PubMed Health⌕ Search

Biomedical subjects

N Cajal

Publications and source records attributed to N Cajal.

At least 19 recordsLinked to original sources
PubMed1988

Interferon-induced antiviral state is inhibited by neomycin and mimicked by diacylglycerols.

The antiviral effect of human interferons alpha and beta was inhibited in dose-dependent manner by submillimolar concentrations of neomycin, known to block phosphoinositide hydrolysis and therefore the diacylglycerol formation. On the contrary, the synthetic permeant diacylglycerols (1-oleoyl-2-acetyl-sn or rac-glycerol) were able to induce an interferon-like antiviral state when tested against the vesicular stomatitis virus and herpes simplex type I virus. Hidaka's compound H-8 (1.2 microM), expected to inhibit cAMP- and cGMP-dependent protein kinases, did not modify the antiviral effect of interferon. Our data suggest that the phosphoinositide pathway is involved in transducing the interferon antiviral signal, but, since the exogenous phospholipase C (0.1-1 U/ml) failed to induce an antiviral state, this pathway, although implicated, seems not the only one.

Cell Line↗
PubMed1985

Some physico-chemical and biological properties of egg-Sendai virus with altered haemagglutinin-neuraminidase protein.

Some physico-chemical and biological properties of egg-cultivated Sendai (egg-Sendai) virus particles with altered haemagglutinin-neuraminidase (HN) protein were studied. These particles were obtained accidentally from purified egg-Sendai virus stored at +4 degrees C. Egg-Sendai with altered HN protein was not infectious for cultured cells, but could still infect embryonated eggs. Though egg-Sendai virus with altered HN protein and glycoproteins had no haemagglutination activity, it unexpectedly possessed a relatively high neuraminidase (NA) activity representing about 70% of the activity of normal particles. Since polyacrylamide gel and rocket immunoelectrophoresis indicated that the altered particles contained only F protein, possibly the native HN was converted into a molecule of the same molecular mass as F protein.

Antigens, Viral↗
PubMed1985

Effect of some anthracycline antibiotics on the neuraminidase activity of Sendai virus and its isolated glycoproteins.

Anthracycline antibiotics violamycin BI (VBI) and adriamycin (Adr) strongly inhibited the neuraminidase (NA) activity of Sendai virus and of its isolated glycoproteins, occurring either in solution or associated in liposome-like particles. NA did not exhibit the classical Michaelis-Menten kinetics: the plot of reaction velocity versus substrate concentration was sigmoidal, while Hill's plotting indicated that the enzyme has at least two binding sites for the substrate. The reaction kinetics obtained suggested that Sendai virus NA acts as an allosteric enzyme, when its material support, the HN is located on the virus surface. The inhibitory effect of the anthracycline antibiotics in question on the NA activity seemed to be similar to that of negative effectors.

Allosteric Site↗
PubMed1984

Interaction of influenza and parainfluenza viruses with polycations, organic oligocations and chromosome preparations.

As evaluated by light scattering at 90 degrees, natural organic oligocations such as putrescine, spermidine and spermine interfered with myxovirus aggregates which were induced by the histone H2A and strongly amplified by shaking during incubation. In contrast, the synthetic oligocation 1.7-diamino heptane itself aggregated the virus particles, its action being unmodified by adding polycationic H2A in abundance. When human chromosome preparations treated with protamine solution and shaked during incubation were covered with a stable polycationic molecular layer, the chromosomes had become unstainable by the Giemsa method even if the dye was used in excess. Nevertheless, the affinity of influenza virus particles for protamine was so high that they were able to dissociate the protamine molecules from the preformed complexes reconstituting the affinity of chromosome preparations to Giemsa stain. The virus-caused shift in the staining ability of chromosomes did not occur when bacterial suspension was added instead of the viral one. The model of oligocationic relaxation and of polycation condensation accounting for the modulatory effects of polyamines is discussed.

Cations↗
PubMed1980

Peculiarities of the virus-host cell relationship in a calf kidney cell line persistently infected with measles virus.

Persistent infection with measles virus established in a calf kidney cell line differed in some features from other measles virus carrier systems. After a variable life span, ranging from 50 to 1100 days, six of the chronically infected cell lines showed an evolution towards lytic infection. Only one of these lines, the K-2 cell line, exhibited marked morphological, growth and chromosomal alterations suggesting in vitro cellular transformation. The transformed K-2 cells released infectious measles virus with several modified biological parameters. Persistent infection was not due to the accumulation of thermosensitive mutants or defective particles. The role of the host-cell factor and of the selection of the virus population during its passage in RV cells are discussed.

Animals↗
PubMed1979

Sendai virus multiplication in the presence of ceruloplasmin and homologous virus envelopes.

Preincubation of Sendai virus with ceruloplasmin induced in chorioallantoic membrane (CAM) fragments the synthesis of a population with decreased infectivity and high haemagglutinating (HA) and neuraminidase (NA) activities, whereas preincubation with solubilized virus envelopes led to the production of a viral population with the same infectivity as the control, but with lower HA and NA activities. Preincubation of the virus with a mixture of ceruloplasmin and solubilized envelopes depressed the overall virus synthesis; the resulting population had a low infectivity and high HA and NA activities. The variation in the HA/NA ratio indicates a modification in the envelope structure.

Animals↗
PubMed1975

The presence of interferon and type A immunoglobulins in the nasopharyngeal secretions of volunteers immunized with an inactivated influenza vaccine.

The presence of interferon and type A immunoglobulins (IgA) was followed up in the nasopharyngeal washings collected from volunteers immunized intranasally with an inactivated influenza vaccine [strain A/Rom 1/73 (H3N2)]. Interferon was detected 24 hours after vaccine administration, its incidence being similar to that in the course of acute infection. Intranasal administration of inactivated influenza vaccine stimulated the production of secretory IgA in 3 of 10 samples collected 12 days after vaccination. At the same time, IgA were found in 4 samples collected before vaccination, and inhibited in certain cases the stimulation of interferon synthesis. The practical importance of the route of influenza vaccine administration is discussed.

Administration, Intranasal↗