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Biomedical subjects

G G Miller

Publications and source records attributed to G G Miller.

At least 109 records · Page 6Linked to original sources
PubMed1983

[Detection of endogenous intracisternal type A particles in early mouse zygotes].

Electron microscopy was used to examine early zygotes from C57BL/6 mice aged 5-7 h after mating. A great number of intracisternal type A particles (IAP) in the cavity of smooth endoplasmic reticulum and in the large vesicles of the Golgi complex were demonstrated in ultrathin sections of any of the 70 embryos under examination. IAP were detected in different areas of zygote cytoplasm and near the vitelline membrane of the zygote. Expression of virus particles in so early zygotes provides evidence in favour of the hypothesis of IAP involvement in the processes of normal differentiation.

Animals↗
PubMed1982

Modification of T cell antinuclease idiotype expression by in vivo administration of anti-idiotype.

Immunization of BALB/c mice with nuclease leads to the production of anti-nuclease antibodies bearing a set of cross-reactive idiotypes (Id) distinct from those produced by B10.D2 mice after similar immunization. In both strains, such immunization with nuclease also leads to the production of splenic T helper cells (TH), which provide nuclease-specific help in an in vitro plaque-forming cell response to nuclease-TNP. Pig anti-(BALB/c antinuclease) anti-idiotypic antibodies (pig anti-BALB/c Id) react only with TH of nuclease-primed BALB/c and not with B10.D2 animals. After administration of pig anti-BALB/c Id in complete Freund's adjuvant to BALB/c and B10.D2 mice, Id-bearing nonantigen-binding molecules were induced in both strains. Such treatment also resulted in the induction of nuclease-specific splenic TH cells in both strains. BALB/c TH cells induced by anti-Id, like the majority of nuclease-primed BALB/c TH cells, bore BALB/c Id, as shown by their functional elimination with anti-Id plus complement. B10.D2 TH cells induced by anti-Id, unlike TH cells from nuclease-primed B10.D2 mice, also bore BALB/c idiotypic determinants by the same criterion. Thus, it appears that one can manipulate the expression of Id on serum immunoglobulins and on antigen-specific TH cells by administration of exogenous anti-Id reagents. These results have implications both for network interactions in the immune response and for the genetic basis of Igh-C linked Id expression.

Animals↗
PubMed1982

The expression and functional involvement of nuclease- specific idiotype on nuclease-primed helper T cells.

The expression and functional significance of idiotypic determinants on antigen-specific helper T (Th) cell populations for responses to Staphylococcal nuclease (Nase) were evaluated in an in vitro antibody response system. Trinitrophenyl (TNP)- specific plaque-forming cell responses to TNP-conjugates of Nase (TNP-Nase) were shown to require the cooperation of Nase-primed Th cells as well as unprimed B and accessory cells. The expression on these antigen-primed Th cells of idiotypic determinants cross-reactive with those on anti-Nase antibodies was demonstrated by the specific elimination of Th cells for TNP-Nase by treatment with affinity-purified anti-idiotypic antibodies plus complement. The susceptibility of Nase-primed Th cells to elimination by such treatment was specific in that anti-idiotypic antibodies affected Th cells only from strains normally expressing the same (or a cross-reactive) idiotype on anti-Nase antibodies. A functional role of the idiotypes expressed on Nase-primed Th cells was suggested by the fact that anti-idiotypic antibody present throughout the period of culture, in the absence of complement, suppressed responses to TNP-Nase in an antigen- and strain-specific manner. It was further shown, by cell mixing experiments, that this inhibition appeared to occur at the level of the Th cells and was not dependent on the strain of origin of the B cells. Thus, antigen-specific Nase-primed Th cells express strain-specific idiotypic determinants cross-reactive with, or identical to, those of anti-Nase antibodies. These cell surface idiotypic determinants appear to be functionally involved in the activity of Th cells for the induction of antibody responses to TNP-Nase in vitro.

Animals↗
PubMed1982

Dependence of the structural MuMTV protein expression on hormone-induced murine mammary carcinoma GR/mt cell differentiation in vitro.

Effect of three hormones on the clonal cell line, originating from the stable GR/mt mammary carcinoma (MC) cell line was studied. In the hormones free media the cells had fibroblast-like shapes. Normal differentiation markers and MuMTV protein processing could not be revealed. Insulin favors epithelial cell shape and growth pattern induction, Thy 1.2 antigen expression, as it was shown by FIF test and increased clonogenicity in semisolid medium. Prolactin produces elongated, fusiform cells, milk protein synthesis and loss of clonogenicity. Both hormones exert no influence on the MuMTV protein precursors processing, as it was revealed in RIP test. Dexamethasone renders no visible influence on the cell differentiation except influence on the actin filament expression and intensification of the morphogenetic insulin action. Besides, dexamethasone switches on the env (but not the gag) product precursor processing, however, expression of the mature envelope protein on the cellular membranes occurred only in cells, entering the insulin-induced type of differentiation, as it was shown by RIP test with iodinated cells and MIF test. The gag precursor processing occurred only in extracellular virions. Delay of this process might be responsible for the preferential A-particle production by the cells described.

Animals↗
PubMed1981

Induction of idiotype-bearing, nuclease-specific helper T cells by in vivo treatment with anti-idiotype.

Treatment of BALB/c mice with purified pig anti-(BALB/c anti-nuclease) anti-idiotypic antibodies has been found to induce the appearance of idiotype-bearing immunoglobulins (Id') in the serum of these mice in the absence of detectable antigen binding activity. This phenomenon appeared to require T cells in the hosts because no Id' was detected in the serum of nude mice similarly treated. Furthermore, the spleens of BALB/c mice treated with anti-idiotype were found to contain helper T cells capable of providing help in an in vitro plaque-forming cell response to trinitrophenyl-nuclease equivalent to that provided by helper T cells from the spleens of nuclease-primed animals. Helper T cells from both anti-idiotype-treated and nuclease-treated animals were found to be antigen-specific and to be similarly susceptible to elimination by treatment with anti-idiotype plus complement. Therefore, treatment with both antigen and anti-idiotype appeared to prime similar populations of antigen-specific helper T cells, while having different effects on the induction of antibody. These findings are consistent with the network theory of receptor interactions in the immune response, and may provide a means for studying individual cell populations involved in such interactions.

Animals↗
PubMed1981

[Characteristics of A-type intracytoplasmic particles produced by human cells].

Radioimmunoprecipitation was used to analyse comparatively proteins in cytoplasmic A-type particles (CAP) and structural proteins of D-type virions in Hep-2 system of cultivated human cells. Proteins of CAP were iodinated and studied by electrophoresis in SDS-PAAG. In the preparations obtained, 60 000 (p60), 45 000, 42 000 and 20 000 dalton proteins wee detected. p60 was the main protein in CAP. It was precipitated by purified CAP antiserum rather than by antisera against structural proteins of D-type virions. It was thus demonstrated that the main structural protein of CAP Hep-2 cells contains no antigenic determinants of structural proteins of D-type oncoviruses.

Animals↗
PubMed1979

Adaptation of thymidine utilization to changing rates of DNA synthesis in the cell cycle.

In synchronous cultures of P-815 murine mastocytoma and of Chinese hamster ovary (CHO) cells, the relative contribution of exogenous thymidine to DNA synthesis was studied by comparing rates of (3H)thymidine incorporation with the rate of DNA synthesis as derived from incorporation of (3H)thymidine (10(-5) M) in the presence of amethopterin. In synchronous P-815 cultures, time-dependent variations of DNA synthesis rates were in close agreement with those of (3H)thymidine incorporation rates at concentrations of the precursor ranging from 5 x 10(-8) to 10(-5) M. Similarly, in synchronous CHO cell cultures prepared by two different methods, time-dependent changes in DNA synthesis rate were almost identical with those of the rate of incorporation of (3H)thymidine supplied at 5 x 10(-8) M. Thus, at a given thymidine concentration in the medium, the proportion of thymine residues in DNA that were derived from exogenous thymidine remained nearly constant, even though rates of cellular DNA synthesis underwent pronounced changes. This indicates that in the synchronous culture systems used, utilization of exogenous thymidine is efficiently adapted to changing rates of DNA synthesis.

Animals↗
PubMed1977

Inhibition of virus-induced plaque formation by atoxic derivatives of purified cobra neurotoxins.

Venom from Naja naja siamensis was resolved into 16 toxic and nontoxic fractions by chromatography on SP-Sephadex, C-25. The principal neurotoxin preparations were chromatographically and electrophoretically homogeneous. Of the purified constituents, only the principal neurotoxin and minor neurotoxins were precursors of inhibitors of plaque formation among baby hamster kidney fibroblasts infected with Semliki Forest Virus.

Cell Line↗
PubMed1976

Phenotypic mixing of vesicular stomatitis virus and D-type oncornavirus.

After mixed infection of cells with vesicular stomatitis virus (VSV, thermolabile mutant tl 17) and oncornavirus type D, phenotypically mixed virions are formed containing the VSV genome and oncornavirus and VSV envelope. The virions are thermostable and have serologic characteristics of both viruses.

Animals↗
PubMed1976

Presence of the p27 antigenicity and absence of the gp52 antigenicity and leukemia virus antigens in intracytoplasmic A particles (iAp) of mouse mammary tumour origin.

Using the Ouchterlony immunodiffusion method and indirect immunofluorescence tests on tissue slices the antigenic structure of iAp of mouse mammary tumour origin has further been investigated. Antisera against iAp, MTV-B particles, B particle polypeptide p27 and glycoprotein gp52, and leukemia C-type particles were used in these studies. The most prominent antigen of iAp in mammary tumours was found to be identical to the p27 antigen of B particles. This finding was not unexpected in view of recently published data by other authors showing the presence of p27 in iAp of leukemia cells and Leydig cell tumours. The p27 polypeptide is considered to be a group-specific antigen of mouse mammary tumour viruses associated with iAp of different tissue sources and inner structural components of mature B particles. On the other hand, the gp52 antigen and leukemia virus antigens were shown to be absent from iAp of mammary carcinomas. Therefore, the assumption is confirmed that the gp52 glycoprotein represents a group-specific antigen of B type viruses, presumably located at the virion surface. The failure to demonstrate leukemia virus antigens in iAp supports the suggestion that this kind of particles is not related to C type viruses.

Animals↗
PubMed1975

[Methods of obtaining antisera against antigens of the mammary cancer virus].

The authors used various methods of producing virus-containing preparations from mouse mammary carcinoma to obtain rabbit antisera against the mammary carcinoma antigens. The best results were achieved by means of the virus precipitation from the cultural fluids of carcinomas growing in vitro after preliminary hormonal stimulation of the virus yield followed by its purification in the sucrose density gradient.

Animals↗
PubMed1974

Intracellular virus-specific structures and RNAs in oncornavirus-producing human cells.

Two kinds of virus-specific structures were isolated from the cytoplasm of Detroit-6 and human amnion cells producing oncornavirus-like particles. These structures represented A particles with the diameter of 70 to 80 nm and aggregated strands of nucleocapsids with the diameter of 3 and 6 nm. The structures were separated from cellular contaminants by isopycnic banding in linear sucrose gradients and subsequently further purified by sedimentation in velocity sucrose gradients. Their sedimentation coefficient was 250 and 150S, respectively. Both structures contain 60, 45, and 35S RNA species, and 150S structures also contained 20S RNA. The 35 and 20S RNA from the 150S structure formed hybrids with DNA enzymatically synthesized on extracellular virions. The structures displayed endogeneous polymerase activity, DNA product of the reaction being predominantly associated with 60S RNA. No 70S RNA was found in the cell structures of various densities. Also, the virions purified from tissue culture fluid contained 70S RNA. These findings are consistent with those on extracellular maturation of oncornavirus RNA.

Amnion↗
PubMed1974

Properties of intracytoplasmic A particles isolated from oncornavirus-producing human cells.

A particles with the diameter of 70 to 80 nm were isolated from the cytoplasm of HEp-2, HeLa, and AO cells producing oncornavirus of Mason-Pfizer-like type. Most of the A particles banded at 1.23 to 1.24 g/ml, whereas 3 to 10% banded at 1.29 g/ml in equilibrium sucrose gradients. They banded at 1.30 g/ml in CsCl gradients suggesting that they contained 8% RNA. Individual A particles sedimented at 200 to 250S in velocity sucrose gradients, but their significant part was found aggregated and sedimented at more than 300S. They were resistant to RNase digestion. A particles possessed polymerase activity which was preferentially activated by Mn(2+) rather than by Mg(2+), the RNA template being 60S RNA. Cross-hybridization with two DNA products and immunoassay showed that A particles and Mason-Pfizer-like oncornavirus produced by the same cells contained neither homological RNA sequences nor common antigens, suggesting that A particles are not intracellular precursors of Mason-Pfizer-like oncornavirus but represent an independent oncornavirus. Hybridization of A particle RNA with excess of cellular DNA revealed about 20 proviral copies per HEp-2 cell genome and no proviral copies in human embryo and placenta cell genomes.

Antigens, Viral↗
PubMed1974

Rapid identification of Candida albicans septicemia in man by gas-liquid chromatography.

Gas-liquid chromatography (GLC) was used to study normal serum and serum from patients with septicemia caused by a variety of bacteria and by Candida albicans. The gas chromatograms of seven sera from six patients with septicemia due to C. albicans were found to be significantly and reproducibly different from those of normal sera. Chromatograms of serum from 19 bacteremic patients were indistinguishable from normals. The major peaks present in chromatograms of normal sera were identified by GLC and mass spectroscopy as the methyl esters of palmitic, oleic, linoleic, and stearic acids. In addition to these peaks, serum from patients with candidemia contained abnormal peaks that were also present in cultures of C. albicans grown in normal serum and in washed C. albicans harvested from cultures in yeast nitrogen base broth. Chromatograms from 11 cases of mucosal candidates differed little from normal and were easily distinguished from those of fungemia patients. Chromatograms of serum from two of four patients with deep-invasive candidiasis were indistinguishable from those of fungemia and reverted to normal after infections were eradicated.

Bacterial Infections↗