Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Encephale ; 42(6): 582-588, 2016 Dec.
Artículo en Francés | MEDLINE | ID: mdl-27644917

RESUMEN

Left temporal arachnoid cyst and specific learning disorders associated with pervasive developmental disorders - not otherwise specified (PDD-NOS): contributions of an integrative neuro-psychomotor, neuropsychological, psychopathological and neurosurgical approach about a case report in a child (François). With DSM-IV and DSM-IV-TR, the terminology of pervasive developmental disorders (PDD) covers two main categories of infantile disorders: disorders of "strictly" autistic nature and pervasive developmental disorders - not otherwise specified (PDD-NOS). Under the terminology of multiple complex developmental disorder (MCDD), it is proposed to classify children presenting symptoms approaching the psychotic disharmonies and usually diagnosed as PDD-NOS. Such a category of developmental disorders is now included without nosographic distinction in the autistic spectrum in the Diagnostic and Statistical Manual of mental disorders (DSM-V). CASE REPORT: We are reporting a case report of a 6-year-old boy which shows a PDD-NoS/MCDD complex symptomatology type. This child presents multiple disorders: minor neurological signs (soft signs), neuro-psychomotor disorders, developmental coordination disorder (DCD), communication, thought, and regulation of emotions disorders, attention deficit disorders (ADD); in the presence of a high verbal intellectual potential, which makes it difficult to establish a clear diagnosis. A cerebral magnetic resonance imaging (MRI) was carried out due to the presence of minor neurological signs (soft signs) and of neurodevelopmental multiple disorders. The MRI revealed a voluminous arachnoid temporo-polar left cyst with a marked mass effect on the left temporal lobe. DISCUSSION: A neurosurgical intervention allowed to observe the gradual disappearance of the specific symptomatology (in particular soft signs, neuro-psychomotor functions and autistic symptoms) secondary to the interference of the cyst's pressure with intracranial areas involving neurological and psychopathological abnormalities, underlying at the same time the reversibility of the disorders after decompression as demonstrated in some studies. There are always, with a quantitative and qualitative decrease, an emotional dysregulation, a DCD, an ADD as well as impairments in the executive functions. CONCLUSION: This clinical case underlines the necessity of an evaluation in a transdisciplinary way and to follow the developmental evolution of the child in order to focus adapted therapeutics. Furthermore, with neurodevelopmental disorders not specified, it is important to examine the presence of soft signs with standardized neuro-psychomotor assessment, and then, to propose an MRI investigation. To our knowledge, this is the first report in the literature with a school age child of an unusual association between a temporal arachnoid cyst associated with PDD-NOS/MCDD.


Asunto(s)
Quistes Aracnoideos/terapia , Trastornos Generalizados del Desarrollo Infantil/terapia , Procedimientos Neuroquirúrgicos/métodos , Trastorno Específico de Aprendizaje/terapia , Lóbulo Temporal/cirugía , Quistes Aracnoideos/psicología , Quistes Aracnoideos/cirugía , Trastorno por Déficit de Atención con Hiperactividad/etiología , Trastorno Autístico/etiología , Trastorno Autístico/terapia , Niño , Trastornos Generalizados del Desarrollo Infantil/psicología , Trastornos Generalizados del Desarrollo Infantil/cirugía , Terapia Combinada , Humanos , Imagen por Resonancia Magnética , Masculino , Trastornos de la Destreza Motora/etiología , Escalas de Valoración Psiquiátrica , Trastornos Psicomotores/etiología , Trastornos Psicomotores/terapia , Trastorno Específico de Aprendizaje/psicología , Trastorno Específico de Aprendizaje/cirugía , Resultado del Tratamiento
2.
Encephale ; 38(4): 318-28, 2012 Sep.
Artículo en Francés | MEDLINE | ID: mdl-22980473

RESUMEN

BACKGROUND: Specific language impairment (SLI) is a primary developmental disorder in which language is significantly more impaired than other developmental domains. Abnormal electroencephalographic recordings without clinical seizures are often observed. The aim of this retrospective study was to characterize the frequency of these abnormalities, to describe them and to analyze their association with anamnestic, clinical, paraclinical and evolution characteristics. METHODS: The cases of 35 children with a diagnosis of SLI, who also underwent electroencephalography and MRI, were systematically reviewed retrospectively. RESULTS: In this population, aged between 4 and 7 years, 49% (n=17) of patients exhibited a specific expressive language disorder and 51% (n=18) a specific receptive disorder. Forty-nine percent of the children featured abnormal electroencephalography results. Abnormalities were essentially localized on the left side of the brain and in two specific regions: the temporo-occipital (60%) and the frontorolandic (30%) regions. The groups with and without abnormalities were compared statistically with each other in terms of clinical, paraclinical and evolution characteristics. Evolution data were available for 24 patients through a telephone interview and for nine patients through a new complete language evaluation. The comparison of the two groups showed significant differences in terms of severity of the phonological disorder, a higher number of delayed acquisition of walking and cleanliness and a higher range of non specific psychomotor difficulties. DISCUSSION: A large proportion of children suffering from SLI present abnormal electroencephalography recordings with no clinical seizures. This rate is much higher than in the general population and the abnormalities are essentially localized on the left side of the brain in regions known for their specific role in language development. These abnormalities are more frequent in children with a severe phonological disorder, suggesting that they may share common pathophysiological features with SLI. CONCLUSION: The presence of EEG abnormalities in a large group of patients suffering from SLI associated with minor neurological abnormalities suggests a possible theoretical neurodevelopmental model. Minor neurodevelopmental abnormalities, genetically transmitted or acquired during the pre- or perinatal period, may create vulnerability towards SLI. This vulnerability, in conjunction with environmental influences such as family environment, linguistic stimuli, exposure to multiple languages, or transitory hearing loss, might take the form of SLI. This hypothesis underlines the importance of prevention and early detection of SLI when identifying vulnerable subjects. Monitoring the family early through parental guidance and early school support would facilitate the acquisition of language.


Asunto(s)
Daño Encefálico Crónico/diagnóstico , Daño Encefálico Crónico/fisiopatología , Corteza Cerebral/fisiopatología , Electroencefalografía , Trastornos del Desarrollo del Lenguaje/diagnóstico , Trastornos del Desarrollo del Lenguaje/fisiopatología , Mapeo Encefálico , Niño , Preescolar , Conducta Cooperativa , Dominancia Cerebral/fisiología , Potenciales Evocados/fisiología , Femenino , Lóbulo Frontal/fisiopatología , Humanos , Comunicación Interdisciplinaria , Pruebas del Lenguaje , Imagen por Resonancia Magnética , Masculino , Lóbulo Occipital/fisiopatología , Estudios Retrospectivos , Factores de Riesgo , Lóbulo Temporal/fisiopatología
3.
Arch Virol ; 151(10): 1933-46, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16732496

RESUMEN

Interferons induced by viral infections can have powerful immuno- modulatory effects, and several epidemiologic studies have found an association between certain viral infections and reduced prevalence of allergy. We hypothesized that allergenic proteins could be synthesized by a replicating virus, and this construct could be useful as an immunomodulator. To test this hypothesis, we cloned an allergenic protein (ovomucoid [OVM]) into a murine picornavirus (Mengo virus) vector. This plasmid has a multicloning site surrounded by auto-catalytic sequences so that a foreign protein will be cleaved from viral proteins during replication. OVM sequences were cloned in the context of full-length viral genome cDNA, T7 RNA transcripts of this plasmid were transfected into HeLa cells, and recombinant virus plaques appeared on the second passage. Sequence analysis of recombinant viruses derived from individual plaques demonstrated that three viral isolates contained up to 2/3 of the OVM coding sequence, which was retained by the viruses after 5 additional passages in HeLa cells. The experiments verify the stable expression of immunoreactive OVM subunits by replicating viruses. These virus/allergen constructs could provide a tool to evaluate whether intracellular presentation of allergenic proteins in the context of a viral infection could prevent allergic sensitization upon re-challenge.


Asunto(s)
Alérgenos/biosíntesis , Mengovirus/fisiología , Ovomucina/biosíntesis , Virus Reordenados/fisiología , Alérgenos/genética , Animales , Infecciones por Cardiovirus/virología , Vectores Genéticos/metabolismo , Vectores Genéticos/fisiología , Genoma Viral/genética , Células HeLa/metabolismo , Humanos , Mengovirus/genética , Mengovirus/metabolismo , Ratones , Ovomucina/genética , Ovomucina/inmunología , Plásmidos/genética , Virus Reordenados/metabolismo , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/inmunología , Recombinación Genética , Pase Seriado , Especificidad de la Especie , Transfección , Replicación Viral
4.
J Med Genet ; 41(1): 6-10, 2004 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-14729817

RESUMEN

BACKGROUND: Patients with hereditary haemochromatosis (HH) are usually homozygous for the C282Y mutation in the HFE gene. They have variable expression of iron overload and present with a variety of complications, including liver disease, diabetes, arthropathy, fatigue, and cardiomyopathy. The mitochondrial 16189 variant is associated with diabetes, dilated cardiomyopathy, and low body fat at birth, and might contribute to genetic predisposition in further multifactorial disorders. The objective of this study was to determine the frequency of the 16189 variant in a range of patients with haemochromatosis, who had mutations in the HFE gene. METHODS: Blood DNA was analysed for the presence of the 16189 variant in British, French, and Australian C282Y homozygotes and controls, with known iron status, and in birth cohorts. RESULTS: The frequency of the mitochondrial 16189 variant was found to be elevated in individuals with haemochromatosis who were homozygous for the C282Y allele, compared with population controls and with C282Y homozygotes who were asymptomatic (42/292 (14.4%); 102/1186 (8.6%) (p = 0.003); and 2/64 (3.1%) (p = 0.023), respectively). CONCLUSIONS: Iron loading in C282Y homozygotes with HH was exacerbated by the presence of the mitochondrial 16189 variant.


Asunto(s)
Sustitución de Aminoácidos/genética , ADN Mitocondrial/genética , Hemocromatosis/genética , Homocigoto , Mutación/genética , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Cisteína/genética , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/patología , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patología , Frecuencia de los Genes/genética , Genotipo , Proteína de la Hemocromatosis , Antígenos de Histocompatibilidad Clase I/genética , Humanos , Sobrecarga de Hierro/genética , Proteínas de la Membrana/genética , Persona de Mediana Edad , Fenotipo , Tirosina/genética
5.
J Mol Recognit ; 13(2): 71-82, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10822251

RESUMEN

The influence of peptide structure on immunogenicity has been investigated by constructing a series of cowpea mosaic virus (CPMV) chimaeras expressing the 14 amino acid NIm-1A epitope from human rhinovirus 14 (HRV-14) at different positions on the capsid surface. Biochemical and crystallographic analysis of a CPMV/HRV chimaera expressing the NIm-1A epitope inserted into the betaC'-betaC" loop of the S protein revealed that, although the inserted peptide was free at its C-terminus, it adopted a conformation distinct from that previously found when a similarly cleaved peptide was expressed in the betaB-betaC loop of the S protein. Adjustment of the site of insertion within the betaB-betaC loop resulted in the isolation of a chimaera in which cleavage at the C-terminus of the epitope was much reduced. Crystallographic analysis confirmed that in this case the epitope was presented as a closed loop. Polyclonal antisera raised against the CPMV/ HRV chimaera presenting the NIm-1A epitope as a closed loop had a significantly enhanced ability to bind to intact HRV-14 particles compared with antisera raised against chimaeras presenting the same sequence as peptides with free C-termini. These results demonstrate that the mode of presentation of an epitope on a heterologous carrier can dramatically affect its immunological properties.


Asunto(s)
Comovirus/química , Péptidos/inmunología , Proteínas Recombinantes de Fusión/inmunología , Rhinovirus/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Cápside/química , Cápside/metabolismo , Comovirus/genética , Comovirus/inmunología , Comovirus/metabolismo , Cristalografía por Rayos X , Electroforesis en Gel de Poliacrilamida , Epítopos , Humanos , Sueros Inmunes/biosíntesis , Inyecciones Intramusculares , Datos de Secuencia Molecular , Péptidos/química , Péptidos/metabolismo , Conformación Proteica , Conejos , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo
7.
J Virol ; 72(6): 4610-22, 1998 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9573224

RESUMEN

The structures of three different human rhinovirus 14 (HRV14)-Fab complexes have been explored with X-ray crystallography and cryoelectron microscopy procedures. All three antibodies bind to the NIm-IA site of HRV14, which is the beta-B-beta-C loop of the viral capsid protein VP1. Two antibodies, Fab17-IA (Fab17) and Fab12-IA (Fab12), bind bivalently to the virion surface and strongly neutralize viral infectivity whereas Fab1-IA (Fab1) strongly aggregates and weakly neutralizes virions. The structures of the two classes of virion-Fab complexes clearly differ and correlate with observed binding neutralization differences. Fab17 and Fab12 bind in essentially identical, tangential orientations to the viral surface, which favors bidentate binding over icosahedral twofold axes. Fab1 binds in a more radial orientation that makes bidentate binding unlikely. Although the binding orientations of these two antibody groups differ, nearly identical charge interactions occur at all paratope-epitope interfaces. Nucleotide sequence comparisons suggest that Fab17 and Fab12 are from the same progenitor cell and that some of the differing residues contact the south wall of the receptor binding canyon that encircles each of the icosahedral fivefold vertices. All of the antibodies contact a significant proportion of the canyon region and directly overlap much of the receptor (intercellular adhesion molecule 1 [ICAM-1]) binding site. Fab1, however, does not contact the same residues on the upper south wall (the side facing away from fivefold axes) at the receptor binding region as do Fab12 and Fab17. All three antibodies cause some stabilization of HRV14 against pH-induced inactivation; thus, stabilization may be mediated by invariant contacts with the canyon.


Asunto(s)
Anticuerpos Antivirales/inmunología , Fragmentos Fab de Inmunoglobulinas/inmunología , Rhinovirus/inmunología , Secuencia de Aminoácidos , Anticuerpos Antivirales/química , Anticuerpos Antivirales/ultraestructura , Reacciones Antígeno-Anticuerpo , Sitios de Unión , Cristalografía por Rayos X , Grabado por Congelación , Humanos , Fragmentos Fab de Inmunoglobulinas/química , Fragmentos Fab de Inmunoglobulinas/ultraestructura , Microscopía Electrónica , Datos de Secuencia Molecular , Rhinovirus/química , Rhinovirus/ultraestructura , Electricidad Estática
8.
J Virol ; 72(2): 1210-8, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9445020

RESUMEN

Three drug-dependent mutants of human rhinovirus 16 (HRV16) were characterized by sequence analyses of spontaneous mutant isolates and were genetically reconstructed from a parental cDNA plasmid. These mutants formed plaques in the presence but not in the absence of the selecting antiviral drug, WIN 52035, which binds to the capsid of wild-type virus and inhibits its attachment to the host cell. The drug-dependent phenotype of each mutant was caused by a single amino acid substitution in the VP1 coat protein. The three independent mutations conferring drug dependence are M1103T, T1208A, and V1210A. Single-step growth experiments involving rescue of one of the three mutants (V1210A) by delayed drug addition suggested (i) that the drug dependence lesion is at the stage of virus assembly and (ii) that one or more components of the viral assembly pool decay in the absence of drug. RNA accumulation and infectivity were unaffected by the absence of drug in all three mutants, suggesting that the labile assembly component is coat protein.


Asunto(s)
Antivirales/farmacología , Isoxazoles/farmacología , Mutación , Rhinovirus/fisiología , Ensamble de Virus/genética , Humanos , Modelos Moleculares , Virión/química , Virión/genética , Ensamble de Virus/efectos de los fármacos
9.
Lancet ; 347(9002): 644-8, 1996 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-8596378

RESUMEN

BACKGROUND: In less developed countries, rheumatic fever still occurs. We started a long-term educational programme in two French Caribbean islands that was directed at the public and at health-care workers to see whether we could reduce the incidence of rheumatic fever. METHODS: Our 10-year programme started in 1981 in Martinique and Guadeloupe, and was based in the community and in clinics and hospitals. The programme established a registry of all cases of primary and secondary rheumatic fever (diagnosed by Jones' modified criteria), with systematic hospital admission of children. We graded carditis as severe, mild, or subclinical, and acute glomerulonephritis was defined by oedema, proteinuria, and haematuria for less than 3 months. The educational part of the programme targeted the public and health-care workers, including doctors, with written information distributed in schools or via radio and television broadcasts or videotapes. For the public, the benign clinical presentation of the initial streptococcal infection was contrasted with the severity of later heart disease. FINDINGS: The first months of the programme led to a 10-20% increase in the number of rheumatic fever cases admitted to hospital, because of the renewed attention paid to the disease. Therefore we took 1982 as the baseline year. In 1982-83 the incidence of rheumatic fever was 19.6 per 100 000 inhabitants aged under 20 in Martinique, and 17.4 per 100 000 in Guadeloupe. In 100 Martinique children and 97 Guadeloupe children in 1982-83, 40 and 71% had carditis, respectively (severe in 10 and 32%). Rheumatic fever was preceded by symptomatic sore throat in 52 and 41% of cases, respectively. The disease was not seen in children with active streptococcal cutaneous infections. Disease frequency was highest in the poorest areas and families, a finding that persisted over time. The programme was associated with a progressive decline in the frequency of rheumatic fever: final reduction of 78% in Martinique and 74% in Guadeloupe. The frequency of carditis also fell. Apart from two outbreaks in one hospital, the frequency of acute glomerulonephritis also declined; 31% of cases had had sore throat, while 56% had skin infections. The cost of the programme during the 4 most intensive years was FFr 250 000 (US$ 44 500) in each island. The cost of childhood rheumatic fever, excluding late sequelae, was initially (in 1982) about FFr 7.8 million (US$ 1426 000). The cost fell to an average of Ffr 550 000 (US$ 100 000) per year in 1991-92. INTERPRETATION: A rapid decline in rheumatic fever incidence was achieved at modest cost. Such a programme needs to be continued because of the risk of disease resurgence.


Asunto(s)
Educación en Salud , Servicios Preventivos de Salud , Fiebre Reumática/prevención & control , Adolescente , Adulto , Niño , Preescolar , Costos y Análisis de Costo , Femenino , Educación en Salud/economía , Personal de Salud/educación , Hospitalización , Humanos , Incidencia , Masculino , Martinica/epidemiología , Tamizaje Masivo , Faringe/microbiología , Servicios Preventivos de Salud/economía , Sistema de Registros , Fiebre Reumática/epidemiología , Factores Socioeconómicos , Streptococcus/aislamiento & purificación , Indias Occidentales/epidemiología
10.
Acta Crystallogr D Biol Crystallogr ; 51(Pt 4): 490-5, 1995 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-15299835

RESUMEN

Capsid-binding drugs that inhibit the first stage of picornaviral uncoating were used to select drug-resistant mutants of the Sabin strain of poliovirus type 3. Such mutants provide information about parts of the capsid that are important for functions blocked by the drugs, and also about pathways to drug resistance. Amino-acid substitutions allowing virus to produce progeny in the presence of drug were mapped to 13 different residues occupying three distinct locations: (I) the canyon base; (II) the lining of the drug-binding pocket; and (III) the base of the protomer. These loci might be thought of as action points for transmitting the uncoating signal from receptor, through the pocket, and to the base of the protomer. All of the mutations in a special class of drug-dependent mutants were clustered at site (III) and all were hyperlabile, i.e., uncoated spontaneously (without receptor) at growth temperature unless prevented from doing so by the presence of drug in the pocket. Thus, site (III) seems to represent a kind of thermostat which regulates the temperature at which the uncoating transition (release of VP4 to form A particles) is triggered.

11.
J Virol ; 68(12): 8193-201, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7966611

RESUMEN

We have previously described the use of an uncoating inhibitor, WIN 51711, to select drug-resistant mutants of the Sabin strain of poliovirus type 3. Two-thirds of the mutants proved to be dependent on the drug for plaque formation because of extreme thermolability (A. G. Mosser and R. R. Rueckert, J. Virol. 67:1246-1254, 1993). Here we report the responsible mutations; all were traced to single amino acid substitutions. Mutations conferring dependence and thermolability occurred in all four capsid proteins (VP1 to VP4), but all were clustered near residue 53 of VP4 at the inner capsid surface. Amino acid substitutions of the remaining non-drug-dependent mutants were mapped to three distinct loci: (i) on or near the inner capsid surface, at VP4 residue 46 or VP1 residue 129, in the vicinity of the drug dependence substitutions; (ii) at residues 192, 194, and 260 in the lining of the VP1 beta barrel, which is the drug-binding site; and (iii) at VP1 residue 105 on the edge of the canyon surrounding the fivefold axis of symmetry, the putative receptor-binding site. All of the mutations increased the eclipse rate of cell-attached virus. Such mutants help identify parts of the capsid that play a role in viral uncoating functions.


Asunto(s)
Cápside/química , Farmacorresistencia Microbiana/genética , Proteínas de la Membrana , Mutación Puntual , Poliovirus/genética , Secuencia de Aminoácidos , Antivirales/farmacología , Sitios de Unión , Cápside/genética , Cápside/metabolismo , Células HeLa , Humanos , Isoxazoles/farmacología , Cinética , Modelos Biológicos , Modelos Moleculares , Poliovirus/efectos de los fármacos , Poliovirus/metabolismo , Conformación Proteica , Estructura Secundaria de Proteína , ARN Viral/química , ARN Viral/metabolismo , Receptores Virales/fisiología , Temperatura , Ensayo de Placa Viral
12.
J Mol Biol ; 240(2): 127-37, 1994 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-8027997

RESUMEN

The crystal structure of Fab17-IA, an antigen-binding fragment from a murine immunoglobulin that neutralizes human rhinovirus 14 (HRV14), has been solved to 2.7 A resolution. Fab17-IA crystallized into three different space groups depending upon the method used to purify the intact antibody. The structure was determined by use of molecular and isomorphous replacement methods. The current model has a crystallographic R-factor of approximately 19% for 10,192 independent reflections between 8 and 2.7 A. Correlation coefficient calculations showed that the Fab17-IA structure can be fit into the Fab17-IA/HRV14 image reconstruction density to within 5 A positional accuracy and to within a few degrees of rotation. The resulting interface of the docked antibody was examined and showed extensive charge and shape complementarity with the virus surface that was supported by site-directed mutagenesis experiments. The success of this approach validates the utility of combining X-ray crystallography with cryo-electron microscopy of complex macromolecular assemblies.


Asunto(s)
Anticuerpos Antivirales/química , Complejo Antígeno-Anticuerpo/química , Fragmentos Fab de Inmunoglobulinas/química , Rhinovirus/química , Secuencia de Aminoácidos , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , Complejo Antígeno-Anticuerpo/inmunología , Complejo Antígeno-Anticuerpo/ultraestructura , Secuencia de Bases , Criopreservación , Cristalografía por Rayos X , Humanos , Fragmentos Fab de Inmunoglobulinas/inmunología , Fragmentos Fab de Inmunoglobulinas/ultraestructura , Microscopía Electrónica , Modelos Moleculares , Datos de Secuencia Molecular , Pruebas de Neutralización , Conformación Proteica , Rhinovirus/inmunología , Rhinovirus/ultraestructura , Homología de Secuencia de Aminoácido , Relación Estructura-Actividad
13.
Arch Virol Suppl ; 9: 111-9, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-8032243

RESUMEN

The WIN drugs and similar hydrophobic compounds that insert into the capsid of picornaviruses have been shown to block viral uncoating. In some of the human rhinoviruses they also block attachment of virus to cells. Spontaneously occurring drug-resistant mutants of human rhinovirus 14 and poliovirus type 3 were selected for their ability to make plaques in the presence of the selecting drug. The HRV-14 mutants either prevented drug binding or allowed the virus to attach to cells in the presence of drug. About two thirds of the poliovirus mutants were dependent on the presence of drug for plaque formation. In single cycle growth curves, drug was not required for the formation of drug-dependent progeny virus. However, progeny virus grown without drug never accumulated outside of cells, thus making the formation of plaques impossible. This behavior was apparently caused by the extreme thermolability of these mutants. In the absence of drug, heating to 37 degrees C rapidly converted them to non-infectious particles with a sedimentation coefficient of 135S.


Asunto(s)
Antivirales/farmacología , Cápside/genética , Mutación , Poliovirus/genética , Rhinovirus/genética , Farmacorresistencia Microbiana/genética , Calor/efectos adversos , Poliovirus/efectos de los fármacos , Poliovirus/crecimiento & desarrollo , Rhinovirus/efectos de los fármacos , Rhinovirus/crecimiento & desarrollo , Relación Estructura-Actividad , Replicación Viral/efectos de los fármacos
14.
J Virol ; 67(6): 3126-33, 1993 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8388493

RESUMEN

Nineteen neutralizing murine monoclonal antibodies against poliovirus type 1, including representatives reacting with each of the antigenic sites on the virion, were tested for their abilities to neutralize the virus either before or after attachment to susceptible cells. All antibodies neutralized unattached virus; six had reasonable titers of postabsorption neutralization (PAN). Experiments with antibodies lacking PAN activity showed that Fc-specific rabbit anti-mouse antibodies could confer PAN activity. PAN was shown to involve the prevention of the cell-mediated conversion of virus to 135S and 80S particles. Evidence that one of the PAN-positive antibodies probably bound bivalently to preabsorbed virions, whereas a PAN-negative antibody bound monovalently, is presented. Two PAN-positive antibodies were added to an excess of virus in suspension, and only one antibody caused the virus to aggregate.


Asunto(s)
Anticuerpos Antivirales , Poliovirus/inmunología , Virión/inmunología , Anticuerpos Monoclonales , Reacciones Antígeno-Anticuerpo , Fragmentos Fc de Inmunoglobulinas/inmunología , Cadenas kappa de Inmunoglobulina/inmunología , Pruebas de Neutralización , Poliovirus/crecimiento & desarrollo , Poliovirus/metabolismo , Virión/crecimiento & desarrollo , Virión/metabolismo , Replicación Viral/inmunología
15.
J Virol ; 67(3): 1246-54, 1993 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8382293

RESUMEN

Twenty-two spontaneous mutants of the Sabin strain of poliovirus type 3 were selected for drug resistance by plating on HeLa cell monolayers in the presence of WIN 51711, an uncoating inhibitor. When replated in the presence and absence of drug, two classes of mutants were observed; mutants displayed either a drug-dependent or a non-drug-dependent phenotype, in the proportion 14:8. Non-drug-dependent mutants plaqued with equal efficiency in the presence or absence of drug. By contrast, drug-dependent mutants made no plaques in the absence of drug, except for revertants. In single-step growth curve experiments, however, drug-dependent mutants grew as well in the absence of drug as in its presence. This paradoxical behavior of dependent mutants was traced to extreme thermolability at 37 degrees C (12- to 30-s half-life) in the absence of drug. Thermolability was exhibited only after the virus was released from the cell, implying the presence of a cell-associated protective factor, possibly pocket factor. Thus, in the absence of a thermostabilizing drug, drug-dependent mutants decayed too rapidly after release to permit spread in the plaque assay. The thermodecay product was shown to consist of 135S particles lacking VP4.


Asunto(s)
Antivirales/farmacología , Farmacorresistencia Microbiana , Isoxazoles/farmacología , Poliovirus/crecimiento & desarrollo , Virión/crecimiento & desarrollo , Células HeLa , Calor , Humanos , Mutagénesis , Poliovirus/efectos de los fármacos , Poliovirus/genética , Virión/efectos de los fármacos , Replicación Viral
16.
J Virol ; 67(3): 1148-58, 1993 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7679742

RESUMEN

We have determined the structure of a human rhinovirus (HRV)-Fab complex by using cryoelectron microscopy and image reconstruction techniques. This is the first view of an intact human virus complexed with a monoclonal Fab (Fab17-IA) for which both atomic structures are known. The surface area on HRV type 14 (HRV14) in contact with Fab17-IA was approximately 500 A2 (5 nm2), which is much larger than the area that constitutes the NIm-IA epitope (on viral protein VP1) defined by natural escape mutants. From modeling studies and electrostatic potential calculations, charged residues outside the neutralizing immunogenic site IA (NIm-IA) were also predicted to be involved in antibody recognition. These predictions were confirmed by site-specific mutations and analysis of the Fab17-IA-HRV14 complex, along with knowledge of the crystallographic structures of HRV14 and Fab17-IA. The bound Fab17-IA reaches across a surface depression (the canyon) and meets a related Fab at the nearest icosahedral twofold axis. By adjusting the elbow angles of the bound Fab fragments from 162 degrees to 198 degrees, an intact antibody molecule can be easily modeled. This, along with aggregation and binding stoichiometry results, supports the earlier proposal that this antibody binds bivalently to the surface of HRV14 across icosahedral twofold axes. One prediction of this model, that the intact canyon-spanning immunoglobulin G molecule would block attachment of the virus to HeLa cells, was confirmed experimentally.


Asunto(s)
Anticuerpos Antivirales/ultraestructura , Fragmentos Fab de Inmunoglobulinas/ultraestructura , Inmunoglobulina G/ultraestructura , Rhinovirus/ultraestructura , Anticuerpos Monoclonales , Anticuerpos Antivirales/química , Anticuerpos Antivirales/inmunología , Sitios de Unión de Anticuerpos , Cápside/inmunología , Cápside/ultraestructura , Proteínas de la Cápside , Criopreservación , Análisis Mutacional de ADN , Electricidad , Epítopos , Procesamiento de Imagen Asistido por Computador , Fragmentos Fab de Inmunoglobulinas/química , Fragmentos Fab de Inmunoglobulinas/inmunología , Inmunoglobulina G/química , Inmunoglobulina G/inmunología , Sustancias Macromoleculares , Microscopía Electrónica/métodos , Modelos Biológicos , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Pruebas de Neutralización , Rhinovirus/química , Rhinovirus/inmunología , Difracción de Rayos X
18.
Biomaterials ; 11: 57-62, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-2168765

RESUMEN

After a brief review of the main characteristics of some spectroscopic and microscopic methods for surface and interface analysis, preliminary and prospective studies of biocompatible materials (hydroxyapatite, alumina) for implant coating purposes are presented. The results show that the use of complementary techniques allows information on the physical and chemical properties of the coatings both on a microscopic and on an atomic scale to be obtained.


Asunto(s)
Materiales Biocompatibles , Ensayo de Materiales , Prótesis e Implantes , Acero Inoxidable , Óxido de Aluminio , Clavos Ortopédicos , Durapatita , Hidroxiapatitas , Microscopía Electrónica de Rastreo , Estudios Prospectivos , Propiedades de Superficie
19.
Virology ; 174(1): 305-7, 1990 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-1688474

RESUMEN

Using a set of neutralizing monoclonal antibodies targeted against the four known antigenic sites of poliovirus type 1, it was shown that three out of four antigenic sites are already present on 14 S subunits (pentamers of the structural unit). Site 3B, in contrast, is formed upon assembly of 14 S subunits into capsids. The data support the hypothesis that site 3B spans the boundary between pentamers in the virion.


Asunto(s)
Antígenos Virales/biosíntesis , Cápside/metabolismo , Poliovirus/inmunología , Anticuerpos Monoclonales/inmunología , Epítopos/inmunología
20.
Ann Trop Med Parasitol ; 83(3): 263-9, 1989 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2513787

RESUMEN

In Martinique, intestinal schistosomiasis was discovered at the beginning of this century. The intermediate host snail, Biomphalaria glabrata, was considered in the past as a common species in the different habitats of the island, but during the last decade it has been found only in water-cress beds. Several of these water-cress cultures contained mixed populations of B. glabrata and B. straminea. Moreover, these habitats also constituted transmission sites for Schistosoma mansoni infection. In 1979 the thiarid snail Thiara ( = Melanoides) tuberculata was discovered in Madame river, Fort-de-France, and in the following years at other sites. In 1983 a programme of biological control using this snail was started in two groups of water-cress beds. In 1981-1982 the study site, Roxelane valley, sheltered important populations of B. glabrata (45-256 individuals/m2) and of B. straminea (2-30 ind./m2). In January 1983 the competitor T. tuberculata was introduced into the two groups of water-cress beds (1.3 and 1.7 ind./m2 respectively) and during subsequent years snail population sampling was carried out. The results showed rapid colonization by the competitor snail, whose densities reached 178 and 325 ind./m2 in November 1983 and a maximum of 9941 and 13,388 ind./m2 in October 1984. During that time, B. glabrata populations declined: 153 and 41 ind./m2 in November 1983, 4 and 0 ind./m2 in October 1984, and 0 ind./m2 in the two groups of water-cress beds in October 1985. A similar phenomenon was observed for B. straminea. Since October 1985 neither planorbid species has been found by exhaustive sampling of the habitats.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Biomphalaria/crecimiento & desarrollo , Vectores de Enfermedades , Control Biológico de Vectores , Esquistosomiasis mansoni/prevención & control , Caracoles/crecimiento & desarrollo , Animales , Martinica , Esquistosomiasis mansoni/transmisión
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...