5-HT1A+B) and 5-hydroxytrypt-amine1B5-HT1B) binding sites, physical-state “fluidity” of the membrane, and its susceptibility to peroxidation in vitro was investigated in the cerebral cortex of gerbils. Ischemia was induced by bilateral carotid artery occlusion for 15 min alone or with release for 1 h. Ischemia both with and without reflow decreased the number of 5-HT1A+B and 5-HT1B binding sites, whereas ischemia and reflow altered the affinity for 5-HT1B binding sites. Resistance to the temperature-dependent increase in “fluidity” of the membrane was detected (by fluorescence anisotropy using l,6-diphenyl-l,3,5-hexatriene as a probe) after ischemia and reflow but not in ischemia alone. Susceptibility of the membranes to Fe2+- and ascorbic acid-stimulated lipid peroxidation in vitro was decreased following ischemia and recirculation only. These findings strongly suggest that the composition and the function of the membrane are markedly disturbed during recirculation after ischemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1989.tb07375.x
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  • 7
    Electronic Resource
    Electronic Resource
    Endothelin-1 Receptor Binding and Cellular Signal Transduction in Cultured Human Brain Endothelial Cells (1994)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 62 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The kinetic properties of endothelin-1 (ET-1) binding sites and the production of inositol phosphates (IPs; IP1, IP2, IP3), cyclic AMP, thromboxane B2, and prostaglandin F2α induced by various endothelins (ET-1, ET-2, ET-3, and sarafotoxin S6b) were examined in endothelial cells derived from human brain microvessels (HBECs). The presence of both high- and low-affinity binding sites for ET-1 with KD1 = 122 pM and KD2 = 31 nM, and Bmax1 = 124 fmol/mg of protein and Bmax2 = 909 fmol/mg of protein, respectively, was demonstrated on intact HBECs. ET-1 dose-dependently stimulated IP accumulation with EC50 (IP3) = 0.79 nM, whereas ET-3 was ineffective. The order of potency for displacing ET-1 from high-affinity binding sites (ET-1 〉 ET-2 〉 sarafotoxin S6b 〉 ET-3) correlated exponentially with the ability of respective ligands to induce IP3 formation. ET-1-induced IP3 formation by HBEC was inhibited by the ETA receptor antagonist, BQ123. The protein kinase C activator phorbol myristate ester dose-dependently inhibited the ET-1-stimulated production of IPs, whereas pertussis toxin was ineffective. Cyclic AMP production by HBECs was enhanced by both phorbol myristate ester and ET-1, and potentiated by combined treatment with ET-1 and phorbol myristate ester. Data indicate that protein kinase C plays a role in regulating the ET-1-induced activation of phospholipase C, whereas interaction of different messenger systems may regulate ET-1-induced accumulation of cyclic AMP. ET-1 also stimulated endothelial prostaglandin F2α production, suggesting that activation of phospholipase A2 is most likely secondary to IP3-mediated intracellular calcium mobilization because both ET-1-induced IP3 and prostaglandin F2α were inhibited by BQ123. These findings are the first demonstration of ET-1 (ETA-type) receptors linked to phospholipase C and phospholipase A2 activation in HBECs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.62020592.x
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of Hypoxia on Na+-K+-Cl− Cotransport in Cultured Brain Capillary Endothelial Cells of the Rat (1996)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 66 (1996), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effect of hypoxia on Na+,K+-ATPase and Na+-K+-Cl− cotransport activity in cultured rat brain capillary endothelial cells (RBECs) was investigated by measuring 86Rb+ uptake as a tracer for K+. RBECs expressed both Na+,K+-ATPase and Na+-K+-Cl− cotransport activity (4.6 and 5.5 nmol/mg of protein/min, respectively). Hypoxia (24 h) decreased cellular ATP content by 43.5% and reduced Na+,K+-ATPase activity by 38.9%, whereas it significantly increased Na+-K+-Cl− cotransport activity by 49.1% in RBECs. To clarify further the mechanism responsible for these observations, the effect of oligomycin-induced ATP depletion on these ion transport systems was examined. Exposure of RBECs to oligomycin led to a time-dependent decrease of cellular ATP content (by ∼65%) along with a complete inhibition of Na+,K+-ATPase and a coordinated increase of Na+-K+-Cl− cotransport activity (up to 100% above control values). Oligomycin augmentation of Na+-K+-Cl− cotransport activity was not observed in the presence of 2-deoxy-d-glucose (a competitive inhibitor of glucose transport and glycolysis) or in the absence of glucose. These results strongly suggest that under hypoxic conditions when Na+,K+-ATPase activity is reduced, RBECs have the ability to increase K+ uptake through Na+-K+-Cl− cotransport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1996.66062572.x
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  • 9
    Electronic Resource
    Electronic Resource
    Use of the Contrast Volume to Estimated Creatinine Clearance Ratio to Predict Renal Failure After Angiography (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of interventional cardiology 10 (1997), S. 0 
    Details
    ISSN: 1540-8183
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Little data exists regarding the relationship between the volume of radiographic contrast infused and the risk of contrast nephropathy for individual patients based on specific patient characteristics. Because the likelihood of renal failure is increased when there is preexisting azotemia or when larger volumes of contrast are used, it was hypothesized that the contrast volume:estimated creatinine clearance ratio would serve as a predictor of nephropathy following cardiac angiography. A retrospective analysis was performed of 152 high risk patients whose baseline serum creatinine concentration was 〉2.0 mg/dL or who received ± 300 ce of contrast. Nephropathy, defined as in increase in serum creatinine of 〉 1.0 mg/dL within 48 hours, occurred in 11 patients (7%). The contrast volume: creatinine clearance ratio was 〉 6.0 in 64% of patients who developed nephropathy and 31% of patients who did not (P 〈 0.05). The contrast volume:creatinine clearance ratio was then studied prospectively in 250 consecutive patients. The risk of nephropathy was 61% for patients with a ratio 〉 6.0, but only 1% otherwise (P 〈 0.01). This ratio can be used to calculate an upper limit for contrast volume and might reduce the chance of renal failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8183.1997.tb00018.x
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  • 10
    Electronic Resource
    Electronic Resource
    Mycophenolic acid in psoriasis (1978)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 98 (1978), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Mycophenolic acid (MPA) is a fermentation product of a penicillium mould which has shown anti-tumour activity in certain animal models. It blocks nucleic acid synthesis by interfering with the interconversions of inosine monophosphate (IMP), xanthine monophosphate (XMP) and guanine monophosphate (GMP) thereby inhibiting growth and/or replication of tumour cells. In vivo activity depends on the presence of a β-glucuronidase which is abundant in the cell wall of epithelial tissues. Encouraged by results obtained in earlier clinical trials, we have studied 28 patients with psoriasis, 21 in double-blind fashion. A comparison of disease severity in patients before and after receiving MPA versus patients receiving placebo clearly showed the superiority of drug over placebo. The mean severity score of patients receiving MPA as an initial course of therapy improved by 56% versus 9% in patients receiving placebo. Patients receiving MPA after an initial course of placebo therapy showed improvement in their mean severity score averaging 86%. Those patients receiving placebo after an initial course of MPA showed worsening of their mean severity score averaging 70%. Overall, about 75% of MPA treated patients have shown good to excellent responses, and toxicity appears low. Evidence suggests that MPA may be very useful in treating severe psoriasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2133.1978.tb06537.x
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