Diterpenoids isolated from Labiatae family herbs have strong antitumor activities with low toxicity. In this study, Eriocalyxin B (EriB), a diterpenoid extracted from Isodon eriocalyx, was tested on human leukemia/lymphoma cells and murine leukemia models. Acute myeloid leukemia cell line Kasumi-1 was most sensitive to EriB. Significant apoptosis was observed, concomitant with Bcl-2/Bcl-X L downregulation, mitochondrial instability and caspase-3 activation. AML1-ETO oncoprotein was degraded in parallel to caspase-3 activation. EriB-mediated apoptosis was associated with NF-jB inactivation by preventing NF-jB nuclear translocation and inducing IjBa cleavage, and disturbance of MAPK pathway by downregulating ERK1/2 phosphorylation and activating AP-1. Without affecting normal hematopoietic progenitor cells proliferation, EriB was effective on primary t(8;21) leukemia blasts and caused AML1-ETO degradation. In murine t(8;21) leukemia models, EriB remarkably prolonged the survival time or decreased the xenograft tumor size. Together, EriB might be a potential treatment for t(8;21) leukemia by targeting AML1-ETO oncoprotein and activating apoptosis pathways.

One of the central questions in vision research is how attention influences visual information processing. Numerous studies have shown that the directing of attention to a spatial location or to an object increases the speed and/or accuracy of processing stimuli there relative to elsewhere (e.g., Baylis & Driver, 1993;Chen, 1998bChen, , 2000bDuncan, 1984;Egly, Driver, & Rafal, 1994;Hoffman & Nelson, 1981;Posner, Snyder, & Davidson, 1980;Shaw & Shaw, 1977). Furthermore, attention reduces response variability (e.g., Prinzmetal, Amiri, Allen, & Edwards, 1998;Prinzmetal & Wilson, 1997) and enhances signal-to-noise ratio of a briefly presented stimulus (e.g., Bashinski & Bacharach, 1980;C. J. Downing, 1988). These effects suggest that attention acts to enhance visual information processing.However, recent studies suggest that the effect of attention on visual information processing may be more varied than had been previously appreciated. For example, Yeshurun and Carrasco (1998) showed that, whereas attention facilitates texture segregation at peripheral locations, it impairs it at central locations. Chen (2000c) reports that although spatial attention reduces response interference from incompatible distractors when target selection does not require a narrow attentional window, the effect is abolished when the task is made more difficult so that a narrow attentional window is needed to complete the task. Furthermore, allocating attention to an incompatible color word (e.g., the word RED written in green ink and the task is to identify the color of the ink as quickly as possible) increases the Stroop interference effect (Stroop, 1935) rather than reducing it (Chen, 2000a). These findings indicate that how attention influences visual information processing may depend on such factors as the nature of the task and the spread of attention during task completion.In addition to the factors mentioned above, the efficiency of selective attention appears to be modulated by the perceptual load involved in the processing of the target. Lavie and her colleagues (e.g., Lavie, 1995Lavie, , 2000Lavie & Cox, 1997;Lavie & Tsal, 1994) have proposed that high perceptual load for a task is a necessary requirement for efficient selective attention and that perception proceeds automatically to the extent of available resources. When the processing of relevant task information does not consume all available resources (described as a lowload condition), the processing of task-irrelevant information will continue until all resources are used, and this will lead to high distractor interference. In contrast, when the processing load of the relevant task is high (the highload condition), no spare resources are available to process the task-irrelevant information. Hence, little distractor interference occurs. For example, in one experiment, Lavie and Cox asked participants to search for a target letter displayed simultaneously with a compatible, a neutral, or an incompatible irrelevant letter in the periphery. Participants suffered more interfere...

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