Medium-Chain Lipid Conjugation Facilitates Cell-Permeability and Bioactivity.

The majority of bioactive molecules act on membrane proteins or intracellular targets and therefore needs to partition into or cross biological membranes. Natural products often exhibit lipid modifications to facilitate critical molecule-membrane interactions, and in many cases their bioactivity is markedly reduced upon removal of a lipid group. However, despite its importance in nature, lipid-conjugation of small molecules is not commonly used in chemical biology and medicinal chemistry, and the effect of such conjugation has not been systematically studied. To understand the composition of lipids found in natural products, we carried out a chemoinformatic characterization of the "natural product lipidome". According to this analysis, lipidated natural products predominantly contain saturated medium-chain lipids (MCLs), which are significantly shorter than the long-chain lipids (LCLs) found in membranes and lipidated proteins. To study the usefulness of such modifications in probe design, we systematically explored the effect of lipid conjugation on five different small molecule chemotypes and find that permeability, cellular retention, subcellular localization, and bioactivity can be significantly modulated depending on the type of lipid tail used. We demonstrate that MCL conjugation can render molecules cell-permeable and modulate their bioactivity. With all explored chemotypes, MCL-conjugates consistently exhibited superior uptake or bioactivity compared to LCL-conjugates and either comparable or superior uptake or bioactivity to short-chain lipid (SCL)-conjugates. Together, our findings suggest that conjugation of small molecules with MCLs could be a powerful strategy for the design of probes and drugs.

Discordance between Anterior Segment Anatomy and Axial Length in Cataract Surgery Candidates in France.

INTRODUCTION: The aims of this study were to study ocular biometric data and their association with age and sex in a population of cataract surgery candidates and to assess the proportion of inhomogeneous eyes and the ratio anterior segment (AS) to axial length (AL). Multicentric cross-sectional analysis was conducted between April 2008 and May 2021 in public and private ophthalmic institutions in Montpellier, France. Individuals ≥40 years old who underwent ocular biometry before cataract surgery were included. METHODS: Right phakic eyes were included. Ocular biometrics were measured by using the Lenstar LS900 device. We defined AS as anterior chamber depth (ACD) plus lens thickness (LT) and calculated the ratio of AS to AL. We defined inhomogeneous eyes as those with deep AS (≥4th quartile) and short AL (≤1st quartile) (AS+) or with short AS and high AL (AL+). RESULTS: We included 11,650 individuals (11,650 eyes) (mean [SD] age 71.64 [10.50] years; 54.51% women). Older age was associated with shorter AL (p < 0.01), shallower ACD (p < 0.01), thinner central corneal thickness (p < 0.01), and larger LT (p < 0.001). Women had shorter AL, shallower ACD, and thinner central corneal thickness than men (p < 0.001). In total, 778 (6.68%) eyes were inhomogeneous (3.22% AS+ and 3.46% AL+), for a mean (SD) AS/AL ratio of 0.36 (0.01) and 0.28 (0.01), respectively, as compared with 0.32 (0.02) for homogeneous eyes (p < 0.001). CONCLUSION: The AS/AL ratio could be useful to screen inhomogeneous eyes before cataract surgery and justify the use of new generation formulas in these eyes to avoid the risk of refractive error.

Determinants in the Ig Variable Domain of Human HAVCR1 (TIM-1) Are Required To Enhance Hepatitis C Virus Entry.

Hepatitis C virus (HCV) is the leading cause of chronic hepatitis in humans. Several host molecules participate in HCV cell entry, but this process remains unclear. The complete unraveling of the HCV entry process is important to further understand viral pathogenesis and develop therapeutics. Human hepatitis A virus (HAV) cellular receptor 1 (HAVCR1), CD365, also known as TIM-1, functions as a phospholipid receptor involved in cell entry of several enveloped viruses. Here, we studied the role of HAVCR1 in HCV infection. HAVCR1 antibody inhibited entry in a dose-dependent manner. HAVCR1 soluble constructs neutralized HCV, which did not require the HAVCR1 mucinlike region and was abrogated by a mutation of N to A at position 94 (N94A) in the Ig variable (IgV) domain phospholipid-binding pocket, indicating a direct interaction of the HAVCR1 IgV domain with HCV virions. However, knockout of HAVCR1 in Huh7 cells reduced but did not prevent HCV growth. Interestingly, the mouse HAVCR1 ortholog, also a phospholipid receptor, did not enhance infection and a soluble form failed to neutralize HCV, although replacement of the mouse IgV domain with the human HAVCR1 IgV domain restored the enhancement of HCV infection. Mutations in the cytoplasmic tail revealed that direct HAVCR1 signaling is not required to enhance HCV infection. Our data show that the phospholipid-binding function and other determinant(s) in the IgV domain of human HAVCR1 enhance HCV infection. Although the exact mechanism is not known, it is possible that HAVCR1 facilitates entry by stabilizing or enhancing attachment, leading to direct interactions with specific receptors, such as CD81.IMPORTANCE Hepatitis C virus (HCV) enters cells through a multifaceted process. We identified the human hepatitis A virus cellular receptor 1 (HAVCR1), CD365, also known as TIM-1, as a facilitator of HCV entry. Antibody blocking and silencing or knockout of HAVCR1 in hepatoma cells reduced HCV entry. Our findings that the interaction of HAVCR1 with HCV early during infection enhances entry but is not required for infection support the hypothesis that HAVCR1 facilitates entry by stabilizing or enhancing virus binding to the cell surface membrane and allowing the correct virus-receptor positioning for interaction with the main HCV receptors. Furthermore, our data show that in addition to the phospholipid-binding function of HAVCR1, the enhancement of HCV infection involves other determinants in the IgV domain of HAVCR1. These findings expand the repertoire of molecules that HCV uses for cell entry, adding to the already complex mechanism of HCV infection and pathogenesis.

Evisceration with autogenous scleral graft and bioceramic implantation within the modified scleral shell: 133 cases over 17 years.

INTRODUCTION: To present long-term follow-up data on evisceration performed with autogenous scleral grafting and ceramic implantation in a modified scleral shell. METHODS: This was a retrospective analysis of all consecutive eviscerations performed in the Department of Ophthalmology, Montpellier University Hospital, France, between February 1998 and October 2015. For all patients, the technique used was a conventional anterior evisceration after total keratectomy, disinsertion of the medial rectus muscle, sectioning of the optic nerve and excision of sclera centered on the papilla. The scleral graft was then sutured just behind the sutured keratectomy, and the bioceramic implant was inserted by posterior way in the scleral shell. Demographic characteristics, implant size and type, cosmetic results from pictures of all patients and complications were recorded. This study was performed with Ethics Review Committee Approval, and in compliance with the Declaration of Helsinki. RESULTS: In total, 133 patients (36.6% women) were identified during the study period. The mean (SD) implant size was 17.32 (1.84) mm. The median follow-up after evisceration was 57.43 (24.7, 68.3) months. Two cases of implant exposure (1.5%) were recorded. For 24 patients (17.9%), additional surgeries were performed for ptosis (2.2%), conjunctival cyst (1.5%), or post-evisceration socket syndrome (6.7%). Cosmetics results were excellent for 50.1% of cases, good for 33.3% and fair for 16.6%; using a grading scale based on the superior sulcus deformity. CONCLUSION: Evisceration with autogenous scleral grafting and ceramic implantation can result in a high volume of restoration, good cosmetic results, and low risk of exposure of the implant.

Glycosylation, hypogammaglobulinemia, and resistance to viral infections.

Genetic defects in MOGS, the gene encoding mannosyl-oligosaccharide glucosidase (the first enzyme in the processing pathway of N-linked oligosaccharide), cause the rare congenital disorder of glycosylation type IIb (CDG-IIb), also known as MOGS-CDG. MOGS is expressed in the endoplasmic reticulum and is involved in the trimming of N-glycans. We evaluated two siblings with CDG-IIb who presented with multiple neurologic complications and a paradoxical immunologic phenotype characterized by severe hypogammaglobulinemia but limited clinical evidence of an infectious diathesis. A shortened immunoglobulin half-life was determined to be the mechanism underlying the hypogammaglobulinemia. Impaired viral replication and cellular entry may explain a decreased susceptibility to infections.

Binding of hepatitis A virus to its cellular receptor 1 inhibits T-regulatory cell functions in humans.

BACKGROUND & AIMS: CD4+ T-regulatory (Treg) cells suppress immune responses and control self-tolerance and immunity to pathogens, cancer, and alloantigens. Most pathogens activate Treg cells to minimize immune-mediated tissue damage and prevent clearance, which promotes chronic infections. However, hepatitis A virus (HAV) temporarily inhibits Treg-cell functions. We investigated whether the interaction of HAV with its cellular receptor 1 (HAVCR1), a T-cell co-stimulatory molecule, inhibits the function of Treg cells to control HAV infection. METHODS: We studied the effects of HAV interaction with HAVCR1 on human T cells using binding, signal transduction, apoptosis, activation, suppression, cytokine production, and confocal microscopy analyses. Cytokines were analyzed in sera from 14 patients with HAV infection using bead arrays. RESULTS: Human Treg cells constitutively express HAVCR1. Binding of HAV to HAVCR1 blocked phosphorylation of Akt, prevented activation of the T-cell receptor, and inhibited function of Treg cells. At the peak viremia, patients with acute HAV infection had no Treg-cell suppression function, produced low levels of transforming growth factor-ß , which limited leukocyte recruitment and survival, and produced high levels of interleukin-22, which prevented liver damage. CONCLUSIONS: Interaction between HAV and its receptor HAVCR1 inhibits Treg-cell function, resulting in an immune imbalance that allows viral expansion with limited hepatocellular damage during early stages of infection-a characteristic of HAV pathogenesis. The mechanism by which HAV is cleared in the absence of Treg-cell function could be used as a model to develop anticancer therapies, modulate autoimmune and allergic responses, and prevent transplant rejection.

Induction of ebolavirus cross-species immunity using retrovirus-like particles bearing the Ebola virus glycoprotein lacking the mucin-like domain.

BACKGROUND: The genus Ebolavirus includes five distinct viruses. Four of these viruses cause hemorrhagic fever in humans. Currently there are no licensed vaccines for any of them; however, several vaccines are under development. Ebola virus envelope glycoprotein (GP1,2) is highly immunogenic, but antibodies frequently arise against its least conserved mucin-like domain (MLD). We hypothesized that immunization with MLD-deleted GP1,2 (GPΔMLD) would induce cross-species immunity by making more conserved regions accessible to the immune system. METHODS: To test this hypothesis, mice were immunized with retrovirus-like particles (retroVLPs) bearing Ebola virus GPΔMLD, DNA plasmids (plasmo-retroVLP) that can produce such retroVLPs in vivo, or plasmo-retroVLP followed by retroVLPs. RESULTS: Cross-species neutralizing antibody and GP1,2-specific cellular immune responses were successfully induced. CONCLUSION: Our findings suggest that GPΔMLD presented through retroVLPs may provide a strategy for development of a vaccine against multiple ebolaviruses. Similar vaccination strategies may be adopted for other viruses whose envelope proteins contain highly variable regions that may mask more conserved domains from the immune system.

[Human enteroviruses and respiratory infections]. / Entérovirus non poliomyélitiques et pathologies respiratoires.

Enteroviruses (EV) (Picornaviridae) are common infectious agents divided into 4 species, including 108 serotypes and responsible for a wide range of human pathologies including upper and lower respiratory tract infections occurring in adults and infants. Recent clinical studies indicated that these viruses are considered as the third etiological cause of bronchiolitis in young infants aged 1-12 months. Moreover, several clinical case studies reported the etiological role of the coxsackievirus A16 (CV-A16), the enterovirus 71 (EV-71) and of a newly discovered genotype (EV-104) in the development of acute or fatal pneumonia indicating that EV belonging to species A to C can be responsible for severe lower respiratory tract infections in immunocompetent infants or adults. Taking into account these recent epidemiological and clinical data and because of frequent mutations and intra-species enteroviral RNA genomic recombination events, the EV respiratory strains have to be considered as potential agents of further emerging infectious diseases in human populations.

Epidemiological, molecular, and clinical features of enterovirus respiratory infections in French children between 1999 and 2005.

Enteroviruses (EVs) can induce nonspecific respiratory tract infections in children, but their epidemiological, virological, and clinical features remain to be assessed. In the present study, we analyzed 252 EV-related infection cases (median age of subjects, 5.1 years) diagnosed among 11,509 consecutive children visiting emergency departments within a 7-year period in the north of France. EV strains were isolated from nasopharyngeal samples by viral cell culture, identified by seroneutralization assay, and genetically compared by partial amplification and sequencing of the VP1 gene. The respiratory syndromes (79 [31%] of 252 EV infections) appeared as the second most common EV-induced pediatric pathology after meningitis (111 [44%] of 252 cases) (44 versus 31%, P < 10(-3)), contributing to lower respiratory tract infection (LRTI) in 43 (54%) of 79 EV respiratory infection cases. Bronchiolitis was the most common EV-induced LRTI (34 [43%] of 79 cases, P < 10(-3)) occurring more often in infants aged 1 to 12 months (P = 0.0002), with spring-fall seasonality. Viruses ECHO 11, 6, and 13 were the more frequently identified respiratory strains (24, 13, and 11%, respectively). The VP1 gene phylogenetic analysis showed the concomitant or successive circulation of genetically distinct EV respiratory strains (species A or B) during the same month or annual epidemic period. Our findings indicated that respiratory tract infections accounted for the 30% of EV-induced pediatric pathologies, contributing to LRTIs in 54% of these cases. Moreover, the concomitant or successive circulation of genetically distinct EV strains indicated the possibility of pediatric repeated respiratory infections within the same epidemic season.

Human Bocavirus quantitative DNA detection in French children hospitalized for acute bronchiolitis.

BACKGROUND: Human Bocavirus (HBoV) is a newly discovered parvovirus whose role as a causative agent of respiratory disease remains unclear. STUDY DESIGN: We investigated the presence of HBoV by quantitative PCR in the nasopharyngeal samples of 192 French children consecutively hospitalized for acute bronchiolitis. Other common respiratory viruses were detected using immunofluorescence assays, cell culture detection, or RT-PCR assays. RESULTS: HBoV was detected in 24 (12.5%) of 192 study children. In 14/192 cases (7%) HBoV was the sole isolate and in 10/192 (5%) it was part of a mixed viral infection. HBoV was the third most common pathogen detected after respiratory syncytial virus (45/192; 23%) and rhinovirus (24/192; 12%). It occurred more often in infants aged 1-12 months (P=0.002). Median levels of HBoV DNA genome in respiratory samples were significantly higher in patients with single HBoV infection than in patients with mixed respiratory viral infection with HBoV (4x10(8)copies/ml vs. 2x10(3)copies/ml, P<0.001). CONCLUSIONS: Our data suggest that HBoV at a high viral load could be an etiologic agent of respiratory tract disease, whereas the exact role of HBoV at a low viral load, as etiological cause or as pathophysiological co-factor of respiratory diseases, remains to be determined.

Clinical and virological features of an aseptic meningitis outbreak in North-Eastern France, 2005.

BACKGROUND: Enteroviruses (EVs) are considered as a major viral etiological cause of aseptic meningitis in children. OBJECTIVES: We assessed the clinical and virological features of an aseptic meningitis outbreak in North-East of France, 2005. STUDY DESIGN: Classical bacteriological analysis, Herpesviridae and EV PCR assays had been prospectively performed on cerebrospinal fluid (CSF) samples taken from 80 children hospitalized for aseptic meningitis. For each EV strain identified as etiological agent, a phylogenetic comparison of partial EV VP1 capsid protein coding gene was performed. RESULTS: The children older than 12 months (n=75) presented a typical aseptic meningitis syndrome, whereas the children aged less than 1 year (n=5) demonstrated only fever and hypotonia. Among the 80 studied children, EV was identified as the etiological cause of aseptic meningitis in 73 (91%) cases. Echovirus 30 (E30) was the most common isolated serotype (84% of 51 EV strains). VP1 phylogenetic analysis revealed that E30 strains were genetically closer to those isolated during 2000 aseptic meningitis outbreak comparatively to those identified during 2003 and 2006 non-epidemic years. Moreover, the genetic study demonstrated the co-circulation of four distinct lineages without any difference in temporal distribution or clinical features during the 2005 outbreak. CONCLUSIONS: The present report demonstrates the co-circulation of distinct E30 lineages during the same aseptic meningitis outbreak season. This E30 genetic diversity may be a prerequisite for the emergence of new strains potentially responsible for further aseptic meningitis outbreaks.

Association of respiratory picornaviruses with acute bronchiolitis in French infants.

BACKGROUND: Human rhinoviruses and enteroviruses (Picornaviridae) are suspected to be major viral etiological causes of bronchiolitis in infants. OBJECTIVES: In the present study, we assessed the potential role of the respiratory picornaviruses as causative agents of bronchiolitis in French infants. STUDY DESIGN: From September 2001 to June 2002, we prospectively selected 192 infants < or =36 months of age and hospitalized for acute bronchiolitis. The detection of common respiratory viruses (respiratory syncytial virus, influenza virus A and B, parainfluenza virus 1, 2, 3 and adenovirus) was performed using classical immunofluorescence antigen and cell-culture detection assays on nasopharyngeal aspirates whereas the detection of human metapneumovirus (HMPV) was performed by a real-time RT-PCR assay. The presence of rhinovirus and/or enterovirus was assessed in respiratory samples by a picornavirus RT-PCR detection assay followed by a differential Southern blotting procedure. RESULTS: A potential causative virus was detected in 72.5% of the 192 study infants. RSV (30%), rhinovirus (21%), enterovirus (9%), influenza virus A (6%) and human metapneumovirus (4%) were the most frequent causative agents detected. Rhinoviruses or enteroviruses were detected as the only evidence of respiratory viral tract infection in 57 (30%) of 192 infants, whereas rhinovirus or enterovirus occurred in mixed viral infection detected in 25 (13%) of 192 study cases (30% versus 13%, p<10(-3)). CONCLUSIONS: Our data suggest that respiratory picornaviruses are one of the leading etiological causes of bronchiolitis in French infants. These findings highlight the need to implement a rapid picornavirus RT-PCR detection assay for the clinical diagnosis of respiratory infections in pediatric patients with bronchiolitis.

A unique role for Kv3 voltage-gated potassium channels in starburst amacrine cell signaling in mouse retina.

Direction-selective retinal ganglion cells show an increased activity evoked by light stimuli moving in the preferred direction. This selectivity is governed by direction-selective inhibition from starburst amacrine cells occurring during stimulus movement in the opposite or null direction. To understand the intrinsic membrane properties of starburst cells responsible for direction-selective GABA release, we performed whole-cell recordings from starburst cells in mouse retina. Voltage-clamp recordings revealed prominent voltage-dependent K(+) currents. The currents were mostly blocked by 1 mm TEA, activated rapidly at voltages more positive than -20 mV, and deactivated quickly, properties reminiscent of the currents carried by the Kv3 subfamily of K+ channels. Immunoblots confirmed the presence of Kv3.1 and Kv3.2 proteins in retina and immunohistochemistry revealed their expression in starburst cell somata and dendrites. The Kv3-like current in starburst cells was absent in Kv3.1-Kv3.2 knock-out mice. Current-clamp recordings showed that the fast activation of the Kv3 channels provides a voltage-dependent shunt that limits depolarization of the soma to potentials more positive than -20 mV. This provides a mechanism likely to contribute to the electrical isolation of individual starburst cell dendrites, a property thought essential for direction selectivity. This function of Kv3 channels differs from that in other neurons where they facilitate high-frequency repetitive firing. Moreover, we found a gradient in the intensity of Kv3.1b immunolabeling favoring proximal regions of starburst cells. We hypothesize that this Kv3 channel gradient contributes to the preference for centrifugal signal flow in dendrites underlying direction-selective GABA release from starburst amacrine cells

Preliminary investigation of a mice model of Klebsiella pneumoniae subsp. ozaenae induced pneumonia.

In the present study, we comparatively assessed the pathophysiological mechanisms developed during lung infection of BALB/C female mice infected by an original wild type Klebsiella pneumoniae subsp. ozaenae strain (CH137) or by a referent subspecies K. pneumoniae. subsp. pneumoniae strain (ATCC10031). The mice infected with 2.106 CFU K. p. subsp. pneumoniae (n = 10) showed transient signs of infection and all of them recovered. All of those infected with 1.106 CFU K. p. subsp. ozaenae (n = 10) developed pneumonia within 24 h and died between 48 and 72 h. Few macrophages, numerous polymorphonuclear cells and lymphocytes were observed in their lungs in opposite to K. p. subsp. pneumoniae. In bronchoalveolar lavage, a significant increase in MIP-2, IL-6, KC and MCP-1 levels was only observed in K. p. subsp. ozaenae infected mice whereas high levels of TNF-α were evidenced with the two subspecies. Our findings indicated a lethal effect of a wild type K. p. subsp. ozaenae strain by acute pneumonia reflecting an insufficient alveolar macrophage response. This model might be of a major interest to comparatively explore the pathogenicity of K. p. subsp ozaenae strains and to further explore the physiopathological mechanisms of gram-negative bacteria induced human pneumonia.

Ebola virus glycoprotein Fc fusion protein confers protection against lethal challenge in vaccinated mice.

Ebola virus is a Filoviridae that causes hemorrhagic fever in humans and induces high morbidity and mortality rates. Filoviruses are classified as "Category A bioterrorism agents", and currently there are no licensed therapeutics or vaccines to treat and prevent infection. The Filovirus glycoprotein (GP) is sufficient to protect individuals against infection, and several vaccines based on GP are under development including recombinant adenovirus, parainfluenza virus, Venezuelan equine encephalitis virus, vesicular stomatitis virus (VSV) and virus-like particles. Here we describe the development of a GP Fc fusion protein as a vaccine candidate. We expressed the extracellular domain of the Zaire Ebola virus (ZEBOV) GP fused to the Fc fragment of human IgG1 (ZEBOVGP-Fc) in mammalian cells and showed that GP undergoes the complex furin cleavage and processing observed in the native membrane-bound GP. Mice immunized with ZEBOVGP-Fc developed T-cell immunity against ZEBOV GP and neutralizing antibodies against replication-competent VSV-G deleted recombinant VSV containing ZEBOV GP. The ZEBOVGP-Fc vaccinated mice were protected against challenge with a lethal dose of ZEBOV. These results show that vaccination with the ZEBOVGP-Fc fusion protein alone without the need of a viral vector or assembly into virus-like particles is sufficient to induce protective immunity against ZEBOV in mice. Our data suggested that Filovirus GP Fc fusion proteins could be developed as a simple, safe, efficacious, and cost effective vaccine against Filovirus infection for human use.

Respiratory echovirus 30 and coxsackievirus B5 can induce production of RANTES, MCP-1 and IL-8 by human bronchial epithelial cells.

Human Enteroviruses (HEV) (picornaviridae) are considered as one the major viral causes of childhood acute respiratory wheezing illnesses including bronchiolitis and asthma exacerbation. To identify the mechanisms that can regulate the development of airway mucosa inflammation during HEV respiratory lower tract infection, we investigated the profile and the levels of mRNA and protein secretion for CC and CXC human chemokines by HEV-infected primary human bronchial epithelial cells (SAE cells) using RT-PCR array and Bio-Plex assay. Cultures of SAE cells were infected by reference and wild-type HEV respiratory strains, demonstrating a replicative and productive viral infection. We observed that the replicative infection of the SAE cells by reference and wild-type HEV strains induced specific dose and time-dependent increases in mRNA and protein secretion only for RANTES, MCP-1 and IL-8 and not for all other CC and CXC human chemokines tested. The protein secretion of these chemokines appeared to be significantly increased at 48 or 72h post-infection in cultures treated by low-doses of IFN-gamma comparatively to mock-infected cells (P<0.001), and was correlated to the viral replication activity. In conclusion, our findings demonstrated a selective production of RANTES, IL-8 and MCP-1 released by HEV-infected epithelial cells of the small bronchioles along with mechanisms of amplification mediated by IFN-gamma.

Phylogenetic analysis of Echovirus 30 isolated during the 2005 outbreak in France reveals existence of multiple lineages and suggests frequent recombination events.

BACKGROUND: Echovirus 30 (E-30) was responsible in France for a major aseptic meningitis outbreak during 2005 summer season. However, the virological mechanisms responsible for the periodic emergence of the epidemic strains remain to be investigated. OBJECTIVES: To assess the genetic diversity of two genome regions, VP1 and 3Dpol, of echovirus 30 strains isolated during the 2005 aseptic meningitis outbreak in Champagne Ardenne (CA) area (France). STUDY DESIGN: Partial VP1 genomic region of 23 E-30 strains isolated in CA was sequenced and compared with 73 E-30 strains originating from different French areas to estimate the number and the diversity of E-30 lineages. Partial sequences for 3D polymerase (3Dpol) were analyzed to detect potential recombination events within the non-structural (NS) region of the genome of EV neurotropic strains. RESULTS: Phylogenetic analysis of the VP1 evidenced the co-circulation of 6 distinct E-30 lineages responsible for the 2005 aseptic meningitis outbreak in France of which three had co-circulated in CA. Partial sequencing of the 3Dpol coding region showed that all of the E-30 strains exhibited different phylogenetic links between VP1 and 3Dpol genomic regions, suggesting multiple intra- or inter-serotypic recombination events within the NS part of the genome. CONCLUSIONS: Our findings revealed existence of multiple lineages and suggested frequent recombination events among E-30 strains having co-circulated in a restricted area during a short time outbreak period. Moreover, our data demonstrated that study of single VP1 genome region analysis could not accurately describe the phylogenetic origin of E-30 isolates.

Synaptic regulation of the light-dependent oscillatory currents in starburst amacrine cells of the mouse retina.

Responses of on-center starburst amacrine cells to steady light stimuli were recorded in the dark-adapted mouse retina. The response to spots of dim white light appear to show two components, an initial peak that correspond to the onset of the light stimulus and a series of oscillations that ride on top of the initial peak relaxation. The frequency of oscillations during light stimulation was three time higher than the frequency of spontaneous oscillations recorded in the dark. The light-evoked responses in starburst cells were exclusively dependent on the release of glutamate likely from presynaptic bipolar axon terminals and the binding of glutamate to AMPA/kainate receptors because they were blocked by 6-cyano-7-nitroquinoxalene-2,3-dione. The synaptic pathway responsible for the light responses was blocked by AP4, an agonist of metabotropic glutamate receptors that hyperpolarize on-center bipolar cells on activation. Light responses were inhibited by the calcium channel blockers cadmium ions and nifedipine, suggesting that the release of glutamate was calcium dependent. The oscillatory component of the response was specifically inhibited by blocking the glutamate transporter with d-threo-beta-benzyloxyaspartic acid, suggesting that glutamate reuptake is necessary for the oscillatory release. GABAergic antagonists bicuculline, SR 95531, and picrotoxin increased the amplitude of the initial peak while they inhibit the frequency of oscillations. TTX had a similar effect. Strychnine, the blocker of glycine receptors did not affect the initial peak but strongly decreased the oscillations frequency. These inhibitory inputs onto the bipolar axon terminals shape and synchronize the oscillatory component.

Fatal echovirus 18 leukoencephalitis in a child.

Rare cases of leukoencephalitis have been reported in infants with documented enterovirus (EV) central nervous system (CNS) infections. A case of fatal encephalitis with white matter lesions caused by echovirus 18 is described, and it highlights the role of EV CNS infection as a potential cause of leukoencephalitis in infants.

Genetic and phenotypic features of blood and genital viral populations of clinically asymptomatic and antiretroviral-treatment-naive clade a human immunodeficiency virus type 1-infected women.

In the present study, we assessed whether human immunodeficiency virus type 1 (HIV-1) genetic compartmentalization was associated with phenotypic CCR5 (R5) or CXCR4 (X4) coreceptor usage differences between the systemic and the genital viral populations. Four clinically asymptomatic and treatment-naïve clade A HIV-1-infected patients were selected from a cohort of 274 African women, because they were free of all the biological cofactors known to modify the kinetics of viral production in the genital tract. HIV RNA envelope sequences (V1 to V3) derived from plasma and cervicovaginal secretions (CVS) were amplified, subcloned, and sequenced. CCR5 or CXCR4 coreceptor usage was determined by production of recombinant viral particles, followed by single-cycle infection assays of indicator cell lines, using the tropism recombinant test. In these four selected patients, CVS-derived sequences appeared to be genetically distinct from blood-derived sequences (P < or = 0.001). Two patients were found to harbor virus populations with only the R5 phenotype in both compartments, whereas viruses using CXCR4 in addition to CCR5 were detected in two other patients. In particular, one woman harbored genital virus populations with mixed R5 and X4 phenotypes associated with peripheral blood populations with only the R5 phenotype. These results demonstrate genetic compartmentalization of HIV between the plasma and genital secretions of clinically asymptomatic, treatment-naïve, clade A-infected women. Also, for one patient, we report phenotypic coreceptor usage differences between the systemic (R5) and genital (R5/X4) viral populations. These features may be critical for the development of further mucosal vaccines, therapies, or new preventive strategies to block heterosexual transmission.