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Toll-like receptor 4 (TLR4) of macrophages recognizes LPS of Gram-negative bacteria in cooperation with CD14, which is also involved in the recognition of apoptotic cells. In this study we asked whether TLR4 plays a role in the phagocytic clearance of apoptotic cells by macrophages. Macrophages were prepared from peritoneal fluid of thioglycolate-treated mice carrying either a wild-type or a disrupted TLR4-encoding gene and were examined for their ability to phagocytose apoptotic mouse thymocytes, apoptotic Jurkat T cells, Ig-opsonized mouse thymocytes, Ig-opsonized zymosan particles, and latex beads. Both populations of macrophages equally expressed CD14 on their surfaces and showed almost equal activities of binding to and engulfing all these targets. However, apoptotic thymocytes, apoptotic Jurkat cells, and opsonized thymocytes disappeared more rapidly in TLR4-deficient macrophages than in wild-type macrophages, and the fusion between endosomes/lysosomes and phagosomes containing any target cells or particles was accelerated in mutant macrophages. Activation of the transcription factor NF-κB appeared not to occur in wild-type macrophages after engulfment, and the rate of apoptotic cell degradation in wild-type macrophages remained the same regardless of the activation of NF-κB. Finally, immunohistochemical analyses showed that ectopically expressed TLR4 was associated with phagosomes in a macrophage-derived cell line. All these results collectively indicate that TLR4 negatively regulates the degradation of engulfed cells in macrophages via a pathway independent of NF-κB.

Background-Drugs with I Kr -blocking action cause secondary long-QT syndrome. Several cases have been associated with mutations of genes coding cardiac ion channels, but their frequency among patients affected by drug-induced long-QT syndrome (dLQTS) and the resultant molecular effects remain unknown. Methods and Results-Genetic testing was carried out for long-QT syndrome-related genes in 20 subjects with dLQTS and 176 subjects with congenital long-QT syndrome (cLQTS); electrophysiological characteristics of dLQTS-associated mutations were analyzed using a heterologous expression system with Chinese hamster ovary cells together with a computer simulation model. The positive mutation rate in dLQTS was similar to cLQTS (dLQTS versus cLQTS, 8 of 20 [40%] versus 91 of 176 [52%] subjects, Pϭ0.32). The incidence of mutations was higher in patients with torsades de pointes induced by nonantiarrhythmic drugs than by antiarrhythmic drugs (antiarrhythmic versus others, 3 of 14 [21%] versus 5 of 6 [83%] subjects, PϽ0.05). When reconstituted in Chinese hamster ovary cells, KCNQ1 and KCNH2 mutant channels showed complex gating defects without dominant negative effects or a relatively mild decreased current density. Drug sensitivity for mutant channels was similar to that of the wild-type channel. With the Luo-Rudy simulation model of action potentials, action potential durations of most mutant channels were between those of wild-type and cLQTS. Conclusions-dLQTS had a similar positive mutation rate compared with cLQTS, whereas the functional changes of these mutations identified in dLQTS were mild. When I Kr -blocking agents produce excessive QT prolongation (dLQTS), the underlying genetic background of the dLQTS subject should also be taken into consideration, as would be the case with cLQTS; dLQTS can be regarded as a latent form of long-QT syndrome. (Circ Arrhythmia Electrophysiol. 2009;2:511-523.)Key Words: long-QT syndrome Ⅲ secondary Ⅲ drug Ⅲ electrophysiology Ⅲ ion channel C ongenital long-QT syndrome (cLQTS) is characterized by abnormally prolonged ventricular repolarization and familial inheritance, leading to polymorphic ventricular tachycardia (torsades de pointes [TdP]), causing sudden cardiac death. 1,2 In contrast, secondary long-QT syndrome can be induced by a variety of commercially available drugs, including antiarrhythmic drugs, antihistamines, antibiotics, Clinical Perspective on p 523and major tranquilizers. 3 In patients with drug-induced long-QT syndrome (dLQTS), after a washout period of the culprit drugs, the QT interval usually returns to within normal range. Genetic factors may underlie the susceptibility to drug-induced serious adverse reactions such as a long QT Received February 29, 2008; accepted July 6, 2009. (eg, drugs, hypokalemia, or bradycardia). Among the subjects, 20 probands had drug-induced cardiac events (10.2% of long-QT syndrome probands). Their clinical information was collected, including family history of sudden death age 30 years or younger and long-QT syndrome members, previ...

TLR2 plays a role as a pattern-recognition receptor in the innate immune response involving secreted proteins against microbial pathogens. To examine its possible involvement in the cellular response, we determined the levels of the engulfment and subsequent killing of bacteria by macrophages prepared from TLR2-deficient and wild-type mice. The level of the engulfment of Staphylococcus aureus or Escherichia coli was almost the same between TLR2-lacking and wild-type macrophages. However, the colony-forming ability of engulfed S. aureus, but not of E. coli, decreased to a greater extent in TLR2-lacking macrophages than in the wild-type control. The incubation with S. aureus caused activation of JNK in wild-type macrophages but not in TLR2-lacking macrophages, and the pretreatment of wild-type macrophages with a JNK inhibitor increased the rate of killing of engulfed S. aureus, but again not of E. coli. In addition, the number of colonies formed by engulfed S. aureus increased in the JNK-dependent manner when TLR2-lacking macrophages were pretreated with LPS. Furthermore, JNK seemed to inhibit the generation of superoxide, not of NO, in macrophages. These results collectively suggested that the level of superoxide is reduced in macrophages that have engulfed S. aureus through the actions of TLR2-activated JNK, resulting in the prolonged survival of the bacterium in phagosomes. The same regulation did not influence the survival of E. coli, because this bacterium was more resistant to superoxide than S. aureus. We propose a novel bacterial strategy for survival in macrophages involving the hijacking of an innate immune receptor.

Although hyperlactemia is known to accompany hepatic failure and metabolic acidosis, few reports examined the relationships between lactate concentrations and outcome after liver resection. We examined the ability of arterial plasma lactate concentration to predict the patient outcome after hepatectomy. The relationships of arterial lactate and base excess (BE) measured on admission to the intensive care unit (ICU) after hepatectomy to postoperative outcome were investigated in 151 consecutive patients. Lactate level was significantly higher in nonsurvivors than in survivors (P < 0.001), and in patients with postoperative complications than in those without complications (P < 0.001). Base excess was significantly reduced in nonsurvivors (P < 0.001) and in patients with postoperative complications (P = 0.004). The area under the receiver-operator curve of lactate to mortality was 0.86, whereas that of BE to the mortality was 0.82. Moderate correlation was observed between the lactate level at ICU admission and the highest total bilirubin concentration measured within 14 days after the surgery (r = 0.61), whereas the correlation between BE and bilirubin levels was lower (r = 0.35). Using multivariate analysis, the lactate level independently predicted mortality (P = 0.008) and morbidity (P = 0.013). Lactate (P < 0.001) and BE (P = 0.0068) levels both independently predicted the highest bilirubin concentration. The arterial plasma lactate concentration measured on admission to ICU seemed an excellent predictor of patient outcome after liver resection.

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The combination of oncolytic virus with gemcitabine is a promising new strategy against advanced pancreatic cancer. Each virus has different functional characteristics, and can affect the results of the combination of viruses and chemotherapy drugs. The results indicate that there is a complicated interaction among viruses, cells, and chemotherapy drugs and that the best combination of oncolytic virus and chemotherapeutic agents should be studied more extensively before embarking on a clinical trial.