PRINCIPAL SCIENTIST
Callahan, D

STUDENTS
Larkin, J
Sonel, N

STAFF
Staff Names Coming Soon

 


Daniel E. Callahan is a biophysicist in the Department of Cell and Molecular Biology and joined LBNL in 1991 as a Staff Scientist. One objective of his research in the Cancer and Tissue Biology Group is the development, use, and commercialization of Visual Servoing Optical Microscopy (VSOM) for biophysical studies of living cells in vitro.

 


This technology is being used and developed in two separate research projects (i) Antisense Oligonucleotides for PET Imaging of Gene Expression, sponsored by the DOE Office of Biological and Energy Research, Molecular Nuclear Medicine Program , and (ii) Visual Servoing Optical Microscopy for Quantification of MultiDrug Resistance in Living Cells, sponsored by the University of California Industry-University Cooperative Research Program (IUCRP). Initial development of VSOM took place under a project entitled Visual Servoing for Optimization of Anticancer Drug Uptake in Human Breast Cancer Cells sponsored by the Department of Defense, Breast Cancer Research Program, under the U.S. Army Medical Research and Materiel Command, DAMD17-98-1-8177.

In the first project, PET imaging agents are being developed that are based on custom-synthesized, artificial DNA and RNA fragments called antisense oligonucleotides (AS-ONs). The objective is to extend nuclear medicine (Positron Emission Tomography, or PET) to the cellular level by developing new tools for imaging gene expression in humans. A companion grant, entitled Strategies for Imaging Gene Expression with PET is underway in the Life Sciences Department of Nuclear Medicine and Functional Imaging. To fully explore the potential of AS-ON imaging agents, an infrastructure has been developed for intelligent design and modification of AS-ON agents and delivery vehicles. VSOM is just one component of a multi-step development process that brings together and leverages LBNL’s expertise in automation, computer science, medical imaging, and gene technology. This project is a joint effort with Dr. Bahram Parvin of the LBNL Computational Research Division, Imaging and Informatics Group. In the second project, (also a collaboration with Dr. Parvin) new in vitro capabilities for imaging and characterizing multidrug resistance in living, human breast cancer cells are being developed and demonstrated.

Dr. Callahan has also performed and published fluorescence microscope studies performed on living human brain tumor cells. The objective of this research was to enhance the preferential uptake and retention of a boronated protoporphyrin (BOPP) in human brain tumors relative to normal tissue. BOPP is a compound that may prove useful in the cancer radiation treatment known as boron neutron capture therapy (BNCT) In BNCT patients are treated with a boronated compound that accumulates in brain tumors. Patients are then irradiated with neutrons.

As a biophysicist, Dr. Callahan has used nuclear magnetic resonance (NMR), fluorescence, and circular dichroism (CD) spectroscopy to study the conformation of DNA and DNA analogs designed for use as antisense anticancer and antiviral agents. He has also investigated magnetic resonance imaging (MRI) techniques designed to optimize differences in the intracellular water of normal and cancer cells. His publications in the field of fluorescence microscopy include the mapping and quantitation of human papilloma virus (HPV) integration sites in human cervical cancer, and multicolor, 3D studies of chromosome organization in human lymphocytes.

Daniel E. Callahan
Staff Scientist/
Life Sciences Division

One Cyclotron Rd.
Mailstop: 74-157
Berkeley, CA 94720
tel: (510)486-5979
fax: (510)486-6746
email: DECallahan@lbl.gov

 

 

Selected Publications

Callahan, D.E., Trapane, T.L., Miller, P.S., Ts'o, P.O.P. and Kan, L.-S. "Comparative Circular Dichroism and Fluorescence Studies of Oligodeoxyribonucleotide and Oligodeoxyribonucleoside Methylphosphonate Pyrimidine Strands in Duplex and Triplex Formation", Biochemistry 30, 1650-1655 (1991).

Callahan, D.E., Deamond, S.F., Creasey, D.C., Trapane, Bruce, S.A., Ts'o, P.O.P., and Kan, L.-S. "NMR Studies of Intracellular Water at 300 Mhz: T2-Specific Relaxation Mechanisms in Synchronized or EGF-Stimulated Cells", Magn. Res. Med., 22, 68-80 (1991).

Callahan, D.E., Karim, A., Zheng, G., Ts'o, P.O.P. and Lesko, S.A. "Quantitation and Mapping of Integrated Human Papillomavirus on Human Metaphase Chromosomes Using Fluorescence Microscope Imaging System", Cytometry, 13, 453-461 (1992).

Parvin, B., Taylor, J., Callahan, D.E., Johnston, W. and Dahmen, U. "Visual Servoing for On-Line Facilities" IEEE Computer, 30, 56-62 (1997).

Callahan, D.E., Forte, T.M., Afzal, J.S.M., Deen, D.F., Kahl, S.B., Bjornstad, K.A., Bauer, W.F., and Blakely, E.A. "Boronated Protophorphyrin (BOPP): Localization in Lysosomes of the Human Glioma Cell Line SF-767 with Uptake Modulated by Lipoprotein Levels" Int. J. Radiation Oncol. Biol. Phys., 45, 761-771 (1999).

Hsieh, H. B., R. A. Lersch, D.E. Callahan, S. Hayward, M. Wong , O.H. Clark, and Weier, H.G. "Monitoring signal transduction in cancer: cDNA microarray for semiquantitative analysis". J Histochem and Cytochem. 49, 1057-1058 (2001).

Parvin, B. and Callahan, D.E. "BioSig: An Informatics Framework for Representing the Physiological Responses of Living Cells", BioSilico (Elsevier Science, Lo