Showing papers on "Bacillus anthracis published in 1967"

Value of field data for extrapolation in anthrax.

Abstract: : Data are presented to support the hypothesis that animals resistant to the establishment of anthrax are susceptible to its toxin, the former shown by dose of organisms and the latter by challenge with sterile toxin, and by the number of organisms and units of toxin per ml in terminal blood. The variables discussed are dose, doubling rate in the blood, terminal number of organisms per ml of blood, units of toxin per ml of terminal blood, inhibition of phagocytosis by toxin, spore germination within the phagocyte, quantitative phagocytosis in vitro, and lysis of phagocytes in vitro. The need for quantitative information from field cases of anthrax is emphasized for its usefulness as research information per se and to more completely understand field anthrax. In addition, the information obtainable by a field serological survey and its use are discussed.

Capillary thrombosis as a cause of death in experimental anthrax.

Abstract: : The lungs of rats, rabbits, and guinea pigs that died of anthrax septicemia were studied by light and electron microscopy In all three species, the clinical signs of respiratory failure that occurred during the terminal phase of the disease were associated with widespread pulmonary capillary thrombosis The thrombi occurred in intact capillaries and were composed of platelets and fibrin These results are compared with previous observations in rats given anthrax toxin and the significance of pulmonary capillary thrombosis as a factor in the cause of death in anthrax is discussed

In Vivo Growth and Distribution of Anthrax Bacilli in Resistant, Susceptible, and Immunized Hosts

Abstract: Differences in in vivo growth rates of Bacillus anthracis in the bodies of infected rats and guinea pigs showed the effect of innate species resistance. The effect of two levels of immunity imposed on these hosts demonstrated that, as the degree of immunity increased, the growth rate of organisms decreased and was accompanied by a decrease in terminal population. It was shown that growth rates in the blood best reflected the population growth in the entire host. Data obtained from the naturally resistant rat that had been immunized with both the Belton-Strange protective antigen and live vaccine demonstrated the role of “toxins” in terminal anthrax. The in vivo morphological changes in anthrax bacilli pointed out errors regarding estimates of true terminal population of organisms when samples for counting were taken postmortem rather than at the time of death. Images

Pathophysiological and biochemical changes in anthrax.

Abstract: : Pathophysiological and biochemical changes in anthrax are reviewed. The comparison between spore- and toxin-challenged animals shows a remarkable similarity, indicating that the toxin of Bacillus anthracis caused death although the organisms per se caused little pathophysiological response. Death was primarily due to a respiratory depression of central nervous system origin; the cardiovascular system remained intact. Death occurred with an extreme anoxia that was accompanied late in the disease by numerous secondary or nonspecific changes in the blood cellular, chemical, and gaseous elements.

Biochemical and biophysical characterization of anthrax toxin

Abstract: : The literature on isolation and purification of anthrax toxin is discussed. The three major components of the toxin, edema factor, protective antigen, and lethal factor, were purified 197-, 156-, and 1025-fold, respectively. The final preparations were all serologically active. Edema factor remained biologically active and produced an edema when mixed with protective antigen; however, lethal factor was no longer lethal when injected in combination with protective antigen. Protective antigen remained immunogenic. Evidence is presented, with toxin produced both in vivo and in vitro, that the individual components and the whole toxin may exist in different aggregate or polymeric forms. Protective antigen and lethal factor were sensitive to hydrogen bond - disrupting reagents, but edema factor was resistant to these reagents. The molecular weight of protective antigen is 60,000 to 100,000. The influence of these data upon the course of future experimentation is discussed.

A unique defense mechanism against anthrax demonstrated in dwarf swine.

Abstract: : A unique defense mechanism against Bacillus anthracis was demonstrated by the Pitman-Moore variety of dwarf swine. A large percentage of spores failed to germinate in vivo when massive doses were administered via either the respiratory or intraperitoneal route. Only spores with no apparent outgrowth of vegetative cells could be cultured from the blood. Therefore the defense mechanism enables the swine to prevent germination and outgrowth of B. anthracis spores in vivo.

Anthrax toxin: primary site of action.

Abstract: : Administration of anthrax toxin via the cerebrospinal fluid demonstrates positively that the toxin alters the body's physiology, primarily via the central nervous system, and kills by terminal anoxia mediated by the central nervous system. The use of a positive-pressure respirator and isoproterenol prevented death in animals that had received lethal doses of toxin. This demonstration of therapy for a lethal bacterial toxin opens new avenues of investigation.

Temperature response in animals infected with bacillus anthracis

Abstract: Rats, rabbits, swine, guinea pigs, and monkeys were infected with anthrax spores, and their temperature responses were recorded. These were characteristic for a species and appeared independent of resistance or susceptibility of the species toward establishment of the disease. The rabbit appeared unique in that it not only failed to demonstrate a dose-response relationship over an 8-log dose range, but acted independently producing erratic body temperatures depending on spore dose. This limits the usefulness of the rabbit in studying anthrax pathogenesis, and poses questions regarding published data with the rabbit as the test animal.

A comparative study of anthrax bacteriophages

Abstract: : A study of the morphology of negative colonies of various anthrax bacteriophages showed that according to morphology the negative colonies of anthrax bacteriophages included all the known types described in other bacteriophages. On the basis of the study of the antigenic properties the anthrax bacteriophages can be divided into two groups: the gamma (Brown and Cherry) and BA-9 (Moldavian Institute of Epidemiology and Hygiene) bacteriophages should be classed in one group; in the other group -- the alpha C, beta(McCloy), L7 (Stamatin) and Saratov bacteriophages. Separation of the anthrax bacteriophages studied into two groups corresponded to their lytic properties. Phages belonging to the first group had a wider lytic spectrum, not only with respect to homologous microorganisms but also with respect to Bac. cereus. For the purpose of increasing the specificity of the phagolysis test for identification of anthrax cultures one should at present simultaneously use anthrax bacteriophages belonging to different antigen groups, for example BA-9 gamma and Saratov, or gamma and alpha C bacteriophages.