Acoustic tokamak with strongly coupled toroidal bubbles.

Gas bubbles stabilized in toroidal 3D-printed cages are good acoustic resonators with an unusual topology. We arrange them in a circular array to obtain what we call an "acoustic tokamak" because of the torus shape of the whole array. We demonstrate experimentally and theoretically that the system features several acoustic modes resulting from the acoustic interaction between tori.

In vitro evidence for impaired neuroprotective capacities of adult mesenchymal stem cells derived from a rat model of familial amyotrophic lateral sclerosis (hSOD1(G93A)).

Protection of neurons by stem cells is an attractive challenge in the development of efficient therapies of neurodegenerative diseases. When giving preference to autologous grafts, the bone marrow constitutes a valuable source of adult stem cells. Therefore, we herein studied the acquisition of neuroprotective functions by cultured mesenchymal stem cells (MSCs) exposed to growth factors known to promote the differentiation of neural stem cells into astrocytes.

Specific regulation of rat glial cell line-derived neurotrophic factor gene expression by riluzole in C6 glioma cells.

Contrasting with its robust expression during embryogenesis, the glial cell line-derived neurotrophic factor (GDNF) is repressed in the adult organism. However, rapid induction of this neuronal growth factor is observed following diverse neuronal insults and it is now widely accepted that the control of its expression could constitute a powerful target in neuropharmacology. We investigated the effects of the neuroprotective drug, riluzole, on the GDNF gene expression in glial cells.

Whole blood real-time quantitative PCR for cytomegalovirus infection follow-up in transplant recipients.

Background: Cytomegalovirus (CMV) remains a major opportunistic agent among transplant recipients. While detection of CMV pp65-lower matrix protein (pp65Ag) is still widely used for monitoring CMV infection, real-time PCR assays have been recently developed for routine quantitation of CMV DNA. However, correlations are lacking between results of pp65Ag and quantitative PCR assays and there is no consensus yet as to the more appropriate blood compartment (whole blood (WB), leukocytes, plasma) to be tested with PCR assays.

Amantadine and memantine induce the expression of the glial cell line-derived neurotrophic factor in C6 glioma cells.

Aminoadamantanes are commonly used in the treatment of Parkinson's and Alzheimer's diseases. While these drugs are shown to antagonise ionotropic glutamate receptors on neuronal cells, additional mechanisms could contribute to their neuroprotective properties. The aim of the present study was to investigate the effect of aminoadamantanes on the production of the glial cell line-derived neurotrophic factor (GDNF) in glial cells.

Intraneuronal amyloid-beta1-42 production triggered by sustained increase of cytosolic calcium concentration induces neuronal death.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the presence in the brain of senile plaques which contain an amyloid core made of beta-amyloid peptide (Abeta). Abeta is produced by the cleavage of the amyloid precursor protein (APP). Since impairment of neuronal calcium signalling has been causally implicated in ageing and AD, we have investigated the influence of an influx of extracellular calcium on the metabolism of human APP in rat cortical neurones.

Biochemical and random mutagenesis analysis of the region carrying the catalytic E152 amino acid of HIV-1 integrase.

HIV-1 integrase (IN) catalyzes the integration of the proviral DNA into the cellular genome. The catalytic triad D64, D116 and E152 of HIV-1 IN is involved in the reaction mechanism and the DNA binding. Since the integration and substrate binding processes are not yet exactly known, we studied the role of amino acids localized in the catalytic site.

The lethal phenotype observed after HIV-1 integrase expression in yeast cells is related to DNA repair and recombination events.

Human immunodeficiency virus type 1 (HIV-1) integrase (IN) catalyzes the insertion of the viral genome into the host cell DNA, an essential reaction during the retroviral cycle. We described previously that expression of HIV-1 IN in some yeast strains may lead to the emergence of a lethal phenotype which was not observed when the catalytically crucial residues D, D, (35)E were mutated. The lethal effect in yeast seems to be related to the mutagenic effect of the recombinant HIV-1 IN, most probably via the non-sequence-specific endonucleolytic activity carried by this enzyme.

HIV type 1 diversity in France, 1999-2001: molecular characterization of non-B HIV type 1 subtypes and potential impact on susceptibility to antiretroviral drugs.

Non-B HIV-1 samples collected in France between 1999 and 2001 were sequenced in the env, reverse transcriptase (RT), and protease genes (1) to characterize further the non-B strains circulating in the country, (2) to assess the importance of recombination, and (3) to describe the polymorphism of RT and protease genes and appreciate a possible impact on susceptibility to antiretroviral (ARV) drugs. The results show that, within a background of CRF02_AG predominance, there is a high genetic diversity of non-B isolates, including intersubtype recombinants. There is an extensive polymorphism of protease and RT genes compared with B consensus sequences; we have so far no data indicating that these non-B isolates may have reduced sensitivity to ARV drugs.

Virologic response to nelfinavir-based regimens: pharmacokinetics and drug resistance mutations (VIRAPHAR study).

Objective: To assess the impact of HIV-1 protease and reverse transcriptase (RT) mutations, and pharmacokinetic parameters on virological responses to nelfinavir (NFV)-containing highly active antiretroviral therapy.

Design: Naive or antiretroviral-experienced HIV-1-infected subjects were included in a non-randomized, observational cohort study and received two nucleoside RT inhibitors + NFV (750 mg three times per day or 1250 mg twice per day). Virologic success was defined as a virus load < 50 copies/ml for > 6 months.

A novel short peptide is a specific inhibitor of the human immunodeficiency virus type 1 integrase.

The retroviral encoded protein integrase (IN) is required for the insertion of the human immunodeficiency virus type 1 (HIV-1) proviral DNA into the host genome. In spite of the crucial role played by IN in the retroviral life cycle, which makes this enzyme an attractive target for the development of new anti-AIDS agents, very few inhibitors have been described and none seems to have a potential use in anti-HIV therapy. To obtain potent and specific IN inhibitors, we used the two-hybrid system to isolate short peptides.

HIV-1 integrase interacts with yeast microtubule-associated proteins.

The human immunodeficiency virus type 1 (HIV-1) integrase (IN) mediates the insertion of viral DNA into the human genome. In addition to IN, cellular and viral proteins are associated to proviral DNA in the so-called preintegration complex (PIC). We previously reported that the expression of HIV-1 IN in yeast leads to the emergence of a lethal phenotype.

Functional interactions of human immunodeficiency virus type 1 integrase with human and yeast HSP60.

Integration of human immunodeficiency virus type 1 (HIV-1) proviral DNA in the nuclear genome is catalyzed by the retroviral integrase (IN). In addition to IN, viral and cellular proteins associated in the high-molecular-weight preintegration complex have been suggested to be involved in this process. In an attempt to define host factors interacting with IN, we used an in vitro system to identify cellular proteins in interaction with HIV-1 IN.

Sequence analysis of env C2/V3, gag p17/p24, and pol protease regions of 25 HIV type 1 isolates from Ho Chi Minh City, Vietnam.

Env C2/V3, gag p17/p24, pol protease, and RT regions of HIV-1 isolates recently obtained from 25 HIV-1 seropositive individuals from Ho Chi Minh City (Vietnam) were studied, and genes subtypes were determined by DNA sequence analyses. Twenty-three isolates out of 25 were identified as belonging to subtype E, now recognized as circulating recombinant form 1 (CRF01_AE). The motif at the top of the V3 loop (generally GPGQ) was then preceded by an isoleucine or a methionine (M) residue; the M residue might be a local signature of Vietnamese E isolates compared to Thai E viruses.

Comparison of capillary electrophoresis sequencing with the new CEQ 2000 DNA Analysis System to conventional gel based systems for HIV drug resistance analysis.

To date the majority of sequencing technologies have been based on use of gel plates. In this study sequencing by capillary electrophoresis for HIV-1 genotyping on the CEQ 2000 sequencer (Beckman Coulter Inc.) has been investigated and compared to an 'in house' protocol on the Prism-377 sequencer (Applied Biosystems) and to the HIV-1 TruGene kit (Visible Genetics Inc.

Phospholipase D1: a key factor for the exocytotic machinery in neuroendocrine cells.

Phospholipase D (PLD) has been proposed to mediate cytoskeletal remodeling and vesicular trafficking along the secretory pathway. We recently described the activation of an ADP ribosylation factor-regulated PLD at the plasma membrane of chromaffin cells undergoing secretagogue-stimulated exocytosis. We show here that the isoform involved is PLD1b, and, using a real-time assay for individual cells, that PLD activation and exocytosis are closely correlated.

Inhibition of HIV-1 integrase-catalysed reaction by new DNA minor groove ligands: the oligo-1,3-thiazolecarboxamide derivatives.

Human immunodeficiency virus type 1 (HIV-1) integrase (IN) is an essential enzyme in the life cycle of the retrovirus, responsible for catalysing the insertion of the viral genome into the host cell chromosome. For this reason it provides an attractive target for antiviral drug design. We synthesized a series of novel thiazole (Tz)-containing oligopeptides (TCOs; oligo-1,3-thiazolecarboxamides), specifically interacting within the minor groove of DNA.

Insight in the exocytotic process in chromaffin cells: regulation by trimeric and monomeric G proteins.

Catecholamine secretion from chromaffin cells has been used for a long time as a general model to study exocytosis of large dense core secretory granules. Permeabilization and microinjection techniques have brought the possibility to dissect at the molecular level the multi-protein machinery involved in this complex physiological process. Regulated exocytosis comprises distinct and sequential steps including the priming of secretory granules, the formation of a docking complex between granules and the plasma membrane and the subsequent fusion of the granule with the plasma membrane.

Inactivation of the SNF5 transcription factor gene abolishes the lethal phenotype induced by the expression of HIV-1 integrase in yeast.

The ubiquitous human transcription factor Ini1 has been shown to interact with HIV-1 integrase (IN) and to stimulate in vitro the reactions catalyzed by this enzyme. We have previously used a yeast model to study the effect of HIV-1 IN expression (Caumont, A.B.

Identification of a plasma membrane-associated guanine nucleotide exchange factor for ARF6 in chromaffin cells. Possible role in the regulated exocytotic pathway.

ADP-ribosylation factors (ARFs) constitute a family of structurally related proteins that forms a subset of the Ras superfamily of regulatory GTP-binding proteins. Like other GTPases, activation of ARFs is facilitated by specific guanine nucleotide exchange factors (GEFs). In chromaffin cells, ARF6 is associated with the membrane of secretory granules.

Selection of amino acid substitutions restoring activity of HIV-1 integrase mutated in its catalytic site using the yeast Saccharomyces cerevisiae.

The integration of proviral DNA into the genome of the host cell is an essential step in the replication of retroviruses. This reaction is catalyzed by a viral-encoded enzyme, the integrase (IN). We have previously shown that human immunodeficiency virus type 1 (HIV-1) IN causes a lethal effect when expressed in yeast cells.

High affinity interaction of HIV-1 integrase with specific and non-specific single-stranded short oligonucleotides.

Retroviral integrase (IN) catalyzes the integration of double-stranded viral DNA into the host cell genome. The reaction can be divided in two steps: 3'-end processing and DNA strand transfer. Here we studied the effect of short oligonucleotides (ODNs) on human immunodeficiency virus type 1 (HIV-1) IN.