John G. Vallone
University of Southern California
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Featured researches published by John G. Vallone.
Proteomics Clinical Applications | 2014
Jessica M. Skeie; Stephen H. Tsang; Ryan Vande Zande; Macy M. Fickbohm; Shaival S. Shah; John G. Vallone; Vinit B. Mahajan
Biorepositories are collections of surgically obtained human tissues for current and future investigations of disease mechanisms, therapeutics, and diagnostics. In ophthalmology, a critical challenge is how to interface the operating room with the laboratory. To attain standards required for basic research, clinical and research teams must cooperate to collect, annotate, and store specimens that yield consistent results required for advanced molecular techniques. We developed an efficient platform for obtaining vitreous and other eye tissues from the operating room and transferring them to the lab. The platform includes a mobile lab cart for on‐site tissue processing, a multi‐user, web‐based database for point‐of‐care phenotypic capture, and an integrated data tracking system for long‐term storage. These biorepository instruments have proven essential for our studies in ophthalmic disease proteomics. This system can be implemented in other operating rooms and laboratories for a variety of biological tissues.
The American Journal of Surgical Pathology | 2016
Jennifer Smith; Alfred J Garcia; Ruth Zhang; Steven R. DeMeester; John G. Vallone; Parakrama Chandrasoma
Barrett esophagus is presently defined in the United States by the presence of intestinal metaplasia in columnar-lined esophagus based on the premise that the risk for adenocarcinoma depends on the presence of intestinal metaplasia. Recently, arguments have been made that nonintestinalized cardiac epithelium is also at risk and should be included in the definition of Barrett esophagus, as it is in England and Japan. One of these arguments is that residual intestinal metaplasia is frequently absent around early adenocarcinomas removed by endoscopic mucosal resection (EMR). We reviewed 27 EMRs performed in 21 patients. Residual intestinal metaplasia was absent in 10/27 (37%) EMR specimens. An in-depth study of these 10 cases showed that 3 had intestinal metaplasia in a concurrent second EMR specimen, 4 had intestinal metaplasia in prior biopsy material available in our unit, and 2 had intestinal metaplasia in an esophagectomy that followed the EMR. The single patient in whom no intestinal metaplasia was found, neither in biopsies nor in EMR, and who did not undergo an esophagectomy had been under surveillance for Barrett esophagus for over 20 years. We conclude that the frequent absence of residual intestinal metaplasia around an adenocarcinoma in an EMR specimen is the result of sampling error. When evaluated in depth by looking at history, biopsies preceding the EMR, and esophagectomy following the EMR, all of these patients with adenocarcinoma had intestinal metaplasia in their columnar-lined esophagus. This indicates that intestinal metaplasia is a necessary precursor to adenocarcinoma of the esophagus.
The Prostate | 2015
Shigang Xiong; Qingcai Wang; Stephen V. Liu; Robert B. Montgomery; Frank Z. Stanczyk; John G. Vallone; Noah Merin; Jacek Pinski
The importance of androgen signaling in prostate cancer (PC) is well described and prostate cancer cells retain the ability to directly synthesize androgens. Luteinizing hormone (LH) can induce expression of steroidogenic enzymes and trigger androgen production, but the regulation of this process is not well‐described. Here, we explored the impact of silencing LH receptor (LHR) silencing on androgen synthesis and on several relevant signaling pathways in PC.
Journal of Pathology Informatics | 2015
David C. Wilbur; Elena F. Brachtel; John R. Gilbertson; Nicholas C. Jones; John G. Vallone; Savitra Krishnamurthy
Background: The use of digital whole slide imaging for human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) could create improvements in workflow and performance, allowing for central archiving of specimens, distributed and remote interpretation, and the potential for additional computerized automation. Procedures: The accuracy, precision, and reproducibility of manual digital interpretation for HER2 IHC were determined by comparison to manual glass slide interpretation. Inter- and intra-pathologist reproducibility and precision between the glass slide and digital interpretations of HER2 IHC were determined in 5 studies using DAKO HercepTest-stained breast cancer slides with the Philips Digital Pathology System. In 2 inter-method studies, 3 pathologists interpreted glass and digital slides in sequence or in random order with a minimum of 7 days as a washout period. These studies also measured inter-observer reproducibility and precision. Another two studies measured intra-pathologist reproducibility on cases read 10 times by glass and digital methods. One additional study evaluated the effects of adding IHC control slides with each run, using 1 pathologist interpreting glass and digital slides randomized from the sets above along with appropriate controls for each slide in the set. Results: The overall results show that there is no statistical difference between the variance of performance when comparing glass and digital HER2 interpretations; and there were no effects noted when control tissues were evaluated in conjunction with the test slides. Conclusions: The results show that there is an equivalence of result when interpreting HER2 IHC slides in breast cancer by either glass slides or digital images. Digital interpretation can therefore be safely and effectively used for this purpose.
Journal of medical imaging | 2015
Thomas Cummins; Changhan Yoon; Hojong Choi; Payam Eliahoo; Hyung Ham Kim; Mary Yamashita; Linda Hovanessian-Larsen; Julie E. Lang; Stephen F. Sener; John G. Vallone; Sue Ellen Martin; K. Kirk Shung
Abstract. Image-guided core needle biopsy is the current gold standard for breast cancer diagnosis. Microcalcifications, an important radiographic finding on mammography suggestive of early breast cancer such as ductal carcinoma in situ, are usually biopsied under stereotactic guidance. This procedure, however, is uncomfortable for patients and requires the use of ionizing radiation. It would be preferable to biopsy microcalcifications under ultrasound guidance since it is a faster procedure, more comfortable for the patient, and requires no radiation. However, microcalcifications cannot reliably be detected with the current standard ultrasound imaging systems. This study is motivated by the clinical need for real-time high-resolution ultrasound imaging of microcalcifications, so that biopsies can be accurately performed under ultrasound guidance. We have investigated how high-frequency ultrasound imaging can enable visualization of microstructures in ex vivo breast tissue biopsy samples. We generated B-mode images of breast tissue and applied the Nakagami filtering technique to help refine image output so that microcalcifications could be better assessed during ultrasound-guided core biopsies. We describe the preliminary clinical results of high-frequency ultrasound imaging of ex vivo breast biopsy tissue with microcalcifications and without Nakagami filtering and the correlation of these images with the pathology examination by hematoxylin and eosin stain and whole slide digital scanning.
Clinical Ophthalmology | 2015
John J. Chen; Lucas J. Wendel; Emily S. Birkholz; John G. Vallone; Anne L. Coleman; Fei Yu; Vinit B. Mahajan
Background While metabolic syndrome has been strongly implicated as a risk factor for macrovascular diseases, such as stroke and cardiovascular disease, its relationship with microvascular diseases, including diabetic retinopathy, has been less defined. The purpose of this pilot study was to investigate the association between metabolic syndrome and the presence and severity of diabetic retinopathy. Methods A retrospective case–control chart review at the University of Iowa ophthalmology and primary care clinics included 100 patients with proliferative diabetic retinopathy (PDR), 100 patients with nonproliferative diabetic retinopathy (NPDR), 100 diabetic patients without diabetic retinopathy, and 100 nondiabetic patients who were randomly selected. Using the International Diabetes Foundation definition, the prevalence of metabolic syndrome and the number of components of metabolic syndrome were compared among these groups. Results The prevalence of metabolic syndrome in patients with diabetes was 69.3%, which was significantly higher than that in patients without diabetes (27%; P<0.0001) (odds ratio [OR] =6.28; 95% confidence interval [CI]: 3.76–10.49; P=0.0004). However, there was no significant difference in the prevalence of metabolic syndrome between diabetics with and without diabetic retinopathy, with rates of 67.5% and 73%, respectively (P=0.36) (OR =0.77; 95% CI: 0.45–1.32; P=0.34). In addition, there was no significant difference between the PDR and NPDR groups, with rates of 63% and 72%, respectively (P=0.23) (OR =0.70; 95% CI: 0.38–1.30; P=0.26). Conclusion The metabolic syndrome was highly prevalent in patients with diabetes, but it was not associated with the presence or severity of retinopathy.
Journal of Gastrointestinal Surgery | 2016
Joshua A. Boys; Stephanie G. Worrell; Parakrama Chandrasoma; John G. Vallone; Dipen M. Maru; Lizhi Zhang; Shanda H. Blackmon; Karen J. Dickinson; Christy M. Dunst; Wayne L. Hofstetter; Michael J. Lada; Brian E. Louie; Daniela Molena; Thomas J. Watson; Steven R. DeMeester
Journal of Gastrointestinal Surgery | 2016
Stephanie G. Worrell; Joshua A. Boys; Parakrama Chandrasoma; John G. Vallone; Christy M. Dunst; Corey S. Johnson; Michael J. Lada; Brian E. Louie; Thomas J. Watson; Steven R. DeMeester
Molecular Vision | 2010
Vinit B. Mahajan; John G. Vallone; Jonathan H. Lin; Robert F. Mullins; Audrey C. Ko; James C. Folk; Edwin M. Stone
Journal of Gastrointestinal Surgery | 2016
Christina L. Greene; Stephanie G. Worrell; Stephen Attwood; Parakrama Chandrasoma; Kenneth J. Chang; Tom R. DeMeester; Reginald V. Lord; Elizabeth Montgomery; Oliver Pech; John G. Vallone; Michael Vieth; Kenneth K. Wang; Steven R. DeMeester