To overcome the limitations and misjudgments of conventional prediction of arrhythmic cardiotoxicity, we have developed an on-chip in vitro predictive cardiotoxicity assay using cardiomyocytes derived from human stem cells employing a constructive spatiotemporal two step measurement of fluctuation (short-term variability; STV) of cell's repolarization and cell-to-cell conduction time, representing two origins of lethal arrhythmia. Temporal STV of field potential duration (FPD) showed a potential to predict the risks of lethal arrhythmia originated from repolarization dispersion for false negative compounds, which was not correctly predicted by conventional measurements using animal cells, even for non-QT prolonging clinical positive compounds. Spatial STV of conduction time delay also unveiled the proarrhythmic risk of asynchronous propagation in cell networks, whose risk cannot be correctly predicted by single-cell-based measurements, indicating the importance of the spatiotemporal fluctuation viewpoint of in vitro cell networks for precise prediction of lethal arrhythmia reaching clinical assessment such as thorough QT assay.

SUMMARYWe have investigated the effects of recombinant murine interferon-gamma (rIFN-y) on type II collagen-induced arthritis (CA) in DBA/1 mice. Therapetitic as well as prophylactic treatment with subcutaneous rlFN-y, at 10'' U/mousc six times a week, inhibited the development of CA without any obvious side effects. The accompanying suppression of anti-CII antibody responses may partly explain the inhibition ofCA by rlFN-y. The possible role of the anti-inflammatory effect of systemic IFN-y in the inhibition of CA is discussed.

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DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate), a novel calmodulin antagonist, provides effective protection against Ca²⁺ ionophore-induced cytotoxicity and brain injury induced by transient focal ischemia. In this study, we evaluated the effect of DY-9760e on ischemic infarct volume in rats subjected to permanent focal ischemia. DY-9760e (0.5 mg/kg/h for 6 h) significantly reduced the infarct volume when administered immediately after middle cerebral artery occlusion. Furthermore, this neuroprotection was also exerted by treatment with a 3-hour delay, implying that the therapeutic time window for this compound is at least 3 h. In addition, although treatment with 0.1 mg/kg/h for 24 h was ineffective, the combination of a loading dose of 0.3 mg/kg/h for 2 h followed by 0.1 mg/kg/h for 22 h yielded a significant reduction in infarct volume. Thus, prolonged infusion preceded by a loading dose is an efficacious dosing regimen for DY-9760e, especially at a low infusion rate. These data demonstrate the substantial neuroprotective effect of DY-9760e in a permanent focal ischemia model and indicate that this neuroprotectant may be of therapeutic value for the treatment of acute stroke.

SUMMARYWe developed a convenient and reliable procedure for the cell-mediated passive transfer of type II collagen (Cil)-indueed arthritis (CA). Spleen cells from DBA/I miee with CA were intravenously transferred into syngeneie recipient mice. Arthritis developed only in those recipients which had received whole-body x-irradiation (8 Gy)just before cell transfer and intraperitoneally given soluble CII without adjuvant immediately after transfer. Non-immunized splenoeytes could not induce arthritis even in irradiated recipients given soluble CIL Development ofarthritis depended on the number of cells transferred; 5x10' cells induced severe and long-lasting arthritis in every reeipient approximately 10 days after transfer. Severity of this arthritis was clinically and histologically similar to classical CA in donors. Arlhritogenic ,splcnocyte.s were gcnevatcd in donors no hlev than 20 days after priming with Cil in Freund's complete adjuvant, when arthritis had yet to occur, and were detected for more than 5 weeks. One splenoeyte population responsible for transferring arthritis was CD4^ T cells. We then applied this system to show that prophylactic treatment of Cll-immunized mice with cyclophosphamide (CY. 7 mg/kg), but not interferon-gamma (IFN-y. lO' U/mouse). suppressed the arthritogenic ability oi their spleen cells, although both treatments inhibited the development of CA. Treatment of recipients with IFN-y. however, inhibited the development of arthritis upon transfer with Cll-immunized splenocytes. These results indicate that CY and IFN-7 act at the induction and effector phases of arthritogenic lymphocytes, respectively. Thus, this system facilitates investigation of pathological meehanisms of CA. and of mechanisms of anti-arthritics.