OBJECTIVE Though doxorubicin is highly active in the treatment of multiple myeloma, its toxicity profile limits its therapeutic index. We performed this study to evaluate the efficacy and liposomal doxorubicin （PLD, ...OBJECTIVE Though doxorubicin is highly active in the treatment of multiple myeloma, its toxicity profile limits its therapeutic index. We performed this study to evaluate the efficacy and liposomal doxorubicin （PLD, Ca of pegylated , vincristine, and reduced-dose dexamethasone combination therapy in newly diagnosed multiple myeloma （MM） patients in a Chinese population. METHODS This was an open-label, single-arm study in which newly diagnosed patients with MM received PLD 40 mg/m2 intravenously on Day 1, vincristine 1.4 mg/m2 intravenously （maximum 2 rag） on Day 1, and 40 mg of dexamethasone （intravenously or orally） from Day 1 to Day 4. Treatment was repeated every 28 days for at least 4 cycles. RESULTS In the intent-to-treat （ITT） analysis, the overall response rate was 68.29%, and the complete remission rate was 10.98%. The incidence of all adverse events was 46.34%. The most common non-hematologic toxicities were palmar-plantar erythrodysesthesia （13.4%） and stomatitis （6.1%）. CONCLUSION PLD, vincristine, and a reduceddose dexamethasone combination （DVd） is an effective and safe regimen in newly diagnosed MM patients in a Chinese population.展开更多
Objective To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase （eNOS）. Methods ＆ Results A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopte...Objective To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase （eNOS）. Methods ＆ Results A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopterin （BH4）. Treatment of human EA.hy 926 endothelial cells with dexamethasone decreased mRNA and protein expression of both BH4-synthesizing enzymes： GTP cyclobydrolase I and dihydrofolate reductase. Consistently, a concentration- and time-dependent reduction of BH4, dihydrobiopterin （BH2） as well as BH4：BH2 ratio was observed in dexamethasone-treated cells. Surprisingly, no evidence for eNOS uncoupling was found. We then analyzed the expression and phosphorylation of the eNOS enzyme. Dexamethasone treatment led to a down-regulation of eNOS protein and a reduction of eNOS phosphorylation at serine 1177. A reduction of eNOS expression may lead to a relatively normal BH4： eNOS molar ratio in dexamethasone-treated cells. Because the BH4-eNOS stoichiometry rather than the absolute BH4 amount is the key determinant of eNOS functionality （i.e., coupled or uncoupled）, the down-regulation of eNOS may represent an explanation for the absence of eNOS uncoupling. Phosphorylation of eNOS at serine 1177 is needed for both the NO-producing activity of the coupled eNOS and the superoxide-producing activity of the uncoupled eNOS. Thus, a reduction of serine 1177 phosphorylation may render a potentially uncoupled eNOS hardly detectable. Conclusions Although dexamethasone reduces BH4 levels in endothelial cells, eNOS uncoupling is not evident. The reduction of NO production in dexamethasone-treated endothelial cells is mainly attributable to reduced eNOS expression and decreased eNOS phosphorylation at serine 1177.展开更多
文摘OBJECTIVE Though doxorubicin is highly active in the treatment of multiple myeloma, its toxicity profile limits its therapeutic index. We performed this study to evaluate the efficacy and liposomal doxorubicin （PLD, Ca of pegylated , vincristine, and reduced-dose dexamethasone combination therapy in newly diagnosed multiple myeloma （MM） patients in a Chinese population. METHODS This was an open-label, single-arm study in which newly diagnosed patients with MM received PLD 40 mg/m2 intravenously on Day 1, vincristine 1.4 mg/m2 intravenously （maximum 2 rag） on Day 1, and 40 mg of dexamethasone （intravenously or orally） from Day 1 to Day 4. Treatment was repeated every 28 days for at least 4 cycles. RESULTS In the intent-to-treat （ITT） analysis, the overall response rate was 68.29%, and the complete remission rate was 10.98%. The incidence of all adverse events was 46.34%. The most common non-hematologic toxicities were palmar-plantar erythrodysesthesia （13.4%） and stomatitis （6.1%）. CONCLUSION PLD, vincristine, and a reduceddose dexamethasone combination （DVd） is an effective and safe regimen in newly diagnosed MM patients in a Chinese population.
文摘Objective To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase （eNOS）. Methods ＆ Results A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopterin （BH4）. Treatment of human EA.hy 926 endothelial cells with dexamethasone decreased mRNA and protein expression of both BH4-synthesizing enzymes： GTP cyclobydrolase I and dihydrofolate reductase. Consistently, a concentration- and time-dependent reduction of BH4, dihydrobiopterin （BH2） as well as BH4：BH2 ratio was observed in dexamethasone-treated cells. Surprisingly, no evidence for eNOS uncoupling was found. We then analyzed the expression and phosphorylation of the eNOS enzyme. Dexamethasone treatment led to a down-regulation of eNOS protein and a reduction of eNOS phosphorylation at serine 1177. A reduction of eNOS expression may lead to a relatively normal BH4： eNOS molar ratio in dexamethasone-treated cells. Because the BH4-eNOS stoichiometry rather than the absolute BH4 amount is the key determinant of eNOS functionality （i.e., coupled or uncoupled）, the down-regulation of eNOS may represent an explanation for the absence of eNOS uncoupling. Phosphorylation of eNOS at serine 1177 is needed for both the NO-producing activity of the coupled eNOS and the superoxide-producing activity of the uncoupled eNOS. Thus, a reduction of serine 1177 phosphorylation may render a potentially uncoupled eNOS hardly detectable. Conclusions Although dexamethasone reduces BH4 levels in endothelial cells, eNOS uncoupling is not evident. The reduction of NO production in dexamethasone-treated endothelial cells is mainly attributable to reduced eNOS expression and decreased eNOS phosphorylation at serine 1177.
