Probing Enhanced Cytochrome P450 2B1/2 Activity in Rat Hepatocyte Spheroids through Confocal Laser Scanning Microscopy

2001 ◽  
Vol 10 (3) ◽  
pp. 329-342 ◽  
Author(s):  
Emmanouhl S. Tzanakakis ◽  
Chang-Chun Hsiao ◽  
Taku Matsushita ◽  
Rory P. Remmel ◽  
Wei-Shou Hu
Keyword(s):  
Cytochrome P450 ◽  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Constitutive Expression ◽  
Rat Hepatocytes ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser

Cytochrome P450 (CYP450) enzymes are essential for xenobiotic metabolism. Although CYP450s are found in many tissues, CYP2B1/2 are primarily expressed in the rat liver. The constitutive expression in vivo of CYP2B1/2 is low but it is induced in the presence of various drugs such as phenobarbital (PB). In this study, CYP2B1/2 activity in cultured hepatocytes was assessed in situ with the introduction of a fluorogenic sub-strate, pentoxyresorufin. The product of 7-pentoxyresorufin-O-dealkylation (PROD), which is catalyzed specifically by CYP2B1/2, was detected using confocal laser scanning microscopy (CLSM). Primary hepatocytes cultured as monolayers on collagen-coated surfaces exhibited background PROD activity and minimal PB inducibility after 4 days in culture. In contrast, rat hepatocytes organized in compacted aggregates, or spheroids, exhibited higher levels of PROD activity and retained their ability for PB induction. The results from the CLSM analysis were verified by RT-PCR and Western immunoblotting analysis. Furthermore, CLSM in conjunction with image processing techniques and three-dimensional reconstruction revealed the localization of enhanced PROD activity in the center of spheroids. The results support the use of CLSM as a powerful tool for investigating CYP2B1/2 activity in cultured rat hepatocytes.

Consequences of topoisomerase II inhibition in early embryogenesis of Drosophila revealed by in vivo confocal laser scanning microscopy

1993 ◽  
Vol 104 (4) ◽  
pp. 1175-1185 ◽  
Author(s):  
P. Buchenau ◽  
H. Saumweber ◽  
D.J. Arndt-Jovin
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Topoisomerase Ii ◽  
Metaphase Plate ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser

The regulation of DNA topology by topoisomerase II from Drosophila melanogaster has been studied extensively by biochemical methods but little is known about its roles in vivo. We have performed experiments on the inhibition of topoisomerase II in living Drosophila blastoderm embryos. We show that the enzymatic activity can be specifically disrupted by microinjection of antitopoisomerase II antibodies as well as the epipodophyllotoxin VM26, a known inhibitor of topoisomerase II in vitro. By labeling the chromatin of live embryos with tetramethylrhodamine-coupled histones, the effects of inhibition on nuclear morphology and behaviour was followed in vivo using confocal laser scanning microscopy. Both the antibodies and the drug prevented or hindered the segregation of chromatin daughter sets at the anaphase stage of mitosis. In addition, high concentrations of inhibitor interfered with the condensation of chromatin and its proper arrangement into the metaphase plate. The observed effects yielded non-functional nuclei, which were drawn into the inner yolk mass of the embryo. Concurrently, undamaged nuclei surrounding the affected region underwent compensatory division, leading to the restoration of the nuclear population, and thereby demonstrating the regulative capacity of Drosophila blastoderm embryos.

scholarly journals Confocal Laser Scanning Microscopy, a New In Vivo Diagnostic Tool for Schistosomiasis

PLoS ONE ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. e34869 ◽  
Author(s):  
Carlos Fritzsche ◽  
Oliver Stachs ◽  
Martha Charlotte Holtfreter ◽  
Constanze Nohr-Łuczak ◽  
Rudolf Friedrich Guthoff ◽  
...  
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Diagnostic Tool ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser

scholarly journals Diagnostic Applicability of In Vivo Confocal Laser Scanning Microscopy in Melanocytic Skin Tumors

2005 ◽  
Vol 124 (3) ◽  
pp. 493-498 ◽  
Author(s):  
Armin Gerger ◽  
Silvia Koller ◽  
Thomas Kern ◽  
Cesare Massone ◽  
Karin Steiger ◽  
...  
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Skin Tumors ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser
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