Publications by authors named "Papageorgiou G"

We present measurements of the resonant microwave excitation of Rydberg energy levels for surface-state electrons on superfluid helium. The temperature-dependent contribution to the linewidth gamma(T) agrees with theoretical predictions and is very small below 700 mK, in the ripplon scattering regime. Absorption saturation and power broadening were observed as the fraction of electrons in the first excited state was increased to 0.

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Background: Quality of life is poor in morbidly obese patients, because of impaired physical and psychosocial functioning. Surgical treatment offers long-term weight reduction and amelioration of most associated comorbidities. Studies of the effect of weight loss on patients' mental well-being are required, because discrimination and psychopathologic consequences represent a heavy burden.

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Diplopia caused by local anesthesia at the superior posterior alveolar nerve for the removal of the maxillary third molar is a rare complication. The diplopia is due to facial palsy of the oculomotor muscles of the globe. This paper describes the case of a 22-year-old woman, in whom diplopia was observed after an overall uncomplicated removal of the semi-impacted third molar.

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The effect of intramuscular administration of high (30 mg/kg body weight for 3 days) or very high (300 mg/kg body weight for 3 days) doses of a-tocopherol to Wistar rats subjected to total severe warm hepatic ischemia and reperfusion was investigated. After a 60-minute period of total hepatic ischemia and 120 minutes of reperfusion, animals were killed, and liver samples were taken for determination of malondialdehyde (MDA) and histological examinations. Blood samples were also taken for assay of serum a-tocopherol, alanine transaminase (ALT), aspartate transaminase (AST), and lactic dehydrogenase (LDH).

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Using the VIRMETADEN (acronym derived from virus adsorption enumeration) method to count cytopathogenic viruses adsorbed to cellulose nitrate membrane filters from prefiltered and decontaminated sewage samples was shown to be feasible. The numbers of naturally occurring enteroviruses recovered by the VIRMETADEN method were significantly higher than those obtained by standard plaque assay. For prefiltration of sewage samples, low protein binding polyvinylidene fluoride (PVDF) membranes of 0.

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The chlorophyll a (Chla) fluorescence of cyanobacteria, which at physiological temperature originates from photosystem (PS) II holochromes, is suppressed in hyperosmotic suspension, and enhanced in hypo-osmotic suspension (G.C. Papageorgiou, A.

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Counting culturable viruses adsorbed to cellulose nitrate filters (the VIRADEN method) is proposed as a simple procedure for the evaluation of the virucidal activity of antiseptics and disinfectants. The virucidal activities of two different doses of iodine, chlorine, glutaraldehyde, and chlorhexidine digluconate on poliovirus 1 were tested with a standardized procedure and with the VIRADEN method. The two procedures assayed provided similar results.

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Reperfusion injury of the liver occurs in liver transplantation and in major hepatectomies. It triggers a severe oxidative stress that leads to increased lipid peroxidation. In our study we examined the effect of parenteral supranutritional administration of alpha-tocopherol, a vitamin that plays a key role in the endogenous antioxidant system, to rats subjected to severe ischemia/reperfusion (I/R) injury of the liver.

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We present measurements of the conduction of nondegenerate free electrons along a low-dimensional channel at low temperatures, using surface-state electrons on liquid helium in novel microelectronic devices. Above 1 K, the electrons form an ideal classical Drude conductor. Below 1 K, Coulomb interactions produce electronic spatial order, leading to strong non-Ohmic effects and negative differential conductivity.

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Reagents capable of rapid and efficient release of neuroactive amino acids (L-glutamate, GABA and glycine) upon flash photolysis of thermally stable, inert precursors have been elusive. 7-Nitroindolinyl (NI)-caged and 4-methoxy-7-nitroindolinyl (MNI)-caged compounds that fulfil these criteria are evaluated here. These caged precursors are highly resistant to hydrolysis.

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1. Tetanic stimulation of parallel fibres (PFs) produces a slow EPSP (sEPSP) or slow EPSC (sEPSC) in Purkinje neurones (PNs), mediated by type 1 metabotropic glutamate receptors (mGluR1). The conductance change underlying the sEPSP was investigated with rapid photolytic release of L-glutamate from nitroindolinyl (NI)-caged glutamate with ionotropic glutamate receptors blocked, and showed a slow mGluR1-activated cation channel.

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Purpose: To report the concurrent endovascular treatment of multiple stenoses in different vascular territories.

Methods And Results: A 45-year-old male presented with an aortic arch syndrome, renovascular hypertension, and Leriche syndrome. Intra-arterial digital arteriography disclosed occlusion of the left subclavian artery and stenoses in the left common carotid artery (CCA), the right CCA at the bifurcation, the left renal artery, and both iliac arteries.

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We identified conditions under which Buffalo green monkey cells grew on the surfaces of cellulose nitrate membrane filters in such a way that they covered the entire surface of each filter and penetrated through the pores. When such conditions were used, poliovirus that had previously been adsorbed on the membranes infected the cells and replicated. A plaque assay method and a quantal method (most probable number of cytopathic units) were used to detect and count the viruses adsorbed on the membrane filters.

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Freshwater species of the cyanobacterial genus Synechococcus import NaCl passively, and export Na(+) actively, by means of primary and secondary extrusion mechanisms. As a result of the ion and water fluxes, cell volumes are enlarged. We show in this paper that the NaCl-induced volume enlargement of Synechococcus sp.

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Purpose: Evaluation of the treatment of malignant obstructive jaundice by percutaneous insertion of uncovered stents.

Material And Methods: 51 patients (35 men, 16 women) with inoperable malignant biliary obstruction underwent percutaneous placement of uncovered Wallstent biliary endoprostheses. A total of 65 endoprostheses were inserted.

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Daunomycin-induced cardiotoxicity has been regarded to be the result of oxygen-mediated lipid peroxidation of cell membranes. The aim of the present work was to evaluate the extent of lipid peroxidation in rat heart after administration of this anticancer drug and, further, to examine possible activation of some endogenous antioxidant defense systems. Myocardial tissue from both control and drug-treated rats was tested for lipid peroxidation using a selective third-order derivative method that is based on the analysis of the free malondialdehyde produced.

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Background/aims: The hemodynamic disturbances in the cirrhotic liver following severe variceal bleeding and subsequent restoration by blood transfusion is an ischemia/reperfusion injury event which represents the clinical situation of liver dysfunction. Therefore, the aim of this study was to evaluate the microcirculation, oxygenation and energy charge of the cirrhotic rat liver after ischemia/reperfusion.

Methodology: In eight carbon tetrachloride-induced cirrhotic rats and an equal number of controls subjected to 30 minutes of ischemia and 60 minutes of reperfusion by hepatoduodenal ligament clamping, the following parameters were assessed: hepatic microcirculation by laser-Doppler fluxmetry, hepatic tissue oxygenation by a Clark-type electrode, hepatic energy charge by tissue sampling and adenine-nucleotides determination by means of high-performance liquid chromatography.

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Forty-three schizophrenic patients participating in this study were serotyped for human leukocyte antigens (HLA-A, -B, -C, -DR, -DQ antigens). Thirty-six of them were hospitalised in two state mental hospitals and 7 in our general hospital, psychiatric unit. The patients from our unit were typed for HLA before commencing clozapine treatment whereas the patients from state hospitals were typed after commencing treatment.

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Lipid peroxidation is a critical pathway of reactive oxygen species inducing tissue injury in postischemic acute renal failure. In order to evaluate the effect of renal ischemia reperfusion on kidneys, renal tissue malondialdehyde (MDA, nmol/g wet weight) concentration was measured in 29 male Wistar rats subjected to a midline abdominal incision and 60 min occlusion of the left renal artery. A right nephrectomy was performed at the beginning of the ischemic period.

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Redox cycling compounds such as daunorubicin have been assumed to be toxic because they stimulate reactive oxygen-mediated lipid peroxidation. Furthermore, both DT-diaphorase and glutathione (GSH) have been regarded as protective cellular compounds against daunorubicin cardiotoxicity, but their role in daunorubicin nephrotoxicity remains unclear. To investigate this issue, 10 adult Wistar rats were twice injected with a single dose of 20 mg/kg body weight daunorubicin into the tail vein; the interval between injections was 48 h.

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We investigated the photodynamic action of hypericin, a natural naphthodianthrone, on photosynthetic electron transport and fluorescence of the cyanobacterium Anacystis nidulans (Synechococcus 6301). The most drastic effect was the inactivation of photosynthetic oxygen evolution in the presence of the electron acceptor phenyl-p-benzoquinone in aerobic cells which required 1 hypericin/5 chlorophyll a for half-maximal effect. Anaerobic A.

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A derivative spectrophotometric method for rapid monitoring of amphotericin B in serum and urine down to 30 ng/mliters is described. Samples are treated with acetonitrile, and amphotericin B is directly quantified in the crude extracts on the basis of the intensity of the peak that appears at 402 nm when the normal absorption spectrum is submitted to third-order derivative processing. Accuracy data suggested recoveries in the range of 84.

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Whereas in normal human thyroid tissue total cell mass is maintained by a balance between cell proliferation and apoptosis, the programmed cell death, in thyroid tumors this equilibrium is disrupted. In tumor cells, an augmented proliferation rate is no longer counterbalanced by an equally enhanced apoptosis resulting in an increased netto growth rate. To investigate regulation of apoptosis in thyroid tumors, we analyzed the expression of apoptosis-related proteins of the bcl-2 family in human thyroid tissues and in the human thyroid carcinoma cell lines FTC 133, HTC, HTC-TSHr and HTh74.

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