Effects of MR imaging on murine natural killer cell cytotoxicity

To determine the effect of MR imaging on the immune system, 21 male C57BL/6 X DBA/2 F1 mice were exposed to MR imaging at a field strength of 0.15 T for 2 hr. Another nine mice (controls) were sham exposed for the same amount of time. Mice were sacrificed and their spleens removed 24, 72, and 144 hr after the exposure (MR or sham). Spleen cell suspensions were passed over nylon wool columns and then used as effector cells in a short-term natural killer cell cytotoxicity assay with 51Cr-labeled YAC-1 cells as target cells. The results showed no evidence of decreased cytotoxicity due to exposure to MR. On the contrary, at all three times after exposure and for all target-to-effector cell ratios, mean cytotoxicity was greater for MR-exposed groups than for sham-exposed groups. The results show that MR exposure has no adverse effect on the immune system, as evidenced by natural killer cell activity.     

Tubuloreticular inclusions in equine connective tissue neoplasms

Abnormal irregularly branched and anastomosing tubules within cisternae of endoplasmic reticulum were observed by transmission electron microscopy in tumour cells comprising connective tissue neoplasms (sarcoids) from three horses and a mule. These tubuloreticular inclusions were also observed in cultured tumour cells from one of these horses examined, but were not detected in fibroblasts (fibrocytes), epidermis, or vascular endothelial cells in skin biopsy specimens from five clinically healthy horses, nor in one additional equine connective tissue neoplasm.