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R Repanovici

Publications and source records attributed to R Repanovici.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

UV-A and PUV-A action on Sendai virus HN glycoprotein.

The UV-A and PUV-A treatments were applied on the Sendai virus and the changes of the biological properties of HN surface glycoprotein were monitorized. Under the UV-A action the HA and NA activities are inhibited in a dose-correlated way. When the irradiation was done in the presence of a photoreagent (8-MOP) the HA activity remained unchanged, but the enzymic activity was affected. The possible mechanisms of these inhibition processes are discussed.

Dose-Response Relationship, Radiation↗
PubMedDate not supplied

Human papillomavirus and human cytomegalovirus DNAs presence in patients suspected of condylomatosis or papillomatosis.

17 samples of total cell DNA isolated from cervical smears from women suspected of condyloma or papilloma were analysed by PCR with appropriate primers, in order to establish the presence of viral DNAs (HPV and/or HCMV). HPV DNA was found in seven cases, and so was for HCMV DNA. Only in three cases a coinfection was present. The RFLP allowed to specify the involvement of HPV6 in 3 cases suspected of condyloma and in one suspected of papilloma; the other three HPV positive samples had another genotype, which we could not determine by the methods used.

Adult↗
PubMedDate not supplied

Is the human papillomavirus DNA present in penile warts?

Infection with human papillomavirus (HPV) has been established to be a sexually transmitted disease, with a potential risk of intraepithelial neoplasia and invasive cancer, function of the genotype involved. Scraped cells from lesions of 27 men establishing various types of penile warts were investigated by PCR for HPV DNA detection. Twenty patients (76.9%) were found to have an HPV infection. By RFLP genotyping of only 13 samples, 4 HPV16. 2 HPV6 and 7 HPV ND infections were determined. Comments about these cases, in correlation with other factors are presented. The findings in this study confirmed the HPV involvement in penile warts.

Adolescent↗
PubMedDate not supplied

[Unconventional culture of the human hepatitis B virus (HBV)].

The investigation of the key stages of the HBV vital cycle was realised recently through an unconventional cultivation technique, using transfection with an adequate DNA, cloned in plasmids. Transfections was achieved in cell lines, differentiated or not. The results showed that expression of some of the HBV genes is under the control of hepatospecific factors.

Animals↗
PubMedDate not supplied

[The electrophoresis of biotinylated nucleic acids].

A simple and rapid method was worked out to evaluate the biotinylation level of the pBR322 and pSVK1H genetic cloning vectors, using gel electrophoresis. Avidin was used to slow down the migration of biotinylated DNA: the DNA migration speed diminished as the biotinylation level rose, due to DNA complexation. The highest level of biotinylation is characterized by the formation of a biotinylated nucleic acid-avidin complex with no electrophoretical mobility.

Avidin↗
PubMedDate not supplied

[The detection of human papillomaviruses in histological preparations by using dot-blot hybridization].

The 56 tissue samples were obtained from female patients with anogenital tumors, benign or malign, subsequently confirmed through pathomorphological analysis. The investigations were aimed at the discovering of HPV presence using hybridization techniques with biotinylated molecular probes and monitorisation through enzymatic reaction. The presence of ADN types 11, 16 and 18 was detected on about 52% of all the cases; the ADN HPV incidence was 57% among the patients with a neoplasm and/or cervix uteri papillomatosis diagnosis.

Adult↗
PubMedDate not supplied

[Early anti-HPV 16 protein antibodies in patients with anogenital tumors].

A study was worked out in female patients with anogenital tumors and in apparently healthy women, aimed at the detection of antibodies against E4 and E7 HPV 16 proteins. As regards the detection of HPV 16 infection, the DNA hybridization and Western-blot results were in good agreement. The HPV 16 infection was detected in a relatively high number of the patients (17 out of 24) and of the apparently healthy women using Western blot.

Adult↗
PubMedDate not supplied

Estimation of avidin activity by two methods.

The biological activity of avidin was estimated by two different methods. The spectrophotometric method used the avidin titration with biotin in the presence of 4 hydroxiazobenzen-2'carboxilic acid as indicator. In the radioisotopic determination the titration with tritiated biotin was accomplished. Both methods led to the same results, but the spectrophotometric one is less avidin expensive and more rapid, being more convenient.

Animals↗
PubMedDate not supplied

Photodynamic effect of toluidine blue on MM virus.

The photodynamic effect of toluidine blue (TB) was studied on MM virus cultivated in L cells and on the RNA extracted form MM virus inoculated to mice by intracerebral route. MM virus infectivity is completely inhibited by the photodynamic action of TB, due to lesions at the molecular level of the viral RNA.

Encephalomyocarditis virus↗
PubMedDate not supplied

Separation of a glycoprotein antigen for the diagnosis of bovine leukemia and some of its biochemical properties.

Data are presented on the separation and on some biochemical properties of an antigen to be used in the immunodiffusion (ID) test for detection of bovine leukemia virus. The antigen obtained proved to have the same efficiency in the ID test as a commercially available standard antigen. Experimental results suggest that the antigen is released into the culture fluid in the form of a glycoprotein molecule consisting of two subunits with a molecular weight of 60,000 linked by--SH bonds.

Animals↗
PubMedDate not supplied

[Demonstration of viral proteins by silver staining].

Investigations were conducted to establish the optimal conditions for silver staining of polypeptides separated by polyacryle-amide gel electrophoresis. The thickness of the gel layer was of 1.5 mm. The experiments showed that the modified Hankeshover and Dernick's technique (4) (replacement of the fixative for the electrophoretically separated polypeptides and extension of the bleaching by Farmer's reagent time) had the best sensitivity and reproducibility. This technique can be performed also on polyacryle-amide gel preparations already stained by the Coomassie Brilliant Blue method. To check the efficiency of this silver staining technique, the authors used it to detect the Sendai virus and B hepatitis virus surface antigen polypeptides.

Electrophoresis, Polyacrylamide Gel↗
PubMedDate not supplied

[The protector effect of ribosomal preparations against experimental influenza infection in mice].

A study was conducted on the protective effect of some ribosomal preparations, isolated from chorionic-allantoic membranes of chicken embryos, infected or not with parainfluenza (Sendai) or influenza (AoPR8) virus, in mice experimentally inoculated with influenza virus strain AoPR8 adapted to the mouse. Results showed that the tested preparation, containing ribosomes and polysomes isolated from chorio-allantoic membranes of Sendai virus inoculated chicken embryos, ensure the mice complete protection against AoPR8 virus, if administrated before the control infection.

Allantois↗
PubMedDate not supplied

Some physico-chemical properties of the rigid form of the Sendai virus nucleocapsid.

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).

Capsid↗
PubMedDate not supplied

Cationic anticancer drugs and their modes of action.

This report focuses on two groups of cationic cancerostatics, anthracycline antibiotics and 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone (ambazone), lining up biophysical and biochemical effects on the level of membranes and membrane constituents. The interaction of both drugs with multilamellar liposomes consisting of phosphatidylcholine used as a simple model membrane system could be ensured by means of steady state and nanosecond time-resolved fluorometric investigations. The biochemical effect on membranes is underlined by the inhibition of the neuraminidase activity of the Sendai virus, modification of the CAMP phosphodiesterase activity of leukemia L 1210 cells of mice and reduction of the lymphocyte blast transformation.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

[Research conducted at the Stefan S. Nicolau Institute of Virology of Bucharest in the area of nucleic acids and genetic engineering].

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.

Academies and Institutes↗
PubMedDate not supplied

[Study of the encapsulation and transport of several proteins to different organs by means of liposomal type particles of viral origin].

Liposomal particles may be more efficiently incorporated by cells through mechanisms still incompletely elucidated. This property allowed to use them as a vehicle for macromolecules. Research was conducted to obtain liposomal type particles of viral origin charged with various proteins (bovine serum albumin, ovalbumin, ribosomes, human 125I-immunoglobulin G) and to establish the distribution of proteins encapsulated in viral envelopes among various organs after inoculation to laboratory animals.

Animals↗