Some physical, chemical, and taxonomic features of the soluble antigens of the Brucellae.
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Antigens↗
Biomedical subjects
B A Freeman
Publications and source records attributed to B A Freeman.
Osmotically sensitive Brucella in infected normal and immune macrophages.
When Brucella suis is grown in tissue cultures of normal guinea pig macrophages, the Brucella multiplies significantly without the induction of osmotically sensitive forms. In immune macrophages in the presence of normal guinea pig serum, there is a reduction in the number of intracellular Brucella and no multiplication is seen over a 72-hr period. After 6 hr of exposure to immune macrophages, however, approximately 50% of the surviving intracellular Brucella are osmotically sensitive, i.e., they will survive and grow only on medium containing 0.2 m sucrose. Brucella grown in immune macrophages, in the presence of rabbit antiserum against whole guinea pig serum, show the presence of osmotically sensitive forms, although at a reduced level compared to the number seen with immune macrophages in normal guinea pig serum.
Journal Article↗
Separation of soluble Brucella antigens by gel-filtration chromatography.
Soluble precipitating antigens of Brucella suis have been, in various degrees, purified by filtration on Sephadex gels. The most useful gels employed were Sephadex G-150, Sephadex G-200, and Sepharose 4B. Although not all fractions proved to be immunologically pure, some crude molecular-size estimates of most of the 13 soluble antigens of the Brucella cell could be given. In addition, monospecific antisera to three purified Brucella antigens have been prepared. By using purified preparations, physical and chemical data were obtained on two major antigens, E and 1, and a minor antigen, f. Antigen E is not an agglutinogen and may be toxic. Antigen 1 is of low molecular weight and is neither toxic nor agglutinogenic. The minor antigen f is an agglutinogen as well as a precipitinogen and is found on the cell surface. Both major antigens, when purified, were immunogenic in rabbits.
Journal Article↗
Fractionation of Phenol Extracts from Brucella suis: Separation of Multiple Biologically Active Components.
Brucella suis endotoxin prepared by a modification of Westphal's method was purified further by gel filtration and ion-exchange chromatography. The latter proved to be the most effective means of separating antigenic components associated with this fraction. All of the toxic activity was located in a single peak from carboxymethyl-Sephadex. Subsequent separation of this material on diethylaminoethyl (DEAE)-Sephadex indicated the presence of two or more toxic components in phenol extracts of B. suis. A factor which increases vascular permeability was separated by use of the ion exchanger DEAE-Sephadex, and was associated with the first peak. Its manifestations could be destroyed by heating at 60 C for 30 min or neutralized by reaction with specific antiserum. This permeability factor is believed to be distinct from other toxins which appear in column eluates and which can be assayed by skin induration.
Journal Article↗
Effect of lysosomal enzymes on Brucella.
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Biological Assay↗
Separation of type 2 toxins of Vibrio cholerae.
Choleragenic toxin was separated from vascular permeability factor by ion-exchange chromatography of supernatants of dialyzed peptone cultures of Vibrio cholerae. The choleragenic toxin eluted from columns of QAE-Sephadex with low-ionicity systems is free of permeability factor activity. Further elution of these columns with 0.5M NaCl removes both the permeability factor and residual choleragenic toxin. When this latter material is chromatographed on columns of carboxymethyl-Sephadex, the permeability factor toxin is eluted by 0.02M phosphate buffer and is free of choleragenic activity. Therefore, choleragenic and permeability factor activities of the type 2 cholera toxins are different and can be separated by these procedures.
Animals↗
Antigenic structure of Brucella suis spheroplasts.
Baughn, Robert E. (University of Tennessee, Memphis), and Bob A. Freeman. Antigenic structure of Brucella suis spheroplasts. J. Bacteriol. 92:1298-1303. 1966.-Immunoelectrophoresis was used to differentiate between the antigenic mosaics of normal cells of Brucella suis and of spheroplasts prepared by treatment with penicillin, glycine, and a combination of these agents. Smooth cells possessed at least 13 antigens, 10 of which were precipitated with homologous antiserum. Three additional antigens were visualized by reaction with spheroplast antisera. Spheroplasts induced with glycine were the least complex, with only six antigens. Penicillin-glycine spheroplasts were similar, but possessed one additional antigen. Penicillin spheroplasts were the most complex, with eight antigens. Although there appeared to be quantitative differences between the antigens of spheroplasts and normal cells, no completely new antigens were detected in spheroplasts. Serum absorption studies indicated that four antigens were associated with the surface of normal B. suis, none of which occurred in spheroplasts.
Antigens↗
Oxygen: the air-borne nutrient that both sustains and threatens life.
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Air↗
Nitric oxide regulation of tissue free radical injury.
We have presented evidence from a broad range of chemical, cell biological, and in vivo studies showing that .NO can mediate tissue-protective reactions during oxidant stress, as well as toxic and tissue prooxidant effects. One predominant factor that has been identified which influences .NO being protective versus toxic is the relative rates of production and concentrations of .NO and the more "traditional" family of reactive oxygen species, including O2.-, H2O2, .OH, LO., LOO., and high valency complexes of iron. Also, since so many anti-neutrophil actions of .NO have been described, it is likely that .NO will serve a protective role in acute inflammatory reactions. One issue is certain--many new truths remain to be revealed, as we continue to develop our understanding of the toxicology of reactive oxygen- and nitrogen-containing species.
Animals↗
Intelligibility of time-expanded speech with normally hearing and elderly subjects.
The effects of time-expanded monosyllabic words (NU-6) on the auditory discrimination performance of 15 young adults with normal hearing and 20 elderly subjects were studied. Three conditions of time expansion, 30, 60 and 100%, plus a 0% control condition, were presented at four sensation levels (8, 16, 24 and 32 dB). For the normally hearing subjects, auditory discrimination performance at all ratios of time expansion was equal to the 0% condition. Results for the elderly subjects indicated intelligibility was inversely related to time expansion at the 30 and 60% conditions. However, at the 100% condition, speech intelligibility improved over the 60% condition at 8 and 16 dB sensation level. At 24 and 32 dB sensation level, performance at 100% was equal to the 60% condition. With the normal and elderly subjects, ear and list effects were minimal. The results are discussed in terms of the clinical value of this procedure and in light of literature that reviews the performance of subjects on tests employing various temporally altered stimuli.
Acoustic Stimulation↗
Recall and repetition of time-compressed sentential approximations by normal-hearing young adults.
This study investigated the performance of a group of normal young adults on time-compressed five-word first-order sentential approximation. The results supported the contention that intelligibility decreased as a function of increasing time compression and decreasing presentation level. The findings are discussed with regard to the perceptual strategies employed for the recall of these stimuli, and the stimuli's potential clinical utility for assessing auditory processing abilities of both children and adults.
Audiometry↗