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Biomedical subjects

S G Campbell

Publications and source records attributed to S G Campbell.

At least 19 recordsLinked to original sources
PubMed1986

The influence of opsonins on the bactericidal effect of bovine alveolar macrophages against Pasteurella multocida.

Monolayers of bovine alveolar macrophages were infected with smooth and rough strains of Pasteurella multocida to determine their bactericidal function. Heat inactivated normal bovine serum, fresh bovine serum, specific immune serum and a combination of specific immune serum and fresh bovine serum were used as opsonins. A substantial difference in the bactericidal effect of macrophages against the logarithmic and stationary phase p. multocida was observed. Opsonization of the rough strain of P. multocida with the combination of specific immune and fresh serum increased their association with alveolar macrophages compared to those opsonized with either normal serum, fresh serum or specific immune serum. Opsonization of the smooth strain of P. multocida with normal bovine serum resulted in substantially fewer bacteria associated with macrophages at time zero, compared with other opsonins. Regardless of the kind of opsonins used in these experiments, the number of the rough strain of P. multocida killed by macrophages was always higher than those of the smooth strain.

Animals↗
PubMed1985

Immunization against experimental murine salmonellosis with liposome-associated O-antigen.

Partially delipidated Salmonella typhimurium (O-1,4,5,12) lipopolysaccharide was incorporated into small multilamellar liposomes composed of either naturally occurring or synthetic phospholipids. Vaccination of mice with the liposome-lipopolysaccharide complexes induced a cellular response specific for O-1,4,5,12 determinants, as determined by the development of a delayed-type hypersensitivity reaction. The liposome-lipopolysaccharide vaccines were significantly more effective, compared with other nonviable vaccines tested, in protecting mice against a lethal intravenous challenge infection with virulent S. typhimurium. Protection afforded by the liposome-lipopolysaccharide vaccines was comparable to that conferred by a live S. typhimurium vaccine. Results suggest that liposome-induced modulation of the host immune response in favor of cell-mediated immunity may be more efficacious in preventing diseases in which cell-mediated immunity is of prime importance.

Animals↗
PubMed1983

Intraphagocytic killing of Salmonella typhimurium by liposome-encapsulated cephalothin.

Multilamellar liposomes (lipid bilayer vesicles) composed of phosphatidylcholine, cholesterol, and phosphatidylserine (molar ratio, 6:3:1) were produced and then made to entrap an aqueous solution of cephalothin. Resident murine peritoneal macrophages were shown to be capable of interiorizing the liposome-antibiotic complex; this event resulted in a relatively high intracellular concentration of cephalothin. In macrophages infected in vitro with Salmonella typhimurium, intracellular killing of the bacteria was maximal at 60 min of incubation; at this time, 60% of the interiorized organisms had been killed. Treatment of infected macrophages with liposome-encapsulated cephalothin enhanced the intraphagocytic killing of S typhimurium over that by macrophages treated with free cephalothin. These results demonstrate the superiority of liposome-encapsulated antibiotics to free antibiotics in effecting the elimination of a facultative intracellular bacterium from its intracellular site. This type of complex may find application in the treatment of diseases caused by this group of microorganisms.

Animals↗
PubMed1983

Fate of Pasteurella hemolytica in conventionally raised and germfree mice.

When Pasteurella hemolytica was introduced into conventionally raised ICR mice by a variety of routes (intraperitoneal, aerogenic, and oral), the inoculum was rapidly eliminated, and none of the mice died. Even when the inoculum was injected intraperitoneally into sublethally irradiated (600 rads) mice, the organisms were eliminated rapidly unless suspended in 10% hog gastric mucin. When germfree ICR mice were orally infected with P. hemolytica, the infection established itself in the intestinal tract and spread to the mesenteric lymph nodes but did not progress beyond this point. Despite the inability of P. hemolytica to establish itself systemically, the organism multiplied freely in mouse blood and a homogenate of normal mouse lung in vitro. Normal mouse peritoneal macrophages could phagocytose P. hemolytica in vitro, although not as efficiently as the control Listeria monocytogenes suspensions. The addition of hyperimmune bovine serum (opsonin) to the P. hemolytica suspension increased phagocytosis but did not greatly affect the subsequent bactericidal activity of the macrophages in vitro. The reason for the lack of pathogenicity shown by P. hemolytica in normal mice remains enigmatic.

Animals↗
PubMed1983

Liposome-encapsulated cephalothin in the treatment of experimental murine salmonellosis.

The effectiveness of liposome-encapsulated cephalothin was compared with free cephalothin for the treatment of mice experimentally infected with Salmonella typhimurium. Compared with free cephalothin, following intravenous administration, liposome-encapsulated cephalothin was cleared from the circulation more rapidly and concentrated in the liver and spleen. Treatment of infected mice with the liposome antibiotic complex was more efficacious in terms of reducing the number of S. typhimurium in these organs as compared with the free antibiotic. The results suggest that liposome-encapsulated antimicrobial agents may possess a therapeutic advantage in the treatment of diseases caused by facultative intracellular bacteria since this manipulation favors delivery of the entrapped antibiotic to intracellular sites occupied by S. typhimurium.

Animals↗
PubMed1979

Serum proteins of normal goats and goats with caseous lymphadenitis.

Values for total serum proteins and relative percentages of albumin, alpha 1-globulin, alpha 2-globulin, beta-globulin, and gamma-globulin were determined for the goat. These normal values were compared with those obtained for goats infected with Corynebacterium pseudotuberculosis. Goats chronically infected with C pseudotuberculosis show significantly higher total serum protein values than normal goats, apparently due to increased gamma-globulins. This higher protein value is also associated with a decrease in serum alpha 2- and beta-globulins.

Animals↗
PubMed1978

The immunogenicity of milk from various species for the guinea-pig.

Young guinea-pigs, sensitized and challenged by the parenteral administration of bovine and human milks, died of anaphylaxis while others, sensitized and challenged with guinea-pig milk, were unaffected. The type of milk fed to young guinea-pigs from birth did not alter the basic immunogenicity of cow's milk or the lack of immunogenicity of guinea-pig milk for the young guinea-pig.

Anaphylaxis↗
PubMed1975

An unusual epizootic of actinobacillosis in dairy heifers.

Actinobacillosis developed in a group of 52 Holstein-Friesian replacement heifers. They were confined to 4 pens in a barn. Cervical abscesses were first observed by the owner in 1 heifer a month after the heifers were fed chopped haylage that was particularly dry, tough, and stemmy. During the weeks that followed, morbidity reached 73% in heifers given the feed. Calves up to 4 months old were not given the haylage and did not develop the disease. Standard bacteriologic methods were used to identify Actinobacillus lignieresii from exudate of abscesses. A biopsy of superficial granulomatous tissue of the lips revealed fibers thought to be of plant origin. Affected cattle recovered in 3 to 6 months. The lesions of 3 cattle given sodium iodide intravenously and of 4 given streptomycin regressed sooner than those given penicillin or no treatment.

Abscess↗