Search PubMed⌕ Search

Biomedical subjects

J L Anderson

Publications and source records attributed to J L Anderson.

At least 343 records · Page 19Linked to original sources
PubMed1977

Characterization of the myosin-phosphorylating system in normal murine astrocytes and derivative sv40 wild-type and A-mutant transformant.

Myosin and myosin light-chain kinase have been isolated and characterized from small quantities of normal and SV40-transformed, murine astrocytic neuroglial cells in culture and from intact normal mouse brain. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the astrocyte myosins revealed a heavy chain of 200,000 daltons and two light chains of 20,000 and 15,000 daltons. These myosins are similar to other cytyplasmic myosins. The astrocyte 20,000-dalton light chain can be phosphorylated by an endogenous myosin light-chain kinase which has properties similar to those of the myosin light-chain kinase found in human platelets. No differences were detected in either the astrocyte myosins or myosin light-chain kinases between (a) the normal and transformed cells, (b) the transformed cells grown at the permissive and nonpermissive temperatures, or (c) the SV40 wild-type and A-mutant transformants.

Actins↗
PubMed1977

Expression and thermal stability of simian virus 40 tumor-specific transplantation antigen and tumor antigen in wild type- and tsA mutant-transformed cells.

We have explored aspects of a suggested relationship between the expression of simian virus 40 tumor-specific transplantation antigen (TSTA) and tumor antigen (TA). A unique rat embryo cell line transformed by a temperature-sensitive A mutant that loses TA during exposure to the nonpermissive temperature (A28-RE) was found to lose TSTA. On the other hand, a typical control tsA-transformed cell line (A239-MB) expressed both TA and TSTA at the non-permissive temperature. TA in lysates obtained from A239-MB cells was found to be three to four times more thermolabile by covwt-mb) when incubated at either 33 or 40 degrees C. These data complement previous reports using TA from lytic infection and are consistent with the suggestion that TA is virus encoded. In contrast to TA, which even in wild-type-transformed cells was completely destroyed in less than 10 min at 50 degrees C, TSTA, assayed in vivo by tumor rejection, and tumor-specific surface antigen(s) TSSA) defined by an in vitro cytolytic assay, were thermostabile. Even after 24 h of incubation of extracts of 50 degrees C, high levels of TSTA and TSSA activity were present. Since these surface antigens when obtained from cells transformed by tsA mutants were also thermostabile, they could not be distinguished from the wild-type antigens. These results (i) indicate a coordinate expression of TA and TSTA in transformed cells; (ii) confirm that TA is virus encoded; and (iii) confirm that tha antigenic and immunogenic determinants that characterize TA and TSTA activities are distinct. However, the possibility that TSTA, like TA, is of viral rather than cellular origin is not excluded.

Animals↗
PubMed1977

Expression of tumor-specific transplantation antigen in cell lines transformed by wild-type of tsA mutant simian virus 40.

The simian virus 40-induced tumor-specific surface antigen(s) (TSSA) and tumor-specific transplantation antigen(s) (TSTA)were detected in cells transformed by wild-type or temperature-sensitive mutant simian virus 40 by an antibody-mediated cytolytic assay for TSSA and an immunization test for TSTA. Cells transformed by tsA mutants, which lose their transformed phenotype when grown at nonpermissive temperatures, nonetheless do express TSSA and TSTA as well as T-antigen at both temperatures.

Animals↗
PubMed1976

Spectroelectrochemical investigations of stoichiometry and oxidation-reduction potentials of cytochrome c oxidase components in the presence of carbon monoxide: the "invisible" copper.

Spectroelectrochemical studies are presented for the carbon monoxide complex of isolated, purified cytochrome c oxidase (EC 1.9.3.1) in solutions saturated with carbon monoxide. The results indicate a stoichiometry of three equivalents per oxidase-carbon monoxide complex molecule. Formal reduction potentials (Eo) of the two copper and one heme component at pH 7.0 were obtained by means of quantitative absorbance-charge titrations in the absence and presence of cytochrome c, and by means of a Nernstian "Minnaert" plot in the presence of cytochrome c. Analysis of the absorbance-charge curves from these titrations gave an indirect determination of the high potential, "invisible" copper component. The copper potentials in the carbon monoxide complex were found to be relatively unchanged with respect to those of the native enzyme. The Eo values obtained were: high potential ("invisible") copper (340 +/- 20 mV (NHE)), low potential copper (190 +/- 20 mV), and low potential heme (250 +/- 10 mV).

Carbon Monoxide↗
PubMed1976

SV40 transformation of mouse brain cells: critical role of gene A in maintenance of the transformed phenotype.

Brain cells derived from the NIH Swiss mouse strain have been established in tissue culture. Astrocytic neuroglial cells, identified by morphology and staining properties, predominate. The brain cell culture was successfully transformed with SV40 wild type virus and with a representative early (A239) and late (C219) mutant. When subjected to growth analysis the A239 transformant displayed selective loss of six characteristics of the transformed phenotype at the restrictive temperature (40.5 degrees C): doubling time, saturation density, ability to grow in low serum, efficiency of growth on plastic and on normal brain cell layers, and cloning in soft agar. Temperature shift experiment demonstrated the reversibility of the differences in saturation density. T-antigen was expressed at both temperatures. Alteration in uptake of 2-deoxyglucose was not a characteristic of the transformed phenotype. The cell lines may be utility in brain culture work and in studies on the mechanism of SV40 transformation.

Antigens↗
PubMed1975

Neutrophil dysfunction in diabetes mellitus.

The neutrophil bactericidal capacity of 31 patients with diabetes mellitus in a nonketoacidotic state, including 21 without infections and 10 with recurrent infections, were evaluated. The killed intracellular bacteria (KICB) expressed as the percentage of the initial inoculum for 25 normal control subjects was 95.4 (SD equal plus and minus (2.7) and that for the diabetic patients, the KICB was 72.8 (SD=+30.7)with a p value of less than or equal to 0.01. In 17 out of 31 diabetic atients, the KICB was greater than minus two standard deviations of the control mean. Using the lysostaphin assay technic, 11 patients were shown to phagocytize poorly, 3 had impaired intracellular killing and 3 had a combined defect. These defects were not correctable by normal serum nor related to blood-glucose levels. No apparent correlation with infection could be demonstrated. Fiver of the 10 patients with recurrent infections and 12 out ot of 21 patients without infections has a neutrophil dysfunction. However, all 3 patients with a combined defect had severe bacterial infections.

Adolescent↗
PubMed1974

Restricted transport in small pores. A model for steric exclusion and hindered particle motion.

The basic hydrodynamic equations governing transport in submicron pores are reexamined. Conditions necessary for a simplified, one-dimensional treatment of the diffusion/convection process are established. Steric restrictions and Brownian motion are incorporated directly into the resulting model. Currently available fluid mechanical results are used to evaluate an upper limit on hindered diffusion; this limit is valid for small particle-to-pore ratios. Extensions of the analysis are shown to depend on numerical solutions of the related hydrodynamic problem, that of asymmetrical particle motion in a bounded fluid.

Biological Transport↗
PubMed1974

Mechanism of osmotic flow in porous membranes.

A model for osmotic flow in porous membranes is developed from classical transport and thermodynamic relations. Mathematical expressions for the reflection coefficient as a function of solute dimension and shape, and more generally pore/bulk distribution coefficient, are derived for long cylindrical pores of circular cross section. For a rigid, spherical macromolecule the osmotic reflection coefficient equals (1 - Phi)(2), where Phi is the solute distribution coefficient; this result differs significantly from expressions found in the literature. The effect of weak solute adsorption to (or repulsion from) the pore wall can also be accounted for in the derivation. The driving force for osmotic flow arises from solute-pore wall interactions which cause radial variations in concentration and concomitant gradients in pressure normal to the wall. Implications of this three-dimensionality of osmotic phenomena are discussed with particular reference to the adequacy of one-dimensional treatments in relating reflection coefficient to membrane and solute properties.

Biological Transport↗