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Biomedical subjects

G Darai

Publications and source records attributed to G Darai.

At least 145 records · Page 8Linked to original sources
PubMed1983

Role of transferrin in uptake of non-physiological metals into cells.

At physiological concentrations of citrate the uptake of 59Fe, 67Ga, and 239Pu into human type B lymphocytes of splenic origin is the same in viable and in non-viable cells. Addition of transferrin has no effect on the uptake into non-viable cells but in viable cells it increases the uptake of Fe and Ga but decreases that of Pu. Uptake decreases as transferrin concentration increases although this is less marked with Ga.

Biological Transport, Active↗
PubMed1983

Detection of an element of the SV40 late promoter in vectors used for expression studies in COS cells.

Plasmids containing hepatitis B virus (HBV) DNA and a 232-bp SV40 DNA fragment encoding the origin of replication were constructed. When introduced by transfection into COS cells, these plasmids directed the synthesis of hepatitis B surface antigen. S1 mapping of the mRNAs covering the S gene showed that transcriptional initiation was promoted by the interaction of HBV sequences with an SV40 promoter element: transcription started on HBV DNA but had several properties of SV40 late transcription. The detection of a promoter element in an SV40 origin fragment commonly used in the COS system is important for the interpretation of data deriving from expression studies in COS cells.

Animals↗
PubMed1983

Tupaia (tree shrew) adenovirus DNA: sequence of the left-hand fragment corresponding to the transforming early region of human adenoviruses.

The nucleotide sequence of the left-hand region of the adenovirus DNA of the phylogenetically interesting tree shrew, (Tupaia belangeri) has been determined. Transcription signals, initiation codons, splice sites and termination codons were assigned on the basis of its relatedness to the EIA region of human adenoviruses 5, 7 and 12. A consensus sequence for encapsidation of adenoviral DNA that is based on the established packaging region of adenovirus 16 is proposed. The sequenced region includes the gene for a 18 000 dalton polypeptide that corresponds to the EIA proteins of the transforming region of the human serotypes. The deduced amino acid sequence of the 18 000 dalton TAV polypeptide contains a highly conserved central domain that is homologous to the middle of the 30 000 dalton polypeptides of human adenovirus indicating the significance of the central amino acid residues for the biological function of the EIA proteins.

Adenoviridae↗
PubMed1983

Mink lung cells as a tool for detection of Mycoplasma hyorhinis contamination in cell cultures and virus stocks.

In an extensive host range study of M. hyorhinis mink lung cells (MvlLu, ATCC CCL 64) were found to be the cells of choice for the propagation of this mycoplasm, which otherwise is often difficult to grow in a cell-free medium. Furthermore, rapid plaque assay and plaque purification procedures were developed for M. hyorhinis. The titer of M. hyorhinis grew to 1 X 10(7) to 1 X 10(8) pfu/ml within three d postinoculation on mink lung cells. DNA restriction enzyme analysis of the genome of M. hyorhinis was performed. Endonucleases Bst EII and Xho I are the most suitable enzymes for cleaving M. hyorhinis DNA into distinct fragment patterns. Thus, the use of the combination mink lung cells for mycoplasma growth with subsequent restriction enzyme analysis leads to an unambiguous detection and identification of M. hyorhinis strains even in minute amounts.

Animals↗
PubMed1983

Induction of generalized and lethal herpesvirus infection in the tree shrew by intrahepatic transfection of herpes simplex virus DNA.

The infectivity of herpes simplex virus (HSV) genome was investigated in vivo using the tree shrew, which is highly susceptible to HSV, as an animal model. Individual tree shrews were inoculated intrahepatically with 0.2 ml of a transfection mixture containing 25 micrograms HSV DNA, 50 micrograms salmon sperm DNA, and 250 micrograms DEAE-dextran. Seven out of nine tree shrews transfected with HSV DNA developed a generalized herpesvirus infection. The new virus progeny was found in different organs of transfected animals.

Animals↗
PubMed1983

The nucleotide sequence of the inverted terminal repetition of the tree shrew adenovirus DNA.

The termini of the tupaia (tree shrew) adenovirus (TAV) DNA have been sequenced. The inverted terminal repetitions (ITR) are 166 bp long containing the A + T-rich, highly conserved sequence present in all adenovirus DNAs so far analysed. An unusual feature within the TAV ITR is the presence of four sets of a conserved sequence TGACCG which occur at or near the ends of many adenovirus ITR.

Adenoviridae↗
PubMed1983

Goat herpesviruses: biological and physicochemical properties.

Two herpesvirus isolates from goats are known which cause afflictions of the digestive tract in kids and, in some cases, abortion. An antigenic relationship of these goat herpesviruses with infectious bovine rhinotracheitis/infectious pustular vulvo-vaginitis virus (bovid herpesvirus 1, BHV-1) was reported and because of the species-specific pathogenicity, the goat isolates were named caprine herpesvirus 1. In this report the two isolates are further characterized and compared with BHV-1. Although the caprine herpesviruses share many biological and physicochemical properties with BHV-1, they can be differentiated from the bovine viruses with respect to growth cycle, one-way cross-neutralization and, most importantly, the restriction endonuclease fragments of their DNAs. The molecular weight of the caprine herpesvirus DNA, based on electron microscopic length measurement is 90 X 10(6), similar to that of BHV-1 (95 X 10(6]. On the basis of these genomic differences, we propose that DNA restriction endonuclease patterns of the caprine herpesviruses should be designated as prototypic of bovid herpesvirus 6 (BHV-6).

Animals↗
PubMed1983

Hepatitis B after infection of a chimpanzee with cloned HBV DNA.

Transfection of chimpanzee liver cells in vivo or in vitro with cloned HBV DNA induced typical hepatitis B in the inoculated animal. Intravenous inoculation of a 1000-fold greater dose of the same cloned HBV DNA did not induce infection or disease. The experiment proved that cloned HBV DNA is fully functional and that the nick gap structure, proteins covalently linked to the HBV genome, or any other HBV particle associated protein are not needed for initiation of virus replication.

Animals↗
PubMed1983

Effect of vaccination schedule and dialysis on hepatitis B vaccination response in uraemic patients.

Antibody response to vaccination with hepatitis B vaccine (HB-Vax) was evaluated in 43 staff, 81 dialysis patients and 12 non-dialysed uraemic patients. We confirmed less frequent seroconversion and lower concentration of antibody to hepatitis B surface antigen (anti-HBs) in dialysis patients despite a higher dose (40 micrograms vaccine). However, more frequent vaccination (5 times vs 3) increased anti-HBs concentration to almost normal. Concomitant administration of hepatitis B immunoglobulin (HBIG) and hepatitis B vaccine (passive/active) did not interfere with vaccination success. Antibody response was equally poor in dialysed non-dialysed uraemic patients.

Adult↗
PubMed1982

Distribution and retention of 239Pu in the tree shrew (Tupaia belangeri) following intramuscular injection.

The retention of intramuscularly injected monomeric 239Pu has been studied in the tree shrew (Tupaia belangeri), a primitive prosimian species. Data for the first 2 yr are presented. Resorption from the injection site is rapid, and the main depository organs are skeleton and liver with approximately 50 and 20% of the absorbed dose, respectively. The half life of retention in skeleton is approximately 500-600 days and in liver approximately 150 days, these half lives are compared to data for the retention of transuranium elements in other animal species. Indications of liver lesions were found in 5 animals and 1 animal died at day 790 with an osteosarcoma.

Animals↗
PubMed1982

Analysis of polypeptides of the tree shrew (Tupaia) herpesvirus by gel electrophoresis.

The virion polypeptide composition of three independently isolated tree shrew herpesviruses (THV) was analysed by SDS-polyacrylamide slab gel electrophoresis and by a two-dimensional technique using isoelectric focusing. Two of the virus isolates analysed were from malignant tumours; the other isolate (THV, strain 1) was from an apparently healthy animal. The polypeptide patterns of the three purified Tupaia herpesvirus isolates were remarkably similar, each consisting of at least 35 polypeptides ranging in mol. wt. from 12,000 to 230,000. Whilst the majority of analogous polypeptides of the three viruses were of indistinguishable electrophoretic mobility, some (e.g. polypeptides of 82K to 86K) showed small differences in apparent mol. wt. which were characteristic of the virus strain. Comparative SDS-polyacrylamide gel electrophoresis made it possible to distinguish the Tupaia herpesvirus isolates from each other. At least five glycoproteins were found in purified THV virions. The two-dimensional electropherograms revealed at least 47 discernible protein spots, some of which were specific for a given THV isolate and which were detectable even in lysates of THV-infected cells.

Animals↗
PubMed1982

Analysis of Mycoplasma hyorhinis genome by use of restriction endonucleases and by electron microscopy.

The chromosome of Mycoplasma hyorhinis was analyzed by using different restriction endonucleases and electron microscopy. It was found that restriction enzymes BstEII, XhoI, and SacI are the enzymes of choice for analysis and characterization of M. hyorhinis. The bands resulting from digestion of M. hyorhinis DNA with BstEII had apparent molecular weights ranging from 1.2 X 10(6) to 75 X 10(6). The apparent total molecular weight of DNA was calculated from the molecular weights of the individual bands and found to be 251 X 10(6). Electron microscopic contour length measurements of the largest DNA fragments verified the molecular weight values calculated from gel analysis. Electron microscopic contour length measurements of intact DNA of M. hyorhinis revealed a molecular weight of 5.4 +/- 5 X 10(8). The discrepancy between the values of molecular weight of M. hyorhinis DNA as determined by restriction enzyme analysis and contour length measurement is based on the fact that some of the DNA fragments which migrate as an apparent single band in the agarose gel really are double or multiple DNA fragments.

Base Sequence↗
PubMed1982

Protein kinase and specific phosphate acceptor proteins associated with tupaia herpesvirus.

A protein kinase activity was found to be associated with tree shrew (tupaia) herpesvirus. The protein kinase was characterized with respect to its requirements for enzymatic activity. A divalent cation such as Mg2+ or Mn2+ was necessary as well as ATP as the phosphate donor. Distinct tupaia herpesvirus polypeptides (molecular weights of 100,000 [100K], 82K, and 53K) were found to be phosphate acceptor proteins when 5 mM Mg2+ was used. At a higher Mg2+ concentration (20 mM), additional viral proteins (220K, 71K, 31K, and 20K) were phosphorylated. The viral phosphoproteins were analyzed by chemical and enzymatic hydrolyses. The predominant sites of phosphorylation were the beta-OH groups of the serine and threonine residues of these tupaia herpesvirus proteins. Kinase activity was not stimulated by cyclic nucleoside monophosphates. Endogenously added proteins did not enhance protein kinase activity. Protein kinase activity was inhibited by 5'-p-fluorosulfonylbenzoyladenosine.

Adenosine↗
PubMed1982

Alterations in protein and glycoprotein composition of rat embryo fibroblasts transformed by herpes simplex virus type 2.

Total and superficially exposed plasma membrane components of tumorigenic herpes-simplex-virus (HSV)-transformed fibroblasts were studied. As a result of oncogenic HSV transformation, a significant decrease of polypeptides 230,000, 180,000, 56,000 and 43,000 daltons was found. These changes were accompanied by a significant increase in superficial exposition of several sialopeptides and two peptides of 30,000 and 15,000 daltons. It was suggested that these two peptides may represent virus-coded components of HSV-transformed fibroblasts. The present results indicate that the HSV-transformed tumorigenic cell clone meets all previously described criteria for oncogenically transformed cells.

Animals↗
PubMed1982

Intertypic superinfection of herpes simplex virus in vivo leads to reisolation of latent viruses with newly acquired lymphotropic properties.

The susceptibility of juvenile Tupaias to several strains of temperature-sensitive mutants of HSV-1 and 2 was tested. It was found that in all cases the animal survived an infection of 1 X 10(7) PFU of temperature-sensitive mutants which were administered intravenously. In contrast, an infection dose of 1 X 10(3) PFU of wild-type HSV-2 and 1 X 10(2) PFU or HSV-1 was fatal for juvenile Tupaias. Those animals which had initially been infected with the ts-mutants of HSV-1 and/or 2 were protected against a superinfection of a lethal dose of HSV-1 or HSV-2. The state of HSV latency in surviving animals was investigated. The infectious virus was recovered from the spinal cords of those animals which had been initially infected with wild-type HSV-1 or 2 and/or superinfected with HSV-1 or 2. In contrast, the infectious viruses were recovered only from the spleens of those animals which had initially been infected with ts-mutants of HSV-2 and superinfected with HSV-1. These recovered viruses were plaque-purified and analysed in detail. It was found, firstly, that recovered viruses from the spleens of Tupaias lost their pathogenicity and tropism in Tupaias. Secondly, significant changes in the genome of the recovered viruses from the spleen of Tupaias were detected. The results indicate that an intertypic interaction between HSV-1 and 2 occurred in vivo which is responsible for the observed change in organotropism and pathogenicity of the recovered viruses.

Animals↗