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Biomedical subjects

K A Mason

Publications and source records attributed to K A Mason.

84 records · Page 5Linked to original sources
PubMed1977

A simple and inexpensive method for maintaining a defined flora mouse colony.

The use of autoclaved cages, feed, bedding, water, and filter caps combined with aseptic techniques of animal husbandry in an existing mouse colony was ineffective in maintaining a defined flora colony. The addition of a laminar air flow bench equipped with a high efficiency particulate air filter provided a sterile environment in which to manipulate mice when the filter caps were removed. The installation of a duct to direct all air entering the room through the bench filter reduced the airborne bacterial counts in the room. This modification combined with the culling or marking of infected cages so that no future breeders would be taken from these cages eliminated a number of bacterial contaminants (Staphylococcus aureus, S epidermidis, and streptococci) from the colony.

Air Microbiology↗
PubMedDate not supplied

A role for T lymphocytes in the antitumour action of systemic C. parvum.

The frequency of tumours arising from s.c. injection of a syngeneic chemically-induced fibrosarcoma (Fsa) was not influenced by systemic administration of C. parvum (day + 3) except when doses less than the TD50 were injected. Then the number of takes was increased. The tumour normally grows progressively however regression was frequent in intact mice treated with C. parvum. Tumour regression did not occur in T cell-depleted mice treated in the same way. Splenic T cell-enriched populations of cells taken from Fsa-bearing C. parvum-treated mice caused tumour regression when adoptively transferred to Fsa-bearing T cell-depleted mice. Although this assay measures systemic rather than intratumoral T cell activity, it is proposed that C. parvum-induced regression of the fibrosarcoma is to a large extent due to enhanced T cell reactivity.

Animals↗
PubMedDate not supplied

In vivo transfer of antitumor activity by peritoneal exudate cells from mice treated with C. parvum.

We have investigated whether peritoneal exudate cells (PEC) from C. parvum (CP) treated (C3Hf/Bu mice could transfer in vivo the resistance against a syngeneic fibrosarcoma (FSa). Inhibition of tumour development and prolongation of survival of recipients were observed when CP-activated PEC were admixed with FSa cells before their intraperitoneal (ip) or subcutaneous (sc) injections into normal mice. The antitumour activity increased with the increase of the ratio of effector to target cells. Heat killed CP-PEC were unable to transfer the resistance. Also, pretreatment of recipients with 600 rads whole body irradiation (WBI) substantially reduced the efficacy of CP-PEC. Reconstitution of WBI mice with mixed normal spleen and lymph node cells, or spleen cells alone, or bone marrow cells did not restore the antitumor activity of transferred CP-PEC. In fact, reconstituted mice showed a further reduction of transferred antitumor resistance. CP-PEC activity was also inhibited in sc transfer experiments when normal PEC, spleen cells, T-cells or even fetal fibroblasts were admixed with tumor cells and CP-PEC. Possible reasons for the failure of WBI recipients to be fully protected by transferred CP-PEC are discussed.

Animals↗