Abstract

The potential of NADH autofluorescence as an in vivo intrinsic optical signature to monitor tissue metabolism is well recognized and supported by experimental results mainly in animal models. In this work, we propose a non-contact implementation of this method using large area excitation and employing a normalization method to account for non-metabolic signal changes. Proof of principle in vivo experiments were carried out using an autofluorescence imaging experimental system and a rat renal ischemia model. A hand-held fiber-optic probe was utilized to test the ability of the signal normalization method to address operational conditions associated with the translation of this method to a clinical setting. Preliminary pre-clinical in vivo test of the probe system was carried out using the same rat model.

© 2009 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. B. Chance, P. Cohen, F. Jobsis, and B. Schoener, "Intracellular oxidation-reduction states in vivo," Science 137, 499-508 (1962).
    [CrossRef] [PubMed]
  2. A. Mayevsky and B. Chance, "Intracellular oxidation-reduction state measured in situ by a multichannel fiber-optic surface fluorometer," Science 217, 537-540 (1982).
    [CrossRef] [PubMed]
  3. J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
    [CrossRef] [PubMed]
  4. R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
    [CrossRef]
  5. Valery Tuchin, Tissue Optics: Light Scattering Methods and Instruments for Medical Diagnosis (SPIE Press, 2000).
  6. R. N. Raman, C. D. Pivetti, D. L. Matthews, C. Troppmann, and S. G. Demos, "Quantification of in vivo autofluorescence dynamics during renal ischemia and reperfusion under 355 nm excitation," Opt. Express 16, 4930-4944 (2008).
    [CrossRef] [PubMed]
  7. A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
    [CrossRef] [PubMed]
  8. R. F. Pitts, Physiology of the Kidney and Body Fluids: An Introductory Text, 3rd ed. (Year Book Medical Publishers, 1974).
  9. B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
    [PubMed]
  10. J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
    [CrossRef]
  11. A. Weber and J. S. Schulz, "Fiber-optic fluorimetry in biosensors: comparison between evanescent wave generation and distal-face generation of fluorescent light," Biosens. Bioelectron. 7, 193-197 (1992).
    [CrossRef]
  12. K. C. Calman, R. O. Quinn, and P. R. Bell, "Metabolic aspects of organ storage and the prediction of viability," in Organ Preservation, D. E. Pegg, ed. (Churchill Press, 1973), pp. 225-240.
  13. P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
    [CrossRef]
  14. American National Standards Institute. Z136.1 American National Standards Institute (1993).

2008 (2)

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

R. N. Raman, C. D. Pivetti, D. L. Matthews, C. Troppmann, and S. G. Demos, "Quantification of in vivo autofluorescence dynamics during renal ischemia and reperfusion under 355 nm excitation," Opt. Express 16, 4930-4944 (2008).
[CrossRef] [PubMed]

2005 (1)

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

2004 (1)

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

2000 (1)

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

1992 (1)

A. Weber and J. S. Schulz, "Fiber-optic fluorimetry in biosensors: comparison between evanescent wave generation and distal-face generation of fluorescent light," Biosens. Bioelectron. 7, 193-197 (1992).
[CrossRef]

1983 (1)

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

1982 (1)

A. Mayevsky and B. Chance, "Intracellular oxidation-reduction state measured in situ by a multichannel fiber-optic surface fluorometer," Science 217, 537-540 (1982).
[CrossRef] [PubMed]

1979 (1)

B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
[PubMed]

1962 (1)

B. Chance, P. Cohen, F. Jobsis, and B. Schoener, "Intracellular oxidation-reduction states in vivo," Science 137, 499-508 (1962).
[CrossRef] [PubMed]

A’Amar, O.

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

Arnorosino, M. S.

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

Bigio, I. J.

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

Birrell, C. S.

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

Bottcher, J.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Brauer, R.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Bruining, H. A.

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

Calabro, K. W.

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

Chance, B.

A. Mayevsky and B. Chance, "Intracellular oxidation-reduction state measured in situ by a multichannel fiber-optic surface fluorometer," Science 217, 537-540 (1982).
[CrossRef] [PubMed]

B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
[PubMed]

B. Chance, P. Cohen, F. Jobsis, and B. Schoener, "Intracellular oxidation-reduction states in vivo," Science 137, 499-508 (1962).
[CrossRef] [PubMed]

Cohen, P.

B. Chance, P. Cohen, F. Jobsis, and B. Schoener, "Intracellular oxidation-reduction states in vivo," Science 137, 499-508 (1962).
[CrossRef] [PubMed]

Coremans, J. M. C. C.

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

Demos, S. G.

R. N. Raman, C. D. Pivetti, D. L. Matthews, C. Troppmann, and S. G. Demos, "Quantification of in vivo autofluorescence dynamics during renal ischemia and reperfusion under 355 nm excitation," Opt. Express 16, 4930-4944 (2008).
[CrossRef] [PubMed]

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

Fitzgerald, J. T.

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

Frey, O.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Hansch, A.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Hilger, I.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Howden, B. O.

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

Itshak, F.

B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
[PubMed]

Jablonski, P.

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

Jobsis, F.

B. Chance, P. Cohen, F. Jobsis, and B. Schoener, "Intracellular oxidation-reduction states in vivo," Science 137, 499-508 (1962).
[CrossRef] [PubMed]

Kaiser, W. A.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Malich, A.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Marshall, V. C.

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

Matthews, D. L.

Mayevsky, A.

A. Mayevsky and B. Chance, "Intracellular oxidation-reduction state measured in situ by a multichannel fiber-optic surface fluorometer," Science 217, 537-540 (1982).
[CrossRef] [PubMed]

Michalopoulou, A. P.

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

Nakase, Y.

B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
[PubMed]

Naus, D. C. W. H

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

Oshino, R.

B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
[PubMed]

Pivetti, C. D.

R. N. Raman, C. D. Pivetti, D. L. Matthews, C. Troppmann, and S. G. Demos, "Quantification of in vivo autofluorescence dynamics during renal ischemia and reperfusion under 355 nm excitation," Opt. Express 16, 4930-4944 (2008).
[CrossRef] [PubMed]

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

Puppels, G. J.

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

Rae, D. A.

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

Raman, R. N.

R. N. Raman, C. D. Pivetti, D. L. Matthews, C. Troppmann, and S. G. Demos, "Quantification of in vivo autofluorescence dynamics during renal ischemia and reperfusion under 355 nm excitation," Opt. Express 16, 4930-4944 (2008).
[CrossRef] [PubMed]

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

Reif, R.

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

Sauner, D.

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Schoener, B.

B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
[PubMed]

B. Chance, P. Cohen, F. Jobsis, and B. Schoener, "Intracellular oxidation-reduction states in vivo," Science 137, 499-508 (1962).
[CrossRef] [PubMed]

Schulz, J. S.

A. Weber and J. S. Schulz, "Fiber-optic fluorimetry in biosensors: comparison between evanescent wave generation and distal-face generation of fluorescent light," Biosens. Bioelectron. 7, 193-197 (1992).
[CrossRef]

Singh, S. K.

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

Tange, J.

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

Troppmann, C.

R. N. Raman, C. D. Pivetti, D. L. Matthews, C. Troppmann, and S. G. Demos, "Quantification of in vivo autofluorescence dynamics during renal ischemia and reperfusion under 355 nm excitation," Opt. Express 16, 4930-4944 (2008).
[CrossRef] [PubMed]

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

Van Aken, M.

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

Van Velthuysen, M. F.

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

Weber, A.

A. Weber and J. S. Schulz, "Fiber-optic fluorimetry in biosensors: comparison between evanescent wave generation and distal-face generation of fluorescent light," Biosens. Bioelectron. 7, 193-197 (1992).
[CrossRef]

Acad. Radiol. (1)

A. Hansch, D. Sauner, I. Hilger, J. Bottcher, A. Malich, O. Frey, R. Brauer, and W. A. Kaiser, "Autofluorescence spectroscopy in whole organs with a mobile detector system,"Acad. Radiol. 11, 1229-1236 (2004).
[CrossRef] [PubMed]

Biosens. Bioelectron. (1)

A. Weber and J. S. Schulz, "Fiber-optic fluorimetry in biosensors: comparison between evanescent wave generation and distal-face generation of fluorescent light," Biosens. Bioelectron. 7, 193-197 (1992).
[CrossRef]

J. Biol. Chem. (1)

B. Chance, B. Schoener, R. Oshino, F. Itshak, and Y. Nakase, "Oxidation-reduction ratio studies of mitochondria in freeze-trapped samples," J. Biol. Chem. 254, 4764-4771 (1979).
[PubMed]

J. Biomed. Opt. (2)

J. T. Fitzgerald, A. P. Michalopoulou, C. D. Pivetti, R. N. Raman, C. Troppmann, and S. G. Demos, "Real-time assessment of in vivo renal ischemia using laser autofluorescence imaging," J. Biomed. Opt. 10,044018 (2005).
[CrossRef]

R. Reif, M. S. Arnorosino, K. W. Calabro, O. A’Amar, S. K. Singh, and I. J. Bigio, "Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures," J. Biomed. Opt. 13, 07424LR (2008).
[CrossRef]

Kidney Int. (1)

J. M. C. C. Coremans, M. Van Aken, D. C. W. H Naus, M. F. Van Velthuysen, H. A. Bruining, and G. J. Puppels, "Pretransplantation assessment of renal viability with NADH fluorimetry," Kidney Int. 57, 671-683 (2000).
[CrossRef] [PubMed]

Opt. Express (1)

Science (2)

B. Chance, P. Cohen, F. Jobsis, and B. Schoener, "Intracellular oxidation-reduction states in vivo," Science 137, 499-508 (1962).
[CrossRef] [PubMed]

A. Mayevsky and B. Chance, "Intracellular oxidation-reduction state measured in situ by a multichannel fiber-optic surface fluorometer," Science 217, 537-540 (1982).
[CrossRef] [PubMed]

Tranplantation (1)

P. Jablonski, B. O. Howden, D. A. Rae, C. S. Birrell, V. C. Marshall, and J. Tange, "An experimental model for assessment of renal recovery from warm ischemia," Tranplantation 35, 198-204 (1983).
[CrossRef]

Other (4)

American National Standards Institute. Z136.1 American National Standards Institute (1993).

K. C. Calman, R. O. Quinn, and P. R. Bell, "Metabolic aspects of organ storage and the prediction of viability," in Organ Preservation, D. E. Pegg, ed. (Churchill Press, 1973), pp. 225-240.

R. F. Pitts, Physiology of the Kidney and Body Fluids: An Introductory Text, 3rd ed. (Year Book Medical Publishers, 1974).

Valery Tuchin, Tissue Optics: Light Scattering Methods and Instruments for Medical Diagnosis (SPIE Press, 2000).

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (6)

Fig. 1.
Fig. 1.

Schematic of imaging experimental arrangement. DC=dichroic mirror, F=filter, CM=collection mirror.

Fig. 2.
Fig. 2.

Schematic of fiber probe experimental arrangement. NDF=neutral density filter, BS=beam splitter, CF=collection fibers, PD=photodetector, PM=photomultiplier.

Fig. 3.
Fig. 3.

(a) Typical temporal responses of autofluorescence intensities (under 355 nm excitation and 266 nm excitation), and the resultant signal ratio for rat kidney that underwent 50 min ischemia followed by 60 min reperfusion. (b) Fit of signal ratio in 3(a) during reperfusion to the model. Values of extracted time constants are displayed. (c) The values of τE vs Δτ and (d) τE vs τN obtained from fitting the reperfusion signal ratio profile from all rats.

Fig. 4.
Fig. 4.

Responses of ex vivo porcine kidney tissue autofluorescence and signal ratio immediately submerged in saline bath.

Fig. 5.
Fig. 5.

Sensitivity of autofluorescence intensities and signal ratio to (a) probe-tissue separation and (b) probe-tissue angle for grocery-grade porcine kidney immersed in saline.

Fig. 6.
Fig. 6.

In vivo responses of autofluorescence intensities and the resultant signal ratio using the fiber probe system on a rat kidney subjected to 30 min ischemia followed by 45 min reperfusion.

Tables (1)

Tables Icon

Table 1. Time constants and ANOVA results for three injury times (N=12 rats for each group) derived from the autofluorescence intensity under 355 nm excitation vs. the signal ratio.

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

Component1:RN={RN0tr<t<ΔτRN0ΔRN*(1Exp((tΔτ)/τN))t>Δτ}
Component2:RE=RE0+ΔRE*(1Exp(t/τE))

Metrics