Victoria Gerolami

Use of Phylogenetic Analysis of Hepatitis C Virus (HCV) Hypervariable Region 1 Sequences To Trace an Outbreak of HCV in an Autodialysis Unit

ABSTRACT Hemodialysis patients are at high risk of infection by hepatitis C virus (HCV). The aim of this study was to investigate an HCV outbreak that occurred in an autodialysis unit by using epidemiological and molecular methods. Seroconversion to HCV antibody (anti-HCV) was observed in two patients over an 18-month period; two other patients had previously been recorded as anti-HCV positive. All four patients involved in the outbreak were tested for HCV RNA, and hepatitis C genotype determination was accomplished by a reverse hybridization assay. Furthermore, part of hypervariable region 1 (HVR1) of the hepatitis C genome was amplified and sequenced in samples from all HCV RNA-positive patients. Phylogenetic analysis of the nucleotide sequences obtained was carried out in order to investigate any possible epidemiological linkages among patients. The nucleotide sequences of the HVR1 regions of both newly infected patients were found to be identical to sequences of samples from previously recorded anti-HCV-positive original patients, suggesting that they were infected by the same isolate. Molecular and epidemiological analysis suggested that nosocomial patient-to-patient transmission was the most likely explanation for the virus spread in the autodialysis unit under study.

Head-up tilt induced syncope and adenosine A2A receptor gene polymorphism

AIMS High adenosine plasma levels and high expression of adenosine A(2A) receptors are observed in patients with unexplained syncope and a positive head-up tilt test (HUT). This study aimed to evaluate the single nucleotide polymorphism (SNP) (c.1364 T>C) which is the most commonly found polymorphism in the A(2A) receptor gene, in patients with unexplained syncope undergoing HUT. METHODS AND RESULTS One hundred and five patients with unexplained syncope who underwent HUT were included. Fifty-two had a positive test. Receptor genotype determinations were performed in patients and in 121 healthy subjects. Genotype (TT, CC, TC) was determined from DNA leucocytes. The distribution of the polymorphism showed significant (P < 0.0001) difference when the results of HUT were analysed. Fifty-two per cent of patients with a positive HUT had a CC genotype and 34.6% a TC genotype, whereas 13.2% of the patients with a negative HUT had a CC genotype and 71.7% a TC genotype. Patients with a CC genotype had a higher incidence of spontaneous syncopal episodes. CONCLUSION In patients with unexplained syncope, a significant association between high incidence of syncopal episodes, positive HUT, and the presence of the CC variant in the adenosine A(2A) receptor gene was elicited.

Patterns of gene expressions induced by arsenic trioxide in cultured human fibroblasts

Arsenic exposure is associated with several human diseases and particularly, with neoplasia. Although the mechanism of arsenic toxicity is not fully understood, several recent works pointed out the involvement of oxidative stress in arsenic-induced DNA damage that, in living cells, correlates with changes in gene expressions. In cultured human fibroblasts exposed for 24 h to micromolar arsenic concentrations, we studied, using real-time RT-PCR, the expression profile of a limited number of genes: genes coding for a stress protein (HSP70), transcription factors (cJUN, cFOS, ETR103, ETR101 and TTP) and cell cycle or DNA repair proteins (P21, GADD153). We observed that the expression profile of genes followed individual different patterns that can be summed up in early-transient gene expression by contrast to delayed gene expression.

Adenosine A2A receptor hyperexpression in patients with severe SIRS after cardiopulmonary bypass.

Objective Adenosine (ADO) is an endogenous nucleoside, which has been involved in blood pressure failure during severe systemic inflammatory response syndrome (severe SIRS) after cardiac surgery with cardiopulmonary bypass (CPB). Adenosine acts via its receptor subtypes, namely A1, A2A, A2B, or A3. Because A2A receptors are implicated in vascular tone, their expression might contribute to severe SIRS. We compared adenosine plasma levels (APLs) and A2A ADO receptor expression (ie, B, K, and mRNA amount) in patients with or without postoperative SIRS. Patients This was a prospective comparative observational study. Forty-four patients who underwent cardiac surgery involving CPB. Ten healthy subjects served as controls. Measurements and Results Among the patients, 11 presented operative vasoplegia and postoperative SIRS (named complicated patients) and 33 were without vasoplegia or SIRS (named uncomplicated patients). Adenosine plasma levels, K, B, and mRNA amount (mean ± SD) were measured on peripheral blood mononuclear cells. Adenosine plasma levels, B, and K were significantly higher in complicated patients than in uncomplicated patients (APLs: 2.7 ± 1.0 vs 1.0 ± 0.5 μmol l−1, P < 0.05; B: 210 ± 43 vs 65 ± 26 fmol/mg, P < 0.05; K: 35 ± 10 vs 2 ± 1 nM, P < 0.05). In uncomplicated patients, APLs remain higher than in controls (1 ± 0.5 vs 0.6 ± 0.25 μmol/L; P < 0.05). Mean arterial pressure was inversely correlated to APLs (R = −0.58; P < 0.001) and B (R = −0.64; P < 0.001) leading to an increased requirement of vasoactive drugs during the postoperative period in vasoplegic patients. Conclusions High expression of A2A ADO receptor and high APLs may be a predictive factor of postoperative severe SIRS after CPB.

Adenosine and Clinical Forms of Neurally-Mediated Syncope

Central or peripheral baroreceptor reflex abnormalities, alterations in neurohumoral mechanisms, or both, are thought to play a role in causing neurally-mediated syncope. Because adenosine and its receptors are involved in some forms of syncope [(1–3)][1], we evaluated the purinergic profile of 4

Relationship between A2A Adenosine Receptor Expression and Intradialytic Hypotension during Hemodialysis

Background Intradialytic hypotension (IDH) is a common complication of hemodialysis sessions (HDSs). Adenosine may contribute to the drop in blood pressure during IDH events because it has hypotensive effects. As A2A adenosine receptor expression is essential for blood pressure control, we compared the expression of A2A receptors (Bmax, KD, and messenger ribonucleic acid [mRNA] levels) in peripheral blood mononuclear cells from IDH and non-IDH patients and from controls. We also evaluated adenosine plasma levels (APLs). Methods We included 10 hemodialyzed patients with at least three IDH events per month. We also included 11 hemodialyzed patients with no history of IDH events and 10 healthy subjects as controls. Results IDH patients had higher Bmax values than non-IDH patients (mean before HDS, +86%; after HDS, +112%), whereas non-IDH patients had lower Bmax values than controls (mean −72%). KD values were not significantly different between patients and controls. The levels of mRNA increased significantly during HDS but without an increase in receptor expression on the cell membranes. APLs were higher in hemodialyzed patients than in controls. Conclusion We found that A2A receptors are more expressed in IDH patients than in non-IDH patients, whereas APL was high in all patients. Both high APL and a relative increase in A2A receptor expression may favor IDH events.

Purinergic profile of fainting divers is different from patients with vasovagal syncope.

a UMR MD2, AMU, Faculty of Medicine, Marseille, France b IRBA, France c Toulon University, France d Department of Hyperbaric Medicine, Sainte Marguerite Hospital, Marseille, France e Laboratoire de Biologie Moléculaire, Hôpital de la Conception, AP-HM, France f Department of Intensive Care, AP-HM, France g Department of Emergency Medicine, AP-HM, France h Department of Cardiology, Syncope Unit, Lavagna, Italy i Department of Cardiology, Timone University Hospital, Marseille, France j Laboratory of Biochemistry, Timone University Hospital, AP-HM, France

SKCa Channels Blockage Increases the Expression of Adenosine A2A Receptor in Jurkat Human T Cells

Abstract Adenosine is a nucleoside displaying various biological effects via stimulation of four G-protein–coupled receptors, A1, A2A, A2B, and A3. Adenosine also modulates voltage-gated (Kv) and small conductance calcium-activated (SKCa) potassium channels. The effect of these potassium channels on the expression of adenosine receptors is poorly understood. We evaluated the action of BgK (a natural Kv channel blocker) and Lei-Dab7 (a synthetic SKCa channel blocker) on the expression of adenosine A2A receptors (A2AR) in Jurkat human T cells. We found that Lei-Dab7, but not BgK, increased the maximal binding value of the tritiated ligand ZM241385 to A2AR in a dose-dependent manner (+45% at 5 nM; +70% at 50 nM as compared to control). These results were further confirmed by Western blotting using a specific monoclonal antibody to human A2AR. The ligand affinity-related dissociation constant and A2AR mRNA amount were not significantly modified by either drug. We suggest that modulation of SKCa channels can influence membrane expression of A2AR and thus has a therapeutic potential.