Showing papers by "University of Ioannina published in 2000"

A randomized study of antiretroviral management based on plasma genotypic antiretroviral resistance testing in patients failing therapy

Abstract: Objective To determine the short-term effects of using genotypic antiretroviral resistance testing (GART) with expert advice in the management of patients failing on a protease inhibitor and two nucleoside reverse transcriptase inhibitors. Design Prospective randomized controlled trial. Setting Multicenter community-based clinical trials network. Patients One-hundred and fifty-three HIV-infected adults with a threefold or greater rise in plasma HIV-1 RNA on at least 16 weeks of combination antiretroviral therapy. Interventions Randomization was either to a GART group, where genotype interpretation and suggested regimens were provided to clinicians, or to a no-GART group, where treatment choices were made without such input. Main outcomes measures Plasma HIV-1 RNA levels and CD4 cell counts were measured at 4, 8, and 12 weeks following randomization. The primary endpoint was change in HIV-1 RNA levels from baseline to the average of the 4 and 8 week levels. Results The average baseline CD4 cell count was 230 x 10(6) cells/l and the median HIV-1 RNA was 28,085 copies/ml. At entry, 82 patients were failing on regimens containing indinavir, 51 on nelfinavir, 11 on ritonavir, and nine on saquinavir. HIV-1 RNA, averaged at 4 and 8 weeks, decreased by 1.19 log10 for the 78 GART patients and -0.61 log10 for the 75 no-GART patients (treatment difference: -0.53 log, 95% confidence interval, -0.77 to -0.29; P = 0.00001). Overall, the best virologic responses occurred in patients who received three or more drugs to which their HIV-1 appeared to be susceptible. Conclusion In patients failing triple drug therapy, GART with expert advice was superior to no-GART as measured by short-term viral load responses.

Neural-network methods for boundary value problems with irregular boundaries

Abstract: Partial differential equations (PDEs) with boundary conditions (Dirichlet or Neumann) defined on boundaries with simple geometry have been successfully treated using sigmoidal multilayer perceptrons in previous works. The article deals with the case of complex boundary geometry, where the boundary is determined by a number of points that belong to it and are closely located, so as to offer a reasonable representation. Two networks are employed: a multilayer perceptron and a radial basis function network. The later is used to account for the exact satisfaction of the boundary conditions. The method has been successfully tested on two-dimensional and three-dimensional PDEs and has yielded accurate results.

The Eps8 protein coordinates EGF receptor signalling through Rac and trafficking through Rab5

Abstract: How epidermal growth factor receptor (EGFR) signalling is linked to EGFR trafficking is largely unknown. Signalling and trafficking involve small GTPases of the Rho and Rab families, respectively. But it remains unknown whether the signalling relying on these two classes of GTPases is integrated, and, if it is, what molecular machinery is involved. Here we report that the protein Eps8 connects these signalling pathways. Eps8 is a substrate of the EGFR, which is held in a complex with Sos1 by the adaptor protein E3bl (ref. 2), thereby mediating activation of Rac. Through its src homology-3 domain, Eps8 interacts with RN-tre. We show that RN-tre is a Rab5 GTPase-activating protein, whose activity is regulated by the EGFR. By entering in a complex with Eps8, RN-tre acts on Rab5 and inhibits internalization of the EGFR. Furthermore, RN-tre diverts Eps8 from its Rac-activating function, resulting in the attenuation of Rac signalling. Thus, depending on its state of association with E3b1 or RN-tre, Eps8 participates in both EGFR signalling through Rac, and trafficking through Rab5.

Contribution of Dexamethasone to Control of Chemotherapy-Induced Nausea and Vomiting: A Meta-Analysis of Randomized Evidence

Abstract: PURPOSE: To synthesize the available randomized evidence on the efficacy of dexamethasone when used for protection against acute and delayed nausea and vomiting in patients receiving highly or moderately emetogenic cancer chemotherapy. MATERIALS AND METHODS: A meta-analysis was performed using trials identified through MEDLINE (1966 to April 1999), Embase, Derwent Drug File, and the Cochrane Library’s Database of Controlled Trials. Data on acute and delayed emesis and nausea were collected. All randomized studies comparing dexamethasone to placebo, no treatment, or other antiemetics qualified, including cross-over trials providing first-cycle data. RESULTS: Of 1,200 citations screened, 32 studies with 42 pertinent comparisons and 5,613 patients were included in the meta-analysis. Dexamethasone was superior to placebo or no treatment for complete protection from acute emesis (odds ratio, 2.22; 95% confidence interval [CI], 1.89 to 2.60) and for complete protection from delayed emesis (odds ratio, 2.04; 95%...

Dealuminated H-Y zeolites : Influence of the degree and the type of dealumination method on the structural and acidic characteristics of H-Y zeolites

Abstract: Dealuminated zeolite samples prepared by different methods are characterized by different techniques, and the structural and acidic characteristics are investigated in an effort to identify the parameters that decide their structural and acidic characteristics. The investigation gave evidence that the structure breakdown of the parent type-Y zeolite is mainly dependent on the degree of dealumination, but the nature of extraframework aluminum (EFAl) species formed is dependent on the type of dealumination procedure. Monomeric Al species and oligomeric Si,Al species were formed by steam treatment at relatively low and high temperatures, respectively. Aluminosilicate phases of Si/Al ratios 2.0−4.0 and 8.0 were found in SiCl4-treated and ammonium hexafluorosilicate (AHFS)-treated samples, respectively. EFAl species of octahedral and tetrahedral coordination were observed by NMR spectra in steam and SiCl4-treated samples. High degrees of dealumination within each type of treatment resulted in loss of microporo...

Outcome of lupus pregnancy: a controlled study

Abstract: OBJECTIVE The reciprocal relationship between systemic lupus erythematosus (SLE) and pregnancy was investigated in a controlled study. METHOD The outcome of 47 pregnant SLE patients with 59 pregnancies was compared with that of 57 healthy control women and 59 pregnancies. The results were also compared with those of 59 non-pregnant control SLE patients. RESULTS All pregnant SLE patients but one were in remission at the onset of pregnancy and were being treated with low doses of prednisone (< or = 10 mg/day, 26 patients), hydroxychloroquine (200 mg/day, eight patients) or azathioprine (100 mg/day, one patient). Sixty-one per cent of SLE pregnancies were delivered at term and 5% had premature deliveries. The rates of spontaneous abortion and total fetal loss were significantly higher in the mothers with SLE than in the control population (P: < 0.001 and P: < 0.01 respectively). None of the 39 neonates from SLE mothers had neonatal lupus, anti-Ro(SSA) or anti-La(SSB) antibodies. Eight out of 59 pregnancies of SLE mothers (13.5%) were characterized by disease exacerbation. Arthralgias or arthritis, fever and skin lesions were observed more frequently in the mothers with SLE than in the non-pregnant group (P: < 0.001). Renal involvement was found in three SLE patients during pregnancy and in three after delivery. CONCLUSIONS Pregnant women with SLE are at high risk of fetal loss and spontaneous abortion. Pregnancy does not cause life-threatening manifestations of the disease. Thus, for a better outcome of lupus pregnancy, it is essential to control disease activity and to achieve clinical remission.

String-Inspired Higher-Curvature Terms and the Randall-Sundrum Scenario

Abstract: We consider the $O({\ensuremath{\alpha}}^{\ensuremath{'}})$ string effective action, with Gauss-Bonnet curvature-squared and fourth-order dilaton-derivative terms, which is derived by a matching procedure with string amplitudes in five space-time dimensions. We show that a non-factorizable metric of the Randall-Sundrum (RS) type, with a four-dimensional conformal factor ${e}^{\ensuremath{-}2k|z|},$ can be a solution of the pertinent equations of motion. The parameter k is found to be proportional to the string coupling ${g}_{s}$ and thus the solution appears to be non-perturbative. It is crucial that the Gauss-Bonnet combination have the right (positive in our conventions) sign, relative to the Einstein term, which is the case necessitated by compatibility with string (tree) amplitude computations. We study the general solution for the dilaton and metric functions, and thus construct the appropriate phase-space diagram in the solution space. In the case of an anti--de Sitter bulk, we demonstrate that there exists a continuous interpolation between (part of) the RS solution at $z=+\ensuremath{\infty}$ and an (integrable) naked singularity at $z=0.$ This implies the dynamical formation of domain walls (separated by an infinite distance), thus restricting the physical bulk space-time to the positive z axis. Some brief comments on the possibility of fine-tuning the four-dimensional cosmological constant to zero are also presented.

Anaemia in systemic lupus erythematosus: aetiological profile and the role of erythropoietin

Abstract: Objective—To study the prevalence of different causes of anaemia in patients with systemic lupus erythematosus (SLE) and their associations with immunological and clinical parameters and to evaluate the contribution of erythropoietin (Epo) and anti-erythropoietin (anti-Epo) autoantibodies to the development of SLE anaemia. Methods—132 SLE patients with anaemia (defined as haemoglobin of 12 g/dl or less for women and 13.5 g/dl or less for men) from among a total of 345 consecutive SLE patients were prospectively enrolled into the study. Standard haematological and immunological tests were performed and serum Epo and anti-Epo antibodies were assayed. Results—The identified causes were anaemia of chronic disease (ACD) n=49 (37.1%), iron deficiency anaemia (IDA) n=47 (35.6%), autoimmune haemolytic anaemia (AHA) n=19 (14.4%) and other causes n=17 (12.9%). There was significant heterogeneity in the severity of anaemia between the four groups (p<0.01) with AHA cases being on average more severe. Theproportionofpatientswithanticardiolipin antibodies, low complement levels and anti-dsDNA diVered significantly among the four groups; these markers were particularly common in patients with AHA, and uncommon in patients with IDA. Twenty one of 100 tested patients had anti-Epo antibodies. Such antibodies were seen practically only in patients with ACD (odds ratio 3.1, p=0.041) and in patients with high lupus activity (ECLAM) scores (odds ratio 1.27 per point, p=0.055). Epo response was inadequate in 42.4% and 41.2% of patients with ACD and AHA, respectively. Conclusions—Anaemia in SLE usually takes the form of ACD and IDA, however autoimmune haemolysis is not uncommon. SLE patients with diVerent causes of anaemia diVer in regard to several immunological parameters. Epo response is blunted in anaemic SLE patients, particularly those with ACD and AHA. (Ann Rheum Dis 2000;59:217‐222)

The role of cytokines in sickle cell disease.

Abstract: Sickle cell disease (SCD) is characterized by chronic hemolysis, frequent infections, and recurrent occlusions of microcirculation, which cause painful crises and result in chronic organ damage and failure. Occlusions of the microcirculation and infections are important factors that stimulate the production of cytokines and acute-phase proteins. Cytokines seem to be involved with several possible mechanisms in the pathogenesis of vasoocclusive phenomena in SCD: vascular endothelial activation, induction of red-cell adhesiveness to vascular endothelium, induction of neutrophil adhesiveness to endothelium, development of vascular intimal hyperplasia, platelet activation, endothelin-1 production, and dysregulation of endothelial apoptosis. Cytokines are also thought to be involved in the regulation of hemopoiesis, the inhibition of immune functions, and the development of growth deficits. Investigation of cytokines in SCD patients will elucidate the pathogenesis of the disease and its complications and may help in assessing disease severity and prognosis.

Micelle-mediated methodology for speciation of chromium by flame atomic absorption spectrometry

Abstract: The concept of cloud point phenomenon is used to perform metal speciation after the studied metallic forms have reacted with suitable ligands for the formation of hydrophobic complexes, which are subsequently entrapped in the surfactant micelles. As an analytical demonstration, trace concentrations of Cr(III) and Cr(VI) were conveniently detected in samples with a complex matrix, such as sea water, without any laborious and expensive treatment using flame atomic absorption spectrometry. The speciation of Cr is performed using Triton X-114 as surfactant and, as chelating agents, ammonium pyrrolidinedithiocarbamate for Cr(VI) and 8-hydroxyquinoline for Cr(III). Analytical curves were rectilinear up to concentrations of 130 µg l−1 for Cr(III) and 85 µg l−1 for Cr(VI) with detection limits of 1.4 µg l−1 and 0.65 µg l−1, respectively. The method affords recoveries in the range 96–104% and a relative standard deviation lower than 2.2%. It is proved that the method can be successfully employed as an alternative to the commonly used preconcentration and speciation analytical techniques. By selecting the appropriate complexing agent(s) other metal speciations are feasible provided that some detailed study precedes the application.

Energetic, vibrational, and electronic properties of silicon using a nonorthogonal tight-binding model

Abstract: : We present calculations of energetic, electronic, and vibrational properties of silicon using a nonorthogonal tight-binding (TB) model derived to fit accurately first-principles calculations. Although it was fit only to a few high-symmetry bulk structures, the model can be successfully used to compute the energies and structures of a wide range of configurations. These include phonon frequencies at high-symmetry points, bulk point defects such as vacancies and interstitials, and surface reconstructions. The TB parametrization reproduces experimental measurements and ab initio calculations well, indicating that it describes faithfully the underlying physics of bonding in silicon. We apply this model to the study of finite temperature vibrational properties of crystalline silicon and the electronic structure of amorphous systems that are too large to be practically simulated with ab initio methods.

Bioremediation of olive oil mill wastewater: chemical alterations induced by Azotobacter vinelandii.

Abstract: An environmentally friendly bioremediation system of olive oil mill wastewater (OMWW) is studied with respect to its physicochemical characteristics and degradation efficiency on major characteristic constituents. The method exploits the biochemical versatility of the dinitrogen fixing bacterium Azotobacter vinelandii (strain A) to grow in OMWW at the expense of its constituents and to transform it into an organic liquid fertilizer. The system eliminates the phytotoxic principles from OMWW and concomitantly enriches it with an agriculturally beneficial microbial consortium along with useful metabolites of the latter. The end product, branded “biofertilizer”, is used as soil conditioner and liquid organic fertilizer. Growth of A. vinelandii in OMWW results in the decline of content of most of the compounds associated with phytotoxicity, and this is confirmed by the assessment of degradation yields. In parallel, during the process several other compounds noncommittally undergo degradation and biotransformat...

Ventricular pre-excitation in the general population: a study on the mode of presentation and clinical course

Abstract: OBJECTIVE To describe the mode of presentation and the clinical course of patients with ventricular pre-excitation (Wolff-Parkinson-White (WPW) syndrome), with special emphasis on asymptomatic cases in the general population. METHODS Over an eight year period (1990–97) a prospective population based survey of cases with WPW pattern was conducted in a defined population in north west Greece (340 000 inhabitants). ECGs with WPW pattern were obtained from a widespread pool of ECGs within the health system. RESULTS During the study period, 157 cases with WPW pattern were identified (49 female, 108 male). Ages ranged from infants to 84 years, mean (SD) 49.1 (21.0) years in female and 39.6 (20.6) years in male subjects (p v 38.5 (20.6) years, p CONCLUSIONS WPW pattern is more common, and diagnosed at a younger age, in men than in women. About half the patients with WPW pattern on ECG are asymptomatic at diagnosis and tend to remain so thereafter. No sudden cardiac death occurred during the study period.

Posterior cruciate ligament architecture: evaluation under microsurgical dissection.

Abstract: Purpose: Our objective was to verify the fiber anatomy of the posterior cruciate ligament (PCL) and to measure the main dimensions and the femoral and tibial attachment site distances of the ligament after microsurgical dissection. We hypothesized that PCL anatomy is more complex than the 2 traditionally characterized bands. Type of Study: This is a purely anatomic description of microdissections of the PCL, focused on the fine anatomy of the ligament. Materials and Methods: Twenty-four fresh-frozen cadaveric knees were dissected using magnifying loupes and an operative microscope, being careful to avoid creating artificially separated bundles. The main dimensions of the PCL were measured using a micrometer. Results: The anterior, central, posterior-longitudinal, and posterior-oblique were the 4 fiber regions identified based on their orientation and the osseous sites of their insertions. These were partially separable anatomically but were functionally distinct. The anterior and central fiber regions made up the bulk of the ligament, while the remaining 15% consisted of the posterior fiber regions. During manual joint motion, the behavior of these fiber regions was observed. The anterior fiber region appeared to be the most nonisometric and remained in tension mainly between 30° and 90° of flexion. The posterior fiber regions appeared to be the most isometric (especially the posterior-oblique) and remained in tension mainly in extension and partially in deep flexion. The central fiber region appeared to have an intermediate behavior and remained in tension mainly between 30° and 120° of flexion. Additionally, it appeared to be the widest of all fiber regions. Conclusions: These findings should be of interest and help in interpreting some of the anatomy encountered during arthroscopic examination of the PCL, both from the anterior and posterior lateral portals. Furthermore, this information should prove useful in selecting treatment for the PCL. Arthroscopy: The Journal of Arthroscopic and Related surgery, Vol 16, No 6 (September), 2000: pp 627–632

Mechanisms of hyponatraemia in alcohol patients.

Abstract: Hyponatraemia is commonly reported in chronic alcoholic patients. However, the underlying pathogenetic mechanisms are not well delineated. In the current study, we analysed the possible pathophysiological mechanisms of hyponatraemia in a group of alcoholic patients (n = 127) admitted to our hospital for causes related to alcohol misuse. Hyponatraemia (serum sodium <134 mmol/l) was found in 22 patients (17.3%). The most common cause of hyponatraemia in our cohort was hypovolaemia (12 patients); pseudohyponatraemia was diagnosed in six patients with alcohol-induced severe hypertriglyceridaemia. It is of interest that two patients fulfilled the criteria of the so-called 'beer potomania' syndrome, while in two others, hyponatraemia was due to reset osmostat or to cerebral salt wasting syndrome, not previously described in alcoholic patients. It is concluded that hyponatraemia is a frequently observed electrolyte disorder in hospitalized alcoholic patients and is related to various pathophysiological mechanisms.

Shell model calculations for light supersymmetric particle scattering off light nuclei

Abstract: We investigate the elastic scattering cross section of cold dark matter candidates, i.e., lightest supersymmetric particles (LSP), with light nuclei ${(}^{19}\mathrm{F},$ ${}^{23}\mathrm{Na},$ and ${}^{29}\mathrm{Si}).$ These nuclei are promising targets of direct detection for such cold dark matter. We pay special attention to the spin dependence of the differential event rate. Our calculations are performed in the $s\ensuremath{-}d$ shell model space with the Wilthental interaction. We also examine the momentum transfer dependence of the differential cross section.

Supersymmetric fluid mechanics

Abstract: When anticommuting Grassmann variables are introduced into a fluid dynamical model with irrotational velocity and no vorticity, the velocity acquires a nonvanishing curl and the resultant vorticity is described by Gaussian potentials formed from the Grassmann variables. Upon adding a further specific interaction with the Grassmann degrees of freedom, the model becomes supersymmetric.

Potential aetiological factors concerning the development of osteonecrosis of the femoral head.

Abstract: Background The aetiology and pathogenesis of non-traumatic osteonecrosis (ON) of the femoral head have not been fully elucidated. The present study was conducted to evaluate the possible correlation of relevant haematological and biochemical factors with the development of ON. Patients and methods Our investigation consisted of measurement of haematological indices and assessment of the biochemical and lipid profile of a study population of 68 patients with non-traumatic ON of the femoral head and 36 healthy controls. The disease was considered idiopathic in 17 and secondary in 51 patients. Results There were no statistically significant differences in the parameters measured among the idiopathic ON, secondary ON and control groups, except for globulins α1, α2 and β, which were significantly increased in both patient groups, and apolipoprotein B (Apo B), which was increased in patients with idiopathic disease compared with the control group. Both patient groups presented increased von Willebrand factor (VWF) and lipoprotein (a) [Lp(a)] levels and decreased protein C and S concentrations, but without statistical significance. However, both patient groups exhibited a greater proportion of abnormal values of any of these parameters, in 58.9% of the idiopathic and in 62.7% of the secondary ON patients, compared with 8.3% of the controls. Conclusion Our study underlines the potential association of abnormal values of protein C, protein S, VWF and Lp(a) with ON. To our knowledge this is the first reported association of VWF with the disease. The majority of both idiopathic and secondary ON patients in our series exhibits a thrombotic potential that adds further support to the postulation that intravascular coagulation is a major pathogenetic mechanism leading to the disease.

Culture-Based Knowledge on Biodiversity, Development and Stability of Human Gastrointestinal Microflora

Abstract: The human large intestine harbours an abundant and extremely diverse microflora with more than 400–500 microbial species estimated. The dominant microflora in faecal samples is obligately anaerobic: Especially Bacteroides spp. , Eubacterium spp. , Bi?dobacterium spp. , lactobacilli, anaerobic cocci and Clostridium spp. are detected in high numbers by bacterial culture. In addition, facultatively anaerobic organisms such as Escherichia coli , enterococci and streptococci are commonly encountered. Although several thorough studies on the diversity of the faecal flora has been performed during 1970’s, investigation of intestinal flora by culture-based methods has several limitations: The lack of culture media supporting the growth of some components of dominant flora, difficulties in identification of bacteria by traditional phenotypic methods and continuous changes in taxonomy complicate studies on the intestinal flora by bacterial culture. Since invasive sampling techniques are required to obtain intestinal samples, most studies on human intestinal flora have been restricted mainly to the analysis of the faecal flora. A faecal sample seems to represent the microflora in the large intestine, whereas the microflora in the upper parts of the intestinal tract is sparse and less diverse. During the development of the intestinal flora in newborns, facultatively anaerobic species, especially E. coli , staphylococci and streptococci are colonising first and subsequently obligate anaerobes including Bacteroides spp. , Bifidobacterium spp. and Clostridium spp. appear in faeces within few days. By the end of the second year of life the faecal flora resembles that of adults. Although a great variation in the flora composition exists between individuals, the faecal microflora in adults is relatively stable. However, several factors such as changes in age, diet, geographic location and disease may influence the composition of the normal intestinal flora. Keywords: bacteria, cultural method, faecal microflora, gut ecology, intestinal microflora.