Effect of target cell nitric oxide synthesis on the sensitivity to lymphokine-activated killer cell cytotoxicity

BACKGROUND: Nitric oxide (NO), a cytotoxic molecule is produced in various tissues including tumor cells during interleukin-2 (IL-2) therapy . Lymphokine-activated killer (LAK) cells are induced during IL-2 therapy, and have cytotoxic activity against tumor cells. The current study investigated the effects of NO synthesized in target cells or exposure of target cells to NO on the sensitivity of target cells to LAK cell cytotoxicity. METHODS: Cytotoxicity was measured using 4 h chromium release assays. LAK cells which were induced by a 4 day incubation of BALB/c mouse splenocytes with IL-2 (6,000 IU/mL) were employed as effector cells. RD-995 skin tumor cells originated from a C3H/HeN mouse were employed as target cells. NO synthesis in target cells was induced by a 24 h incubation of RD-995 cells with IFN gamma (25 U/mL), TNF (50 U/mL) and IL-1 (20 U/mL). S-nitrosyl acetylpenicillamine (SNAP), an NO donor, was used to expose target cells to NO. N(G) -monomethyl-L-arginine (MLA) and carboxy-PTIO were added during cytotoxicity assays to inhibit NO synthesis, and to scavenge NO produced by target cells, respectively. RESULTS: Sensitivity of NO-producing RD-995 cells to LAK cell cytotoxicity was decreased by addition of MLA and carboxy-PTIO during cytotoxicity assays. However, the two reagents had no effect on the sensitivity of non-NO-producing RD-995 cells. Pretreatment of RD-995 target cells with SNAP increased the sensitivity in comparison with untreated cells. CONCLUSIONS: Sensitivity of target cells to LAK cell cytotoxicity is increased by target cell NO synthesis or exposure to NO. Further studies are needed to evaluate whether these in vitro results have relevance to in vivo phenomena.

Pulmonary mucormycosis with an appearance of consolidation / 결핵

The mucormycosis is a group of serious opportunistic infections caused by fungi of the class Zygomycetes and order Mucorales. Pulmonary mucormycosis is a relatively rare disease but typically manifested by a rapidly progressive, often fatal pneumonia in patients with diabetes mellitus, hematologic malignant neoplasms, or organ transplants. The radiologic manifestations of pulmonary mucormycosis are nonspecific and include progressive lobar or multilobar consolidations, pulmonary masses and pulmonary nodules. Recently, we experienced a pulmonary mucormycosis in 32-year-old man with uncontrolled diabetes. He complained of cough, left pleuritic chest pain and generalized weakness. Initial chest X-ray finding was the consolidation on the lower lobe of the left lung. On the sixth hospital day, bronchoscopic examination with lung biopsy revealed broad, non-septate hyphae with right-angle branching, diagnostic of mucormycosis, and consequently amphotericin B therapy was started. We performed a lobectomy of the left lower lobe of the lung on 29th hospital day.