Pathogenesis of Salmonella typhimurium and interactions with porcine neutrophils

Carrier swine infected with Salmonella typhimurium provide a reservoir of infection for humans and domestic animals. Reduction of the carrier state is desirable, but little is known about the bacterial-host interactions that influence the carrier state in swine. Interactions of S. typhimurium and porcine neutrophils were examined, and the effect of a [delta]cya[delta]crp mutant of S. typhimurium on subsequent wild-type colonization of swine was evaluated;When compared to those from unexposed controls, neutrophils from pigs orally exposed to S. typhimurium demonstrated reduced oxidative metabolism, measured by cytochrome C reduction and iodination; reduced motility, measured by random migration and chemotaxis; and reduced antibody-dependent cell-mediated cytotoxicity (ADCC) 1-2 days after exposure. Function normalized after 3-4 days, but iodination and ADCC were depressed again 7-14 days after exposure. Neutrophil bactericidal activity against S. typhimurium was enhanced in Salmonella-infected pigs 1-14 days after exposure;Treatment of pigs with bacillus Calmette-Guerin (BCG) before exposure to S. typhimurium did not reverse Salmonella-induced alterations in neutrophil function nor did it alter the colonization pattern and persistence of S. typhimurium in porcine internal organs;Bactericidal efficiency of porcine neutrophils against S. typhimurium was affected by bacterial opsonization, incubation interval, bacterial mutations, and by pre-treatment of neutrophils with recombinant human tumor necrosis factor alpha (TNF[alpha]). Opsonization enhanced bactericidal efficiency 0.5-2 hours after exposure, but this enhancement was decreased or lost by 3-4 hours. A phoP mutation in S. typhimurium conferred increased sensitivity to bactericidal activity. TNF[alpha] treatment caused a decrease in bactericidal efficiency 0.5-1 hour after exposure to S. typhimurium. This inhibition diminished by 2-3 hours, and bactericidal efficiency of TNF[alpha]-treated neutrophils was enhanced over nontreated neutrophils by 4 hours;Oral exposure of swine to a [delta]cya[delta]crp mutant of S. typhimurium ([chi]4233) caused a mild fever and soft feces. However, pigs previously exposed to [chi]4233 exhibited a milder clinical response to subsequent wild-type challenge than did pigs not exposed to [chi]4233. Ileal populations of wild-type S. typhimurium in [chi]4233-exposed pigs were 100- to 10,000-fold less than those in pigs not receiving [chi]4233. The liver, spleen, and ileocolic lymph nodes were cleared of wild-type S. typhimurium more quickly in [chi]4233-exposed pigs

Alteration of Neutrophil Function in BCG-Treated and Non-Treated Swine after Exposure to Salmonella typhimurium

Salmonella typhimurium infection in swine causes an enterocolitis followed by a persistent carrier state, but little is known about the mechanisms that allow this organism to colonize and persist in host tissues. Neutrophils provide a first line of defense against invading pathogens such as Salmonella typhimurium. The purpose of this study was to evaluate porcine neutrophil function after in vivo exposure to Salmonella and to determine if the immunomodulator, bacillus Calmette Guerin (BCG), exerts any effect on neutrophil function or on the colonization and persistence of S. typhimurium in the pig. Compared to negative controls, neutrophils from pigs exposed to S. typhimurium exhibited significantly decreased iodination, cytochrome-C reduction, antibody-dependent cell-mediated cytotoxicity, random migration, and chemotaxis (P≤0.05). Neutrophil bactericidal activity against S. typhimurium was significantly enhanced. Most of the significant differences were noted in the first two days after exposure to Salmonella. Often the functional alterations were biphasic, peaking again 7–10 days after exposure. BCG alone significantly depressed random migration and cytochrome-C reduction in unstimulated neutrophils. The clinical course, colonization pattern, and persistence of Salmonella were similar between pigs receiving BCG and untreated pigs. These data suggest that S. typhimurium infection causes a depression in oxidative metabolism and motility, yet an increase in overall bactericidal activity against S. typhimurium in circulating porcine neutrophils. It also appears that BCG treatment, as reported here, does not enhance resistance of pigs to S. typhimurium colonization or reduce the number of persistent organisms in the porcine ileum

The Vehicle, November 1960, Vol. 3 no. 1

CONTENTS To the ReaderStaffpage 2 N’ = N : 1Donald C. Blairpage 3 ConsistencyDonald C. Blairpage 3 Unto MeLinda Kay Campbellpage 4 The Meek Shall InheritE. J. B. page 5 The Infinite QuestLarry W. Dudleypage 6 Dreamer’s DawnMike Hindmanpage 7 BirthNancy Coepage 7 The Lost DutchmanDonald C. Blairpage 8 W. E. Noonan IRobert S. Hodgepage 8 A Soldier’s OrdealDonald E. Shephardsonpage 9 Personal PossessionMary Beilpage 11 Thine The GloryDonald C. Blairpage 12 The ThornJan Holstlawpage 13 A Lord’s Day MorningLinda Campbellpage 14 Observations of a 6-Year-OldTom McPeakpage 15 Jewels of TimeJudith Jerintspage 16 LavenderE. J. B. page 16https://thekeep.eiu.edu/vehicle/1008/thumbnail.jp

Taking Snapshots, Living the Picture: The Kodak Company's Making of Photographic Biography

In this article I explore how George Eastman and the Eastman Kodak Company encouraged early twentieth-century camera users to think of snapshots as pictorial biographies. Analysing a wide selection of articles from the Kodakery, one of Kodak’s most popular magazines in the first half of the twentieth century, I demonstrate that the company endeavoured to secure its prominence in the photographic market by encouraging members of the public to integrate picture-taking into everyday life, and regard photographs as self-contained repositories of biographical details. To this end, Kodak framed the speedy pace of life that characterised the practice of being in the industrial world as a reality that allegedly weakened the human eye and mind’s ability to process the experience of life itself. Introducing the idea of the camera and picturetaking as the ultimate cures for this purported human deficiency, Kodak provided camera users with advice that helped to cement an understanding of photographs as surrogates of both the changing human body and individual subjects’ experiences in time and space. As in popular culture, and sometimes also in academia, photographs are still widely regarded as pictorial biographies, I argue that considering the popular photographic industry’s role in shaping photographic practices and photographs’ perceived meanings can help clarify the relationship between photography and life-writing