Charles R. Geard, Ph.D.

      Center for Radiological Research
      630 West 168th Street, VC 11-205A/243
      New York, N.Y. 10032

      Email: crg4@columbia.edu
      Tel: 212-305-5662 / 914-591-9244 / Fax: 212-305-3229 

   Current Academic and Professional Appointments    

• Professor of Clinical Radiation Oncology, Department of Radiation Oncology College of Physicians & Surgeons of Columbia University

   Current Research  

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   Curriculum Vitae  

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   Select Publications Online  

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• Hei TK, Zhou H, Ivanov VN, Hong M, Lieberman HB, Brenner DJ, Amundson SA, Geard CR. Mechanism of radiation-induced bystander effects: a unifying model. J Pharm Pharmacol. 60: 943-50, (2008). [abstract]

• Meador JA, Zhao M, Su Y, Narayan G, Geard CR, Balajee AS. Histone H2AX is a critical factor for cellular protection against DNA alkylating agents. Oncogene. Epub ahead of print (2008). [abstract]

• Baskar R, Balajee AS, Geard CR, Hande MP. Isoform-specific activation of protein kinase c in irradiated human fibroblasts and their bystander cells. Int J Biochem Cell Biol. 40:125-34, (2008). [abstract]

• Baskar R, Balajee AS and Geard CR. Effects of low and high LET radiations on bystander human lung fibroblast cell survival. Int J Radiat Biol 83:551-9, (2007). [abstract]

• Ponnaiya B, Jenkins-Baker G, Randers-Pherson G and Geard CR. Quantifying a bystander response following microbeam irradiation using single-cell RT-PCR analyses. Exp Hematol 35:64-8, (2007). [abstract]

• Zhu A, Zhou H, Leloup C, Marino SA, Geard CR, Hei TK and Lieberman HB. Differential impact of mouse Rad9 deletion on ionizing radiation-induced bystander effects. Radiat Res 164:655-61, (2005). [abstract]

• Zhou H, Ivanov VN, Gillespie J, Geard CR, Amundson SA, Brenner DJ, Yu Z, Lieberman HB and Hei TK. Mechanism of radiation-induced bystander effect: role of the cyclooxygenase-2 signaling pathway. Proc Natl Acad Sci U S A 102:14641-6, (2005). [abstract]

• Hande MP, Azizova TV, Burak LE, Khokhryakov VF, Geard CR and Brenner DJ. Complex chromosome aberrations persist in individuals many years after occupational exposure to densely ionizing radiation: an mFISH study. Genes Chromosomes Cancer 44:1-9, (2005). [abstract]

• Belyakov OV, Mitchell SA, Parikh D, Randers-Pehrson G, Marino SA, Amundson SA, Geard CR and Brenner DJ. Biological effects in unirradiated human tissue induced by radiation damage up to 1 mm away. Proc Natl Acad Sci U S A 102:14203-8, (2005). [abstract]

• Balajee AS, Ponnaiya B, Baskar R and Geard CR. Induction of replication protein a in bystander cells. Radiat Res 162:677-86, (2004). [abstract]

• Ponnaiya B, Jenkins-Baker G, Bigelow A, Marino S and Geard CR. Detection of chromosomal instability in alpha-irradiated and bystander human fibroblasts. Mutat Res 568:41-8, (2004). [abstract]

• Balajee AS and Geard CR. Replication protein A and gamma-H2AX foci assembly is triggered by cellular response to DNA double-strand breaks. Exp Cell Res 300:320-34, (2004). [abstract]

• Ponnaiya B, Jenkins-Baker G, Brenner DJ, Hall EJ, Randers-Pehrson G and Geard CR. Biological responses in known bystander cells relative to known microbeam-irradiated cells. Radiat Res 162:426-32, (2004). [abstract]

• Mitchell CR, Azizova TV, Hande MP, Burak LE, Tsakok JM, Khokhryakov VF, Geard CR and Brenner DJ. Stable intrachromosomal biomarkers of past exposure to densely ionizing radiation in several chromosomes of exposed individuals. Radiat Res 162:257-63, (2004). [abstract]

• Suzuki M, Zhou H, Geard CR and Hei TK. Effect of medium on chromatin damage in bystander mammalian cells. Radiat Res 162:264-9, (2004). [abstract]

• Geard CR and Ponnaiya B. Chromosomal changes and cell cycle checkpoints in Mammalian cells. Methods Mol Biol 241:315-28, (2004).

• Zhou H, Randers-Pehrson G, Geard CR, Brenner DJ, Hall EJ and Hei TK. Interaction between radiation-induced adaptive response and bystander mutagenesis in mammalian cells. Radiat Res 160:512-6, (2003). [abstract]

• Hande MP, Azizova TV, Geard CR, Burak LE, Mitchell CR, Khokhryakov VF, Vasilenko EK and Brenner DJ. Past exposure to densely ionizing radiation leaves a unique permanent signature in the genome. Am J Hum Genet 72:1162-70, (2003). [abstract]

• Zhou H, Suzuki M, Geard CR, Hei TK. Effects of irradiated medium with or without cells on bystander cell responses. Mutat Res. 499(2):135-41 (2002). [abstract]

• Geard CR, Jenkins-Baker G, Marino SA, Ponnaiya B. Novel approaches with track segment alpha particles and cell co-cultures in studies of bystander effects.
  Radiat Prot Dosimetry 99(1-4):233-6 (2002). [abstract]

• Randers-Pehrson G, Geard CR, Johnson G, Elliston CD, Brenner DJ. The Columbia University single-ion microbeam. Radiat Res. 156(2):210-4 (2001). [abstract]

• Balajee AS, Geard CR. Chromatin-bound PCNA complex formation triggered by DNA damage occurs independent of the ATM gene product in human cells. Nucleic Acids Res. 29(6):1341-51 (2001). [abstract]

• Sawant SG, Randers-Pehrson G, Geard CR, Brenner DJ, Hall EJ. The bystander effect in radiation oncogenesis: I. Transformation in C3H 10T1/2 cells in vitro can be initiated in the unirradiated neighbors of irradiated cells. Radiat Res. 155(3):397-401 (2001). [abstract]

• Brenner DJ, Okladnikova N, Hande P, Burak L, Geard CR, Azizova T.  Biomarkers specific to densely-ionising (high LET) radiations. Radiat Prot Dosimetry. 97(1):69-73 (2001). [abstract]

• Miller RC, Marino SA, Napoli J, Shah H, Hall EJ, Geard CR, Brenner DJ. Oncogenic transformation in C3H10T1/2 cells by low-energy neutrons. Int J Radiat Biol. 76(3):327-33 (2000). [abstract]

• Miller RC, Marino SA, Martin SG, Komatsu K, Geard CR, Brenner DJ, Hall EJ. Neutron-energy-dependent cell survival and oncogenic transformation. J Radiat Res (Tokyo) 40 Suppl:53-9 (1999). [abstract]

• Rakovitch E, Mellado W, Hall EJ, Pandita TK, Sawant S, Geard CR. Paclitaxel sensitivity correlates with p53 status and DNA fragmentation, but not G2/M accumulation. Int J Radiat Oncol Biol Phys. 44(5):1119-24 (1999). [abstract]

• Pandita TK, Westphal CH, Anger M, Sawant SG, Geard CR, Pandita RK, Scherthan H. Atm inactivation results in aberrant telomere clustering during meiotic prophase. Mol Cell Biol. 19(7):5096-105 (1999). [abstract]

• Johnson KL, Brenner DJ, Geard CR, Nath J, Tucker JD. Chromosome aberrations of clonal origin in irradiated and unexposed individuals: assessment and implications. Radiat Res. 152(1):1-5 (1999). [abstract]

• Wu LJ, Randers-Pehrson G, Xu A, Waldren CA, Geard CR, Yu Z, Hei TK. Targeted cytoplasmic irradiation with alpha particles induces mutations in mammalian cells. Proc Natl Acad Sci USA 96(9):4959-64 (1999). [abstract]

• Johnson KL, Brenner DJ, Nath J, Tucker JD, Geard CR. Radiation-induced breakpoint misrejoining in human chromosomes: random or non-random? Int J Radiat Biol. 75(2):131-41. Review (1999). [abstract]

• Miller RC, Randers-Pehrson G, Geard CR, Hall EJ, Brenner DJ. The oncogenic transforming potential of the passage of single alpha particles through mammalian cell nuclei. Proc Natl Acad Sci USA 96(1):19-22 (1999). [abstract]

• Rakovitch E, Mellado W, Hall EJ, Sawant SG, Geard CR, Newman RA, Pandita TK. Penclomedine-induced DNA fragmentation and p53 accumulation correlate with reproductive cell death in colorectal carcinoma cells with altered p53 status. Oncol Rep. 6(1):161-5 (1999). [abstract]

• Pandita TK, Benvenuto JA, Shay JW, Pandita RK, Rakovitch E, Geard CR, Antman KH, Newman RA. Effect of penclomedine (NSC-338720) on telomere fusions, chromatin blebbing, and cell viability with and without telomerase activity and abrogated p53 function. Biochem Pharmacol. 53(3):409-15 (1997). [abstract]

• Pandita TK, Hall EJ, Hei TK, Piatyszek MA, Wright WE, Piao CQ, Pandita RK, Willey JC, Geard CR, Kastan MB, Shay JW. Chromosome end-to-end associations and telomerase activity during cancer progression in human cells after treatment with alpha-particles simulating radon progeny. Oncogene. 13(7):1423-30 (1996). [abstract]

• Geard CR. Neutron induced recoil protons of restricted energy and range and biological effectiveness. Health Phys. 70(6):804-11 (1996). [abstract]

• Pandita TK, Geard CR. Chromosome aberrations in human fibroblasts induced by monoenergetic neutrons. I. Relative biological effectiveness. Radiat Res. 145(6):730-9 (1996). [abstract]