Doxorubicin (DOX) is one of the most potent anticancer drugs and induces acute cardiac arrhythmias and chronic cumulative cardiomyopathy. Though DOX-induced cardiotoxicity is known to be caused mainly by ROS generation, a disturbance of Ca2+ homeostasis is also implicated one of the cardiotoxic mechanisms. In this study, a molecular basis of DOX-induced modulation of intracellular Ca2+ concentration ([Ca2+]i) was investigated. Treatment of adult rat cardiomyocytes with DOX increased [Ca2+]i irrespectively of extracellular Ca2+, indicating DOX-mediated Ca2+ release from intracellular Ca2+ stores. The DOX-induced Ca2+ increase was slowly processed and sustained. The Ca2+ increase was inhibited by pretreatment with a sarcoplasmic reticulum (SR) Ca2+ channel blocker, ryanodine or dantrolene, and an antioxidant, alpha-lipoic acid or alpha-tocopherol. DOX-induced ROS generation was observed immediately after DOX treatment and increased in a time-dependent manner. The ROS production was significantly reduced by the pretreatment of the SR Ca2+ channel blockers and the antioxidants. Moreover, DOX-mediated activation of caspase-3 was significantly inhibited by the Ca2+ channel blockers and a-lipoic acid but not a-tocopherol. In addition, cotreatment of ryanodine with alpha-lipoic acid resulted in further inhibition of the casapse-3 activity. These results demonstrate that DOX-mediated ROS opens ryanodine receptor, resulting in an increase in [Ca2+]i and that the increased [Ca2+]i induces ROS production. These observations also suggest that DOX/ROS-induced increase of [Ca2+]i plays a critical role in damage of cardiomyocytes.
Sarcoplasmic Reticulum/drug effects ; Ryanodine Receptor Calcium Release Channel/metabolism ; Reactive Oxygen Species/*chemical synthesis ; Rats, Sprague-Dawley ; Rats ; Myocytes, Cardiac/*drug effects ; Male ; Female ; Enzyme Activation/drug effects ; Doxorubicin/*pharmacology ; Cells, Cultured ; Caspase 3/metabolism ; Calcium Channel Blockers/pharmacology ; Calcium/*metabolism ; Antioxidants/pharmacology ; Antibiotics, Antineoplastic/pharmacology ; Animals

Lymphoproliferative disorders of the lung consist of a spectrum of several entities from malignant lymphoma to variable non-lymphomatous lymphoproliferative disorders. While an entity may be histologically benign and can be cured without treatment or by surgical removal, malignancy may evolve, and aggressive treatment may thus be required. Radiographic and pathologic findings of an entity may overlap, but differential diagnosis of lymphoproliferative disorders of the lung is nonetheless important. In this paper we illustrate a variety of lymphoproliferative diseases of the lung that have been pathologically proven during the last ten years, and discuss their radiographic and pathologic characteristics.
Diagnosis, Differential ; Lung* ; Lymphoma ; Lymphoproliferative Disorders*

ADP-ribosyl cyclase (ADPR-cyclase) produces a Ca2+-mobilizing second messenger, cyclic ADP- ribose (cADPR), from beta-NAD+. A prototype of mammalian ADPR-cyclases is a lymphocyte antigen CD38. Accumulating evidence indicates that ADPR-cyclases other than CD38 are expressed in various cells and organs. In this study, we discovered a small molecule inhibitor of kidney ADPR-cyclase. This compound inhibited kidney ADPR-cyclase activity but not CD38, spleen, heart or brain ADPR-cyclase activity in vitro. Characterization of the compound in a cell-based system revealed that an extracellular calcium-sensing receptor (CaSR)- mediated cADPR production and a later long-lasting increase in intracellular Ca2+ concentration ([Ca2+]i) in mouse mesangial cells were inhibited by the pre-treatment with this compound. In contrast, the compound did not block CD3/TCR-induced cADPR production and the increase of [Ca2+]i in Jurkat T cells, which express CD38 exclusively. The long-lasting Ca2+ signal generated by both receptors was inhibited by pre-treatment with an antagonistic cADPR derivative, 8-Br-cADPR, indicating that the Ca2+ signal is mediated by the ADPR-cyclse metabolite, cADPR. Moreover, among structurally similar compounds tested, the compound inhibited most potently the cADPR production and Ca2+ signal induced by CaSR. These findings provide evidence for existence of a distinct ADPR-cyclase in the kidney and basis for the development of tissue specific inhibitors.
Receptors, Calcium-Sensing/metabolism ; Rats, Sprague-Dawley ; Rats ; Mice ; Kidney/*enzymology ; Humans ; Enzyme Inhibitors/chemistry/*pharmacology ; Cyclic ADP-Ribose/*metabolism ; Cell Line ; *Calcium Signaling ; Azo Compounds/chemistry/*pharmacology ; Animals ; ADP-ribosyl Cyclase/*antagonists & inhibitors/*metabolism