Abstract. The goal of the present study was to examine the utility of the conscious dog model by assessing the QT-interval-prolonging potential of ten positive compounds that have been reported to induce QT interval prolongation in clinical use and seven negative compounds considered not to have such an effect. Three doses of test compounds or vehicle were administered orally to male beagle dogs (n = 4), and telemetry signals were recorded for 24 h after administration. All positive compounds (astemizole, bepridil, cisapride, E-4031, haloperidol, MK-499, pimozide, quinidine, terfenadine, and thioridazine) caused a significant increase in the corrected QT (QTc) interval, with a greater than 10% increase achieved at high doses. In contrast, administration of negative compounds (amoxicillin, captopril, ciprofloxacin, diphenhydramine, nifedipine, propranolol, and verapamil) did not produce any significant change in the QTc interval, with the exception of nifedipine that may have produced an overcorrection of the QTc interval due to increased heart rate. The estimated plasma concentrations of the positive compounds that caused a 10% increase in the QTc interval were in good agreement with the plasma / serum concentrations achieved in humans who developed prolonged QT interval or torsade de pointes (TdP). Although careful consideration should be given to the interpretation of QT data with marked heart rate change, these data suggest that an in vivo QT assay using the conscious dog is a useful model for the assessment of QT interval prolongation by human pharmaceuticals. Supplementary material (Appendix): available only at http://dx
Abstract. In safety pharmacology studies, the effects on the QT interval of electrocardiograms are routinely assessed using a telemetry system in cynomolgus monkeys. However, there is a lack of integrated databases concerning in vivo QT assays in conscious monkeys. As part of QT Interval Prolongation: Project for Database Construction (QT PRODACT), the present study examined 10 positive compounds with the potential to prolong the QT interval and 6 negative compounds considered to have no such effect on humans. The experiments were conducted at 7 facilities in accordance with a standard protocol established by QT PRODACT. The vehicle or 3 doses of each test compound were administered orally to male cynomolgus monkeys (n = 3 -4), and telemetry signals were recorded for 24 h. None of the negative compounds prolonged the corrected QT using Bazett's formula (QTcB) interval. On the other hand, almost all of the positive compounds prolonged the QTcB interval, but haloperidol, terfenadine, and thioridazine did not. The failure to detect the QTcB interval prolongation appeared to be attributable for the differences in metabolism between species and / or disagreement with Bazett's formula for tachycardia. In the cynomolgus monkeys, astemizole induced Torsade de Pointes and cisapride caused tachyarrhythmia at lower plasma concentrations than those observed in humans and dogs. These results suggest that in vivo QT assays in conscious monkeys represent a useful model for assessing the risks of drug-induced QT interval prolongation. Supplementary material (Appendix): available only at http://dx
T cell receptor (TcR)"y5 cells are known to be a minor population of T lymphocytes in the blood (< 10%) and other peripheral lymphoid organs in healthy donors. We demonstrated here that a large proportion of TcR'y cells, i.e., up to 30% of mononuclear cells (MNC) were detectable in the liver, but not other lymphoid organs of cancer patients. More importantly, the majority of such TcRy5 cells (> 70%) were shown to be lymphoblastic by electron microscopy. An activation marker of T lymphocytes, Leu-19 (CD56) was also highly expressed on the hepatic TcR-y cells. The possibility of hepatic TcRyb cells being activated was further examined in mice. C3H/He mice injected with syngeneic tumor cells were demonstrated to have an increased number of liver MNC; such MNC showed an ability to proliferate in vitro. These mice eventually had a considerable proportion of TcR-y5 cells in the liver, showing activation markers, the Ia and LFA-1 antigens. These results suggest that the liver may be an important organ for activation and probably expansion of TcR'y cells especially in tumor bearing hosts. (J. Clin. Invest. 1990. 86:409-415.)
A patient with small-cell carcinoma of the stomach with long survival after percutaneous microwave coagulating therapy (PMCT) for liver metastasis Abstract A 66-year-old man was admitted to our hospital with epigastralgia. Preoperative examinations revealed an 8.0 ϫ 8.0-cm, Borrmann type 2 tumor in the posterior wall of the cardia, without distant metastases. Total gastrectomy with pancreato-splenectomy and regional lymph node dissection was performed curatively. Histologically, the tumor was composed mainly of small cells with hyperchromatic nuclei and scant cytoplasm, which showed positive staining for Grimelius, γ-neuron-specific enolase (γ-NSE), chromogranin A, and serotonin. About 10 months after the operation, a solitary tumor was revealed in S8 of the liver by abdominal computed tomography (CT), and it was histologically confirmed by needle biopsy to be a metastasis of the small-cell carcinoma from the stomach. Instead of hepatectomy, percutaneous microwave coagulating therapy (PMCT) was indicated, because of the patients' liver dysfunction (ICG R15, 39.9%); CT showed complete necrosis of the metastatic focus in the liver after the PMCT. Now, 33 months after the first detection of the liver metastasis (43 months after the gastrectomy), the patient is still alive without any growth of the liver metastasis. The 67 previously reported cases of small-cell carcinoma of the stomach in Japan, including ours, are also reviewed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.