ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Time-resolved fluorescence lifetime imaging microscopy using a picosecond pulsed tunable dye laser system (1996)

Periasamy, Ammasi ; Wodnicki, Pawel ; Wang, Xue F. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Review of Scientific Instruments 67 (1996), S. 3722-3731

add to mindlist on the mindlist

Details

ISSN: 1089-7623

Source: AIP Digital Archive

Topics: Physics , Electrical Engineering, Measurement and Control Technology

Notes: The design and implementation of a time-resolved fluorescence lifetime imaging microscope (TRFLIM) for the biomedical sciences are described. The measurement of fluorescence lifetimes offers many benefits, among which is that they are independent of local signal intensity and concentration of the fluorophore and they provide visualization of the molecular environment in a single living cell. Unlike single photon counting, which employs a photomultiplier as the detector, TRFLIM uses a nanosecond-gated multichannel plate image intensifier providing a two-dimensional map of the spatial distribution of fluorescent lifetime in the sample under observation. Picosecond laser pulses from a tunable dye laser are delivered to the fluorophore inside living cells on the stage of a fluorescent microscope. Images of the fluorescence emission at various times during the decay of the fluorescence are collected using a high-speed gated image intensifier and the lifetimes are calculated on a pixel-by-pixel basis. Lifetimes measured by TRFLIM are compared with those measured by conventional methods. © 1996 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.1147139

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Bcl-2 protooncogene expression in cervical carcinoma cell lines containing inactive p53 (1995)

Liang, Xiao Huan ; Mungal, Salvatore ; Ayscue, Andrea ; [et al.]

New York, N.Y. : Wiley-Blackwell

Journal of Cellular Biochemistry 57 (1995), S. 509-521

add to mindlist on the mindlist

Details

ISSN: 0730-2312

Keywords: bcl-2 ; p53 ; HPV ; cervical carcinoma ; apoptosis ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: Bcl-2 protein expression has been found to block apoptosis and its overexpression has been implicated in lymphoid malignancies where the chromosomal translocation t(14;18) is present. In this study we investigated bcl-2 transcription and protein expression in cultured cervical carcinoma cell lines and keratinocytes. Western blotting and immunofluorescence microscopy demonstrated bcl-2 expression in the cytoplasm of 4 out of 5 cervical carcinoma cell lines examined (HeLa, CaSki, C-33A, and HT-3, but not SiHa). Bcl-2 protein expression was undetectable in normal keratinocytes. None of the cell lines examined demonstrated chromosomal translocation or rearrangement at the major breakpoint-cluster region (MBR) of the bcl-2 gene using either Southern blot or polymerase chain reaction (PCR) analyses. Northern blot analysis demonstrated low levels of bcl-2 transcription in HeLa, CaSki, and C-33A cell lines while reverse transcriptase (RT)-PCR demonstrated bcl-2 transcription in all cervical carcinoma cell lines which had bcl-2 protein expression. Thus, these data suggest that bcl-2 expression occurs in cervical carcinoma cell lines in the absence of chromosomal translocation or rearrangement of the bcl-2 gene. However, each of these cervical carcinoma cell lines contains inactive p53, either due to mutation (C-33A and HT-3) or via complexation and degradation with human papillomavirus (HPV) 16/18 E6 protein (HeLa and CaSki). Thus, functional p53, which can induce apoptosis in certain cells, is not present in these cervical cells which have increased bcl-2 expression. Increased bcl-2 expression under conditions of p53 inactivation may provide cells with a selective advantage for survival and consequently play a role in the development of cervical carcinogenesis.

Additional Material: 8 Ill.