Publications by authors named "John Popp"

Article Synopsis
  • Colorectal cancer screening guidelines are now recommending that average-risk individuals start at age 45, due to a rise in early-onset colorectal cancer (EOCRC).
  • A study analyzed nearly 3 million colonoscopy results to determine the prevalence of colorectal neoplasia in individuals aged 18 to 54, revealing significant findings especially among those aged 45 to 49.
  • Risk factors such as age, sex, race, and family history strongly influence the likelihood of neoplasia, with findings suggesting that these screening age guidelines are justified and should be communicated effectively to patients and healthcare providers.
View Article and Find Full Text PDF

The purpose of this report is to chronicle a 2-decade period of educational innovation and improvement, as well as governance reform, across the specialty of neurological surgery. Neurological surgery educational and professional governance systems have evolved substantially over the past 2 decades with the goal of improving training outcomes, patient safety, and the quality of US neurosurgical care. Innovations during this period have included the following: creating a consensus national curriculum; standardizing the length and structure of neurosurgical training; introducing educational outcomes milestones and required case minimums; establishing national skills, safety, and professionalism courses; systematically accrediting subspecialty fellowships; expanding professional development for educators; promoting training in research; and coordinating policy and strategy through the cooperation of national stakeholder organizations.

View Article and Find Full Text PDF

Tertiary phosphines are generally known to withstand inversion under moderate conditions. In this work, a remarkable racemization process of three P-chiral ferrocenyl phosphines is reported. Subjected to conventional column chromatography as highly enantioenriched compounds, they greatly experienced racemization when collected at the column outlet within minutes.

View Article and Find Full Text PDF

Half-sandwich arene-metal complexes are commonly used for specific applications. Herein, we report facile arene ligand exchange reactions of two ruthenium(II) complexes of tertiary -stereogenic ferrocenyl phosphines. By mild photochemical activation, the displacement of -cymene and subsequent tethering by η-coordination of the terminal phenyl ring of a biphenylyl-substituted ferrocenyl phosphine were enabled.

View Article and Find Full Text PDF

The role of autophagy in cancer is often complex, ranging from tumor-promoting to -suppressing effects. In this study, two novel hybrid molecules were designed, containing a ruthenacarborane fragment conjugated with a known modulator of autophagy, namely a quinoline derivative. The complex closo-[3-(η -p-cymene)-1-(quinolin-8-yl-acetate)-3,1,2-RuC B H ] (4) showed a dual mode of action against the LN229 (human glioblastoma) cell line, where it inhibited tumor-promoting autophagy, and strongly inhibited cell proliferation, de facto blocking cellular division.

View Article and Find Full Text PDF

As it does periodically, the United States healthcare system is, yet again, undergoing a period of change on multiple fronts, including internal initiatives in education, quality, and the workforce, as well as external pressure responding to changes in reimbursement and oversight. In such times, looking back at the foundations of our specialty is helpful, allowing often-beleaguered neurosurgeons to reflect upon what it means to be a neurosurgeon, and how they can be assured that our specialty will continue to flourish in the future. Harvey Cushing envisioned, espoused, and developed neurological surgery as a "special field"-a comprehensive, encompassing, and distinct discipline that studies the nervous system and manages neurological disorders.

View Article and Find Full Text PDF

Background: The purpose of this study was to compare the long-term safety of infliximab and nonbiologic agents as Crohn's disease (CD) therapy.

Methods: Patients with CD were prospectively evaluated in this large, observational registry.

Results: Patients (n = 6273) participated in this observational registry from July 1999 through March 2012; 3440 (54.

View Article and Find Full Text PDF

Monitoring infliximab (IFX) concentrations and antibodies-to-IFX (ATI) titers during inflammatory bowel disease treatment may allow more informed decisions in assessing exposure/response and determining appropriate dosing. To aid in interpreting results from different commercial tests in the context of Janssen's published Remicade® results, the reliability of Janssen's IFX and ATI assays was compared with commercial assays from KU Leuven, Sanquin, Dynacare, and LabCorp. Test results were independently reported to Janssen.

View Article and Find Full Text PDF

Background & Aims: Most patients with Crohn's disease (CD) eventually require an intestinal resection. However, CD frequently recurs after resection. We performed a randomized trial to compare the ability of infliximab vs placebo to prevent CD recurrence.

View Article and Find Full Text PDF

Background: Placement accuracy of ventriculostomy catheters is reported in a wide and variable range. Development of an efficient image-guidance system may improve physician performance and patient safety.

Objective: We evaluate the prototype of Smart Stylet, a new electromagnetic image-guidance system for use during bedside ventriculostomy.

View Article and Find Full Text PDF

Subspecialization of physicians and regional centers concentrate the volume of certain rare cases into fewer hospitals. Consequently, the primary institution of a neurological surgery training program may not have sufficient case volume to meet the current Residency Review Committee case minimum requirements in some areas. To ensure the competency of graduating residents through a comprehensive neurosurgical education, programs may need for residents to travel to outside institutions for exposure to cases that are either less common or more regionally focused.

View Article and Find Full Text PDF

Background: We evaluated external ventricular drain placement for factors associated with placement accuracy. Data were acquired using an electronic health record data requisition tool.

Method: Medical records of all patients who underwent ventriculostomy from 2003 to 2010 were identified and evaluated.

View Article and Find Full Text PDF

In times of fiscal and political uncertainty, philanthropy has become an increasingly important mechanism for building, maintaining, and expanding neurosurgical research programs. Although philanthropy has historically helped launch many hospital systems, scientists and clinicians have generally relied on government grants and industry investment to support research and program infrastructure. However, competition for funds from all sources has increased at the same time as the pipelines for those funds have eroded.

View Article and Find Full Text PDF

As a result of their presumed benign natural history, cerebral capillary telangiectasias (CCTs) are infrequently addressed in the neurosurgical literature. We performed a comprehensive review of CCTs via the PubMed database to synthesize overall epidemiological, radiographic, natural history, and treatment results. Across ten series with 203 patients, mean age was 47, and 45 % were male [95 % confidence interval (CI), 0.

View Article and Find Full Text PDF

Neurosurgery is a high-risk specialty currently undertaking the pursuit of systematic approaches to reducing risk and to measuring and improving outcomes. The authors performed a review of patterns and frequencies of adverse events in neurosurgery as background for future efforts directed at the improvement of quality and safety in neurosurgery. They found 6 categories of contributory factors in neurosurgical adverse events, categorizing the events as influenced by issues in surgical technique, perioperative medical management, use of and adherence to protocols, preoperative optimization, technology, and communication.

View Article and Find Full Text PDF

Object: Given the feasibility of curative surgical and endovascular therapy for cerebral dural arteriovenous fistulas (DAVFs), there is a relative paucity of radiosurgical series for these lesions as compared with their arteriovenous malformation counterparts.

Methods: The authors reviewed records of 56 patients with 70 cerebral DAVFs treated at their institution over the past 6 years. Ten DAVFs (14%) in 9 patients were treated with stereotactic radiosurgery (SRS), with follow-up obtained for 8 patients with 9 DAVFs.

View Article and Find Full Text PDF

Coupled oscillator models have been used for the low frequency response (50 to 250 Hz) of a guitar. These 2 and 3 mass models correctly predict measured resonance frequency relationships under various laboratory boundary conditions, but did not always represent the true state of a guitar in the players' hands. The model presented has improved these models in three ways, (1) a fourth oscillator includes the guitar body, (2) plate stiffnesses and other fundamental parameters were measured directly and effective areas and masses used to calculate the responses, including resonances and phases, directly, and (3) one of the three resultant resonances varies with neck and side mass and can also be modeled as a bar mode of the neck and body.

View Article and Find Full Text PDF

Background: In July 2009, the Accreditation Council for Graduate Medical Education (ACGME) incorporated postgraduate year 1 (PGY1 intern) level training into all U.S. neurosurgery residency programs.

View Article and Find Full Text PDF

Stroke is the third leading cause of mortality and disability in the United States. Ischemic stroke constitutes 85% of all stroke cases. However, no effective treatment has been found to prevent damage to the brain in such cases except tissue plasminogen activator with narrow therapeutic window, and there is an unmet need to develop therapeutics for neuroprotection from ischemic stroke.

View Article and Find Full Text PDF

Object: Tamoxifen has been shown to be a potent neuroprotectant against stroke in rodents. Because other neuroprotectant medications have failed in human trials, a study of tamoxifen in a large-animal model was necessary to further assess the drug's effectiveness. For this study, the authors developed an endovascular model of anterior circulation infarction in canines to mimic the human clinical condition.

View Article and Find Full Text PDF

Although originally the subject of rare case reports, intramedullary spinal cord cavernous malformations (CMs) have recently surfaced in an increasing number of case series and natural history reports in the literature. The authors reviewed 27 publications with 352 patients to consolidate modern epidemiological, natural history, and clinical and surgical data to facilitate decision making when managing these challenging vascular malformations. The mean age at presentation was 42 years without a sex predilection.

View Article and Find Full Text PDF

Background/aims: A comparison of reimbursement for endovascular coil embolization and surgical clipping of unruptured aneurysms has not been previously reported. The aim of this study is to assess the reimbursement to physicians and hospitals for each of these two unruptured aneurysm treatments with long-term follow-up.

Methods: Hospital and physician payents were determined for 14 patients treated with coil embolization or surgical clipping of a single unruptured aneurysm per patient from 2004 to 2005, retrospectively.

View Article and Find Full Text PDF