PubMed Health⌕ Search

Biomedical subjects

J F Obijeski

Publications and source records attributed to J F Obijeski.

At least 19 recordsLinked to original sources
PubMed1987

Safety issues related to the use of recombinant DNA-derived cell culture products. I. Cellular components.

Anti-thymocyte serum (ATS) treated newborn rats were used to assess the tumorigenic potential of mammalian cell and mammalian cell culture derived substances. Injection of as much as 100 micrograms of Chinese hamster ovary (CHO) DNA, an amount in excess of 10(8) fold more than might be present in one dose of a typical final product derived from mammalian cell cultures, failed to initiate a tumor in immunosuppressed animals. In addition, injection of 10 micrograms of activated oncogene cloned from a human bladder carcinoma was also insufficient to initiate a tumor in immunosuppressed animals. Injection of some but not all CHO cell lines did result in tumor growth which upon isoenzyme analysis was verified to be of hamster origin. Of importance was the finding that recombinant tissue plasminogen activator (rt-PA) and hepatitis B surface antigen (HBsAg) vaccine failed to induce tumors in either normal or immunosuppressed rats. The results suggest that the presence of minute quantities of CHO derived nucleic acid fragments in these final products have no discernable tumorigenic potential.

Animals↗
PubMed1985

Can variola-like viruses be derived from monkeypox virus? An investigation based on DNA mapping.

The results are presented of a special study to determine whether variola-like "whitepox" viruses could arise as white pock variants of monkeypox virus after one or a few mutations. DNA mapping by cross-hybridization of restriction endonuclease DNA fragments was carried out on 18 orthopoxviruses relevant to this study, including variola and monkeypox viruses and white (non-haemorrhagic) pock producers recovered from chorioallantoic membranes infected with red (haemorrhagic) pock-producing monkeypox viruses. The distinctiveness of the DNA maps of true variola and monkeypox viruses indicated that spontaneous production of "whitepox" from monkeypox virus was genetically impossible. These and other observations led to the conclusion that the "whitepox" viruses recovered from monkeypox virus stocks had an exogenous origin.

Animals↗
PubMed1979

Rhabdoviridae. Report of the Rhabdovirus Study Group, International Committee on Taxonomy of Viruses.

The family Rhabdoviridae comprises approximately 75 viruses infecting vertebrates, invertebrates and plants. The main characteristics of the member viruses are: (i) the viruses infecting vertebrates and invertebrates are bullet-shaped and the viruses infecting plants are usually bacilliform; (ii) the viruses have particle lengths varying from 130 to 380 nm and widths varying from 60 to 95 nm; (iii) the viruses possess unit-membrane envelopes from which protrude spikes 5 to 10 nm long; (iv) the viruses have precisely coiled helical nuecleocapsids with a diameter of approx. 50 nm; (v) most of the viruses which have been studied contain 5 proteins; the prototype, vesicular stomatitis virus, contains proteins designated L (large), G (glycoprotein), N (nucleoprotein), NS (nonstructural) and M (matrix); N or NS is phosphorylated in most members which have been studied; (vi) the viruses contain single-stranded RNA which is transcribed into several messenger RNA species with sizes corresponding to the structural proteins; (vii) the nucleocapsid contains the RNA-dependent RNA polymerase and is infectious; and (viii) many of the viruses produce morphologically distinct defective-interfering (T) particles.

RNA, Viral↗
PubMed1978

Diagnosis of California La Crosse virus infection by counterimmunoelectrophoresis.

La Crosse virus cell culture-derived soluble antigen was used in a counterimmunoelectrophoresis procedure to assess the presence or absence of La Crosse antibodies in 79 paired acute- and convalescent-phase human sera. The counterimmunoelectrophoresis test appeared to measure the same antibody as the complement fixation test but was more sensitive and rapid.

Antibodies, Viral↗
PubMed1977

Serological relatedness of monkeypox, variola, and vaccinia viruses.

Closely related human and monkey orthopoxviruses were differentiated by serologic techniques. Antiviral sera were tested by immunodiffusion for reactivity against six different viral antigens prepared from either infected cell cultures or infected chorioallantoic membranes (CAMs) of embryonated eggs. Portions of each antiserum were separately absorbed with heterologous antigens from infected CAMs to remove common reactivity. The absorbed sera formed immunodiffusion precipitates with both types of antigen preparation and revealed specific-character differences that made it possible to classify the viruses as variola, vaccinia, or monkeypox. Cross-complement fixation tests were also used to examine the immunologic reactivities of antisera to detergent-treated, purified preparations of three orthopoxviruses. Only common reactivities were detected by this method, however, and differentiating reactivities were not observed.

Complement Fixation Tests↗
PubMed1977

The virion and soluble antigen proteins of variola, monkeypox, and vaccinia viruses.

The structural proteins in purified preparations of variola, monkeypox, and vaccinia viruses were separated and compared by using a high resolution SDS-polyacrylamide gel electrophoresis system. About 30 proteins were resolved for each virus by autoradiography of longitudinally-sliced gel rods. Although the autoradioelectropherograms of each virus were similar, it was possible to differentiate them by their unique protein pattern in the 30,000 to 40,000 molecular weight region of the gels. A single virion glycoprotein (mol. wt. = 38 X 10(3)) and a virion phosphoprotein (mol. wt. = 12 X 10(3)) were associated with each of the virus preparations. Cross-absorbed monospecific immune sera against variola, monkeypox, and vaccinia virus-infected cells were used in immunodiffusion tests to precipitate radiolabeled, homologous, soluble antigen proteins. The predominant antigen protein associated with each immunospecific precipitate had a molecular weight of approximately 73,000.

Antigens, Viral↗
PubMed1977

The rapid concentration and purification of influenza virus from allantoic fluid.

Influenza virus was quantitatively recovered from infectious allantoic fluid by precipitation with 8 percent (wt/vol) polyethylene glycol 6000 (PEG-6000). Virus concentrated by PEG-6000 treatment was rapidly purified by gel permeation chromatography through controlled pore glass beads. The purity of virus preparations achieved by this method, when judged by three independent criteria, was comparable to virus preparations purified by conventional density gradient procedures.

Allantois↗
PubMed1977

The virus particle nucleic acids and proteins of four bunyaviruses.

The structural polypeptides of five bunyaviruses, snowshoe hare, Lumbo and La Crosse viruses (members of the California encephalitis subgroup of bunyaviruses), Bunyamwera and Main Drain viruses (members of the Bunyamwera subgroup of bunyaviruses), have been compared by polyacrylamide-SDS gel electrophoresis. Each virus was found to possess three major structural polypeptides, two glycoproteins (G1 and G2), and one nucleocapsid protein (N). Although the sizes of the G1 polypeptides (mol. wt. approx. 115 X 10(3)) and G2 polypeptides (mol. wt. approx. 38 X 10(3)) of the five viruses were found to be essentially similar, the sizes of the N polypeptides of the various viruses differed (mol. wt. range 19 to 24 X 10(3)). The RNA genomes of four bunyaviruses (snowshoe hare, La Crosse, Bunyamwera and Main Drain) have also been compared. Each virus has three RNA species of mol. wt. approx. 3 X 10(6), 1-9 X 10(6) and 0-4 X 10(6). Minor size differences were observed for the smallest RNA species of the four viruses (mol. wt. range 0-34 to 0-50 X 10(6)). For snowshoe hare virus the RNA segments hav a 5' sequence of pppAp...which suggests that the RNA is linear and not circular.

Arboviruses↗
PubMed1977

Biochemical characterization of infantile gastroenteritis virus (IGV).

Enzymic and biophysical studies with purified infantile gastroenteritis virus (IGV) nucleic acid indicated that the virion contained a double-stranded RNA genome of approx. 14 x 10(6) daltons which could be separated by gel electrophoresis into eight bands of RNA which were comprised of 15 RNA species. Two major virus proteins, VP2 (mol. wt. = 135,000) and VP8 (mol. wt. = 40,000), which composed about 85% of the total virion protein, were detected in IGV particles by polyacrylamide gel electrophoresis. Eight additional minor proteins were also resolved.

Diarrhea, Infantile↗
PubMed1977

The circular, segmented nucleocapsid of an arenavirus-Tacaribe virus.

The nucleocapsid structures of Tacaribe virus, a member of the Arenaviridae, were purified from detergent-treated virus particles by equilibrium density gradient centrifugation. Negative-contrast electron microscopy indicated that they were coiled, circular filaments. They had a mean diam. of 5 to 10 nm and two predominant length classes of 640 nm and 1300 nm were found.

Arenaviridae↗
PubMed1977

La Crosse virus soluble cell culture antigen.

A virus-free soluble antigen, obtained by ammonium sulfate precipitation of the supernatant fluids of La Crosse virus-infected BHK-21 cell cultures, was more reactive and more specific than infected suckling mouse brain antigen when compared by immunodiffusion and counterelectrophoresis tests. By complement fixation tests, the antigen was cross-reactive with heterologous California group arbovirus hyperimmune mouse ascitic fluids, but to a lesser degree than was the standard sucrose-acetone-extracted infected suckling mouse brain antigen. The major virion nucleocapsid protein of La Crosse virus was found by polyacrylamide gel electrophoresis to be the soluble antigen protein responsible for precipitation in immunodiffusion and counterelectrophoresis tests.

Antigens, Viral↗
PubMed1977

Electron microscopy of the segmented RNA genome ofLa Crosse virus: absence of circular molecules.

The three species of single-stranded RNA present in La Crosse virus were examined in the electron microscope. Because large amounts of contaminating cellular DNA are copurified with the virus despite extensive attempts to purify the virus, it was necessary to use procedures that eliminated the bulk of this DNA before the viral RNA was analyzed. When this was done, the modal lengths of La Crosse virus RNA were 0.4, 2.0, and 3.1 mum. These lengths correspond well to their known molecular weights of 0.4 x 106, 1.8 x 106, and 2.9 x 106. Under the denaturing conditions used to permit complete spreading of these single-stranded RNA molecules, no single-stranded circular molecules are observed. Therefore, the circular nucleocapsids present in La Crosse virus and some other bunyaviruses do not appear to be due to convalent linkage of the ends of the RNA genome.

Cell Line↗
PubMed1976

High resolution polyacrylamide gradient gel electrophoresis.

A method was developed for high resolution electrophoresis of proteins in linear gradient (3 to 30%) polyacrylamide gel rods in a neutral phosphate buffer containing 0.1% sodium dodecyl sulfate. Well-defined protein zones were observed and improved resolution was attained especially for low molecular weight proteins in preparations containing a variety of polypeptides, e.g. viruses that are often separated by continuous gel methods. Electropherograms of continuous (8%) and gradient (3 to 30%) gels were made of purified vesicular stomatitis virus, variola virus, Rickettsia rickettsii, and alpha and beta chains of hemoglobin in order to demonstrate the resolution of the gradient system.

Acrylamides↗
PubMed1976

Structural proteins of La Crosse virus.

Preparations of La Crosse virus, a member of the California encephalitis group of bunyaviruses, were found to possess three major virion proteins. Two of the proteins were glycosylated (G1 and G2) and were located on the surface of the virus particles. These two glycoproteins were present in equimolar amounts and possessed apparent molecular weights of 120 X 10(3) and 34 X 10(3). Virion nucleocapsids, isolated by a nonionic detergent and salt treatment, contained another major protein, N (molecular weight = 23 X 10(3)). A large, but minor, protein species L (molecular weight = 180 X 10(3)) was also found in virus preparations. The approximate number of protein molecules per virion has been determined. Electron microscopy of purified La Crosse virus indicated that the virus particle (mean diameter, 91 nm) is enveloped and possesses irregular surface projections (length, 10 nm).

Arboviruses↗
PubMed1976

Segmented genome and nucleocapsid of La Crosse virus.

La Crosse (LAC) virions purified by velocity and equilibrium gradient centrifugation contained three single-stranded RNA species. The three segments had sedimentation coefficients of 31S, 25S, and 12S by sodium dodecyl sulfate-sucrose gradient centrifugation. By comparison with other viral and cellular RNA species, the LAC viral RNAs had molecular weights of 2.9 x 10(6), 1.8 x 10(6), and 0.4 x 10(6). Phenol-sodium dodecyl sulfate-extracted LAC virion RNA was not infectious for BHK-21 cell cultures under conditions in which Sindbis viral RNA was infectious. Treatment of LAC virus with the nonionic detergent Triton X-100 and salt released three nucleocapsid structures, each containing one species of virion RNA. The nucleocapsids had sedimenation coefficients of 115S, 90S, and 65S. Negative-contrast electron microscopy of the nucleocapsids indicated that they were convoluted, supercoiled, and apparently circular. They had a mean diameter of 10 to 12 nm and modal lengths of 200, 510, and 700 nm (some were even longer). By chemical and enzymatic analysis of purified viral RNA, one type of 5' nucleotide (pppAp) present in the proportion of one per RNA segment was identified. After periodate oxidation, each virion RNA species was labeled by reduction with [3H]sodium borohydride. Taken together, these results suggest that although the nucleocapsids appear as closed loops, the viral RNA has free 5' and 3' ends and is, therefore, not circular.

Capsid↗