Abstract

We have produced an action spectrum of photodamage using femtosecond illumination from 700 to 900 nm by monitoring the onset of DNA synthesis inhibition in cultured HeLa cells without added dyes. Doses (Int) are defined as the nth power of the peak irradiance at the sample multiplied by the total dwell time of the focal volume in a cell. (The irradiance, I, is in photons/s((m2, and n is the number of photons required for a single excitation event, or the excitation order.) Since we have not yet determined the excitation order of damage at all wavelengths, this action spectrum is expressed with n = 2, defining two-photon events. The measured damage thresholds are orders of magnitude above typical imaging doses.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR004224-15
Application #
6657721
Study Section
Project Start
2002-09-01
Project End
2003-08-31
Budget Start
Budget End
Support Year
15
Fiscal Year
2002
Total Cost
Indirect Cost

  Institution

Name
Cornell University
Department
Type
DUNS #
City
Ithaca
State
NY
Country
United States
Zip Code
14850

  Publications

Migone, Fernando F; Cowan, Robert G; Williams, Rebecca M et al. (2016) In vivo imaging reveals an essential role of vasoconstriction in rupture of the ovarian follicle at ovulation. Proc Natl Acad Sci U S A 113:2294-9
O'Dell, Ryan S; Cameron, David A; Zipfel, Warren R et al. (2015) Reelin Prevents Apical Neurite Retraction during Terminal Translocation and Dendrite Initiation. J Neurosci 35:10659-74
Byrnes, Laura J; Singh, Avtar; Szeto, Kylan et al. (2013) Structural basis for conformational switching and GTP loading of the large G protein atlastin. EMBO J 32:369-84
Jain, Manu; Robinson, Brian D; Scherr, Douglas S et al. (2012) Multiphoton microscopy in the evaluation of human bladder biopsies. Arch Pathol Lab Med 136:517-26
Degala, Satish; Williams, Rebecca; Zipfel, Warren et al. (2012) Calcium signaling in response to fluid flow by chondrocytes in 3D alginate culture. J Orthop Res 30:793-9
O'Dell, Ryan S; Ustine, Candida J M; Cameron, David A et al. (2012) Layer 6 cortical neurons require Reelin-Dab1 signaling for cellular orientation, Golgi deployment, and directed neurite growth into the marginal zone. Neural Dev 7:25
McMullen, J D; Kwan, A C; Williams, R M et al. (2011) Enhancing collection efficiency in large field of view multiphoton microscopy. J Microsc 241:119-24
Kim, Sally A; Sanabria, Hugo; Digman, Michelle A et al. (2010) Quantifying translational mobility in neurons: comparison between current optical techniques. J Neurosci 30:16409-16
Bowles, Robby D; Williams, Rebecca M; Zipfel, Warren R et al. (2010) Self-assembly of aligned tissue-engineered annulus fibrosus and intervertebral disc composite via collagen gel contraction. Tissue Eng Part A 16:1339-48
McMullen, Jesse D; Zipfel, Warren R (2010) A multiphoton objective design with incorporated beam splitter for enhanced fluorescence collection. Opt Express 18:5390-8

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