4,634 research outputs found

    Adherence to Nutrition and Physical Activity Cancer Prevention Guidelines and Development of Colorectal Adenoma.

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    Adherence to the American Cancer Society's (ACS) Nutrition and Physical Activity Cancer Prevention Guidelines is associated with reductions in overall cancer incidence and mortality, including site-specific cancers such as colorectal cancer. We examined the relationship between baseline adherence to the ACS guidelines and (1) baseline adenoma characteristics and (2) odds of recurrent colorectal adenomas over 3 years of follow-up. Cross-sectional and prospective analyses with a pooled sample of participants from the Wheat Bran Fiber (n = 503) and Ursodeoxycholic Acid (n = 854) trials were performed. A cumulative adherence score was constructed using baseline self-reported data regarding body size, diet, physical activity and alcohol consumption. Multivariable logistic regression demonstrated significantly reduced odds of having three or more adenomas at baseline for moderately adherent (odds ratio [OR] = 0.67, 95% confidence intervals [CI]: 0.46ā»0.99) and highly adherent (OR = 0.50, 95% CI: 0.31ā»0.81) participants compared to low adherers (p-trend = 0.005). Conversely, guideline adherence was not associated with development of recurrent colorectal adenoma (moderate adherence OR = 1.16, 95% CI: 0.85ā»1.59, high adherence OR = 1.23, 95% CI: 0.85ā»1.79)

    Molecular, genetic, and cellular pathogenesis of neurofibromas and surgical implications

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    Journal ArticleNEUROFIBROMATOSIS 1 (NF1) IS A common autosomal dominant disease characterized by complex and multicellular neurofibroma tumors. Significant advances have been made in the research of the cellular, genetic, and molecular biology of NF1. The NF1 gene was identified by positional cloning. The functions of its protein product, neurofibromin, in RAS signaling and in other signal transduction pathways are being elucidated, and the important roles of loss of heterozygosity and haploinsufficiency in tumorigenesis are better understood. The Schwann cell was discovered to be the cell of origin for neurofibromas, but understanding of a more complicated interplay of multiple cell types in tumorigenesis, specifically recruited heterogenous cell types such as mast cells and fibroblasts, has important implications for surgical therapy of these tumors. This review summarizes the most recent NF1 and neurofibroma literature describing the pathogenesis and treatment of nerve sheath tumors. Understanding the biological underpinnings of tumorigenesis in NF1 has implications for future surgical and medical management of neurofibromas

    Neurosurgical workforce trends in the United States

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    Journal ArticleObject. The purpose of this study was to evaluate the US neurosurgery workforce by reviewing journal recruitment advertisements published during the past 10 years. Methods. The number of available academic and private neurosurgical staff positions was determined based on recruitment advertisements in the Journal of Neurosurgery and Neurosurgery for the 10-year period from 1994 to 2003. Advertisements were evaluated for practice venue, subspecialization, and location. The numbers of active neurosurgeons and graduating residents also were reviewed. The number of advertised neurosurgical positions increased from 141.6 Ā± 38.2 per year from 1994 through 1998 to 282.4 Ā± 13.6 per year from 1999 through 2003 (mean 6 standard deviation, p < 0.05). The mean number of academic positions increased from 50.6 Ā± 11.1 to 95 Ā± 17.5 (p < 0.05), and the mean number of private positions rose from 91 Ā± 30.4 to 187.4 Ā± 6.8 (p < 0.05). Subspecialty positions represented a mean of only 15.6 Ā± 5% per year during the first time period and 18.8 Ā± 3% per year in the second period (p = 0.22), and therefore the majority of positions advertised continued to be those for generalists. The number of practicing neurosurgeons declined after 1998, and by 2002 it was less than it had been in 1991. The numbers of incoming and matriculating residents during the study period were static. Conclusions. The number of recruitment advertisements for neurosurgeons during the last 5 years has increased significantly, concomitant with a severe decline in the number of active neurosurgeons and a static supply of residents

    Trigeminal amyloidoma: case report and review of the literature

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    ManuscriptThe authors present a case of amyloid infiltration involving the trigeminal nerve that mimicked a malignant cavernous sinus tumor with perineural tumor infiltration. A 64-year-old man presented with trigeminal nerve numbness. Imaging revealed a plaque-like enhancing lesion along the right lateral cavernous sinus extending anteriorly into Meckel's cave and involving the proximal V2 and V3 trigeminal nerves. The patient underwent extradural frontotemporal craniotomy with middle fossa exposure of the cavernous sinus to diagnose and treat the presumed malignant cavernous sinus tumor. A reddish mass involving the lateral dural wall of the cavernous sinus was resected. There was also enlargement of the gasserian ganglion and second and third divisions of the trigeminal nerve, the latter of which was biopsied. Permanent histopathological studies demonstrated microscopic eosinophilic, amorphous material, which stained positive for Congo red, and absence of neoplastic cells. The final diagnosis was amyloidoma. Thus, amyloidomas may occur from the trigeminal nerve or ganglia and should be considered in the differential diagnosis of a cavernous sinus lesion mimicking a tumor. The few reports of trigeminal amyloidomas are reviewed and the presentation, imaging, and management of this skull base lesion are discussed. Overall, patients may have symptomatic improvement of trigeminal neuropathy with resection of the amyloidoma outside of the nerve capsule that is compressing the nerve, while resection of the lesion from within the capsule may result in permanent trigeminal nerve dysfunction

    Comparison of radiosurgery and conventional surgery for the treatment of glomus jugulare tumors

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    Journal ArticleObject. The optimal management of glomus jugulare tumors remains controversial. Available treatments were once associated with poor outcomes and significant complication rates. Advances in skull base surgery and the delivery of radiation therapy by stereotactic radiosurgery have improved the results obtained using these treatment options. The authors summarize and compare the contemporary outcomes and complications for these therapies. Methods. Papers published between 1994 and 2004 that detailed the use of radiosurgery or surgery to treat glomus jugulare tumors were reviewed. Eight radiosurgery series including 142 patients and seven surgical studies including 374 patients were evaluated for neurological outcome, change in tumor size (radiosurgery) or percent of total resection (surgery), recurrences, tumor control, need for further treatment, and complications. The mean age at treatment for patients who underwent surgery and radiosurgery was 47.3 and 56.7 years, respectively. The mean follow-up duration was 49.2 and 39.4 months, respectively. The surgical control rate was 92.1%, with 88.2% of tumors totally resected in the initial surgery. A cerebrospinal fluid leak occurred in 8.3% of patients who underwent surgery and recurrences were found in 3.1%; the mortality rate was 1.3%. Among patients who underwent radiosurgery, tumors diminished in 36.5%, whereas 61.3% had no change in tumor size, and subjective or objective improvements occurred in 39%. Despite the presence of residual tumor in 100% of radiosurgically treated patients, recurrences were found in only 2.1%, the morbidity rate was 8.5%, and there were no deaths. Conclusions. Death and recurrences after these treatments are infrequent, and therefore both treatments are considered to be safe and efficacious. Although surgery is associated with higher morbidity rates, it immediately and totally eliminates the tumor. The radiosurgery results are very promising, although the incidence of late recurrence (after 10-20 years) is unknown

    Distal ventriculoperitoneal shunt failure secondary to Clostridium Difficile Colitis

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    Journal ArticleDistal ventriculoperitoneal shunt obstruction is typically associated with cerebrospinal fluid (CSF) infection, fluid pseudocysts, bowel obstruction, bowel perforation, or improper shunt placement in the abdomen. We describe a unique etiology for distal shunt obstruction secondary to Clostridium difficile pancolitis that occurred because of inflammation and ascites, which led to incomplete drainage and absorption of CSF. This case illustrates the importance of considering distal shunt obstruction in a patient with signs of abdominal pathology in the setting of mental status changes, and the effective treatment of this patient initially with distal catheter externalization followed by internalization of a new distal catheter after resolution of the pancoliti

    Triggering information by context

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    With the increased availability of personal computers with attached sensors to capture their environment, there is a big opportunity for context-aware applications; these automatically provide information and/or take actions according to the user's present context, as detected by sensors. When wel l designed, these applications provide an opportunity to tailor the provision of information closely to the user's current needs. A sub-set of context-a ware applications are discrete applications, where discrete pieces of i nformation are attached to individual contexts, to be triggered when the user enters those contexts. The advantage of discrete applications is that authori ng them can be solely a creative process rather than a programming process: it can be a task akin to creating simple web pages. This paper looks at a general system that can be used in any discrete context- aware application. It propounds a general triggering rule, and investigates how this rule applies in practical applications

    E-MCTS: Deep Exploration in Model-Based Reinforcement Learning by Planning with Epistemic Uncertainty

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    One of the most well-studied and highly performing planning approaches used in Model-Based Reinforcement Learning (MBRL) is Monte-Carlo Tree Search (MCTS). Key challenges of MCTS-based MBRL methods remain dedicated deep exploration and reliability in the face of the unknown, and both challenges can be alleviated through principled epistemic uncertainty estimation in the predictions of MCTS. We present two main contributions: First, we develop methodology to propagate epistemic uncertainty in MCTS, enabling agents to estimate the epistemic uncertainty in their predictions. Second, we utilize the propagated uncertainty for a novel deep exploration algorithm by explicitly planning to explore. We incorporate our approach into variations of MCTS-based MBRL approaches with learned and provided dynamics models, and empirically show deep exploration through successful epistemic uncertainty estimation achieved by our approach. We compare to a non-planning-based deep-exploration baseline, and demonstrate that planning with epistemic MCTS significantly outperforms non-planning based exploration in the investigated deep exploration benchmark.Comment: Submitted to NeurIPS 2023, accepted to EWRL 202
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