The International Neuroblastoma Pathology Classification, a system based on a framework of the Shimada classification with minor modifications, is proposed for international use in assessing NTs.

Bioluminescence is a natural light source based on luciferase catalysis of its substrate luciferin. We performed directed evolution on firefly luciferase using a red-shifted and highly deliverable luciferin analog to establish AkaBLI, an all-engineered bioluminescence in vivo imaging system. AkaBLI produced emissions in vivo that were brighter by a factor of 100 to 1000 than conventional systems, allowing noninvasive visualization of single cells deep inside freely moving animals. Single tumorigenic cells trapped in the mouse lung vasculature could be visualized. In the mouse brain, genetic labeling with neural activity sensors allowed tracking of small clusters of hippocampal neurons activated by novel environments. In a marmoset, we recorded video-rate bioluminescence from neurons in the striatum, a deep brain area, for more than 1 year. AkaBLI is therefore a bioengineered light source to spur unprecedented scientific, medical, and industrial applications.

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A new cell line from the human umbilical vein has been established and maintained for more than 5 yr (180 generations; 900 population doublings). This strain, designated ECV304, is characterized by a cobblestone monolayer growth pattern, high proliferative potential without any specific growth factor requirement, and anchorage dependency with contact inhibition. Karyotype analysis of this cell line reveals it to be of human chromosomal constitution with a high trisomic karyotype (mode 80). Ultrastructurally, endothelium-specific Weibel-Palade bodies were identified. Although one of the endothelial cell markers, Factor VIII-related antigen (VIIIR:Ag) was negative in this cell line, immunocytochemical staining for the lectin Ulex europaeus I (UEA-I), and PHM5 (anti-human endothelium as well as glomerular epithelium monoclonal antibody) was positive, and angiotensin-converting enzyme (ACE) activity was also demonstrated. In addition, ECV304 displayed negativity for alkaline and acid phosphatase and for the epithelial marker keratin. All of these findings suggest that ECV304 cells originated from umbilical vein endothelial cells by spontaneous transformation. Ultrastructurally, no viruslike particles have been detected intracellularly. Nude mouse tumorigenicity and rabbit cornea tests were both positive. This is a report on a novel case of phenotypic alteration of normal venous endothelial cells of human origin in vitro, and generation of a transformant with indefinite life spans. This line may be useful in studies of some physiologically active factors available for medical use.

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Oxidative stress induces JNK activation, which leads to apoptosis through mitochondria-dependent caspase activation. However, little is known about the mechanism by which JNK alters mitochondrial function. In this study, we investigated the role of phosphorylation of myeloid cell leukemia 1 (Mcl-1), an anti-apoptotic member of the Bcl-2 family, in oxidative stress-induced apoptosis. We found that JNK phosphorylated Ser-121 and Thr-163 of Mcl-1 in response to stimulation with H 2 O 2 and that transfection of unphosphorylatable Mcl-1 resulted in an enhanced anti-apoptotic activity in response to stimulation with H 2 O 2 . JNK-dependent phosphorylation and thus inactivation of Mcl-1 may be one of the mechanisms through which oxidative stress induces cellular damage.

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Activin, a member of the TGF-␤ superfamily, regulates the growth and differentiation of a variety of cell types. Based on the expression of activin in pancreatic rudiments of rat embryos and stimulation of insulin secretion from adult rat pancreatic islets by activin, activin is implicated in the development and function of islets. To examine the significance of activin signaling in the fetal and postnatal development of islets, transgenic mice expressing a dominant negative form of activin receptor (dn-ActR) or a constitutively active form of activin receptor (ActR-T206D) in islets were generated together with the transgenic mice expressing intact activin receptor (intact ActR) as a negative control. Transgenic mice with both dn-ActR and ActR-T206D showed lower survival rates, smaller islet area, and lower insulin content in the whole pancreas with impaired glucose tolerance when compared with transgenic mice with intact ActR or littermates, but they showed the same ␣ cell/ ␤ cell ratios as their littermates. In addition to islet hypoplasia, the insulin response to glucose was severely impaired in dnActR transgenic mice. It is suggested that a precisely regulated intensity of activin signaling is necessary for the normal development of islets at the stage before differentiation into ␣ and ␤ cells, and that activin plays a role in the postnatal functional maturation of islet ␤ cells. ( J. Clin. Invest. 1998. 102:294-301.)