scholarly journals ON THE ROLE OF RIBONUCLEIC ACID IN ANIMAL VIRUS SYNTHESIS

1960 ◽  
Vol 111 (3) ◽  
pp. 339-349 ◽  
Author(s):  
Igor Tamm ◽  
Marjorie M. Nemes ◽  
Suydam Osterhout
Keyword(s):  
Influenza Virus ◽  
Chorioallantoic Membrane ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Point Of View ◽  
Host Cells ◽  
Animal Virus ◽  
Host Cell Proteins

Adenosine, but not guanosine, was capable of blocking the inhibitory effect of 5,6-dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB) on influenza virus multiplication in the chorioallantoic membrane in vitro. At virus inhibitory concentrations DRB caused marked inhibition in uptake of adenosine-8-C14 into RNA of uninfected host cells, but it had little effect on uptake of C14-L-alanine into host cell proteins or on cellular oxygen consumption. The activity of DRB in inhibiting multiplication of the DNA-containing adenovirus was similar to its inhibitory activity on multiplication of the RNA-containing influenza virus. These and earlier results are discussed from the point of view of the important role of RNA in the reproduction of DNA-containing viruses.

scholarly journals INHIBITION OF INFLUENZA VIRUS MULTIPLICATION BY N-GLYCOSIDES OF BENZIMIDAZOLES

1954 ◽  
Vol 99 (3) ◽  
pp. 227-250 ◽  
Author(s):  
Igor Tamm ◽  
Karl Folkers ◽  
Clifford H. Shunk ◽  
Frank L. Horsfall
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Benzimidazole Derivative ◽  
Chorioallantoic Membrane ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Cellular Growth ◽  
Tissue Proliferation ◽  
Fresh Culture Medium

Chloro derivatives of benzimidazole were found to be 2 to 3 times more active than corresponding methyl derivatives in causing inhibition of Lee virus multiplication in chorioallantoic membrane cultures in vitro. The most active benzimidazole derivative thus far tested is 5,6-dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB); it caused 75 per cent inhibition of Lee virus multiplication in membrane cultures at a concentration of 0.38 x 10–4 M. On the other hand, 5,6-dimethyl-1-alpha;-D-ribofuranosylbenzimidazole, the moiety present in vitamin B12, failed to inhibit Lee virus multiplication at a concentration of 35 x 10–4 M. Other N-glycosides of 5,6-dichlorobenzimidazole were considerably less active than DRB. In single cycle experiments, the degree of inhibition of Lee virus multiplication by DRB in membrane cultures was not dependent on the amount of virus in the inoculum. This compound did not inactivate the infectivity of extracellular Lee virus, had no effect on virus-erythrocyte interaction, did not interfere with the adsorption of the virus by the host tissue, nor affect the release of newly formed virus from the membrane. The inhibitory effect of DRB on Lee virus multiplication, in contrast to that of 2,5-dimethylbenzimidazole, persisted after transfer of infected membranes into fresh culture medium not containing the compound. Both DRB and the 2,5-dimethyl compound caused 99 per cent inhibition of Lee virus multiplication without affecting oxygen uptake of the membrane. Tissue proliferation of membrane pieces in roller tube culture was not significantly affected by DRB at inhibitory concentration, whereas at equivalent concentration the 2,5-dimethyl compound did restrict cellular growth. At higher concentrations, both compounds caused retardation of cell proliferation. This effect was reversible on removal of either compound from the medium. The multiplication of several strains of influenza A and B viruses, i.e. Lee, MB, PR8, and FM1, was inhibited to the same degree by each of the two compounds; DRB was 35 times more active than the 2,5-dimethyl compound relative to each of the strains. DRB caused inhibition of Lee virus multiplication in intact embryonated chicken eggs and in mice without causing significant signs of toxicity in either host. Some of the implications of these findings are discussed in relation to the mechanism of the inhibition of influenza virus multiplication.

scholarly journals INFLUENZA VIRUS MULTIPLICATION IN THE CHORIOALLANTOIC MEMBRANE IN VITRO: KINETIC ASPECTS OF INHIBITION BY 5, 6-DICHLORO-1-ß-D-RIBOFURANOSYLBENZIMIDAZOLE

1954 ◽  
Vol 100 (6) ◽  
pp. 541-562 ◽  
Author(s):  
Igor Tamm ◽  
David A. J. Tyrrell
Keyword(s):  
Influenza Virus ◽  
Chorioallantoic Membrane ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Benzimidazole Derivatives ◽  
Similar Degree ◽  
Virus Concentration ◽  
Virus Particles ◽  
Rate Of Increase

A procedure is described for kinetic studies on the multiplication of Lee virus in the chorioallantoic membrane in vitro employing the hemagglutination technique for measurement of virus concentration. A linear relationship was found between the logarithm of virus adsorbed and the amount of membrane used. Of the virus adsorbed less than 10 per cent could be recovered from the membrane. Of the recoverable virus 90 per cent was eliminated by specific immune serum. Lee virus was adsorbed by the allantoic and chorionic layers of the membrane to a similar degree. Multiplication occurred in both layers and to a similar extent. When 107.66 EID50 of Lee virus was inoculated per 2.9 cm.2 of chorioallantoic membrane, the ratio of infectivity to hemagglutination titer in the yield was low, although the rate of appearance of virus particles was not diminished despite the large inocula. Virus produced in membranes was liberated rapidly and continually into the medium. 5,6-Dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB), 0.000055 M, prolonged the latent period by more than 100 per cent. The rate of increase during the period of rapid rise was similar in the presence or absence of DRB, but the yield was markedly reduced at the end of this period in the presence of DRB. The amount of the virus in the membranes continued to rise in the presence of DRB and eventually approached the maximal levels reached much earlier in the controls. Measurement of the amount of virus in the media indicated a greater degree of inhibition than did measurement in the membranes. Comparative studies with two benzimidazole derivatives on the dependence of the inhibitory effect on the time of addition of the compound showed that processes which could be inhibited by DRB were of shorter duration than those inhibited by 2,5-dimethylbenzimidazole (MB). With MB the relationship between the time of addition and the inhibitory effect was similar both for virus and for soluble complement-fixing antigen; with DRB the inhibitable processes were of shorter duration for the complement-fixing antigen than for virus particles. DRB was not only 35 times more active on a molar basis but also was more selective in its action than MB. DRB interfered with processes which preceded the emergence of either soluble complement-fixing antigen or virus particles. Some of the implications of these findings are discussed in relation to the mechanism of inhibition of influenza virus multiplication by benzimidazole derivatives.

scholarly journals INHIBITION OF INFLUENZA VIRUS MULTIPLICATION BY ALKYL DERIVATIVES OF BENZIMIDAZOLE

1953 ◽  
Vol 98 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Igor Tamm ◽  
Karl Folkers ◽  
Frank L. Horsfall
Keyword(s):  
Influenza Virus ◽  
Latent Period ◽  
Chorioallantoic Membrane ◽  
Virus Multiplication ◽  
Influenza B Virus ◽  
Influenza B ◽  
In Ovo ◽  
Alkyl Derivatives ◽  
Rate Of Increase

At a concentration of 0.0026 M, 2,5-dimethylbenzimidazole caused a number of alterations in the first cycle of multiplication of influenza B virus, Lee strain, in chorioallantoic membrane cultures in vitro. As determined by infectivity titrations in ovo on the membrane per se, the following alterations were observed: The duration of the latent period was increased by 80 per cent. The rate of increase in titer during the incremental period was somewhat decreased. The yield of virus was decreased by about 99 per cent. When the compound was added to membrane cultures at various periods before or after inoculation with the virus, the following findings were obtained: On addition before or along with the virus, the substance caused about 99 per cent inhibition of multiplication. When added during the first 2 hours after inoculation, the compound caused inhibition of a degree which was inversely proportional to the time of addition. When added 3 to 8 hours after inoculation, the substance caused about 80 per cent inhibition. When added after the end of the latent period, no definite inhibition was obtained in the first cycle of multiplication. These results are interpreted as indicating that 2,5-dimethylbenzimidazole acts by reducing the rate of biosynthetic mechanisms necessary for the reproduction of influenza virus particles.

scholarly journals INHIBITION OF INFLUENZA VIRUS MULTIPLICATION BY ALKYL DERIVATIVES OF BENZIMIDAZOLE

1953 ◽  
Vol 98 (3) ◽  
pp. 229-243 ◽  
Author(s):  
Igor Tamm ◽  
Karl Folkers ◽  
Frank L. Horsfall
Keyword(s):  
Influenza Virus ◽  
Culture Medium ◽  
Chorioallantoic Membrane ◽  
Virus Multiplication ◽  
Influenza B Virus ◽  
Influenza B ◽  
Experimental Conditions ◽  
Virus Reproduction ◽  
B Virus

The activity of compounds which inhibit the multiplication of influenza virus can be measured in chorioallantoic membrane cultures in vitro by means of hemagglutination titrations on the medium. Studies on the reproducibility of virus reproduction in membrane cultures have revealed the major variables which affect the results and thus have led to the development of a precise technique. Under strictly controlled experimental conditions, the extent of reproduction of the virus in membrane cultures is predictable within narrow limits of variation. With 105.5 EID50 of influenza B virus, Lee strain, and 5.75 cm.2 of chorioallantoic membrane per ml., the ratio of infective virus particles to susceptible allantoic cells appears to be approximately 1:28. Under these conditions, the evidence indicates that two cycles of multiplication occur and nearly maximal hemagglutination titers are found with culture medium at 36 hours. The extent of the deviation in the absolute titer in different experiments was only 0.112 log unit. At a concentration of 0.0017 M, 2,5-dimethylbenzimidazole caused inhibition of the multiplication of influenza B virus, Lee strain, which persisted for at least 70 hours as measured by hemagglutination titrations on the culture medium. The degree of inhibition was closely comparable to that demonstrated by infectivity titrations on the membrane at the end of the first cycle of virus reproduction (1).

scholarly journals Dual oxidase 1 promotes antiviral innate immunity

2021 ◽  
Vol 118 (26) ◽  
pp. e2017130118
Author(s):  
Demba Sarr ◽  
Aaron D. Gingerich ◽  
Nuha Milad Asthiwi ◽  
Faris Almutairi ◽  
Giuseppe A. Sautto ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Influenza Virus ◽  
Epithelial Cells ◽  
Host Cells ◽  
Dependent Manner ◽  
Dual Oxidase ◽  
Antiviral Innate Immunity

Dual oxidase 1 (DUOX1) is an NADPH oxidase that is highly expre-ssed in respiratory epithelial cells and produces H2O2 in the airway lumen. While a line of prior in vitro observations suggested that DUOX1 works in partnership with an airway peroxidase, lactoperoxidase (LPO), to produce antimicrobial hypothiocyanite (OSCN−) in the airways, the in vivo role of DUOX1 in mammalian organisms has remained unproven to date. Here, we show that Duox1 promotes antiviral innate immunity in vivo. Upon influenza airway challenge, Duox1−/− mice have enhanced mortality, morbidity, and impaired lung viral clearance. Duox1 increases the airway levels of several cytokines (IL-1β, IL-2, CCL1, CCL3, CCL11, CCL19, CCL20, CCL27, CXCL5, and CXCL11), contributes to innate immune cell recruitment, and affects epithelial apoptosis in the airways. In primary human tracheobronchial epithelial cells, OSCN− is generated by LPO using DUOX1-derived H2O2 and inactivates several influenza strains in vitro. We also show that OSCN− diminishes influenza replication and viral RNA synthesis in infected host cells that is inhibited by the H2O2 scavenger catalase. Binding of the influenza virus to host cells and viral entry are both reduced by OSCN− in an H2O2-dependent manner in vitro. OSCN− does not affect the neuraminidase activity or morphology of the influenza virus. Overall, this antiviral function of Duox1 identifies an in vivo role of this gene, defines the steps in the infection cycle targeted by OSCN−, and proposes that boosting this mechanism in vivo can have therapeutic potential in treating viral infections.

scholarly journals The effects of UK 2054 on the multiplication of influenza viruses

1970 ◽  
Vol 68 (1) ◽  
pp. 151-158 ◽  
Author(s):  
R. D. Barry ◽  
Patricia Davies
Keyword(s):  
Influenza Virus ◽  
Chick Embryo ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Influenza Viruses ◽  
Host Cells ◽  
Virus Infectivity ◽  
Virus Growth ◽  
Virus Particles ◽  
Embryo Fibroblasts

SummaryThe isoquinoline compound UK 2054 prevents the uptake of influenza virus by susceptible cells. Pre-incubation of virus particles with 500μg./ml. UK 2054 at 37°C. for 2 hr. does not reduce virus infectivity. Host cells vary in their responsiveness to the inhibitory effect of UK 2054; virus multiplication is inhibited in chick allantoic cells by lower concentrations than those required to inhibit virus growth in chick embryo fibroblasts. The effectiveness of UK 2054 is reduced by the presence of serum.It is concluded that inhibition of influenza virus multiplication by UK2054 might result from interaction of the inhibitor with both virus and cells. Any direct combination between inhibitor and virus is completely reversible.

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

scholarly journals Oxidative Stress as a Possible Target in the Treatment of Toxoplasmosis: Perspectives and Ambiguities

2021 ◽  
Vol 22 (11) ◽  
pp. 5705
Author(s):  
Karolina Szewczyk-Golec ◽  
Marta Pawłowska ◽  
Roland Wesołowski ◽  
Marcin Wróblewski ◽  
Celestyna Mila-Kierzenkowska
Keyword(s):  
Oxidative Stress ◽  
Animal Studies ◽  
Treatment Options ◽  
Natural Antioxidants ◽  
Redox Status ◽  
Host Cells ◽  
Common Disease ◽  
Parasite Viability

Toxoplasma gondii is an apicomplexan parasite causing toxoplasmosis, a common disease, which is most typically asymptomatic. However, toxoplasmosis can be severe and even fatal in immunocompromised patients and fetuses. Available treatment options are limited, so there is a strong impetus to develop novel therapeutics. This review focuses on the role of oxidative stress in the pathophysiology and treatment of T. gondii infection. Chemical compounds that modify redox status can reduce the parasite viability and thus be potential anti-Toxoplasma drugs. On the other hand, oxidative stress caused by the activation of the inflammatory response may have some deleterious consequences in host cells. In this respect, the potential use of natural antioxidants is worth considering, including melatonin and some vitamins, as possible novel anti-Toxoplasma therapeutics. Results of in vitro and animal studies are promising. However, supplementation with some antioxidants was found to promote the increase in parasitemia, and the disease was then characterized by a milder course. Undoubtedly, research in this area may have a significant impact on the future prospects of toxoplasmosis therapy.

scholarly journals Amphetamine-Decreased Progesterone and Estradiol Release in Rat Granulosa Cells: The Regulatory Role of cAMP- and Ca2+-Mediated Signaling Pathways

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 493
Author(s):  
 Chung-Yu Chen ◽  
Chien-Rung Chen ◽  
Chiao-Nan Chen ◽  
Paulus S. Wang ◽  
Toby Mündel ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Prostaglandin F2α ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Steroidogenic Enzyme ◽  
Estradiol Secretion ◽  
Basal Release ◽  
Ca2 Channels

The purpose of this study is to evaluate the amphetamine effects on progesterone and estradiol production in rat granulosa cells and the underlying cellular regulatory mechanisms. Freshly dispersed rat granulosa cells were cultured with various test drugs in the presence of amphetamine, and the estradiol/progesterone production and the cytosolic cAMP level were measured. Additionally, the cytosolic-free Ca2+ concentrations ([Ca2+]i) were measured to examine the role of Ca2+ influx in the presence of amphetamine. Amphetamine in vitro inhibited both basal and porcine follicle-stimulating hormone-stimulated estradiol/progesterone release, and amphetamine significantly decreased steroidogenic enzyme activities. Adding 8-Bromo-cAMP did not recover the inhibitory effects of amphetamine on progesterone and estradiol release. H89 significantly decreased progesterone and estradiol basal release but failed to enhance a further amphetamine inhibitory effect. Amphetamine was capable of further suppressing the release of estradiol release under the presence of nifedipine. Pretreatment with the amphetamine for 2 h decreased the basal [Ca2+]i and prostaglandin F2α-stimulated increase of [Ca2+]i. Amphetamine inhibits progesterone and estradiol secretion in rat granulosa cells through a mechanism involving decreased PKA-downstream steroidogenic enzyme activity and L-type Ca2+ channels. Our current findings show that it is necessary to study the possibility of amphetamine perturbing reproduction in females.

scholarly journals The Role of Pre-Clinical 3-Dimensional Models of Osteosarcoma

2020 ◽  
Vol 21 (15) ◽  
pp. 5499
Author(s):  
Hannah L. Smith ◽  
Stephen A. Beers ◽  
Juliet C. Gray ◽  
Janos M. Kanczler
Keyword(s):  
Three Dimensional ◽  
Chorioallantoic Membrane ◽  
3D Models ◽  
In Ovo ◽  
Future Directions ◽  
3 Dimensional ◽  
In Vivo Animal Models

Treatment for osteosarcoma (OS) has been largely unchanged for several decades, with typical therapies being a mixture of chemotherapy and surgery. Although therapeutic targets and products against cancer are being continually developed, only a limited number have proved therapeutically active in OS. Thus, the understanding of the OS microenvironment and its interactions are becoming more important in developing new therapies. Three-dimensional (3D) models are important tools in increasing our understanding of complex mechanisms and interactions, such as in OS. In this review, in vivo animal models, in vitro 3D models and in ovo chorioallantoic membrane (CAM) models, are evaluated and discussed as to their contribution in understanding the progressive nature of OS, and cancer research. We aim to provide insight and prospective future directions into the potential translation of 3D models in OS.

Sign in / Sign up

Export Citation Format

Share Document