W C Waltzer

Stony Brook University Hospital, Stony Brook, New York, United States

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Publications (140)298.5 Total impact

  • The Journal of Urology 04/2015; 193(4):e777. DOI:10.1016/j.juro.2015.02.2283 · 3.75 Impact Factor
  • The Journal of Urology 04/2015; 193(4):e1074. DOI:10.1016/j.juro.2015.02.1874 · 3.75 Impact Factor
  • Cancer Research 10/2014; 74(19 Supplement):1817-1817. DOI:10.1158/1538-7445.AM2014-1817 · 9.28 Impact Factor
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    ABSTRACT: Prostate cancer is the second leading cause of non-cutaneous cancer-related death in males, and effective strategies for treatment of metastatic disease are currently limited. The tight junction proteins, claudin 3 and claudin 4, serve as cell-surface receptors for the pore-forming Clostridium perfringens enterotoxin [CPE]. Most prostate cancer cells overexpress claudin 3 and claudin 4, and claudins are aberrantly distributed over the plasma membrane, making these cells particularly sensitive to cytolysis by CPE. Prostate cancer cells secrete PSA locally that is proteolytically active; however, circulating PSA is inactivated via binding to protease inhibitors. To overcome systemic toxicity of CPE, a modified protoxin was constructed with a tethered ligand attached to the C-terminus connected by a flexible linker containing a PSA-specific protease cleavage site. This engineered protoxin selectively and efficiently lyses PSA-producing prostate cancer cells whereas CLDN3 and CLDN4 positive cells that do not express PSA are resistant to cytolysis.
    Cancer Letters 06/2014; DOI:10.1016/j.canlet.2014.06.009 · 5.02 Impact Factor
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    ABSTRACT: Ingestion of aristolochic acids (AAs) contained in herbal remedies results in a renal disease and, frequently, urothelial malignancy. The genotoxicity of AA in renal cells, including mutagenic DNA adducts formation, is well documented. However, the mechanisms of AA-induced tubular atrophy and renal fibrosis are largely unknown. To better elucidate some aspects of this process, we studied cell cycle distribution and cell survival of renal epithelial cells treated with AAI at low and high doses. A low dose of AA induces cell cycle arrest in G2/M phase via activation of DNA damage checkpoint pathway ATM-Chk2-p53-p21. DNA damage signaling pathway is activated more likely via increased production of reactive oxygen species (ROS) caused by AA treatment then via DNA damage induced directly by AA. Higher AA concentration induced cell death partly via apoptosis. Since mitogen-activated protein kinases play an important role in cell survival, death and cell cycle progression, we assayed their function in AA-treated renal tubular epithelial cells. ERK1/2 and p38 but not JNK were activated in cells treated with AA. In addition, pharmacological inhibition of ERK1/2 and p38 as well as suppression of ROS generation with N-acetyl-L-cysteine resulted in the partial relief of cells from G2/M checkpoint and a decline of apoptosis level. Cell cycle arrest may be a mechanism for DNA repair, cell survival and reprogramming of epithelial cells to the fibroblast type. An apoptosis of renal epithelial cells at higher AA dose might be necessary to provide space for newly reprogrammed fibrotic cells.
    Archives of Toxicology 05/2014; 89(1). DOI:10.1007/s00204-014-1249-z · 5.08 Impact Factor
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    ABSTRACT: Alemtuzumab is a monoclonal antibody targeting CD52 receptors on B and T lymphocytes and is an effective induction agent in pediatric renal transplantation. We report a seven-yr experience using alemtuzumab induction and steroid-free protocol in the pediatric population as safe and effective. Twenty-one pediatric deceased donor renal transplants were performed at a single academic institution. All received induction with single-dose alemtuzumab and were maintained on a steroid-free protocol using TAC and MMF immunosuppression. There were 15 males and six females in the study whose ages ranged from one to 19 yr. The average follow-up was 32 months (range from 12 to 78.2 months and median 33.7 ± 23.7 months). All patients had immediate graft function. Graft survival was 95%, and patient survival was 100%. Mean 12 and 36 months eGFR were 63.33 ± 21.01 and 59.90 ± 15.27 mL/min/1.73m2, respectively. Three patients developed acute T-cell-mediated rejection due to non-adherence while no recipients developed cytomegalovirus infection, PTLD, or polyoma BK viral nephropathy. Steroid avoidance with single-dose alemtuzumab induction provides adequate and safe immunosuppression in pediatric deceased donor renal transplant recipients receiving TAC and low-dose MMF maintenance therapy.
    Pediatric Transplantation 04/2014; 18(4). DOI:10.1111/petr.12253 · 1.63 Impact Factor
  • The Journal of Urology 04/2014; 191(4):e774-e775. DOI:10.1016/j.juro.2014.02.2126 · 3.75 Impact Factor
  • 02/2014; 1(1). DOI:10.14440/jbm.2014.19
  • The Journal of Urology 04/2013; 189(4):e867-e868. DOI:10.1016/j.juro.2013.02.2026 · 3.75 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e918. DOI:10.1016/j.juro.2012.02.2454 · 3.75 Impact Factor
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    ABSTRACT: We compared the efficacy and potential limitations of white light cystoscopy, narrow band imaging, 5-ALA fluorescence cystoscopy and 3-dimensional optical coherence tomography for early diagnosis of bladder carcinoma in situ. By expressing simian virus 40T antigen in the urothelium carcinoma in situ typically develops in SV40T transgenic mice in about 8 to 20 weeks and then frank high grade papillary urothelial carcinoma starts to emerge. A total of 18 control and 29 SV40T mice were examined during weeks 8 to 22 by white light cystoscopy, fluorescence cystoscopy, narrow band imaging and 3-dimensional optical coherence tomography. Results were validated by histology. Newly improved algorithms for computer aided detection were applied to acquired 3-dimensional optical coherence tomography images to enhance the quantitative diagnosis of carcinoma in situ in near real time. Of 29 carcinoma in situ samples 27 were detected by 3-dimensional optical coherence tomography, 1 by white light cystoscopy, 26 by narrow band imaging and 13 by fluorescence cystoscopy. Of the 18 histologically confirmed benign cases 17 were detected by 3-dimensional optical coherence tomography, 14 by white light cystoscopy, 5 by narrow band imaging and 18 by fluorescence cystoscopy. The diagnostic sensitivity of white light cystoscopy (3.4%) and fluorescence cystoscopy (44.8%), and the specificity of narrow band imaging (27.8%) were significantly enhanced by 3-dimensional optical coherence tomography to 93.1% and 94.4%, respectively (p <0.01). Three-dimensional optical coherence tomography with quantitative computer aided detection can significantly enhance the sensitivity of white light cystoscopy and fluorescence cystoscopy, and the specificity of narrow band imaging for early diagnosis of carcinoma in situ. This suggests the potential of narrow band imaging guided 3-dimensional optical coherence tomography for future clinical detection of carcinoma in situ when effective image guidance is desirable.
    The Journal of urology 03/2012; 187(3):1063-70. DOI:10.1016/j.juro.2011.10.131 · 3.75 Impact Factor
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    ABSTRACT: Bladder carcinoma in situ (CIS) remains a clinical challenge. We compare the efficacies and potential limitations of surface imaging modalities, e.g., white light (WL), fluorescence (FC), blue-light imaging (BL) and 3D optical coherence tomography (3D OCT) for early diagnosis of bladder CIS. SV40T transgenic mice, which develop carcinoma in situ in about 8 to 20 weeks then high grade papillary tumor in the bladder, were employed as the rodent carcinogenesis model to closely mimic human bladder CIS. A total of 30 mice (i.e., SV40T mice blinded with its back strain Balb/c mice) were enrolled in the study, including 20 with CIS and 10 with normal or benign lesions of the bladder mucosa. Our results show that the low diagnostic sensitivities and specificities of WL, FC and BL for early CIS were significantly enhanced by quantitative 3D OCT to 95.0% and 90.0%, suggesting the value of image-guided 3D OCT for future clinical diagnosis of CIS in vivo.
    Proceedings of SPIE - The International Society for Optical Engineering 02/2012; DOI:10.1117/12.909021 · 0.20 Impact Factor
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    ABSTRACT: We examined the usefulness of 3-dimensional optical coherence tomography to enhance the diagnosis of urothelial carcinoma in situ. By expressing SV40T antigen with uroplakin II promoter, carcinoma in situ readily develops in SV40T transgenic mice at about ages 8 to 20 weeks and then frank high grade papillary carcinoma develops in bladder epithelium. We examined 10 control and 40 SV40T mice during weeks 8 to 20 after birth by parallel en face white light imaging and 3-dimensional optical coherence tomography, and compared results with histology findings. We applied quantitative analysis of computer aided detection to 3-dimensional tomography images to enhance the diagnosis of carcinoma in situ, including 3-dimensional segmentation, speckle reduction, fast Fourier transform analysis, and standard deviation and histogram evaluation. We identified carcinoma in situ in 23 SV40T mice by histology. Most carcinoma could not be detected by en face imaging and 2-dimensional optical coherence tomography but was well differentiated by 3-dimensional optical coherence tomography. The 56.5% sensitivity and 61.5% specificity of 2-dimensional optical coherence tomography for carcinoma in situ diagnosis were significantly enhanced by 3-dimensional optical coherence tomography to 95.7% and 92.3%, respectively (p ≤0.031). On quantitative analysis of increased urothelial heterogeneity induced by carcinogenesis we noted that 3-dimensional optical coherence tomography enabled accurate differentiation of carcinoma in situ from normal bladder and benign lesions. Results reveal the potential of cystoscopic 3-dimensional optical coherence tomography to significantly enhance the clinical diagnosis of nonmuscle invasive bladder cancer, particularly carcinoma in situ.
    The Journal of urology 10/2010; 184(4):1499-506. DOI:10.1016/j.juro.2010.05.087 · 3.75 Impact Factor
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    ABSTRACT: We present the results on clinical diagnosis of bladder cancer in vivo with MEMS-based endoscopic OCT and the methods to enhance the detection of carcinoma in situ by 3-D OCT using SV40T transgenic mouse model.
    Biomedical Optics; 04/2010
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    ABSTRACT: To examine the utility and potential limitations of microelectromechanical systems-based spectral-domain cystoscopic optical coherence tomography (COCT) so as to improve the diagnosis of early bladder cancer. An optical coherence tomography catheter was integrated into the single instrument channel of a 22F cystoscope to permit white-light-guided COCT over a large field of view (4.6 mm wide and 2.1 mm deep per scan at 8 frames/s) and 10-microm resolution. Intraoperative COCT diagnosis was performed in 56 patients, with a total of 110 lesions examined and compared with biopsied histology. The overall sensitivity of COCT (94%) was significantly higher than cystoscopy (75%, P = .02) and voided cytology (59%, P = .005); the major enhancement over cystoscopy was for low-grade pTa-1 cancer and carcinoma in situ (P < .018). The overall specificity of COCT (81%) was comparable to voided cytology (88.9%, P = .49), but significantly higher than cystoscopy (62.5%, P = .02). The microelectromechanical systems-based COCT, owing to its high resolution and detection sensitivity and large field of view, offers great potential for "optical biopsy" to enhance the diagnosis of nonpapillary bladder tumors and their recurrences and to guide bladder tumor resection.
    Urology 08/2009; 74(6):1351-7. DOI:10.1016/j.urology.2009.04.090 · 2.13 Impact Factor
  • Frank S Darras, Dilys Whyte, Wayne C. Waltzer
    The Journal of Urology 04/2009; 181(4):805-805. DOI:10.1016/S0022-5347(09)62243-6 · 3.75 Impact Factor
  • Human Immunology 10/2008; 69. DOI:10.1016/j.humimm.2008.08.226 · 2.28 Impact Factor
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    ABSTRACT: This paper summarizes the recent technological development in our lab on cystoscopic optical coherence tomography (COCT) by integrating time-domain OCT (TDOCT) and spectral-domain OCT (SDOCT) with advanced MEMS-mirror technology for endoscopic laser scanning imaging. The COCT catheter can be integrated into the instrument channel of a commercial 22Fr rigid cystoscopic sheath for in vivo imaging of human bladder under the cystosocopic visual guidance; the axial/transverse resolutions of the COCT catheter are roughly 9 μm and 12 μm, respectively, and 2D COCT imaging can be performed with over 110dB dynamic range at 4–8 fps. To examine the utility and potential limitations of OCT for bladder cancer diagnosis, systemic ex vivo rat bladder carcinogenesis studies were performed to follow various morphological changes induced by tumor growth and in vivo porcine study was performed to examine the feasibility of COCT for in vivo imaging. Justified by promising results of the animal studies, preliminary clinical study was conducted on patients scheduled for operating-room cystoscopy for bladder cancers. Double-blind clinical results reveal that COCT can delineate detailed bladder architectures (e.g., urothelium, lamina propria, muscularis) at high resolution and detect bladder cancers based on enhanced urothelial heterogeneity as a result of excessive growing nature of bladder cancers. The diagnostic sensitivity and specificity can be enhanced to 92% and 85%, respectively. Results also suggest that due to reduced imaging depth of COCT in cancerous lesions, staging of bladder cancers may be limited to Ta or T1 for non-outgrowing cancerous lesions.
    Journal of Innovative Optical Health Sciences 06/2008; 01(01). DOI:10.1142/S1793545808000145 · 0.93 Impact Factor
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    ABSTRACT: We report the recent technical improvements in our microelectromechanical systems (MEMS)-based spectral-domain endoscopic OCT (SDEOCT) and applications for in vivo bladder imaging diagnosis. With the technical advances in MEMS mirror fabrication and endoscopic light coupling methods, the new SDEOCT system is able to visualize morphological details of the urinary bladder with high image fidelity close to bench-top OCT (e.g., 10 mum12 mum axial/lateral resolutions, >108 dB dynamic range) at a fourfold to eightfold improved frame rate. An in vivo animal study based on a porcine acute inflammation model following protamine sulfate instillation is performed to further evaluate the utility of SDEOCT system to delineate bladder morphology and inflammatory lesions as well as to detect subsurface blood flow. In addition, a preliminary clinical study is performed to identify the morphological features pertinent to bladder cancer diagnosis, including loss of boundary or image contrast between urothelium and the underlying layers, heterogeneous patterns in the cancerous urothelium, and margin between normal and bladder cancers. The results of a human study (91% sensitivity, 80% specificity) suggest that SDEOCT enables a high-resolution cross-sectional image of human bladder structures to detect transitional cell carcinomas (TCC); however, due to reduced imaging depth of SDEOCT in cancerous lesions, staging of bladder cancers may be limited to T1 to T2a (prior to muscle invasion).
    Journal of Biomedical Optics 05/2007; 12(3):034009. DOI:10.1117/1.2749744 · 2.75 Impact Factor
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    ABSTRACT: An interpixel-shifted spectral imaging technique is applied to MEMS-based spectral-domain endoscopic optical coherence tomography (SDEOCT) to enhance signal-to-noise ratio and effective imaging depth for in vivo imaging diagnosis of biological tissue. To validate the enhancements of pixel-shifted SDEOCT, experimental comparisons are presented to image animal and human bladder architectures in vivo and to diagnose human transitional cell cancers. Preliminary study shows that interpixel shifted SDEOCT not only increases the depth of field of SDOCT but also eliminates excessive artifacts induced by spectral aliasing effect, thus improving image contrast in areas with large depths (e.g. over 1.5 mm). These results suggest that endoscopic OCT equipped with interpixel-shifted spectral camera has the potential to enhance the diagnosis of biological tissue in in vivo settings that require a larger field of view in the axial direction, such as papillary bladder tumors with deep surface irregularities (e.g. asperities or invaginations).
    International Journal of Image and Graphics 01/2007; 7:105-117. DOI:10.1142/S021946780700257X

Publication Stats

687 Citations
298.50 Total Impact Points


  • 2002–2014
    • Stony Brook University Hospital
      Stony Brook, New York, United States
  • 1983–2012
    • Stony Brook University
      • • Department of Biomedical Engineering
      • • Department of Urology
      • • Department of Surgery
      • • Department of Medicine
      • • Health Sciences Center
      Stony Brook, New York, United States
  • 2007
    • University of Florida
      • Department of Electrical and Computer Engineering
      Gainesville, Florida, United States
  • 2003
    • Tel Aviv University
      Tell Afif, Tel Aviv, Israel
  • 1987–2002
    • State University of New York
      New York City, New York, United States
    • Kitasato University
      Edo, Tōkyō, Japan
  • 1995
    • CUNY Graduate Center
      New York, New York, United States
  • 1988
    • St. Joseph Hospital of Atlanta
      Atlanta, Georgia, United States