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Biomedical subjects

R J Russell

Publications and source records attributed to R J Russell.

119 records · Page 7Linked to original sources
PubMed1977

Biphasic pattern of activation of the reticuloendothelial system by anaerobic coryneforms in mice.

Macrophage activation as measured by increased rates of clearance of carbon was explored in five inbred and two outbred strains of mice pretreated with anaerobic coryneform bacilli. Constant differences were found according to strain from DBA (lowest response) to Sha-Sha (highest response). The investigation was continued with mice of CBA strain which also provided highly reproducible and high-level responses. In this strain activation occurred in two phases: an early activation which reached maximum levels at 2 days and attributable to a lipid component of the bacteria, and a late phase reaching maximum at 14 days which appeared to coincide with greatly increased weight of the liver and spleen, due to infiltration by mononuclear cells. Evidence is provided that the early phase of macrophage activation is due to a lipid extract from the anaerobic coryneforms with chemotactic activity.

Animals↗
PubMed1976

Studies of chemotaxis of lymphocytes.

Lymphoblasts migrate into filters towards chemoattractants in vitro. Human lymphoblasts maintained in continuous culture and mouse lymphoblasts from unsensitized lymph nodes show chemotactic responses and migrate towards the same chemotactic factors as neutrophils and macrophages, namely activated plasma, casein, denatured serum albumin, oxazolone. On the other hand, mouse lymphoblasts from oxazolone-sensitized lymph nodes show considerable random migration and chemokinesis but not chemotaxis. The migration of lymphoblasts to these agents appears not to be antigen-specific. These migratory properties of lymphoblasts are probably relevant to their migration into inflammatory sites in vivo.

Animals↗
PubMed1976

Effects of staphylococcal products on locomotion and chemotaxis of human blood neutrophils and monocytes.

The effects of staphylococcal products as chemo-attractants for human blood neutrophils and monocytes and as inhibitors of locomotion of these cells were studied with bacterial cells, culture filtrates and isoelectrically focused fractions from culture filtrates of nine strains of Staphylococcus aureus. Little direct chemotactic activity of staphylococcal products for neutrophils was observed, although a chloroform-soluble extract of the whole organisms contained such activity. The major chemotactic effect of staphylococci for neutrophils was indirect, i.e., generated when the organisms or their products were incubated with plasma, perhaps due to activation of complement. In contrast, direct chemotactic activity for monocytes was found in a large number of staphylococcal fractions. Staphylococci also produced inhibitors of locomotion of both neutrophils and monocytes. Isoelectric focusing showed more fractions inhibitory for neutrophils than for monocytes. Some of the inhibitors could be identified. Staphylococcal alpha-toxin inhibited migration of both neutrophils and monocytes. Sphingomyelinase C (beta toxin) inhibited migration of monocytes but not of neutrophils. Leucocidin-rich strains were strongly active as inhibitors of neutrophil locomotion but less so as inhibitors of monocyte locomotion.

Cell Migration Inhibition↗
PubMed1976

A lipid chemotactic factor from anaerobic coryneform bacteria including Corynebacterium parvum with activity for macrophages and monocytes.

A lipid with chemoattractant (chemotactic) activity for mouse and guinea-pig macrophages and for human blood monocytes is released by anaerobic coryneform bacteria (including Corynebacterium parvum). The active lipid is associated with fibrillar structures which lie on the outside of the bacterial cell and are released spontaneously during growth. The lipid can also be extracted easily by a number of methods. The fibrils are loosely associated with a capsule-like structure composed largely of polysaccharide. Purification of the active lipid was achieved by chloroform-methanol extraction of the whole organisms yielding a chloroform-soluble fraction attracting mononuclear phagocytes at concentrations around 10 microgram/ml. The infra-red spectrum of this material showed lipid but no peptide or sugar. Thin-layer chromatography yielded twelve spots of which three had chemoattractant properties. The most active of these gave staining reactions consistent with the presence of phospholipid, the other two probably contained free fatty acids and triglycerides. Thin-layer electrophoresis also yielded an active phosphorus-containing spot. Saturated fatty acids of chain lengths found in the anaerobic coryne forms had weak monocyte-attractant activity. As the active material was progressively purified, its activity as a monocyte attractant weakened.

Animals↗
PubMed1976

Chemotaxis of mitogen-activated human lymphocytes and the effects of membrane-active enzymes.

Following incubation with polyclonal activators such as PHA or concanavalin A, human peripheral blood lymphocytes show directional migration towards chemotactic factors such as endotoxin-activated plasma, casein or denatured proteins. This migration is inhibited by treatment of the cells with phospholipase C and sphingomyelinase C, but little affected by proteases or glycosidases. In addition, these lymphocytes migrate towards PHA and other lymphocyte activators when these reagents are used as chemoattractants at concentrations well below their mitogenic doses. They also migrate towards staphylococcal protein A. Migration towards PHA and protein A is reduced by pretreating the lymphocytes with proteases but not with phospholipase C. These results suggest two independent membrane interactions which initiate lymphocyte chemotaxis, one acting directly via the lipid bilayer, the other involving the binding of ligands to membrane proteins.

Bacterial Proteins↗
PubMedDate not supplied

Pneumocystis carinii--animal production perspective.

Pneumocystis carinii is an important cause of pneumonia in immunocompromised human patients. The organism is also found as a saprophyte in the lungs of many species of animals. Animal models have been used as a source of P. carinii organisms for study of the disease. The rat model has been especially useful. Initially, the infection was latent in most colonies, and P. carinii pneumonia readily developed when animals were immunosuppressed. Today, many barrier raised rodent colonies are free of adventitious viruses, bacteria, Mycoplasma sp., and parasites, including P. carinii. Variability is now seen in the rat model. The use of cultured organisms to experimentally infect rats and mice prior to immunosuppression has met the need for some investigators, however, latent-infected, barrier-raised and isolator-raised rodents are still required. Colonies specifically infected with P. carinii can provide latent-infected animals and are better protected from potentially interfering organisms than barrier-raised animals. The development of these colonies is feasible as investigators and animal producers work together to define and develop this resource.

Animal Husbandry↗