Virus Inactivation: Inactivation of viruses by non-immune related techniques. They include extremes of pH, HEAT treatment, ultraviolet radiation, IONIZING RADIATION; DESICCATION; ANTISEPTICS; DISINFECTANTS; organic solvents, and DETERGENTS.Calicivirus, Feline: A species of the genus VESIVIRUS infecting cats. Transmission occurs via air and mechanical contact.Disinfection: Rendering pathogens harmless through the use of heat, antiseptics, antibacterial agents, etc.Viral Plaque Assay: Method for measuring viral infectivity and multiplication in CULTURED CELLS. Clear lysed areas or plaques develop as the VIRAL PARTICLES are released from the infected cells during incubation. With some VIRUSES, the cells are killed by a cytopathic effect; with others, the infected cells are not killed but can be detected by their hemadsorptive ability. Sometimes the plaque cells contain VIRAL ANTIGENS which can be measured by IMMUNOFLUORESCENCE.Poliovirus: A species of ENTEROVIRUS which is the causal agent of POLIOMYELITIS in humans. Three serotypes (strains) exist. Transmission is by the fecal-oral route, pharyngeal secretions, or mechanical vector (flies). Vaccines with both inactivated and live attenuated virus have proven effective in immunizing against the infection.Antiviral Agents: Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.RNA Viruses: Viruses whose genetic material is RNA.Vaccinia virus: The type species of ORTHOPOXVIRUS, related to COWPOX VIRUS, but whose true origin is unknown. It has been used as a live vaccine against SMALLPOX. It is also used as a vector for inserting foreign DNA into animals. Rabbitpox virus is a subspecies of VACCINIA VIRUS.Receptors, Virus: Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.Virus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.Virus Cultivation: Process of growing viruses in live animals, plants, or cultured cells.Virus Shedding: The expelling of virus particles from the body. Important routes include the respiratory tract, genital tract, and intestinal tract. Virus shedding is an important means of vertical transmission (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).Virus Diseases: A general term for diseases produced by viruses.Simian virus 40: A species of POLYOMAVIRUS originally isolated from Rhesus monkey kidney tissue. It produces malignancy in human and newborn hamster kidney cell cultures.Virus Assembly: The assembly of VIRAL STRUCTURAL PROTEINS and nucleic acid (VIRAL DNA or VIRAL RNA) to form a VIRUS PARTICLE.DNA Viruses: Viruses whose nucleic acid is DNA.Plant Viruses: Viruses parasitic on plants higher than bacteria.Defective Viruses: Viruses which lack a complete genome so that they cannot completely replicate or cannot form a protein coat. Some are host-dependent defectives, meaning they can replicate only in cell systems which provide the particular genetic function which they lack. Others, called SATELLITE VIRUSES, are able to replicate only when their genetic defect is complemented by a helper virus.Hepatitis E virus: A positive-stranded RNA virus species in the genus HEPEVIRUS, causing enterically-transmitted non-A, non-B hepatitis (HEPATITIS E).Hepatitis E: Acute INFLAMMATION of the LIVER in humans; caused by HEPATITIS E VIRUS, a non-enveloped single-stranded RNA virus. Similar to HEPATITIS A, its incubation period is 15-60 days and is enterically transmitted, usually by fecal-oral transmission.Psoralens: Linear furanocoumarins which are found in many PLANTS, especially UMBELLIFERAE and RUTACEAE, as well as PSORALEA from which they were originally discovered. They can intercalate DNA and, in an UV-initiated reaction of the furan portion, alkylate PYRIMIDINES, resulting in PHOTOSENSITIVITY DISORDERS.Hepatitis Antibodies: Immunoglobulins raised by any form of viral hepatitis; some of these antibodies are used to diagnose the specific kind of hepatitis.Plasma Gases: Ionized gases, consisting of free electrons and ionized atoms or molecules which collectively behave differently than gas, solid, or liquid. Plasma gases are used in biomedical fields in surface modification; biological decontamination; dentistry (e.g., PLASMA ARC DENTAL CURING LIGHTS); and in other treatments (e.g., ARGON PLASMA COAGULATION).Hepevirus: An unassigned genus of RNA viruses with a single officially described species, HEPATITIS E VIRUS. A distantly related virus, Avian hepatitis E virus, has been listed as a tentative species. Strains have also been identified in swine. The family name hepeviridae has been proposed.Hepatitis B: INFLAMMATION of the LIVER in humans caused by a member of the ORTHOHEPADNAVIRUS genus, HEPATITIS B VIRUS. It is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.Formaldehyde: A highly reactive aldehyde gas formed by oxidation or incomplete combustion of hydrocarbons. In solution, it has a wide range of uses: in the manufacture of resins and textiles, as a disinfectant, and as a laboratory fixative or preservative. Formaldehyde solution (formalin) is considered a hazardous compound, and its vapor toxic. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p717)Norovirus: A genus in the family CALICIVIRIDAE, associated with epidemic GASTROENTERITIS in humans. The type species, NORWALK VIRUS, contains multiple strains.Fixatives: Agents employed in the preparation of histologic or pathologic specimens for the purpose of maintaining the existing form and structure of all of the constituent elements. Great numbers of different agents are used; some are also decalcifying and hardening agents. They must quickly kill and coagulate living tissue.Neuraminidase: An enzyme that catalyzes the hydrolysis of alpha-2,3, alpha-2,6-, and alpha-2,8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate. (From Enzyme Nomenclature, 1992)Influenza, Human: An acute viral infection in humans involving the respiratory tract. It is marked by inflammation of the NASAL MUCOSA; the PHARYNX; and conjunctiva, and by headache and severe, often generalized, myalgia.Influenza A virus: The type species of the genus INFLUENZAVIRUS A that causes influenza and other diseases in humans and animals. Antigenic variation occurs frequently between strains, allowing classification into subtypes and variants. Transmission is usually by aerosol (human and most non-aquatic hosts) or waterborne (ducks). Infected birds shed the virus in their saliva, nasal secretions, and feces.Influenza A Virus, H1N1 Subtype: A subtype of INFLUENZA A VIRUS with the surface proteins hemagglutinin 1 and neuraminidase 1. The H1N1 subtype was responsible for the Spanish flu pandemic of 1918.Influenza A Virus, H3N2 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 3 and neuraminidase 2. The H3N2 subtype was responsible for the Hong Kong flu pandemic of 1968.Influenza Vaccines: Vaccines used to prevent infection by viruses in the family ORTHOMYXOVIRIDAE. It includes both killed and attenuated vaccines. The composition of the vaccines is changed each year in response to antigenic shifts and changes in prevalence of influenza virus strains. The vaccine is usually bivalent or trivalent, containing one or two INFLUENZAVIRUS A strains and one INFLUENZAVIRUS B strain.ArchivesBiological Science Disciplines: All of the divisions of the natural sciences dealing with the various aspects of the phenomena of life and vital processes. The concept includes anatomy and physiology, biochemistry and biophysics, and the biology of animals, plants, and microorganisms. It should be differentiated from BIOLOGY, one of its subdivisions, concerned specifically with the origin and life processes of living organisms.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.PubMed: A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.Point-of-Care Systems: Laboratory and other services provided to patients at the bedside. These include diagnostic and laboratory testing using automated information entry.Directories as Topic: Lists of persons or organizations, systematically arranged, usually in alphabetic or classed order, giving address, affiliations, etc., for individuals, and giving address, officers, functions, and similar data for organizations. (ALA Glossary of Library and Information Science, 1983)Hemorrhagic Fever, Ebola: A highly fatal, acute hemorrhagic fever, clinically very similar to MARBURG VIRUS DISEASE, caused by EBOLAVIRUS, first occurring in the Sudan and adjacent northwestern (what was then) Zaire.Stainless Steel: Stainless steel. A steel containing Ni, Cr, or both. It does not tarnish on exposure and is used in corrosive environments. (Grant & Hack's Chemical Dictionary, 5th ed)Staphylococcus hominis: A species of STAPHYLOCOCCUS similar to STAPHYLOCOCCUS HAEMOLYTICUS, but containing different esterases. The subspecies Staphylococcus hominis novobiosepticus is highly virulent and novobiocin resistant.Humidity: A measure of the amount of WATER VAPOR in the air.Orthomyxoviridae: A family of RNA viruses causing INFLUENZA and other diseases. There are five recognized genera: INFLUENZAVIRUS A; INFLUENZAVIRUS B; INFLUENZAVIRUS C; ISAVIRUS; and THOGOTOVIRUS.Blood Coagulation: The process of the interaction of BLOOD COAGULATION FACTORS that results in an insoluble FIBRIN clot.Research: Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. (Webster, 3d ed)Research Personnel: Those individuals engaged in research.Research Support as Topic: Financial support of research activities.Biomedical Research: Research that involves the application of the natural sciences, especially biology and physiology, to medicine.Photosensitizing Agents: Drugs that are pharmacologically inactive but when exposed to ultraviolet radiation or sunlight are converted to their active metabolite to produce a beneficial reaction affecting the diseased tissue. These compounds can be administered topically or systemically and have been used therapeutically to treat psoriasis and various types of neoplasms.Photochemotherapy: Therapy using oral or topical photosensitizing agents with subsequent exposure to light.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Tolonium Chloride: A phenothiazine that has been used as a hemostatic, a biological stain, and a dye for wool and silk. Tolonium chloride has also been used as a diagnostic aid for oral and gastric neoplasms and in the identification of the parathyroid gland in thyroid surgery.Methylene Blue: A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.Porphyrins: A group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached. The nature of the side chain is indicated by a prefix, as uroporphyrin, hematoporphyrin, etc. The porphyrins, in combination with iron, form the heme component in biologically significant compounds such as hemoglobin and myoglobin.

Capsid functions of inactivated human picornaviruses and feline calicivirus. (1/215)

The exceptional stability of enteric viruses probably resides in their capsids. The capsid functions of inactivated human picornaviruses and feline calicivirus (FCV) were determined. Viruses were inactivated by UV, hypochlorite, high temperature (72 degrees C), and physiological temperature (37 degrees C), all of which are pertinent to transmission via food and water. Poliovirus (PV) and hepatitis A virus (HAV) are transmissible via water and food, and FCV is the best available surrogate for the Norwalk-like viruses, which are leading causes of food-borne and waterborne disease in the United States. The capsids of all 37 degrees C-inactivated viruses still protected the viral RNA against RNase, even in the presence of proteinase K, which contrasted with findings with viruses inactivated at 72 degrees C. The loss of ability of the virus to attach to homologous cell receptors was universal, regardless of virus type and inactivation method, except for UV-inactivated HAV, and so virus inactivation was almost always accompanied by the loss of virus attachment. Inactivated HAV and FCV were captured by homologous antibodies. However, inactivated PV type 1 (PV-1) was not captured by homologous antibody and 37 degrees C-inactivated PV-1 was only partially captured. The epitopes on the capsids of HAV and FCV are evidently discrete from the receptor attachment sites, unlike those of PV-1. These findings indicate that the primary target of UV, hypochlorite, and 72 degrees C inactivation is the capsid and that the target of thermal inactivation (37 degrees C versus 72 degrees C) is temperature dependent.  (+info)

Infectivity of RNA from inactivated poliovirus. (2/215)

During inactivation of poliovirus type 1 (PV-1) by exposure to UV, hypochlorite, and heat (72 degrees C), the infectivity of the virus was compared with that of its RNA. DEAE-dextran (1-mg/ml concentration in Dulbecco's modified Eagle medium buffered with 0.05 M Tris, pH 7.4) was used to facilitate transfecting PV-1 RNA into FRhK-4 host cells. After interaction of PV-1 RNA with cell monolayer at room temperature (21 to 22 degrees C) for 20 min, the monolayers were washed with 5 ml of Hanks balanced salt solution. The remainder of the procedure was the same as that for the conventional plaque technique, which was also used for quantifying the PV-1 whole-particle infectivity. Plaque formation by extracted RNA was approximately 100,000-fold less efficient than that by whole virions. The slopes of best-fit regression lines of inactivation curves for virion infectivity and RNA infectivity were compared to determine the target of inactivation. For UV and hypochlorite inactivation the slopes of inactivation curves of virion infectivity and RNA infectivity were not statistically different. However, the difference of slopes of inactivation curves of virion infectivity and RNA infectivity was statistically significant for thermal inactivation. The results of these experiments indicate that viral RNA is a primary target of UV and hypochlorite inactivations but that the sole target of thermal inactivation is the viral capsid.  (+info)

Multiply attenuated, self-inactivating lentiviral vectors efficiently deliver and express genes for extended periods of time in adult rat cardiomyocytes in vivo. (3/215)

BACKGROUND: Among retroviral vectors, lentiviral vectors are unique in that they transduce genes into both dividing and nondividing cells. However, their ability to provide sustained myocardial transgene expression has not been evaluated. METHODS AND RESULTS: Multiply attenuated, self-inactivating lentivectors based on human immunodeficiency virus-1 contained the enhanced green fluorescent protein (EGFP) gene under the transcriptional control of either the cytomegalovirus (CMV) immediate-early enhancer/promoter, the elongation factor-1alpha (EF-1alpha) promoter, or the phosphoglycerate-kinase (PGK) promoter. Lentivectors transduced adult rat cardiomyocytes in a dose-dependent manner (transduction rates, >90%; multiplicity of infection, approximately 5). The CMV promoter achieved higher EGFP expression levels than the EF-1alpha and PGK promoters. Insertion of the central polypurine tract pol sequence improved gene transfer efficiency by approximately 2-fold. In vivo gene transfer kinetics was studied by measuring the copy number of integrated lentivirus DNA and EGFP concentrations in cardiac extracts by real-time polymerase chain reaction and ELISA, respectively. With CMV promoter-containing lentivectors, vector DNA peaked at day 3, declined by approximately 4-fold at day 14, but then remained stable up to week 10. Similarly, EGFP expression peaked at day 7, decreased by approximately 7-fold at day 14, but was essentially stable thereafter. In contrast, vector DNA and EGFP expression declined rapidly with EF-1alpha promoter-containing lentivectors. Peak EGFP expression with titer-matched adenovectors was approximately 35% higher than with CMV lentivectors but was lost rapidly over time. CONCLUSIONS: Lentivectors efficiently transduce and express genes for extended periods of time in cardiomyocytes in vivo. Lentivectors provide a useful tool for studying myocardial biology and a potential system for gene heart therapy.  (+info)

Chlorine inactivation of adenovirus type 40 and feline calicivirus. (4/215)

Ct values, the concentration of free chlorine multiplied by time of contact with virus, were determined for free-chlorine inactivation experiments carried out with chloroform-extracted (dispersed) and non-chloroform-extracted (aggregated) feline calicivirus (FCV), adenovirus type 40 (AD40), and polio virus type 1 (PV-1). Experiments were carried out with high and low pH and temperature conditions. Ct values were calculated directly from bench-scale free-chlorine inactivation experiments and from application of the efficiency factor Hom model. For each experimental condition, Ct values were higher at pH 8 than at pH 6, higher at 5 degrees C than at 15 degrees C, and higher for dispersed AD40 (dAD40) than for dispersed FCV (dFCV). dFCV and dAD40 were more sensitive to free chlorine than dispersed PV-1 (dPV-1). Cts for 2 log inactivation of aggregated FCV (aFCV) and aggregated PV-1 (aPV-1) were 31.0 and 2.8 orders of magnitude higher than those calculated from experiments carried out with dispersed virus. Cts for 2 log inactivation of dFCV and dAD40 in treated groundwater at 15 degrees C were 1.2 and 13.7 times greater than in buffered-demand-free (BDF) water experiments at 5 degrees C. Ct values listed in the U.S. Environmental Protection Agency (EPA) Guidance Manual were close to, or lower than, Ct values generated for experiments conducted with dispersed and aggregated viruses suspended in BDF water and for dispersed viruses suspended in treated groundwater. Since the state of viruses in water is most likely to be aggregated and associated with organic or inorganic matter, reevaluation of the EPA Guidance Manual Ct values is necessary, since they would not be useful for ensuring inactivation of viruses in these states. Under the tested conditions, dAD40, dFCV, aFCV, dPV-1, and aPV-1 particles would be inactivated by commonly used free chlorine concentrations (1 mg/liter) and contact times (60 to 237 min) applied for drinking water treatment in the United States.  (+info)

Cholesterol depletion of human immunodeficiency virus type 1 and simian immunodeficiency virus with beta-cyclodextrin inactivates and permeabilizes the virions: evidence for virion-associated lipid rafts. (5/215)

Recent evidence suggests that human immunodeficiency virus type 1 (HIV-1) particles assemble and bud selectively through areas in the plasma membrane of cells that are highly enriched with glycosylphosphatidylinositol-anchored proteins and cholesterol, called lipid rafts. Since cholesterol is required to maintain lipid raft structure and function, we proposed that virion-associated cholesterol removal with the compound 2-hydroxy-propyl-beta-cyclodextrin (beta-CD) might be disruptive to HIV-1 and simian immunodeficiency virus (SIV). We examined the effect of beta-CD on the structure and infectivity of cell-free virions. We found that beta-CD inactivated HIV-1 and SIV in a dose-dependent manner and permeabilized the viral membranes, resulting in the loss of mature Gag proteins (capsid, matrix, nucleocapsid, p1, and p6) without loss of the envelope glycoproteins. SIV also lost reverse transcriptase (RT), integrase (IN), and viral RNA. IN appeared to be only slightly diminished in HIV-1, and viral RNA, RT, matrix, and nucleocapsid proteins were retained in HIV-1 but to a much lesser degree. Host proteins located internally in the virus (actin, moesin, and ezrin) and membrane-associated host proteins (major histocompatibility complex classes I and II) remained associated with the treated virions. Electron microscopy revealed that under conditions that permeabilized the viruses, holes were present in the viral membranes and the viral core structure was perturbed. These data provide evidence that an intact viral membrane is required to maintain mature virion core integrity. Since the viruses were not fixed before beta-CD treatment and intact virion particles were recovered, the data suggest that virions may possess a protein scaffold that can maintain overall structure despite disruptions in membrane integrity.  (+info)

Differences in participation of innate and adaptive immunity to respiratory syncytial virus in adults and neonates. (6/215)

Innate and adaptive immune responses to respiratory syncytial virus (RSV) in neonates were assessed by cord blood mononuclear cell (MC) cytokine expression and proliferation and these responses were compared with those from adult peripheral blood MCs. In adult cells, inactivated and live virus invoked cytokines reflecting both innate and adaptive immunity (interleukin [IL]-6, interferon [IFN]-gamma, IL-2, tumor necrosis factor [TNF]-alpha, and IL-10). Low levels of IL-4 were detected, although only with inactivated virus. In contrast, in neonatal cells, inactivated virus invoked large levels of the innate immune cytokines IL-6, TNF-alpha, and IL-10 and reduced levels of IFN-gamma and IL-12 but no adaptive cytokines. Live virus induced fewer innate (IL-6, IL-10, and IFN-gamma) and no adaptive immune cytokines. RSV-induced proliferation was absent in neonatal MCs, although positive in adult MCs. Thus, exposure to RSV does not appear to occur before birth, and adaptive immune insufficiency or greater innate responses may account for early life RSV-induced illnesses.  (+info)

Sucrose density gradient centrifugation and cross-flow filtration methods for the production of arbovirus antigens inactivated by binary ethylenimine. (7/215)

BACKGROUND: Sucrose density gradient centrifugation and cross-flow filtration methods have been developed and standardised for the safe and reproducible production of inactivated arbovirus antigens which are appropriate for use in diagnostic serological applications. METHODS: To optimise the maximum titre of growth during the propagation of arboviruses, the multiplicity of infection and choice of cell line were investigated using stocks of Ross River virus and Barmah Forest virus grown in both mosquito and mammalian cell lines. To standardise and improve the efficacy of the inactivation of arboviral suspensions, stocks of Ross River virus, Barmah Forest virus, Japanese encephalitis virus, Murray Valley encephalitis virus and Alfuy virus were chemically inactivated using binary ethylenimine at a final concentration of 3 mM. Aliquots were then taken at hourly intervals and crude inactivation rates were determined for each virus using a plaque assay. To ensure complete inactivation, the same aliquots were each passaged 3 times in Aedes albopictus C6/36 cells and the presence of viral growth was detected using an immunofluorescent assay. For larger quantities of viral suspensions, centrifugation on an isopycnic sucrose density gradient or cross-flow filtration was used to produce concentrated, pure antigens or partially concentrated, semi-purified antigens respectively. RESULTS: The results of the propagation experiments suggested that the maximum viral titres obtained for both Ross River virus and Barmah Forest virus were affected by the incubation period and choice of cell line, rather than the use of different multiplicity of infection values. Results of the binary ethylenimine inactivation trial suggested that standardised periods of 5 or 8 hours would be suitable to ensure effective and complete inactivation for a number of different arboviral antigens. CONCLUSION: Two methods used to prepare inactivated arbovirus antigens have been standardised to minimise production failure and expenditure and to provide reagents that conform to the highest quality and safety requirements of a diagnostic serology laboratory. The antigens are suitable for use in either enzyme linked immunosorbent assays or haemagglutination inhibition assays and the optimised protocols can be directly applied to produce antigens from new or emerging arboviral pathogens.  (+info)

Replication-incompetent virions of Japanese encephalitis virus trigger neuronal cell death by oxidative stress in a culture system. (8/215)

It has been shown that replication of the Japanese encephalitis virus (JEV) can trigger infected cells to undergo apoptosis. In the present study, it is further demonstrated that replication-incompetent virions of JEV, obtained by short-wavelength ultraviolet (UV) irradiation, could also induce host-cell death. It was found that UV-inactivated JEV (UV-JEV) caused cell death in neuronal cells such as mouse neuroblastoma N18 and human neuronal NT-2 cells, but not in non-neuronal baby hamster kidney BHK-21 fibroblast or human cervical HeLa cells. Only actively growing, but not growth-arrested, cells were susceptible to the cytotoxic effects of UV-JEV. Killing of UV-JEV-infected N18 cells could be antagonized by co-infection with live, infectious JEV, suggesting that virions of UV-JEV might engage an as-yet-unidentified receptor-mediated death-signalling pathway. Characteristically, mitochondrial alterations were evident in UV-JEV-infected N18 cells, as revealed by electron microscopy and a loss of membrane potential. N18 cells infected by UV-JEV induced generation of reactive oxygen species (ROS) as well as the activation of nuclear factor kappa B (NF-kappaB), and the addition of anti-oxidants or specific NF-kappaB inhibitors to the media greatly reduced the cytotoxicity of UV-JEV. Together, the results presented here suggest that replication-incompetent UV-JEV damages actively growing neuronal cells through a ROS-mediated pathway.  (+info)

  • The total infectious virus concentration in the suspension of floc particles that eventually formed by dosing with coagulant was measured after the floc particles were dissolved by raising the pH with an alkaline beef extract solution. (
  • Our results suggest that intermediate polymers formed during hydrolysis of the aluminum coagulants sorbed strongly to viruses, either rendering them inactive or preventing infectivity. (
  • Triton X-100 treatment proved to be the easiest-to-use influenza virus inactivation protocol for application in combination with phenotypic NA inhibitor susceptibility assays, while formalin treatment preserved B-cell and T-cell epitope antigenicity, allowing the detection of both humoral and cellular immune responses. (
  • We tested heat, formalin, Triton X-100, and β-propiolactone treatments for their potencies in inactivating human influenza A(H3N2) and avian A(H7N3) viruses, as well as seasonal and pandemic A(H1N1) virus isolates, while allowing the specimens to retain their virological and immunological properties. (
  • Application of these inactivation protocols limits work under BSL-3 conditions to virus culture, thus enabling more timely determination of public health impact and development of protective measures when a new influenza virus, e.g., pandemic A(H1N1)v virus, is introduced in humans. (
  • Introduction of a new influenza virus in humans urges quick analysis of its virological and immunological characteristics to determine the impact on public health and to develop protective measures for the human population. (
  • Examples are the introduction of human immunodeficiency virus, severe acute respiratory syndrome coronavirus, and pandemic influenza A viruses in humans. (
  • Polymerase chain reaction analysis revealed that, in addition to model viruses, the bloodborne viruses hepatitis B virus, hepatitis C virus, human immune deficiency virus-1 and probably also the nonenveloped parvovirus B19 are sensitive to MB/light treatment. (
  • In this study, we systematically investigated the effects of several antiviral treatments on hepatitis C virus (HCV) particles as model for enveloped viruses. (
  • For in vitro testing, we used wild-type EBOV express- evaluate efficacy of methods of chemical inactivation, we compared in vitro and in vivo approaches using Ebola ing enhanced green fluorescent protein (EBOV-eGFP) ( 7 ), virus as a surrogate pathogen. (
  • To evaluate the efficacy of chemical inactivation pro- tro testing, all samples were increased in volume to 3 mL cedures for specimen removal, we used the US prime select and equally divided to infect Vero E6 cells (80% conflu- agent and Tier-1 pathogen ( 4 ) Zaire ebolavirus (EBOV) as ency) in triplicates. (
  • Charles certain biologic, biochemical, and structural features, mak- River Laboratories, Wilmington, MA, USA) were ing them sensitive to the same chemical inactivation meth- housed in microisolator cages and were monitored daily ods. (
  • S.v. Effective chemical inactivation of Ebola virus. (
  • To evaluate the efficacy of chemical inactivation procedures for specimen removal, we used the US prime select agent and Tier-1 pathogen (4) Zaire ebolavirus (EBOV) as a surrogate model for enveloped high-level containment viruses with single-strand, negative-sense RNA genomes, such as arenaviruses, bunyaviruses, filoviruses, orthomyxoviruses, and paramyxoviruses. (
  • These viruses share certain biologic, biochemical, and structural features, making them sensitive to the same chemical inactivation methods. (
  • To evaluate efficacy of methods of chemical inactivation, we compared in vitro and in vivo approaches using Ebola virus as a surrogate pathogen. (
  • To demonstrate a possible dispersal mechanism, we show that bacteriophage T4, archaeal virus Sulfolobus spindle-shaped virus Kamchatka, and vaccinia virus are reversibly inactivated by mineralization in silica under conditions similar to volcanic hot springs. (
  • Viruses tested included bacteriophage T4 ( 16 ), bacteriophage PRD1 ( 17 ), the archaeal virus Sulfolobus spindle-shaped virus Kamchatka (SSV-K) ( 18 ), and vaccinia virus (VACV) ( 19 ). (
  • The resulting viruses were mixed with freshly prepared pH 7.0 to 7.1 sodium metasilicate solution in either 10 mM sodium bicarbonate-5 mM magnesium chloride for bacteriophage T4, PRD1, and SSV-K or Dulbecco's phosphate-buffered saline for VACV to final silica concentrations of 0, 5, and 10 mM (0, 300, and 600 ppm). (
  • The rate of inactivation of bacteriophage f2 and poliovirus 1 (CHAT) by NH3 was strongly influenced by temperature. (
  • Virus stocks were grown in Vero E6 cells and titrated by using a 50% tissue culture infectious dose ([TCID.sub. assay (9). (
  • Infectious virus titers after treatment were determined by TCID 50 assay. (
  • The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. (
  • The dynamic range of the assay, the inactivation of virus, and specimen stability were also evaluated. (
  • The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51-97 copies/mL). (
  • The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. (
  • Based on the measured kO3-Virus and typical ozone exposures applied in water and wastewater treatment, we conclude that ozone is a highly effective disinfectant for virus control. (
  • To check the best type of disinfectant for each virus, see Tables 1 and 4. (
  • The set of tables and figures presented in this section categorize the viruses and agents according to their physical characteristics to show clearly which disinfectant is best used for inactivation. (
  • A protocol, which applied 2% buffered FA for 60 min and a temperature-shift from 25 to 37 °C after 30 min was efficient for the complete inactivation of all test viruses, and therefore has the potential to improve both biosafety and speed of diagnostic electron microscopy. (
  • Complete inactivation was also achieved using one hundred times less UV power than has been used in comparable studies, says the team. (
  • The obtained results showed that the use of Glutaraldehyde, Formalin or TH4® 0.5% without protein load led to complete inactivation of the virus after 15, 30, 60 or 120 min contact time. (
  • In contrast, using Formalin and TH4® (1% and 2%) with and without protein load led to complete inactivation of the virus even at the shortest contact time of 15 min. (
  • Therefore, we tested both enveloped and unenveloped viruses for their susceptibility and response to silicification. (
  • Triton X-100 treatment proved to be the easiest-to-use influenza virus inactivation protocol for application in combination with phenotypic NA inhibitor susceptibility assays, while formalin treatment preserved B-cell and T-cell epitope antigenicity, allowing the detection of both humoral and cellular immune responses. (
  • HPP has been indicated as a promising non-thermal pathogen inactivation strategy for treatment of certain high-risk food commodities, without any noticeable changes in their nature. (
  • After treatment, the presence of residual infectious virus particles was investigated using real-time reverse transcription-PCR and an in vivo experimental model in pigs. (
  • The total infectious virus concentration in the suspension of floc particles that eventually formed by dosing with coagulant was measured after the floc particles were dissolved by raising the pH with an alkaline beef extract solution. (
  • The industrial-scale manufacturing of viruses or virus-like particles in cell culture is necessary for gene therapy and the treatment of cancer with oncolytic viruses. (
  • Complex multistep processes are required in both cases, but the low virus titers in batch cultures and the temperature sensitivity of the virus particles limit the production scale. (
  • Viruses for in vivo applications show a limited affinity for their target cells, they are generally unstable and large doses of infective virus particles (up to 10 12 active virus particles per dose) are needed to achieve a therapeutic effect. (
  • that destroy the virus particles. (
  • PCR was able to detect the RNA associated with inactivated HIV-1 particles in the factor concentrates, which allows the conclusion that PCR is not a useful test with which to monitor virus-inactivation procedures such as heating at 80 degrees C for 72 hours. (
  • Experiences of virus, retrovirus and retrovirus-like particles in Chinese hamster ovary (CHO) and hybridoma cells used for production of protein therapeutics. (
  • Second-order ozone inactivation rate constants (kO3-virus) of five enteric viruses (laboratory and two environmental strains of coxsackievirus B5: CVF, CVEnv1 and CVEnv2, human adenovirus: HAdV, and echovirus 11: EV) and four bacteriophages (MS2, Q, T4 and Φ174) were measured in buffered solutions. (
  • Survival of enteric viruses on environmental fomites. (
  • Effects of sanitation, freezing and frozen storage on enteric viruses in berries and herbs. (
  • The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163-302 copies/mL). (
  • Rotavirus survival on human hands and transfer of infectious virus to animate and nonporous inanimate surfaces. (
  • We tested heat, formalin, Triton X-100, and β-propiolactone treatments for their potencies in inactivating human influenza A(H3N2) and avian A(H7N3) viruses, as well as seasonal and pandemic A(H1N1) virus isolates, while allowing the specimens to retain their virological and immunological properties. (
  • However, the antiviral activity was less against a coronavirus and reassortant H5N1 influenza viruses derived from avian isolates. (
  • STUDY DESIGN AND METHODS: Inactivation was performed with three WNV isolates spiked into WBC-reduced RBCs. (
  • LETTERS travelers returning from Cuba with a rash, similarly to pa- Inactivation and tients returning from other countries in which dengue fever, chikungunya fever, and Zika virus infection are endemic. (
  • Hepatitis E virus (HEV) infection of zoonotic origin is an emerging concern in industrialized countries. (
  • Chronic infection of hepatitis B virus (HBV) is a major public health problem worldwide, with 350-400 million chronic HBV carriers and 0.5-1 million deaths a year as a result of liver cirrhosis, hepatocellular carcinoma, or HBV related liver failure [ 1 ]. (
  • The World Health Organization 's International Agency for Research on Cancer estimated that in 2002, infection caused 17.8% of human cancers, with 11.9% caused by one of seven viruses. (
  • Generally, tumor viruses cause little or no disease after infection in their hosts, or cause non- neoplastic diseases such as acute hepatitis for hepatitis B virus or mononucleosis for Epstein-Barr virus . (
  • Secondly, asymptomatic virus infection and carriage is the norm for most tumor viruses, which violates Koch's third principle. (
  • The recent discovery that human noroviruses (huNoVs) recognize sialic acids (SAs) in addition to histo-blood group antigens (HBGAs) pointed to a new direction in studying virus-host interactions during calicivirus infection. (
  • Our findings further highlight TV as a valuable surrogate for huNoVs, particularly in studying virus-host interactions that may involve two host carbohydrate receptors or co-receptors for infection. (
  • Attachment to a host cell receptor is the first, essential step for a virus to initiate a successful infection. (
  • Hepatitis B virus (HBV) infection is thought to be controlled by virus-specific cytotoxic T lymphocytes (CTL). (
  • We now demonstrate that hepatocellular HBV replication is also abolished noncytopathically during lymphocytic choriomeningitis virus (LCMV) infection, and we show that this process is mediated by TNF-alpha and IFN-alpha/beta produced by LCMV-infected hepatic macrophages. (
  • Quantitative PCR analysis demonstrates that Lgp2 is present in unstimulated cells at a lower level than RIG-I, although both helicases are induced to similar levels after virus infection. (
  • This judgment contrasts with the more definite and sensitive role of PCR in diagnosing HIV-1 infection in patients in whom a positive HIV-1 PCR result correlates with active HIV-1 infection and with PCR's usefulness in monitoring virus removal. (
  • Infection with human immunodeficiency virus type 1 (HIV-1) continues to be a global public health issue, especially in low-resource countries. (
  • Enterically infecting viruses: pathogenicity, transmission and significance for food and waterborne infection. (
  • Distribution of xenotropic murine leukemia virus-related virus (XMRV) infection in chronic fatigue syndrome and prostate cancer. (
  • The monkeypox virus has a lipid membrane, or "envelope," that encases the virus capsid. (
  • However, if viruses could be reversibly coated in a protective coat in addition to their capsid, they could potentially spread very widely. (
  • Adenovirus inactivation likely occurs through breaching the capsid followed by radical attack of DNA and core proteins. (
  • The Impact of Capsid Proteins on Virus Removal and Inactivation During" by Brooke K. Mayer, Yu Yang et al. (
  • The hydroxyl radicals produced during photocatalysis are considered nonspecific, but they likely cause greater overall damage to virus capsid proteins relative to the genome. (
  • Capsid composition did not correlate strongly to virus removal during physicochemical treatment, nor did virus size. (
  • 5,000) causing irreversible HIV-1 inactivation by targeting Env protein, membrane disruption, loss of HIV-1 RNA, gp120 shedding and p24 capsid protein release. (
  • viruses with single-strand, negative-sense RNA genomes, For in vivo testing, samples were increased in volume such as arenaviruses, bunyaviruses, filoviruses, ortho- to 1 mL and equally divided to infect 5 mice intraperi- myxoviruses, and paramyxoviruses. (
  • We reviewed published reports on 254-nm UV inactivation and tabulated the sensitivities of a wide variety of viruses, including those with double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA genomes. (
  • In particular, avian influenza A virus subtypes H5N1, H9N2, and H7N7 have been transmitted directly to humans in the past decade, exhibiting the zoonotic potential of influenza viruses ( 4 , 11 , 19 , 25 ). (
  • Transmission of influenza virus, especially in the event of a pandemic with a highly virulent strain of influenza virus, such as avian influenza H5N1 virus or 2009 H1N1 influenza A virus, is of great concern due to widespread mortality and morbidity ( 7 , 23 ). (
  • High-pathogenicity avian influenza (HPAI) virus, low-pathogenicity avian influenza (LPAI) virus, virulent Newcastle disease virus (vNDV) and low-virulent Newcastle disease virus (lNDV) can be present on the eggshell surface, and HPAI viruses and vNDV can be present in the internal contents of chicken eggs laid by infected hens. (
  • We defined "size-normalized sensitivity" (SnS) by multiplying UV 254 sensitivities ( D 37 values) by the genome size, and SnS values were relatively constant for viruses with similar genetic composition. (
  • The contribution of each base to genome transesterification, and hence inactivation, could be related to the base pKa by means of a Bronsted relationship. (
  • Other viruses are only carcinogenic when they integrate into the host cell genome as part of a biological accident, such as polyomaviruses and papillomaviruses. (
  • Caliciviruses are a group of nonenveloped RNA viruses containing a single-stranded, positive-sense RNA genome in the family Caliciviridae . (
  • Instead, it arises for other reasons, such as environmental factors, and is subsequently finetuned by selection to minimize the time to further cancer progression by means of the inactivation of TSP genes. (
  • This notion applies particularly to the inactivation of tumor suppressor genes, which requires the loss of both alleles. (
  • Whereas CIN can speed up the inactivation of tumor suppressor (TSP) genes, it can also have a negative effect on cancer progression. (
  • Aberrant methylation of normally unmethylated CpG islands has been associated with inactivation of several genes in human cancers. (
  • After molecular characterization and phylogenetic analysis of the HA and NA genes, the strain EGY06 was closely related to the 2006 predecessor Egyptian viruses of 2.2.1 clade, whereas EGY10 clustered within the classic 2.2.1/c group that commonly isolated from small-scale commercial farms and human since 2009. (
  • This work should be a useful step to understanding and eventually predicting the survival of viruses after their release in the environment. (
  • Our data also suggest that absolute humidity is a better predictor of surface inactivation than RH and allows the prediction of survival using two parameters rather than three. (
  • One question that comes to mind is whether this trend of decreasing influenza virus survival with increasing absolute humidity (AH) persists as temperature increases. (
  • Therefore, the generation of survival curves to determine decimal reduction times (DT -values) and change in heat resistance of the viruses (zD-value) within fat-free egg product could provide valuable information for development of risk reduction strategies. (
  • Use of Virkon®S 0.5% with and without protein load led to survival of the virus even after 60 min. (
  • This review summarises current knowledge about the influence of environmental factors on the survival and spread of viruses via contaminated surfaces. (
  • The efficacy of amino-fullerene also demonstrates that singlet oxygen is effective for AdV2 inactivation. (
  • We demonstrate the generation of singlet oxygen in a laser virus inactivation experiment using a low power diode light at 405 nm by detecting photobleaching of the absorption peak of uric acid at 294 nm. (
  • Together with Professor Eike Steinmann, head of the Department for Molecular and Medical Virology at Ruhr-Universität Bochum (RUB), he has compiled comprehensive findings from 22 studies on coronaviruses and their inactivation for a future textbook. (
  • Methylene blue (MB) and its derivatives azure A, B, C and thionine are photoactive and, in principle, are suitable for photodynamic virus inactivation of blood and blood products, such as therapeutic plasma. (
  • To evaluate and understand inactivation of HRV under many physical conditions and chemical agents , HRV86 were selected to expose with temperature, ultraviolet light (UV), Sodium hypochlorite, Virkon S, Peracetic acid (PAA), Glutaraldehyde and Ethanolin, respectively. (
  • Virus also was completely inactivated after exposure to sodium hypochlorite (0.1 g/L) beyond 10 min, glutaraldehyde (10 g/L) for 5 min, Virkon-S (5 g/L) for 10 min, PAA (3 g/L) for 2 min, or 75% alcohol for 5 min or longer. (
  • Inositol, sodium glutamate and calcium lactobionate were found to protect foot-and-mouth disease virus against inactivation during spraying and equilibration in the first 1s in aerosols. (
  • Significant interference with Hepatitis B virus replication by a core-nuclease fusion protein," The Journal ofBiological Chemistry, Mar. 2001, vol. 276, p. 8875-8883. (
  • Using a human glial fibrillary acidic protein (hGFAP) promoter-driven cre transgene, we have achieved efficient inactivation of a floxed connexin43 ( Cx43 ) gene in astrocytes of adult mice. (
  • This type of process is typically used for parvoviruses and other viruses containing a protein coat. (
  • Chromatographic methods of removing viruses are great for purifying the protein and are also effective against all types of viruses, but the level of virus removal is dependent on the column composition and the reagents that are used in the process. (
  • Many viruses contain lipid or protein coats that can be inactivated by chemical alteration. (
  • The Influenza B virus capsidis enveloped while its virionconsists of a matrix protein + envelope + nucleoprotein complex + nucleocapsid, and a polymerasecomplex. (
  • Although genomic damage is likely more extensive than protein damage for viruses treated using UV, proteins are still substantially degraded. (
  • Treatment with a demethylating agent, 5-aza-2′-deoxycytidine, restored PRB expression in all cell lines, suggesting that inactivation of this gene is through methylation. (
  • Non-coding RNAs have a prominent role in gene silencing, e.g. in X chromosome inactivation [ 28 ], and repression of transposable elements and centromeric repeats [ 29 ], and it is therefore possible that X-linked miRNAs contribute to the process of MSCI itself. (
  • To examine the efficiency of FA inactivation, we used Vaccinia virus , Human adenovirus and Murine norovirus as models and treated them with FA under various conditions. (
  • Interestingly, local hot spring virus dispersal can result from aerosolization by fumaroles ( 8 ), indicating at least one possible host-independent dispersal mechanism. (
  • MicroRNAs from the X-chromosome (X-miRNAs) have been reported as potential silencing escapers, and they have been proposed to play a role in the inactivation mechanism itself. (
  • Consider redeveloping the inactivation procedure if you can't identify a variation from the prescribed procedures to explain the failure of viability testing. (
  • Should alternative, generally lower, processing temperatures be required, this report presents guidelines temperature/time equivalents for the inactivation of hepatitis A virus based on available experimental data and according to the product characteristics (e.g. pH and sugar content). (
  • Critical parameters for the inactivation efficiency were the temperature, the duration of the FA treatment, and the resistance of the virus in question. (
  • Our results show that FA inactivation at low temperature (4 °C) bears a high risk of incomplete inactivation. (
  • Poliovirus was inactivated at a greater rate than f2, but the change in the rate of inactivation with increasing temperature in the range of approximately 10 to 40 degrees C was greater for f2 than for poliovirus. (
  • Studies using POMxp showed that 5min treatment at room temperature with 800μg/ml PPs resulted in at least a 3log reduction in the titers of influenza viruses PR8 (H1N1), X31 (H3N2), and a reassortant H5N1 virus derived from a human isolate. (
  • In a recent publication, Shaman and Kohn concluded that absolute humidity, which can be calculated if temperature and relative humidity (RH) are known, is the controlling factor in both the inactivation of influenza virus and the transmission of influenza ( 27 ). (
  • Inactivation is accomplished using a device having a unique temperature control design. (
  • There is compelling evidence for transmission of influenza viruses from infected individuals to uninfected individuals by direct contact, via fomites (inanimate objects capable of carrying infectious organisms), and through large droplets expelled during forceful exhalation, such as during coughing and sneezing ( 2 - 4 , 19 ). (
  • basis of operational experiences rather than well-docu- positive control samples included untreated virus stocks mented protocols ( 1 - 3 ). (
  • Application of these inactivation protocols limits work under BSL-3 conditions to virus culture, thus enabling more timely determination of public health impact and development of protective measures when a new influenza virus, e.g., pandemic A(H1N1)v virus, is introduced in humans. (
  • Mechanical brushing of surfaces with a detergent solution is highly effective in removing contaminating viruses and is fundamental for achieving effective chemical decontamination. (
  • However, the magnitudes of the thermodynamic variables for f2 were low enough, as calculated for the low (10 to 35 degrees C) and high (35 to 60 degrees C) phases, that inactivation could have occurred by breakage of nucleic acid chains. (
  • A rapid bedside inactivation method for nucleic acid tests is obtained by simply adding Magna Pure lysis/binding buffer directly into vacuum blood collection EDTA tubes using a thin needle and syringe prior to sampling. (
  • Instead, the entity can use a standardized nucleic acid extraction kit (from a manufacturer or derived in-house) for inactivation. (
  • On 16 December 2016, it was confirmed that there was an outbreak of the H5N8 virus at a farm near Tetney, Louth - the first outbreak in the United Kingdom. (
  • Erratum published on 4 August 2016, see Viruses 2016 , 8 (8), 217 . (
  • A few days later, just over 60 km away from the first outbreak, a separate outbreak was reported in Standerton, Mpumalanga, where over 25,000 birds were culled to prevent the virus spreading. (
  • This outbreak in the country has led cull more than 100,000 birds at 12 locations across the country to prevent the spread of the virus. (