Characterization of natural killer cytotoxic factor (NKCF) from canine NK cells

We investigated the presence of canine natural killer cytotoxic factor (NKCF). Canine natural killer (NK) cell-mediated cytotoxicity measured by 51chromium (51Cr) release assay was found to be highest in the T-cell population, which was fractionated into the 35-40% Percoll fraction by discontinuous gradient centrifugation. The cytotoxicity of NKCF in the culture supernatant showed a similar tendency to NK activity. Release of NKCF was rapid after contact with target cells, and reached a plateau in 60 min. The cytotoxicity of NKCF could be detected within at least 15 min in coculture with CL-1 target cells, reaching a plateau in 60 min. We also characterized canine NKCF and found it to be a protein, which was stable against both heat and cold treatment. These findings suggest that canine NK cells release NKCF immediately after recognition and binding to the target cell, and that NKCF plays an important role in canine NK-mediated cytotoxicity.

Release of natural killer cytotoxic factor (NKCF) from canine natural killer (NK) cells stimulated with cytoplasmic membrane of target cells

The presence of canine natural killer cytotoxic factor (NKCF) and the mechanism of the release of the NKCF by canine natural killer (NK) cells were studied. The cytotoxicity in the culture supernatant of effector cells cultured with target cells was dependent on the count of NK cells. Therefore, this suggests that the cytotoxic factor in this culture supernatant is NKCF. The NK-sensitive live target cells stimulated the release of NKCF from NK cells, but the NK-insensitive target cells did not. Moreover, NKCF was also released from NK cells stimulated with either killed target cells or their cytoplasmic membrane as well as live target cells. These findings suggest that the structure of the cytoplasmic membrane of target cells is involved in the recognition, binding and the release of NKCF by NK cells.

[The surgical treatment of primary empty sella]

Two cases of the primary empty sella complaining of intractable headache for many years are reported. Case 1. A 73-year-old female was admitted on August 23, 1983 because of intractable headache. Plain skull radiograph showed slightly enlarged sella with deepening of the floor. Metrizamide CT scan demonstrated the sella cavity filled with metrizamide extensively. Operation was done performing intrasellar intradural plugging via transsphenoidal route (Hardy's technique). Postoperatively headache was improved. Case 2. A 43-year-old female was admitted on July 24, 1984 after many years of intractable headache. Craniogram demonstrated deep sella of slightly increased volume and unaltered dorsum sellae. On metrizamide CT scan, contrast medium occupied greater parts of the sellar cavity. Extradural intrasellar plugging (Guiot's technique) was performed. Postoperative course was uneventful. Surgical procedure on the primary empty sella relieved headache by decreasing intrasellar pressure and alleviating pulsatile pressure on the dulla. Operation via transsphenoidal method was the suitable procedure because of less trauma on the optic nerve and advantageous plugging of the sellar cavity. Guiot's technique with extradural intrasellar plugging may be more preferable because of accompanying no postoperative cerebrospinal fluid rhinorrhea.