ABSTRACT
BACKGROUND: Instillation of sterile graded talc in the pleural space is performed to prevent reaccumulation of malignant pleural effusion after drainage. Talc is thought to encourage pleural adhesions as part of the repair process by provoking inflammation, suggesting that adhesions are less likely to form in patients taking corticosteroids or other drugs with anti-inflammatory effects. However, the relationship between steroid therapy and pleurodesis efficacy remains unclear. CASE PRESENTATION: We report the outcomes of six patients who underwent pleurodesis at Hiroshima University Hospital while being treated with systemic steroid therapy for non-cancer-related illnesses. Talc pleurodesis was successful at the first attempt in five of the six patients. The five successful cases were receiving low-dose oral prednisolone or methyl prednisolone (range, 1-20 mg/day) at the time of pleurodesis and had serum albumin levels ranging from 2.2 to 3.0 g/dL. In contrast, the patient in whom pleurodesis was unsuccessful was receiving a higher dose of prednisolone (40 mg/day) intravenously and had a relatively low serum album level (1.7 g/dL). CONCLUSIONS: The outcome of pleurodesis may be affected by the dose and/or route of systemic steroid therapy. Further analysis with more patients will be necessary to clarify the relationship between steroid dosage and talc pleurodesis success rate.
ABSTRACT
This study examined the role of kappa opioid receptors (KOR) in the mechanism underlying tolerance to the analgesic effects of morphine induced by chronic pain. The analgesic effect of morphine (10 mg kg(-1)), estimated by the tail-flick test in mice, gradually decreased during repeated daily morphine treatment. A significant decrease in the analgesic effect of morphine was seen on the fifth day of repeated morphine treatment compared with the first day. Chronic pain was induced by subcutaneous administration of 2% formalin into the dorsal part of the left hind paw, which significantly inhibited development of tolerance to morphine analgesia. The effect of formalin-induced pain on inhibition of morphine tolerance was reversed by the KOR antagonist nor-binaltorphimine. Furthermore, an antisense oligodeoxynucleotide, but not a missense oligodeoxynucleotide, against KOR completely suppressed the inhibitory effect of formalin-induced pain on morphine tolerance. Naltrindole, an antagonist of delta opioid receptor, did not affect chronic-pain-induced tolerance to morphine. Our findings show that the inhibitory effect of chronic pain on analgesic tolerance to morphine is mediated by KOR rather than delta opioid receptors.
