John L. Cameron

Johns Hopkins Medicine, Baltimore, Maryland, United States

Are you John L. Cameron?

Claim your profile

Publications (413)2342.84 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: We assessed circulating tumor cells (CTCs) with epithelial and mesenchymal phenotypes as a potential prognostic biomarker for patients with pancreatic adenocarcinoma (PDAC). Background: PDAC is the fourth leading cause of cancer death in the United States. There is an urgent need to develop biomarkers that predict patient prognosis and allow for better treatment stratification. Methods: Peripheral and portal blood samples were obtained from 50 patients with PDAC before surgical resection and filtered using the Isolation by Size of Epithelial Tumor cells method. CTCs were identified by immunofluorescence using commercially available antibodies to cytokeratin, vimentin, and CD45. Results: Thirty-nine patients (78%) had epithelial CTCs that expressed cytokeratin but not CD45. Twenty-six (67%) of the 39 patients had CTCs which also expressed vimentin, a mesenchymal marker. No patients had cytokeratin-negative and vimentin-positive CTCs. The presence of cytokeratin-positive CTCs (P< 0.01), but not mesenchymal-like CTCs (P= 0.39), was associated with poorer survival. The presence of cytokeratin-positive CTCs remained a significant independent predictor of survival by multivariable analysis after accounting for other prognostic factors (P< 0.01). The detection of CTCs expressing both vimentin and cytokeratin was predictive of recurrence (P= 0.01). Among patients with cancer recurrence, those with vimentin-positive and cytokeratin-expressing CTCs had decreased median time to recurrence compared with patients without CTCs (P= 0.02). Conclusions: CTCs are an exciting potential strategy for understanding the biology of metastases, and provide prognostic utility for PDAC patients. CTCs exist as heterogeneous populations, and assessment should include phenotypic identification tailored to characterize cells based on epithelial and mesenchymal markers.
    No preview · Article · Jan 2016 · Annals of surgery
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Non-invasive intraductal papillary mucinous neoplasm (IPMN) with high-grade dysplasia and IPMN-associated invasive pancreatic ductal adenocarcinoma (PDAC) are frequently included under the term “malignancy”. The goal of this study is to clarify the difference between these two entities.
    Full-text · Article · Dec 2015 · HPB
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Little is known regarding the effects of caseload volume of other relevant members of the "surgical team." The present study sought to report variations in health care utilization and outcomes relative to surgeon and anesthesiologist volume among patients undergoing pancreatic surgery. Methods: A total of 969 patients undergoing pancreatic surgery from 2011-2013 were identified at a large, tertiary care center. Multivariable regression analyses explored the effects of provider volume on crystalloid administration, blood transfusions, mortality, length of stay, and hospital charges. Results: A total of 11 surgeons were identified while 100 anesthesiologists were involved in providing care to all patients. Annual case volume for surgeons ranged from 5-101 pancreatic resections per year; each anesthesiologist was involved in a fewer number of cases per year with a maximum of 15 patients treated by the same anesthesiologist. Higher volume surgeons had higher transfusions (odds ratio [OR], 1.85; 95% confidence interval [CI], 1.38-2.47; P < 0.001), greater crystalloid administration (OR, 1.62; 95% CI, 1.24-2.12; P < 0.001), and longer length of stay (OR, 1.74; 95% CI, 1.20-2.53; P = 0.003). In contrast, 30-d readmission was lower among higher volume surgeons (low volume versus high volume; 23.1% versus 11.6%; P < 0.001). Variations in patient-related outcomes were not associated with anesthesia provider volume (all P > 0.05). Similarly, total hospital charges and mortality were not associated with provider volumes (both P > 0.05). Conclusions: Although variability exists in health care practices among providers at the surgeon level, less is observed among anesthesiologists. Although a proportion of this variability can be explained by provider volumes, a significant proportion remains unexplained possibly due to nonmodifiable factors such as patient case mix.
    No preview · Article · Sep 2015 · Journal of Surgical Research
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The clinico-radiological characteristics and the natural history of postoperative omental infarct (OI) in patients who underwent distal pancreatectomy (DP) and splenectomy have not been defined. Twelve patients who underwent DP over a period of 2 years and were postoperatively diagnosed with OI based on computed tomography (CT) findings were identified. A total of 12 patients were diagnosed with an OI based on their postoperative imaging. Seven (58.3 %) patients had previously undergone laparoscopic DP, one (8.3 %) had undergone a robotic DP, and in one (8.3 %), a laparoscopic DP was converted to an open procedure. The remaining three (25.1 %) were treated with open DP. In five (41.6 %) patients, the diagnosis of OI was made during routine follow-up. One patient underwent surgical resection of OI, and two had drains placed in the mass. Nine patients were managed conservatively. During the study period, on review of CT imaging, the minimum prevalence of postoperative OI after DP was found to be 22.8 %. A review of literature identified nine articles that reported a total of 34 patients who were diagnosed with OI after abdominal surgery. The management of an asymptomatic postoperative OI should be conservative while an early invasive intervention should be performed in patients who are symptomatic or have infected OI.
    Full-text · Article · Aug 2015 · Journal of Gastrointestinal Surgery
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: The purpose of this study was to investigate the prognostic significance of early (30-day) hospital readmission (EHR) on mortality after pancreatectomy. Methods: Using a prospectively collected institutional database linked with a statewide dataset, we evaluated the association between EHR and overall mortality in all patients undergoing pancreatectomy at our tertiary institution (2005 to 2010). Results: Of 595 pancreatectomy patients, EHR occurred in 21.5%. Overall mortality was 29.4% (median follow-up 22.7 months). Patients with EHR had decreased survival compared with those who were not readmitted (P = .011). On multivariate analysis adjusting for baseline group differences, EHR for gastrointestinal-related complications was a significant independent predictor of mortality (hazard ratio 2.30, P = .001). Conclusions: In addition to known risk factors, 30-day readmission for gastrointestinal-related complications following pancreatectomy independently predicts increased mortality. Additional studies are necessary to identify surgical, medical, and social factors contributing to EHR, as well as interventions aimed at decreasing postpancreatectomy morbidity and mortality.
    No preview · Article · Jun 2015 · American journal of surgery

  • No preview · Article · Jun 2015 · Pancreatology
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the feasibility of genotyping pancreatic tumors via fine needle aspirates (FNAs). FNA is a common method of diagnosis for pancreatic cancer, yet it has traditionally been considered inadequate for molecular studies due to the limited quantity of DNA derived from FNA specimens and tumor heterogeneity. In vitro mixing studies were performed to deduce the minimum cellularity needed for genetic analysis. DNA from both simulated FNAs and clinical FNAs was sequenced. Mutational concordance was determined between simulated FNAs and that of the resected specimen. Limiting dilution studies indicated that mutations present at allele frequencies as low as 0.12% are detectable. Comparison of simulated FNAs and matched tumor tissue exhibited a concordance frequency of 100% for all driver genes present. In FNAs obtained from 17 patients with unresectable disease, we identified at least 1 driver gene mutation in all patients including actionable somatic mutations in ATM and MTOR. The constellation of mutations identified in these patients was different than that reported for resectable pancreatic cancers, implying a biologic basis for presentation with locally advanced pancreatic cancer. FNA sequencing is feasible and subsets of patients may harbor actionable mutations that could potentially impact therapy. Moreover, preoperative FNA sequencing has the potential to influence the timing of surgery relative to systemic therapy. FNA sequencing opens the door to clinical trials in which patients undergo neoadjuvant or a surgery-first approach based on their tumor genetics with the goal of utilizing cancer genomics in the clinical management of pancreatic cancer.
    No preview · Article · May 2015 · Annals of surgery

  • No preview · Article · Apr 2015 · Journal of the American College of Surgeons
  • Charles Yeo · Scott Jones · Taylor Riall · Charles Fraser · John L. Cameron

    No preview · Article · Apr 2015 · Journal of the American College of Surgeons
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: The benefit of neoadjuvant therapy over a surgery-first approach in patients with borderline pancreatic ductal adenocarcinoma (PDAC) has not been well defined. Aim: To compare postoperative outcomes of patients with borderline PDAC who underwent pancreatectomy after neoadjuvant treatment with those of patients who underwent upfront surgery. Methods: Between 2008 and 2014, 231 patients were identified as anatomical borderline PDAC. 117 of 231 (50.6%) patients received neoadjuvant therapy and 114 (49.4%) patients had a surgery-first approach. Univariate, multivariate and survival analyses were performed. Results: Compared to surgery first group, neoadjuvant group was associated with smaller tumor size in the pathological specimen (P<.001), lower incidence of metastatic lymph nodes (39% vs. 80%; P<.001), less perineural invasion (61% vs. 97%: P<.001), less micro-vascular invasion (32% vs. 68%: P<.001), less vascular resection rate (31% vs. 57%; P<.001) and a lower rate of positive resection margin (32% vs. 44%; P<.055). Univariate analysis identified nodal status, lymph node ratio as predictor for survival. Multivariate analysis identified LNR > 15% (HR 2.15; P = 0.001) and age > 65 years (HR 2.02; P = 0.042) as independent predictors of poor survival in the analysis. Postoperative mortality and morbidity rates were similar in the 2 groups. However, survival analysis starting from date of first dose of neoadjuvant therapy versus date of upfront surgery showed better median overall survival in favor of the neoadjuvant group (23 months vs. 17 months; P=.006). Conclusion: Neoadjuvant treatment for borderline PDAC is associated with better pathological outcomes and overall survival. Lymph node ratio and the age of the patient can provide significant prognostic information after pancreatectomy for patients with borderline PDAC.
    No preview · Conference Paper · Mar 2015
  • John L Cameron · Andrew M Cameron

    No preview · Article · Mar 2015 · Annals of The Royal College of Surgeons of England
  • [Show abstract] [Hide abstract]
    ABSTRACT: The significance of indeterminate pulmonary nodules (IPNs) in patients undergoing resection of pancreatic ductal adenocarcinoma (PDAC) is unknown. We sought to define the prevalence and impact of IPN in such patients. We studied all patients who underwent surgical resection of PDAC between 1980 and 2013. IPN was defined as ≥1 well-defined lung nodule(s) less than 3 cm in diameter. Survival was assessed using univariate and multivariate Cox models. Of the 2306 resected patients, 374 (16.2 %) had a preoperative chest computed tomography (CT) scan. Of these patients, 183 (49 %) had ≥1 IPN. Demographic and clinicopathological characteristics were similar among patients with or without IPN (all P > 0.05). Median survival was comparable among patients who did (15.6 months) or did not (18.0 months) have IPN (P = 0.66). Of the 183 patients with IPN, 29 (16 %) progressed to clinically recognizable metastatic lung disease compared to 13 % without IPN (P = 0.38). The presence of >1 IPN was associated with the development of lung metastasis (relative risk 1.58, 95 % CI 1.03-2.4; P = 0.05). However, lung metastasis was not associated with survival (P = 0.24). An IPN proved to be a lung metastasis in only one of six patients with PDAC undergoing surgical resection in this study. Survival was not impacted, even among patients who developed lung metastasis. Patients with PDAC who have IPN should not be precluded from surgical consideration.
    No preview · Article · Jan 2015 · Journal of Gastrointestinal Surgery
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Stereotactic body radiation therapy (SBRT) is a promising option for patients with pancreatic cancer (PCA); however, limited data support its efficacy. This study reviews our institutional experience of SBRT in the treatment of locally advanced (LAPC) and borderline resectable (BRPC) PCA. Methods: Charts of all PCA patients receiving SBRT at our institution from 2010 to 2014 were reviewed. Most patients received pre-SBRT chemotherapy. Primary endpoints included overall survival (OS) and local progression-free survival (LPFS). Patients received a total dose of 25-33 Gy in five fractions. Results: A total of 88 patients were included in the analysis, 74 with LAPC and 14 with BRPC. The median age at diagnosis was 67.2 years, and median follow-up from date of diagnosis for LAPC and BRPC patients was 14.5 and 10.3 months, respectively. Median OS from date of diagnosis was 18.4 months (LAPC, 18.4 mo; BRPC, 14.4 mo) and median PFS was 9.8 months (95 % CI 8.0-12.3). Acute toxicity was minimal with only three patients (3.4 %) experiencing acute grade ≥3 toxicity. Late grade ≥2 gastrointestinal toxicity was seen in five patients (5.7 %). Of the 19 patients (21.6 %) who underwent surgery, 79 % were LAPC patients and 84 % had margin-negative resections. Conclusions: Chemotherapy followed by SBRT in patients with LAPC and BRPC resulted in minimal acute and late toxicity. A large proportion of patients underwent surgical resection despite limited radiographic response to therapy. Further refinements in the integration of chemotherapy, SBRT, and surgery might offer additional advancements toward optimizing patient outcomes.
    No preview · Article · Jan 2015 · Annals of Surgical Oncology
  • John L. Cameron · Jin He
    [Show abstract] [Hide abstract]
    ABSTRACT: The first successful local resection of a periampullary tumor was performed by Halsted in 1898. Kausch performed the first regional resection in 1909, and the operation was popularized by Whipple in 1935. The operation was infrequently performed until the 1980s and 1990s. Two thousand consecutive pancreaticoduodenectomies performed by 1 surgeon (JLC) from the 1960s to the 2000s were retrospectively reviewed from a prospectively maintained database. The first 1,000 were performed over a period of 34 years, the second 1,000 over a period of 9 years. The most common indication throughout was adenocarcinoma of the head of the pancreas (PDAC, 46%). Benign intraductal papillary mutinous neoplasm (IPMN) increased from 1% (1990s) to 8% (2000s) (p = 0.002). Age range was 13 years to 103 years. Mean age increased from 59 years (1980s) to 66 (2000s) (p = 0.001), as did those older than 80 (3% to 12%, p = 0.002). Thirty-day mortality was 1.4%; hospital mortality was 1.7%. Delayed gastric emptying (23%), pancreatic fistulas (16%), and wound infections (11%), were the most frequent morbidity, and have not decreased. The median number of blood transfusions decreased from 2 (1980s) to 0 (1990s and 2000s) (p = 0.004). Length of stay decreased from 21 days (1980s) to 13 (1990s) days to 10 days (2000s) (p = 0.002). Five-year survival for PDAC increased from 19% (1990s) to 24% (2000s) (p = 0.02), and 5-year survival for node-negative, margin-negative PDAC patients was 39%. The volume of pancreatic pathology has attracted 22 basic and clinical scientists to Hopkins, which has $28.5 million of direct support and more than $30 million in endowments, to support research in pancreatic cancer. The volume of clinical material has also supported the training of many young surgeons, 15 of whom have become department chairmen, and more than 20 have become division chiefs. Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Jan 2015 · Journal of the American College of Surgeons
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective: Pancreatic adenocarcinoma is a rapidly progressive malignancy characterized by its tendency for early metastatic spread. MDCT is the primary diagnostic modality for the preoperative staging of patients with pancreatic cancer, with an accuracy established in multiple studies. However, for a variety of reasons, there is often a prolonged interval between staging MDCT and the surgical intervention. This study examines the relationship between the interval between imaging and surgery and the accuracy of MDCT in determining the presence or absence of metastatic disease at surgery in patients with pancreatic cancer. Materials and methods: Patients were identified who had undergone surgery for pancreatic cancer at our institution with a dedicated preoperative pancreas-protocol MDCT performed in our department. Findings from the preoperative MDCT report were correlated with the operative findings, as well as the time between imaging and surgery. Results: Two hundred ninety-two MDCT scans were performed on 256 patients who underwent exploration for pancreatic adenocarcinoma. The patients had a median age of 67 years (range, 30-95 years), and 51.6% (132/256) were male. The median time between MDCT and surgical exploration was 15.5 days (range, 1-198 days). MDCT correctly predicted the absence of metastatic disease at surgery in 233 of 274 (85.0%) studies. MDCT was more accurate in predicting the absence of metastatic disease if the study was performed within 25 days of surgery than it was if the study was performed within more than 25 days of surgery (89.3% vs 77.0%; p = 0.0097). Furthermore, regression models showed that the negative predictive value of a given MDCT significantly decreased after approximately 4 weeks. Conclusion: MDCT is an accurate method to stage patients with pancreatic cancer, but its accuracy in excluding distant metastatic disease depreciates over time. Patients should undergo a repeat MDCT within 25 days of any planned definitive operative intervention for pancreatic cancer to avoid unexpectedly finding metastatic disease at surgery.
    Preview · Article · Jan 2015 · American Journal of Roentgenology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Readmission after pancreatectomy is common, but few data compare patterns of readmission to index and nonindex hospitals. To evaluate the rate of readmission to index and nonindex institutions following pancreatectomy at a tertiary high-volume institution and to identify patient-level factors predictive of those readmissions. Retrospective analysis of a prospectively collected institutional database linked to statewide data of patients who underwent pancreatectomy at a tertiary care referral center between January 1, 2005, and December 2, 2010. Pancreatectomy. The primary outcome was unplanned 30-day readmission to index or nonindex hospitals. Risk factors and reasons for readmission were measured and compared by site using univariable and multivariable analyses. Among all 623 patients who underwent pancreatectomy during the study period, 134 (21.5%) were readmitted to our institution (105 [78.4%]) or to an outside institution (29 [21.6%]). Fifty-six patients (41.8%) were readmitted because of a gastrointestinal or nutritional problem related to surgery and 42 patients (31.3%) because of a postoperative infection. On multivariable analysis, factors independently associated with readmission included age 65 years or older (odds ratio [OR], 1.80; 95% CI, 1.19-2.71), preexisting liver disease (OR, 2.28; 95% CI, 1.23-4.24), distal pancreatectomy (OR, 1.77; 95% CI, 1.11-2.84), and postoperative drain placement (OR, 2.81; 95% CI, 1.00-7.14). In total, 21.5% of patients required early readmission after pancreatectomy. Even in the setting of a tertiary care referral center, 21.6% of these readmissions were to nonindex institutions. Specific patient-level factors were associated with an increased risk of readmission.
    Full-text · Article · Dec 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are precursor lesions that progress to invasive cancer through progressively worsening dysplasia. Although smoking is an established risk factor for pancreatic adenocarcinoma, potential associations with IPMN grade of dysplasia remain unclear. Pancreatic resections for IPMN from 1995 to 2013 were retrospectively reviewed. A total of 446 patients in which the smoking status was documented were identified. Smoking history was positive in 47 % of patients. Of smokers, 50 % had branch-duct, 14 % had main-duct, and 36 % had mixed-type IPMN. Patients with main-duct IPMN were more commonly smokers (65 %), compared to smoking history in 46 % with mixed and 44 % with branch-duct IPMN (p = 0.03). High-grade dysplasia occurred in 25 % of smokers and 21 % of nonsmokers (p = 0.32), and invasive carcinoma in 25 % of smokers and 25 % nonsmokers (p = 0.95). On multivariate analysis, duct size was independently associated with high-grade dysplasia (OR = 3.17, 95 %CI = 1.79-5.64, p < 0.001). Presence of mural nodules (OR = 3.34, 95 %CI = 1.82-6.12, p < 0.001), duct size (OR = 3.87, 95 %CI = 2.21-6.75, p < 0.001), and symptoms (OR = 7.10, 95 %CI = 3.80-13.08, p < 0.001), but not smoking history (OR = 1.10, 95 %CI = 0.64-1.88, p = 0.73), were independent predictors of invasive carcinoma. Median overall survival was 70 months for smokers and 88 months for nonsmokers (p = 0.68). Positive smoking history correlated with duct type classification but does not appear to be a risk factor for harboring high-grade dysplasia or invasive carcinoma in IPMNs.
    No preview · Article · Dec 2014 · Journal of Gastrointestinal Surgery

  • No preview · Article · Oct 2014 · Journal of the American College of Surgeons
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Data on the effect of bile duct injuries (BDI) on health-related quality of life (HRQOL) are not well defined. We sought to assess long-term HRQOL after BDI repair in a large cohort of patients spanning a 23-year period. Study design: We identified and mailed HRQOL questionnaires to all patients treated for major BDI after laparoscopic cholecystectomy between January 1, 1990 and December 31, 2012 at Johns Hopkins Hospital. Results: We identified 167 patients alive at the time of the study who met the inclusion criteria. Median age at BDI was 42 years (interquartile range 31 to 54 years); the majority of patients were female (n = 131 [78.4%]) and of white race (n = 137 [83.0%]). Most patients had Bismuth level 2 (n = 56 [33.7%]) or Bismuth level 3 (n = 40 [24.1%]) BDI. Surgical repair most commonly involved a Roux-en-Y hepaticojejunostomy (n = 142 [86.1%]). Sixty-two patients (37.1%) responded to the HRQOL questionnaire. Median follow-up was 169 months (interquartile range 125 to 222 months). At the time of BDI, mental health was most affected, with patients commonly reporting a depressed mood (49.2%) or low energy level (40.0%). These symptoms improved significantly after definitive repair (both p < 0.05). Limitations in physical activity and general health remained unchanged before and after surgical repair (both p > 0.05). Conclusions: Mental health concerns were more commonplace vs physical or general health issues among patients with BDI followed long term. Optimal multidisciplinary management of BDI can help restore HRQOL to preinjury levels.
    Full-text · Article · Jun 2014 · Journal of the American College of Surgeons
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background The impact of postoperative complications on the administration of adjuvant therapy following pancreaticoduodenectomy (PD) for adenocarcinoma is still unclear. Methods A retrospective review of all patients undergoing PD at our institution between 1995 and 2011 was performed. Clinicopathological data, including Clavien–Dindo complication grade, time to adjuvant therapy (TTA), and survival, were analyzed. Results A total of 1,144 patients underwent PD for adenocarcinoma between 1995 and 2011. The overall complication rate was 49.1 % and clinically severe complications (≥IIIb) occurred in 4.2 %. Overall, 621 patients (54.3 %) were known to have received adjuvant therapy. The median TTA was 60 days. Although the presence of a complication was associated with a delay in TTA (p = 0.002), the grade of complication was not (p = 0.112). On multivariate analysis, only age > 68 years (p 9 days (p = 0.002) correlated with no adjuvant therapy. Patients with postoperative complications were more likely to receive single adjuvant chemotherapy or radiation therapy (31.4 %) than were patients without complications (17.1 %; p
    No preview · Article · Apr 2014 · Annals of Surgical Oncology

Publication Stats

32k Citations
2,342.84 Total Impact Points


  • 1971-2015
    • Johns Hopkins Medicine
      • • Department of Surgery
      • • Department of Gynecology & Obstetrics
      • • Department of Pathology
      Baltimore, Maryland, United States
  • 1963-2015
    • Johns Hopkins University
      • • Department of Surgery
      • • Department of Pathology
      • • Department of Medicine
      • • Department of Chemistry
      Baltimore, Maryland, United States
  • 2009
    • Johns Hopkins Bloomberg School of Public Health
      Baltimore, Maryland, United States
  • 2007
    • University of California, San Diego
      San Diego, California, United States
  • 2006
    • Wayne State University
      Detroit, Michigan, United States
  • 2005-2006
    • Indiana University-Purdue University Indianapolis
      • Department of Surgery
      Indianapolis, Indiana, United States
  • 1974-2006
    • University of Maryland, Baltimore
      • Department of Surgery
      Baltimore, Maryland, United States
  • 2003
    • University of Nebraska at Omaha
      Omaha, Nebraska, United States
    • University of Oxford
      • Nuffield Division of Clinical Laboratory Sciences
      Oxford, England, United Kingdom
  • 2002
    • Memorial Sloan-Kettering Cancer Center
      • Department of Surgery
      New York, New York, United States
  • 2001
    • Tulane University
      New Orleans, Louisiana, United States
  • 1993
    • Medical University of Ohio at Toledo
      • Department of Surgery
      Toledo, Ohio, United States
  • 1987
    • Saint Agnes Hospital
      Baltimore, Maryland, United States
  • 1966
    • Walter Reed Army Institute of Research
      Silver Spring, Maryland, United States