Statistical Emulation of Neural Simulators: Application to Neocortical L2/3 Large Basket Cells.

Many scientific systems are studied using computer codes that simulate the phenomena of interest. Computer simulation enables scientists to study a broad range of possible conditions, generating large quantities of data at a faster rate than the laboratory. Computer models are widespread in neuroscience, where they are used to mimic brain function at different levels. These models offer a variety of new possibilities for the neuroscientist, but also numerous challenges, such as: where to sample the input space for the simulator, how to make sense of the data that is generated, and how to estimate unknown parameters in the model. Statistical emulation can be a valuable complement to simulator-based research. Emulators are able to mimic the simulator, often with a much smaller computational burden and they are especially valuable for parameter estimation, which may require many simulator evaluations. This work compares different statistical models that address these challenges, and applies them to simulations of neocortical L2/3 large basket cells, created and run with the NEURON simulator in the context of the European Human Brain Project. The novelty of our approach is the use of fast empirical emulators, which have the ability to accelerate the optimization process for the simulator and to identify which inputs (in this case, different membrane ion channels) are most influential in affecting simulated features. These contributions are complementary, as knowledge of the important features can further improve the optimization process. Subsequent research, conducted after the process is completed, will gain efficiency by focusing on these inputs.

Iliopsoas Mass, Hydroureter, and Back Squats: Using Biomechanics and Diagnostic Persistence to Diagnose a Germ Cell Tumor.

Background: Lesions in the iliopsoas compartment carry a broad differential diagnosis, including infection, tumor, or hematoma, and less commonly, retroperitoneal fibrosis, atrophy secondary to paralysis or muscle disease, foreign body, calcifications secondary to trauma, or rhabdomyolysis. Iliopsoas lesions are oftentimes accompanied by nonspecific symptoms, resulting in a delayed diagnosis. Case Report: We present the case of a 43-year-old male with acute radiating groin pain who was found to have a traumatic iliopsoas hemorrhagic lesion causing ureteral compression and ureteral dilatation, all presumably originating from a new-onset weight-training program. The patient had a drain placed for fluid removal and decompression, with the initial pathologic specimen confirming muscle fibers and an inflammatory process. Further patient symptomology with combined imaging and pathologic persistence yielded a diagnosis of a germ cell tumor. Conclusion: The importance of a plausible differential diagnosis combined with clinical diagnostic persistence must be stressed to all clinicians. Our patient's unrelenting inguinal pain led to a justified repeat psoas mass biopsy, imaging, and laboratory workup that led to a diagnosis of psoas germ cell tumor and immediate chemotherapy plan.

Concise review on the comparative efficacy of endoscopic ultrasound-guided fine-needle aspiration vs core biopsy in pancreatic masses, upper and lower gastrointestinal submucosal tumors.

Endoscopic ultrasound (EUS)-guided fine needle aspiration with or without biopsy (FNA/FNB) are the primary diagnostic tools for gastrointestinal submucosal tumors. EUS-guided fine needle aspiration (EUS-FNA) is considered a first line diagnostic method for the characterization of pancreatic and upper gastrointestinal lesions, since it allows for the direct visualization of the collection of specimens for cytopathologic analysis. EUS-FNA is most effective and accurate when immediate cytologic assessment is permitted by the presence of a cytopathologist on site. Unfortunately, the accuracy and thus the diagnostic yield of collected specimens suffer without this immediate analysis. Recently, a EUS-FNB needle capable of obtaining core samples (fine needle biopsy, FNB) has been developed and has shown promising results. This new tool adds a new dimension to the diagnostic and therapeutic utility of this technique. The aim of the present review is to compare the efficacy of EUS-FNA to that afforded by EUS-FNB in the characterization of pancreatic masses and of upper and lower gastrointestinal submucosal tumors.

A review article on gastric varices with focus on the emerging role of endoscopic ultrasound-guided angiotherapy.

BACKGROUND: Gastric varices (GV) manifest in almost one-fifth of the patients with portal hypertension. Although primary pharmacological prevention of esophageal varices has been identified, there are limited therapeutic options that are optimal for GV bleeding. Recently, the use of endoscopic ultrasound (EUS)-guided angiotherapy [cyanoacrylate (CA) and coils] was introduced for the treatment of GV. Although CA injection is the recommended first-line therapeutic modality, it is associated with systemic, life-threatening embolization as well as technical instrumental challenges. Recently, EUS-guided coiling for GV was used with high safety profile. METHODS: This is a review of the current literature on the treatment of GV, focusing on the role of EUS-guided angiotherapy in the treatment of GV. We performed a Medline/PubMed search, and 37 relevant studies were extracted and examined. RESULTS: EUS-guided angiotherapy has shown a consistent favorable result among the several reports throughout the literature, with better safety and efficacy profile toward EUS-guided coiling; however, a combination treatment with EUS-guided coiling followed by glue injection has shown as well to reduce the embolization adverse events associated with glue injection. CONCLUSION: EUS-guided angiotherapy and specifically EUS-guided coiling is an emerging promising technique and should be considered as a first-line therapeutic option for bleeding GV.

Endoscopic Ultrasound-Guided Choledochoduodenostomy Using a Lumen-Apposing Metal Stent in Pancreatic Head Neoplasm-Associated Biliary Obstruction.

Endoscopic ultrasound (EUS)-guided transluminal drainage of obstructed bile duct with conventional metal and plastic stents has been in practice for several years, but this modality carries its own potential complications and obstacles. Nevertheless, the novel Hot AXIOS stent (Boston Scientific Corp., Marlborough, MA) has been shown to overcome some of those factors, which justifies its application in a variety of clinical indications, such as EUS-guided choledochoduodenostomy (EUS-CDS) for biliary drainage after failed endoscopic retrograde cholangiopancreatography. We present a case of EUS-CDS with an electrocautery enhanced lumen-apposing stent for biliary drainage.