Robert J Weil

Memorial Sloan-Kettering Cancer Center, New York City, New York, United States

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Publications (216)950.62 Total impact

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    ABSTRACT: Retrospective analysis of the Nationwide Inpatient Sample (NIS), 2005-2011.
    Journal of spinal disorders & techniques. 10/2014;
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    ABSTRACT: The association between clinician- and patient-reported health status measures (HSM) after hemicraniectomy for ischemic stroke is understudied. We compared HSMs to determine how HSM type and follow-up affect the interpretation of outcomes.
    Clinical neurology and neurosurgery. 08/2014; 126C:24-29.
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    ABSTRACT: Background Dural lesions in the anterior skull base may occur secondary to benign or malignant pathology that may be difficult to differentiate on imaging. Detailed clinical evaluation in many cases will narrow the differential diagnosis. In spite of using all the available information, in certain cases the underlying etiology of a lesion remains unclear. Participant We report a rare case of metastatic prostate adenocarcinoma to a meningioma in a 67-year-old-man who presented with progressive confusion and mental status alterations with no prior history of malignancy. Neuroimaging revealed a large anterior skull base lesion. Results The lesion was surgically resected, and histopathology revealed a collision tumor, in which prostate adenocarcinoma was found admixed with a World Health Organization grade I meningioma. Conclusion Anterior dural skull base lesions can be either benign or malignant. Although infrequently reported, a benign-appearing dural-based lesion may be a manifestation of an underlying malignancy, and a thorough clinical, radiologic, and pathologic examination may be necessary, especially in the elderly.
    Journal of neurological surgery reports. 08/2014; 75(1):e81-3.
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    ABSTRACT: Studies that have looked at the effect of race on spine surgery outcomes have failed to take into account baseline risk factors for adverse outcomes. We wished to determine the effect of race on outcomes in patients undergoing elective laminectomy or fusion.
    Neurosurgery 08/2014; 61 Suppl 1:206. · 2.53 Impact Factor
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    ABSTRACT: Breast cancer brain metastases (BCBM) are challenging complications that respond poorly to systemic therapy. The role of the blood-tumor barrier in limiting BCBM drug delivery and efficacy has been debated. Herein, we determined tissue and serum levels of capecitabine, its prodrug metabolites, and lapatinib in women with BCBM resected via medically indicated craniotomy.
    Neuro-oncology. 07/2014;
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    ABSTRACT: Study Design. Retrospective cohort analysis of prospectively-collected clinical data.Objective. To compare outcomes of elective spine fusion and laminectomy when performed by neurological and orthopedic surgeons.Summary of Background Data. The relationship between primary specialty training and outcome of spinal surgery is unknown.Methods. We analyzed the 2006-2012 American College of Surgeons National Surgical Quality Improvement Project database of 50,361 patients, 33,235 (66%) of which were operated on by a neurosurgeon. We eliminated all differences in per- and intraoperative risk factors between surgical specialties by matching 17,126 orthopedic surgery (OS) patients to 17,126 neurosurgery (NS) patients on propensity scores. Regular and conditional logistic regression were used to predict adverse postoperative outcomes in the full sample and matched sample, respectively. The effect of perioperative transfusion on outcomes was further assessed in the matched sample.Results. Diagnosis and procedure were the only factors that were found to be significantly different between surgical subspecialties in the full sample. We found that compared to NS patients, OS patients were more than twice as likely to experience prolonged length of stay (LOS) (odds ratio: 2.6, 95% confidence interval: 2.4-2.8), and significantly more likely to receive a transfusion peri-operatively, have complications, and to require discharge with continued care. After matching, OS patients continued to have slightly higher odds for prolonged LOS, and twice the odds for receiving perioperative transfusion compared to NS patients. Taking into account perioperative transfusion did not eliminate the difference in length of hospital stay between OS and NS patients.Conclusions. Patients operated on by OS have twice the odds for undergoing perioperative transfusion and slightly increased odds for prolonged LOS. Other differences between surgical specialties in 30-day postoperative outcomes were minimal. Analysis of a large, multi-institutional sample of prospectively-collected clinical data suggests that surgeon specialty has limited influence on short-term outcomes after elective spine surgery.
    Spine 06/2014; · 2.16 Impact Factor
  • Benjamin P Rosenbaum, Robert J Weil
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    ABSTRACT: Abstract Aneurysmal subarachnoid hemorrhage (SAH) is a common condition treated by neurosurgeons. The inherent variability in the incidence and presentation of ruptured cerebral aneurysms has been investigated in association with seasonality, circadian rhythm, lunar cycle, and climate factors. We aimed to identify an association between solar activity (solar flux and sunspots) and the incidence of aneurysmal SAH, all of which appear to behave in periodic fashions over long time periods. The Nationwide Inpatient Sample (NIS) provided longitudinal, retrospective data on patients hospitalized with SAH in the United States, from 1988 to 2010, who underwent aneurysmal clipping or coiling. Solar activity and SAH incidence data were modeled with the cosinor methodology and a 10-year periodic cycle length. The NIS database contained 32,281 matching hospitalizations from 1988 to 2010. The acrophase (time point in the cycle of highest amplitude) for solar flux and for sunspots were coincident. The acrophase for aneurysmal SAH incidence was out of phase with solar activity determined by non-overlapping 95% confidence intervals (CIs). Aneurysmal SAH incidence peaks appear to be delayed behind solar activity peaks by 64 months (95% CI; 56-73 months) when using a modeled 10-year periodic cycle. Solar activity (solar flux and sunspots) appears to be associated with the incidence of aneurysmal SAH. As solar activity reaches a relative maximum, the incidence of aneurysmal SAH reaches a relative minimum. These observations may help identify future trends in aneurysmal SAH on a population basis. Key Words: Solar flux-Sunspots-Patterns-Nationwide Inpatient Sample-Cerebral aneurysm. Astrobiology 14, xxx-xxx.
    Astrobiology 06/2014; · 2.80 Impact Factor
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    ABSTRACT: Objective: We describe a patient with a large, invasive corticotroph adenoma who developed severe hypercortisolism shortly after starting fractionated radiotherapy.Method: We reviewed the patient's clinical course, along with relevant literature for similarly reported cases.Result: A 29-year-old man was referred for radiotherapy for a residual and recurrent, invasive corticotroph adenoma. Prior to the radiotherapy, he had normal urine free cortisol (UFC) 44.7 μg/24 hr with minimal symptoms. Within 2 weeks of radiotherapy, he developed hypertension, ankle edema, and hypokalemia (K 2.8 mEq/L), with markedly elevated UFC 9203 μg/24 hr. The UFC gradually decreased and normalized by the end of radiotherapy. A month later, the patient became adrenal insufficient with a non-detectable 24-hr urine free cortisol. His adrenal function slowly recovered in 3 months. We are aware of only one previous case report of clinically significant hypercortisolism following radiotherapy in Cushing disease.Conclusion: Radiotherapy may result in acute severe hypercortisolism in patients with a large corticotroph adenoma. This uncommon, but clinically significant, acute adverse effect of radiotherapy may suggest that clinical observation and biochemical monitoring during or soon after radiotherapy may be indicated.
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    ABSTRACT: Ectopic pituitary adenomas are defined by the presence of adenomatous pituitary tissue outside the sella and distinctly separate from the pituitary gland. Ectopic ACTH-secreting pituitary adenomas (EAPAs) are a rare cause of Cushing's syndrome. Detecting these radiologically can prove difficult, in part, due to their typically small size and unpredictable anatomical location. In ACTH-dependent Cushing's syndrome, if, despite comprehensive testing, the source of excess ACTH remains occult (including negative work up for ectopic ACTH syndrome) thought should be given to the possibility of the patient harboring an EAPA. In most cases, ectopic ACTH pituitary adenomas within the sphenoid sinus will manifest with symptoms of hormonal excess, have an obvious sphenoid sinus mass on pre-operative imaging and will demonstrate resolution of hypercortisolism after surgical excision if located and removed. Twenty cases of EAPAs have been reported in the literature to date. This paper will review the current literature on all previously reported EAPAs within the sphenoid sinus in addition to the current case.
    Endocrine. 06/2014;
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    ABSTRACT: Study Design. Observational retrospective cohort study of prospectively collected database.Objective. To determine whether overweight body mass index (BMI) influences 30-day outcomes of elective spine surgery.Summary of Background Data. Obesity is prevalent in the United States, but its impact on the outcome of elective spine surgery remains controversial.Methods. We used National Surgical Quality Improvement Program, a prospective clinical database with proven validity and reproducibility consisting of 256 perioperative standardized variables from surgical patients at nearly 400 academic and non-academic hospitals nationwide. We identified 49,314 patients who underwent elective fusion, laminectomy or both between 2006 and 2012. We divided patients according to BMI (kg/m) as normal (18.5-24.9), pre-obese (25.0-29.9), obese I (30.0-34.9), obese II (35.0-39.9) and obese III (≥40). Relationship between increased BMI and outcome of surgery measured as prolonged hospitalization, complications, return to the operating room, discharged with continued care, readmission, death was determined using logistic regression before and after propensity score matching.Results. All overweight patients (BMI≥25 kg/m) showed increased odds of an adverse outcome compared to normal patients in unmatched analyses, with maximal effect seen in obese III group. In the propensity-matched sample, obese III patients continued to show increased odds for complications (Odds Ratio, OR, 1.6, 95% confidence interval 1.1-2.3), readmission (2.3, 1.1-4.9), and return to the operating room (1.8, 1.1-3.1).Conclusions. Impact of obesity on elective spine surgery outcome is mediated, at least in part, by comorbidities in patients with BMI between 25.0 and 39.9 kg/m. However, BMI itself is an independent risk factor for adverse outcomes in morbidly obese patients.
    Spine 05/2014; · 2.16 Impact Factor
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    ABSTRACT: Studies in various surgical procedures have shown that transfusion of red blood cells (RBC) increases the risk of postoperative morbidity and mortality. Impact of blood transfusion in patients undergoing spine surgery is not well-described. We assessed the impact of intra and postoperative transfusion on postoperative morbidity and mortality in patients undergoing elective spine surgery. We used the American College of Surgeons' National Surgical Quality Improvement Program to identify a retrospective cohort of 36,901 adult patients who underwent elective spine surgery between 2006 and 2011. Patients who received intra or postoperative transfusion (n=3262) were matched to those who did not using propensity scores. Logistic regression predicted adverse postoperative outcomes. We conducted sensitivity analysis in a subset of patients in whom the number of intraoperatively transfused units of RBC or whole blood was known. Upon matching, preoperative hematocrit, length of surgery, and percentage of spinal fusion surgery were not significantly different between transfused and non-transfused patients. After matching, transfusion remained adversely associated with prolonged length of stay (LOS) in hospital (odds ratio [OR] 2.6, 95% confidence interval [CI] 2.3-2.9), postoperative complications (OR 1.6, 95% CI 1.4-1.9), and an increased 30day return to operation room (OR 1.7, 95% CI 1.3-2.2). Transfusion of even one unit of blood intraoperatively was associated with prolonged LOS (OR 2.0, 95% CI 1.5-2.6) and minor complications (OR 2.4, 95% CI 1.3-4.3). Therefore, transfusion of RBC or whole blood, even a single unit, increased LOS and postoperative morbidity in patients undergoing elective spine surgery, independent of preoperative hematocrit level and patient comorbidities.
    Journal of Clinical Neuroscience 05/2014; · 1.25 Impact Factor
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    Postgraduate medical journal 04/2014; · 1.38 Impact Factor
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    ABSTRACT: Object Myelomeningocele repair is an uncommonly performed surgical procedure. The volume of operations has been decreasing in the past 2 decades, probably as the result of public health initiatives for folate supplementation. Because of the rarity of myelomeningocele, data on patient or hospital factors that may be associated with outcome are scarce. To determine these factors, the authors investigated the trends in myelomeningocele surgical repair in the United States over a 23-year period and examined patient and hospital characteristics that were associated with outcome. Methods The Nationwide Inpatient Sample database for 1988-2010 was queried for hospital admissions for myelomeningocele repair. This database reports patient, hospital, and admission characteristics and surgical trends. The authors used univariate and multivariate logistic regression to assess associations between patient and hospital characteristics and in-hospital deaths, nonroutine discharge, long hospital stay, and shunt placement. Results There were 4034 hospitalizations for surgical repair of myelomeningocele. The annual volume decreased since 1988 but plateaued in the last 4 years of the study. The percentages of myelomeningocele patients with low income (30.8%) and Medicaid insurance (48.2%) were disproportionately lower than those for the overall live-born population (p < 0.0001). More operations per 10,000 live births were performed for Hispanic patients (3.2) than for white (2.0) or black (1.5) patients (p < 0.0001). Overall, 56.6% of patients required shunt placement during the same hospital stay as for surgical repair; 95.0% of patients were routinely discharged; and the in-hospital mortality rate was 1.4%. Nonwhite race was associated with increased in-hospital risk for death (OR 2.8, 95% CI 1.2-6.3) independent of socioeconomic or insurance status. Conclusions Overall, the annual surgical volume of myelomeningocele repairs decreased after public health initiatives were introduced but has more recently plateaued. The most disproportionately represented populations are Hispanic, low-income, and Medicaid patients. Among nonwhite patients, increased risk for in-hospital death may represent a disparity in care or a difference in disease severity.
    Journal of Neurosurgery Pediatrics 04/2014; · 1.63 Impact Factor
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    ABSTRACT: Object The goal in this study was to assess whether a current or prior history of smoking and the number of smoking pack years affect the risk for adverse outcomes in the 30-day postoperative period in patients who undergo elective cranial surgery. Methods Data from the 2006-2011 American College of Surgeons' National Surgical Quality Improvement Project were used in this study. The authors identified 8296 patients who underwent elective cranial surgery, of whom 1718 were current smokers, 854 were prior smokers, and 5724 were never smokers. Using propensity scores and age, the authors matched current and prior smokers to never smokers. Odds ratios for adverse postoperative outcomes were predicted with logistic regression. The relationship between number of pack years and poor outcomes was also examined. Results In unadjusted analyses, prior and current smokers did not differ from never smokers for having poor outcomes postoperatively. Similarly, in matched analyses, no association was found between smoking and adverse outcomes. Number of pack years in propensity-matched analyses did not predict worse outcomes in prior or current smokers versus never smokers. Conclusions The authors did not find smoking to be associated with 30-day postoperative morbidity or mortality. Although smoking cessation is beneficial for overall health, it may not improve the short-term (≤ 30 days) outcome of elective cranial surgery. Thus postponement of elective cranial cases only for smoking cessation may not be necessary.
    Journal of Neurosurgery 02/2014; · 3.15 Impact Factor
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    ABSTRACT: Approximately 12,000 glioblastomas are diagnosed annually in the United States. The median survival rate for this disease is 12 months, but individual survival rates can vary with patient-specific factors, including extent of surgical resection (EOR). The goal of our investigation is to develop a reliable strategy for personalized survival prediction and for quantifying the relationship between survival, EOR, and adjuvant chemoradiotherapy. We used accelerated failure time (AFT) modeling using data from 721 newly diagnosed patients with glioblastoma (from 1993 to 2010) to model the factors affecting individualized survival after surgical resection, and we used the model to construct probabilistic, patient-specific tools for survival prediction. We validated this model with independent data from 109 patients from a second institution. AFT modeling using age, Karnofsky performance score, EOR, and adjuvant chemoradiotherapy produced a continuous, nonlinear, multivariable survival model for glioblastoma. The median personalized predictive error was 4.37 months, representing a more than 20% improvement over current methods. Subsequent model-based calculations yield patient-specific predictions of the incremental effects of EOR and adjuvant therapy on survival. Nonlinear, multivariable AFT modeling outperforms current methods for estimating individual survival after glioblastoma resection. The model produces personalized survival curves and quantifies the relationship between variables modulating patient-specific survival. This approach provides comprehensive, personalized, probabilistic, and clinically relevant information regarding the anticipated course of disease, the overall prognosis, and the patient-specific influence of EOR and adjuvant chemoradiotherapy. The continuous, nonlinear relationship identified between expected median survival and EOR argues against a surgical management strategy based on rigid EOR thresholds and instead provides the first explicit evidence supporting a maximum safe resection approach to glioblastoma surgery.
    Journal of Clinical Oncology 02/2014; · 18.04 Impact Factor
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    ABSTRACT: Higher isodose lines (IDL) in Gamma Knife (GK) Perfexion treatment of brain metastases (BMet) could result in lower local control (LC) or higher radiation necrosis (RN) rates, but reduce treatment time. To assess impact of heterogeneity (HI) and conformality (CI) indices on local failure (LF) for patients treated with GK for 1-3 BMet. From an IRB-approved database, 320 patients with 496 BMet were identified, treated for 1-3 BMet from July 2007 to April 2011 on GK Perfexion. Cox proportional hazards regression was used to analyze significance of HI, CI, IDL, dose, tumor diameter, RPA class, tumor radioresistance, primary, smoking history, metastasis location, and WBRT history with LF and RN. Median follow-up by lesion was 6.8 months (range: 0-49.6). Series median survival was 14.2 months. Per RECIST, 9.5% of lesions failed, 33.9% were stable, 38.3% partially responded, 17.1% responded completely, and 1.2% could not be assessed. The 12-month LC rate was 87.3%. On univariate analysis, dose <20 Gy (HR=2.940, p<.001); tumor size (HR=1.674, p<.001); and cerebellum/brainstem location vs. other (HR=1.891, p=.043) were significant for LF. NSCLC (HR=.333, p=.0097) was associated with better LC. On multivariate analysis, tumor size (HR=1.696, p<.001) and cerebellum/brainstem location vs. other (HR=1.959, p=.033) remained significant for LF. Variables not significant for LF included CI, IDL, and HI. Our study of patients with 1-3 BMet treated with GK demonstrated no difference in LC or RN with varying HI, indicating that physicians can treat to IDL at ≥70% IDL to reduce treatment time without increased LF or RN.
    Neurosurgery 01/2014; · 2.53 Impact Factor
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    ABSTRACT: Ventriculostomy is a common neurosurgical procedure. We evaluated a large national sample of data regarding epidemiologic trends in neurosurgical practice relating to ventriculostomy. The USA Nationwide Inpatient Sample (1988 to 2010) provided retrospective data on patients hospitalized who underwent a ventriculostomy procedure. We categorized ventriculostomy procedures as the principal procedure performed for definitive treatment or as any other procedure. We identified 101,577 relevant hospital admissions with an estimated national volume of 507,762 hospital admissions from 1988 to 2010. For all patients, the mean age was 45.0 years and 46.5% were female. The three most common individual principal diagnoses were subarachnoid hemorrhage (19.1%), intracerebral hemorrhage (14.9%), and obstructive hydrocephalus (3.8%). The three most common principal procedures were other excision or destruction of lesion or tissue of brain (16.0%), clipping of aneurysm (13.5%), and temporary tracheostomy (10.8%). Mean length of stay was 20.8 days and in-hospital mortality was 24.5%. In-hospital mortality was associated with emergency admission (multivariate odds ratio 1.98; 95% confidence interval 1.92–2.05), age 45 years or greater (mean of data set) (1.91; 1.85–1.98), multiple ventriculostomies (1.55; 1.44–1.67), and ventriculostomy as a principal procedure (1.39; 1.35–1.44). A total of 32.7% of patients were discharged to home. Most (94.3%) hospitalizations had one, 5.0% had two, and 0.7% multiple (three or more) ventriculostomies performed. Neurosurgeons must be aware of the association of in-hospital mortality, especially during the first days of admission, particularly when ventriculostomy is the principal procedure performed for definitive treatment during the hospitalization.
    Journal of Clinical Neuroscience 01/2014; 21(4):623–632. · 1.25 Impact Factor
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    ABSTRACT: Objective Neurosurgeons have a variety of procedures to offer when treating medically intractable trigeminal neuralgia (TN). We reviewed the national trends in procedural volume for in-hospital treatment of TN. Methods The Nationwide Inpatient Sample (1988–2010) provided data on patients hospitalized with a principal diagnosis of TN and a related principal procedure. We categorized principal procedures as open, other, percutaneous, or radiosurgery. Results We identified 13,466 relevant hospital admissions. The volume for open procedures and radiosurgery remained relatively constant, whereas percutaneous procedures decreased. Mean age of patients undergoing percutaneous and radiosurgery procedures (67.9 and 69.5 years) was higher than open and other procedures (60.4 and 63.4 years) (p-value <0.001). The mean total in-hospital inflation-adjusted charges for all four categories increased over time (p-values <0.001). The mean total in-hospital inflation-adjusted charge for radiosurgery ($37,666) was higher than open ($28,046) procedures (p-value <0.001). Conclusions Patients who undergo an open procedure to treat TN are younger than those who undergo a percutaneous or a radiosurgery procedure. The perceived risk of open surgery in older patients may drive offering percutaneous or radiosurgical procedures. In addition, the in-hospital inflation-adjusted charges for all procedures increased over time, with radiosurgery being higher than those of open procedures.
    Clinical neurology and neurosurgery 01/2014; 120:55–63. · 1.30 Impact Factor
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    ABSTRACT: Gonadotropins secreting pituitary tumors tend to present as sellar mass with hypogonadism. Biologically active LH secretion by these tumors resulting in elevated testosterone is extremely rare. We report a case of a 48-year-old male patient who presented with giant pituitary tumor, elevated testosterone, and elevated levels of gonadotropins. Surgical resection of the tumor resulted in normalization of gonadotropins and fall in serum testosterone to subnormal levels in the postoperative period confirming that the tumor was secreting bioactive luteinizing hormone (LH).
    Case reports in endocrinology. 01/2014; 2014:194716.

Publication Stats

3k Citations
950.62 Total Impact Points


  • 2014
    • Memorial Sloan-Kettering Cancer Center
      New York City, New York, United States
  • 2009–2014
    • Barrow Neurological Institute
      • Department of Neurosurgery
      Phoenix, Arizona, United States
    • Alper Biotech
      Maryland, United States
  • 2012–2013
    • University of Texas MD Anderson Cancer Center
      • Department of NeuroSurgery
      Houston, TX, United States
    • Case Western Reserve University
      • Department of Epidemiology and Biostatistics
      Cleveland, OH, United States
    • Texas Neurosurgical Institute
      Plano, Texas, United States
    • Cancer Research UK Cambridge Institute
      Cambridge, England, United Kingdom
    • University of Cambridge
      • Department of Applied Mathematics and Theoretical Physics
      Cambridge, ENG, United Kingdom
  • 2011–2013
    • Gamma Knife of Spokane
      Spokane, Washington, United States
  • 2005–2013
    • Cleveland Clinic
      • Department of Neurosurgery
      Cleveland, Ohio, United States
    • National Institute of Allergy and Infectious Diseases
      Maryland, United States
    • Lerner Research Institute
      Cleveland, Ohio, United States
  • 1998–2012
    • National Institutes of Health
      • • Laboratory of Molecular Pharmacology
      • • Branch of Radiation Oncology
      • • Laboratory of Pathology
      Maryland, United States
  • 2001–2009
    • Vanderbilt University
      • • Department of Biomedical Engineering
      • • Department of Biochemistry
      Nashville, Michigan, United States
  • 1999–2009
    • National Cancer Institute (USA)
      • • Laboratory of Molecular Pharmacology
      • • Laboratory of Pathology
      Maryland, United States
  • 2008
    • University of Wisconsin, Madison
      • Department of Human Oncology
      Madison, MS, United States
  • 2007
    • National Institute of Child Health and Human Development
      Maryland, United States
    • The Ohio State University
      • Department of Pediatrics
      Columbus, OH, United States