RÉSUMÉ
The efficiency of the adsorption-elution technique using fiber glass filters to concentrate viruses from water was evaluated to detect poliovirus type 1 in drinking, river, and sewage water. At pH 3.5 and with 5 X 10(-4) M aluminium chloride more than 99% were adsorbed at a 0.25-micron filter. Beef extract (3%), pH 9, eluted 85-95% of the adsorbed viruses and organic flocculation at pH 3.5 permitted to reconcentrate the viruses in 1/20 of the elution volume with a 50-72% efficiency. The overall efficiency of the technique for 100 ml to 1000 l of the different types of water using 10(2) to 10(6) PFU was 38 to 58%.
Sujet(s)
Filtres microporeux , Poliovirus/isolement et purification , Microbiologie de l'eau , Eau douce , Concentration en ions d'hydrogène , Eaux d'égout , Alimentation en eauRÉSUMÉ
Seventy-one men who were given live-attenuated A/Hong Kong/68 (H3N2) influenza vaccine during November 1973, and 34 men given placebo were examined for changes in antibody level. Overall, 12 of the 71 men (17%) given the vaccine showed a fourfold rise in haemagglutination-inhibition (HI) antibody titre after 14 days. No such rises were seen in the 34 men given placebo. However, 10 of the men showing a fourfold rise were from 19 who had no detectable HI antibody to this virus before vaccination, representing a conversion rate of 53%. The other two had a HI titre of 1/10 before vaccination. The absence of antibody response, at 14 days, in those with an HI titre of 1/20 or greater may indicated that this represents a protective level against infection. However, the vaccine virus was probably overattenuated and may have constituted a weaker challenge than might occur with a wild strain. No influenza virus was isolated from either group in the week after vaccination and no evidence of transmission to the placebo group was seen. Mild symptoms, chills, muscle pain, and stiffness were more frequently seen in the 12 persons showing a fourfold rise in antibody than in the rest of the volunteers.
Sujet(s)
Anticorps antiviraux/biosynthèse , Virus de la grippe A/immunologie , Vaccins antigrippaux , Vaccins atténués , Administration par voie nasale , Canada , Essais cliniques comme sujet , Tests d'inhibition de l'hémagglutination , Humains , Vaccins antigrippaux/effets indésirables , Mâle , Médecine militaire , Placebo , Vaccination , Vaccins atténués/effets indésirablesRÉSUMÉ
Purified influenza virus contains ribonuclease activity. The enzyme does not hydrolyze viral RNA but both 28 S and 18 S host cell RNA are degraded forming large (about 16 S) and small (about 5 S) fragments with the release of the acid-soluble material. It has an optimum temperature of 37 degrees C, requires no divalent ions, and is inhibited by 0.1 M EDTA and 1% SDS. Treatment with 4 M urea increases enzymatic activity considerably (42%) but is not a prerequisite for eliciting ribonuclease activity suggesting that the enzyme is probably located near the surface of the virus particle. Results show that the observed enzyme activity is virus-associated as no host cell protein is detectable in the purified virus.
Sujet(s)
Ribonucléases/métabolisme , Système acellulaire , Techniques de culture , Acide édétique/pharmacologie , Hydrolyse , Polynucléotides/métabolisme , ARN/métabolisme , Dodécyl-sulfate de sodium/pharmacologie , Température , Urée/pharmacologieRÉSUMÉ
Live human and equine influenza virus strains modified by serial passage on allantois-on-shell system (AOS) in the presence of normal horse serum were administered orally or intranasally to volunteers or horses. Mostly mild clinical short-lasting reactions, replication in nasal mucosae, transmission to placebo recipients and significant local or circulating antibody rises were observed following administration to volunteers of strains modified by five or less serial passages on AOS in the presence of normal horse serum (NHS). Milder clinical reactions, no replication, no viral transmission and lower immunogenicity were observed when up to ten serial passages on AOS+ NHS were carried out. Similar results were observed in horses and colts. Heavy shedding of A/Eq-2 strain following the challenge was observed in placebo recipients. Colts immunized intranasally were completely protected while 33% of those immunized orally shedded small quantities of A/Eq-1 and A/Eq-2 viruses. However, a sharp rise of local antibodies against both strains was measured two days after the challenge in the three groups.
Sujet(s)
Vaccins antigrippaux/administration et posologie , Grippe humaine/prévention et contrôle , Administration par voie nasale , Administration par voie orale , Adolescent , Adulte , Animaux , Anticorps antiviraux/analyse , Essais cliniques comme sujet , Tests d'inhibition de l'hémagglutination , Equus caballus , Humains , Virus de la grippe A/immunologie , Vaccins antigrippaux/effets indésirables , Vaccins antigrippaux/usage thérapeutique , Mâle , Adulte d'âge moyen , Sialidase/immunologie , Vaccins atténués/administration et posologie , Vaccins atténués/effets indésirablesRÉSUMÉ
Budding at the plasmic membrane is the primary mode of production of rubella virus in Vero cells. Intense cytopathic effect is observed even if only 10% of the cells are infected. Actinomycin D has little effect on the multiplication of rubella virus but cycloheximide inhibits its growth. This inhibitiion is probably due to the reduction of cellular protein synthesis and not to a direct action of the inhibitorson the virus multiplication. Viral proteins in infected cells have not been demonstrated. The presence of a viral substance inhibiting normal cellular synthesis is discussed.
Sujet(s)
Lignée cellulaire , Cycloheximide/pharmacologie , Dactinomycine/pharmacologie , Virus de la rubéole/effets des médicaments et des substances chimiques , Réplication virale , Animaux , Effet cytopathogène viral , Dépression chimique , Technique d'immunofluorescence , Haplorhini , Rein , ARN viral/biosynthèse , Virus de la rubéole/croissance et développement , Protéines virales/analyse , Réplication virale/effets des médicaments et des substances chimiquesRÉSUMÉ
Separation of Vero cell membrane in a discontinuous sucrose gradient reveals five fractions. After infection a sixth fraction appears. It contains virioins but mostly modified membranes with subunits 5-6 nm in diameter, probably the hemagglutinin. None of the enzymes used was associated with this fraction. No modification of the other fractions was observed after infection.
Sujet(s)
Lignée cellulaire , Virus de la rubéole , Culture virale , Acid phosphatase/analyse , Animaux , Membrane cellulaire , Glucosephosphatase/analyse , Haplorhini , Rein , NADPH dehydrogenase/analyse , Nucleotidases/analyse , Phosphoric monoester hydrolases/analyse , Virus de la rubéole/enzymologie , Diphosphate de thiamine/analyse , Nucléotides uridyliquesRÉSUMÉ
Degradation of purified rubella virus by heat treatment (37, 45, or 56 degrees C) revealed the following structures. The viral envelope, a modified cellular membrane, bears spherical subunits, 5-6 nm in diameter, hexamers, or pentamers. Two glycoproteins, VP-2 (50 000 daltons) and VP-3 (63 000 daltons), are associated with the envelope. The nucleocapsid if formed by the condensation of the viral ribonucleic acid on acentral structure 10 nm in diameter. Only one protein, VP-1 (35 000 daltons) is present in the nucleocapsid. Similarity between rubella virus and Togaviruses is discussed.
Sujet(s)
Virus de la rubéole/ultrastructure , Protéines virales , Membrane cellulaire/ultrastructure , Électrophorèse sur gel de polyacrylamide , Glycoprotéines , Microscopie électronique , Masse moléculaire , ARN viral , Culture viraleRÉSUMÉ
Intracerebral and intraspinal inoculations of non-neuropathic and neuropathic strains of influenza virus into rhesus, patas and cercopithecus monkeys resulted in an acute focal ependymitis, choroiditis and meningitis followed by focal ependymal denuding without parenchymal involvement. Aqueductal stenosis and moderate hydrocephalus developed in two animals as sequelae of ependymal cell loss.