Virologie

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A brief review is done of some of the most important studies realised by the "Stefan S. Nicolau" Institute researchers in the field of nucleic acids. It is worth mentioning among these the investigations about interactions between nucleic acids and some biologically active substances, the recombinant DNA, as well as the most recent works on DNA-DNA hybridization in the avidine-biotine system.

The paper is a review of researches done at the "Stefan S. Nicolau" Institute of Virology, in Bucharest, the last five years, in the antiviral chemotherapy field, as well as of the chemotherapeutical implications of studies conducted about other aspects of virology.

The author presents the results of researches done at the "Stefan S. Nicolau" Institute of Virology in Bucharest on the infections induced by arboviruses. The characteristics of three tick encephalitis virus strains (two strains isolated from Ixodes ricinus and Ixodes persulcatus ticks and one from a patient with encephalitis symptoms) are given. Most of the report is devoted to the results of serological survey conducted in a human population, in several domestic birds and mammals from some districts of Romania, as well as in migratory birds from the Danube delta, with regards to the incidence of some Toga-, Bunya- and Reoviruses...

The detection of a latent viral flora intrinsic to the central nervous system (CNS) raises the problem to know if some neuropathogenic strains have the property of initiating persistent infections or if the persistence is the result of the immune response particularities at the CNS level. A review is done of the pathogenic explanations of virus persistence in SSPE, followed by the discussion about two pathogenic alternatives issues from the author's studies: the antigenic "drift" hypothesis and the one of the defective interfering particles preferential synthesis...

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The innovative activity of the research team of the "Stefan S. Nicolau" Institute of Virology in the field of scientific tool design is presented, in a brief description of the devices, apparatuses and systems claimed in 32 patents registered not only in Romania, but also in the United States of America, United Kingdom, West Germany, France and Belgium, applied in usual virology diagnosis, research and production, for analytical purposes of computer assisted absorption and fluorescence spectrophotometry and for bichromatic ultramicroanalysis...

Studies conducted on asymmetric triazine derivatives synthetized at the Chemical and Pharmaceutical Research Institute showed that products S1, S16, S17, S19, S20 and S22 have a remarkable O2- radical scavenger activity. Among these derivatives, the product S1 is the most efficient as an antiviral agent.

The report is a review of the research and results of the "Stefan S. Nicolau" Institute of Virology scientists in the field of herpes viruses, as they were materialized in the great number of published or communicated scientific papers these last ten years.

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The study describes the peculiarities of the influenza infection evolution, in 1988, in a large urban centre, B., in Romania, as they result from the active surveillance of the epidemiological process of influenza and other viral respiratory tract infections, by means of a complex methodology based on clinical-epidemiological and laboratory techniques. The low endemic morbidity, the evolution of these seasonally ascendant specific incidence, the endemic aspect of influenza infection being maintained as a consequence of its predominance in infants and children, the clinically mild form of the outbreaks, all these are specific elements of the epidemiologic impact in the surveyed territory...

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The effect of some dissociation agents (SDS, beta-mercaptoethanol, urea, EDTA) on the rigid form of the Sendai virus nucleocapsid was studied. Polyacrylamide gel electrophoresis in the presence of lytic mixture (1% SDS, 2% beta-mercaptoethanol, 5 M urea, for 2 min at 100 degrees C) revealed two types of polypeptide subunits (mol. wts. 46,000 and 14,000), as well as the dissociation in the presence of 0.1% SDS only. The EDTA treatment leads to a disorganization of the protein part (10(-2) M) or of the nucleocapsid structure (5 x 10(-2) M)...

The effect of di- and tetravalent cis-diaminoplatinum chlorides on Sendai virus envelop HN glycoprotein was investigated. The partial inhibition of neuraminidase activity was greater in the case of the divalent platinum complex derivative.

Protein kinase C (PKC) inhibitors: Hidaka's compounds H-7 (10 microM) and H-8 (20 microM), palmitoyl-carnitine (10 microM) and phloretin (50 microM), did not modify the antiviral effect of human natural or recombinant interferon alpha and of natural interferon beta. The tumor promoter 12-o-tetradecanoyl-phorbol-13-acetate (TPA) (200 nM), known as activator of PKC induced an antiviral state when tested on human embryo fibroblasts challenged with the vesicular stomatitis virus. The battery of PKC inhibitors used inhibited the antiviral effect induced by TPA...

Studies were conducted using uni- and multilamellar liposomes to establish optimum conditions for influenza antigen incorporation in view of their transport to the target cells for experimental influenza prophylaxis in hybrid white mice. Radiometric determinations showed a good level of preparation purification, a good efficiency of incorporation in liposomes of the active biological material, the liposome linked radioactivity distribution among different organs. Charged liposomes induced solid and long lasting resistance against influenza control infection...

V-2 and V-8, two preparations containing an extract from Chamenerion angustifolium, were tested in vitro and in vivo, for their anti-influenza properties. In vitro, the two preparations induced a significant reduction of the hemagglutinating titers. In vivo, administration of each of the two products, three times before the influenza virus inoculation significantly reduced (27%) the mortality rate and the hemagglutinating titers, and increased the survival mean time (SMT) (about 3.5 times). These effects were more striking when control infection was done seven days after the last administration of the extract: the mortality rate reduces by 50%, the HA titers lowered to zero and the SMT increased by about 5 times...

Virus pollution was studied in 734 water samples collected from the Dîmboviţa River (310), lakes inside the town of Bucharest (136) and swimming pools (288). The results showed that the works carried out these last years to regularize the Dîmboviţa led to a reduction of the virus pollution rate from 16.6-26.9% in 1984 to 4.16-5% in 1988. As for the lake and swimming pool waters, the pollution rate is directly proportional to the applied general hygiene measures. In summer, in drained lakes strictly controlled from the domestic and industrial sewage discharge point of view, the pollution rate was no higher than 6%, while in the lakes receiving sewage the frequency of isolations was between 12...

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Serum samples from 31 patients with various types of malignancies, 18 patients with different viral infections and 6 healthy subjects as controls, were tested by indirect immunofluorescence (IF) method for antibodies against viral capsid antigens (VCA) and the presence of active EBV infection. EBV antibodies anti-VCA were detected in 19 patients with tumors, in 8 patients with viral infections and in 2 healthy subjects. EBV active infection was found out in 9/19, 3/8 and 0/2 EBV anti-VCA positive patients with malignancies, different viral infections and healthy subjects respectively...