3,597 research outputs found
Surgical management of giant Brunner's gland hamartoma: case report and literature review
Brunner's gland hamartomas (BGH) are uncommon benign tumors of the duodenum forming mature Brunner's glands. We report here an unusual case of a giant BGH that was not amenable to endoscopic or surgical local resection thus requiring a pancreaticoduodenectomy for extirpation. The relevant literature is discussed
Phylogeography of the Central American lancehead Bothrops asper (SERPENTES: VIPERIDAE)
The uplift and final connection of the Central American land bridge is considered the major event that allowed biotic exchange between vertebrate lineages of northern and southern origin in the New World. However, given the complex tectonics that shaped Middle America, there is still substantial controversy over details of this geographical reconnection, and its role in determining biogeographic patterns in the region. Here, we examine the phylogeography of Bothrops asper, a widely distributed pitviper in Middle America and northwestern South America, in an attempt to evaluate how the final Isthmian uplift and other biogeographical boundaries in the region influenced genealogical lineage divergence in this species. We examined sequence data from two mitochondrial genes (MT-CYB and MT-ND4) from 111 specimens of B. asper, representing 70 localities throughout the species' distribution. We reconstructed phylogeographic patterns using maximum likelihood and Bayesian methods and estimated divergence time using the Bayesian relaxed clock method. Within the nominal species, an early split led to two divergent lineages of B. asper: one includes five phylogroups distributed in Caribbean Middle America and southwestern Ecuador, and the other comprises five other groups scattered in the Pacific slope of Isthmian Central America and northwestern South America. Our results provide evidence of a complex transition that involves at least two dispersal events into Middle America during the final closure of the Isthmus
Adult Pancreatic Hemangioma: Case Report and Literature Review
We report an adult pancreatic hemangioma diagnosed on pathological specimen review following pylorus preserving pancreaticoduodenectomy for a symptomatic cystic mass in the head of the pancreas. Eight cases of adult pancreatic hemangioma have been reported in literature since 1939. Presenting symptoms, radiographic diagnosis, pathologic characteristics, and treatment of adult pancreatic hemagiomas are discussed following review of all published cases
BRCA2 secondary mutation-mediated resistance to platinum and PARP inhibitor-based therapy in pancreatic cancer
Background: Pancreatic cancer has become the third leading cause of cancer death with minimal improvements in outcome for
over 40 years. Recent trials of therapies that target-defective DNA maintenance using poly (ADP-ribose) polymerase (PARP)
inhibitors are showing promising results, yet invariably patients recur and succumb to disease. Mechanisms of resistance to
platinum-based and PARP inhibitor therapy in other cancer types include secondary mutations, which restore the integrity of DNA
repair through an increasing number of different mechanisms.
Methods: Here we present a case of a 63-year-old female patient with a germ line pathogenic BRCA2 mutation (6714 deletion)
who developed pancreatic cancer and had an exceptional response to platinum and PARP inhibitor therapy. Through nextgeneration
sequencing and clinical follow-up, we correlated tumour response and resistance to the BRCA2 mutational status in
the tumour.
Results: Initially, the patient had an exceptional response to platinum and PARP inhibitor therapy, most likely due to the BRCA2
mutation. However, the primary lesion recurred while on PARP inhibitor therapy and contained a secondary mutation in BRCA2,
which mostly likely restored BRCA2 function in PARP inhibitor-resistant tumour cells.
Conclusions: To our knowledge, this is the first report of a BRCA2 reversion mutation that conferred resistance to PARP inhibitorbased
therapy in a pancreatic ductal adenocarcinoma patient. Future studies are needed to understand this important mechanism
of resistance and how it may impact the choice of therapy for patients with pancreatic cancer
Association between abdominal adiposity and subclinical measures of left-ventricular remodeling in diabetics, prediabetics and normal controls without history of cardiovascular disease as measured by magnetic resonance imaging: results from the KORA-FF4 Study
Objectives: Local, abdominal fat depots may be related to alterations in cardiac function and morphology due to a metabolic linkage. Thus, we aimed to determine their association with subtle cardiac changes and the potential interaction with hyperglycemic metabolic states.
Methods: Subjects from the general population and without history of cardiovascular disease were drawn from the Cooperative Health Research in the Region of Augsburg FF4 cohort and underwent 3 T cardiac and body MRI. Measures of abdominal adiposity such as hepatic proton-density fat fraction [PDFFhepatic], subcutaneous (SAT) and visceral abdominal fat (VAT) as well as established cardiac left-ventricular (LV) measures including LV remodeling index (LVCI) were derived. Associations were determined using linear regression analysis based on standard deviation normalized predictors.
Results: Among a total of 374 subjects (56.2 ± 9.1 years, 58% males), 49 subjects had diabetes, 99 subjects had prediabetes and 226 represented normal controls. Only subtle cardiac alterations were observed (e.g. LVCI: 1.13 ± 0.30). While SAT was not associated, increasing VAT and increasing PDFFhepatic were independently associated with increasing LVCI (β = 0.11 and 0.06, respectively), decreasing LV end-diastolic volume (β = − 6.70 and 3.23, respectively), and decreasing LV stroke volume (β = − 3.91 and − 2.20, respectively). Hyperglycemic state did not modify the associations between VAT or PDFF and LV measures (interaction term: all p ≥ 0.29).
Conclusion: In a healthy population, VAT but also PDFFhepatic were associated with subclinical measures of LV remodeling without evidence for a modifying effect of hyperglycemic state
Structure of the Current Sheet in the 11 July 2017 Electron Diffusion Region Event.
The structure of the current sheet along the Magnetospheric Multiscale (MMS) orbit is examined during the 11 July 2017 Electron Diffusion Region (EDR) event. The location of MMS relative to the X-line is deduced and used to obtain the spatial changes in the electron parameters. The electron velocity gradient values are used to estimate the reconnection electric field sustained by nongyrotropic pressure. It is shown that the observations are consistent with theoretical expectations for an inner EDR in 2-D reconnection. That is, the magnetic field gradient scale, where the electric field due to electron nongyrotropic pressure dominates, is comparable to the gyroscale of the thermal electrons at the edge of the inner EDR. Our approximation of the MMS observations using a steady state, quasi-2-D, tailward retreating X-line was valid only for about 1.4 s. This suggests that the inner EDR is localized; that is, electron outflow jet braking takes place within an ion inertia scale from the X-line. The existence of multiple events or current sheet processes outside the EDR may play an important role in the geometry of reconnection in the near-Earth magnetotail
Proteins associated with pancreatic cancer survival in patients with resectable pancreatic ductal adenocarcinoma.
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease with a dismal prognosis. However, while most patients die within the first year of diagnosis, very rarely, a few patients can survive for >10 years. Better understanding the molecular characteristics of the pancreatic adenocarcinomas from these very-long-term survivors (VLTS) may provide clues for personalized medicine and improve current pancreatic cancer treatment. To extend our previous investigation, we examined the proteomes of individual pancreas tumor tissues from a group of VLTS patients (survival ≥10 years) and short-term survival patients (STS, survival <14 months). With a given analytical sensitivity, the protein profile of each pancreatic tumor tissue was compared to reveal the proteome alterations that may be associated with pancreatic cancer survival. Pathway analysis of the differential proteins identified suggested that MYC, IGF1R and p53 were the top three upstream regulators for the STS-associated proteins, and VEGFA, APOE and TGFβ-1 were the top three upstream regulators for the VLTS-associated proteins. Immunohistochemistry analysis using an independent cohort of 145 PDAC confirmed that the higher abundance of ribosomal protein S8 (RPS8) and prolargin (PRELP) were correlated with STS and VLTS, respectively. Multivariate Cox analysis indicated that 'High-RPS8 and Low-PRELP' was significantly associated with shorter survival time (HR=2.69, 95% CI 1.46-4.92, P=0.001). In addition, galectin-1, a previously identified protein with its abundance aversely associated with pancreatic cancer survival, was further evaluated for its significance in cancer-associated fibroblasts. Knockdown of galectin-1 in pancreatic cancer-associated fibroblasts dramatically reduced cell migration and invasion. The results from our study suggested that PRELP, LGALS1 and RPS8 might be significant prognostic factors, and RPS8 and LGALS1 could be potential therapeutic targets to improve pancreatic cancer survival if further validated
Planetary Candidates Observed by Kepler. VII. The First Fully Uniform Catalog Based on The Entire 48 Month Dataset (Q1-Q17 DR24)
We present the seventh Kepler planet candidate catalog, which is the first to
be based on the entire, uniformly processed, 48 month Kepler dataset. This is
the first fully automated catalog, employing robotic vetting procedures to
uniformly evaluate every periodic signal detected by the Q1-Q17 Data Release 24
(DR24) Kepler pipeline. While we prioritize uniform vetting over the absolute
correctness of individual objects, we find that our robotic vetting is overall
comparable to, and in most cases is superior to, the human vetting procedures
employed by past catalogs. This catalog is the first to utilize artificial
transit injection to evaluate the performance of our vetting procedures and
quantify potential biases, which are essential for accurate computation of
planetary occurrence rates. With respect to the cumulative Kepler Object of
Interest (KOI) catalog, we designate 1,478 new KOIs, of which 402 are
dispositioned as planet candidates (PCs). Also, 237 KOIs dispositioned as false
positives (FPs) in previous Kepler catalogs have their disposition changed to
PC and 118 PCs have their disposition changed to FP. This brings the total
number of known KOIs to 8,826 and PCs to 4,696. We compare the Q1-Q17 DR24 KOI
catalog to previous KOI catalogs, as well as ancillary Kepler catalogs, finding
good agreement between them. We highlight new PCs that are both potentially
rocky and potentially in the habitable zone of their host stars, many of which
orbit solar-type stars. This work represents significant progress in accurately
determining the fraction of Earth-size planets in the habitable zone of
Sun-like stars. The full catalog is publicly available at the NASA Exoplanet
Archive.Comment: Accepted to the Astrophysical Journal Supplement Series. 30 pages, 9
figures, 7 tables. We make the DR24 robovetter decision code publicly
available at http://github.com/JeffLCoughlin/robovetter, with input and
output examples provided using the same data as contained in the full paper's
table
Probing the Substellar Regime with SIRTF
One of the main scientific drivers of the Space InfraRed Telescope Facility
(SIRTF) is the search for brown dwarfs and extrasolar superplanets. We discuss
observational strategies for identification of these objects, and conclude that
an optimal strategy is a wide IRAC survey (18 deg) with a 5
sensitivity of 3.9 Jy in channel 2 (M). For this sensitivity,
we provide estimates of the number of low mass brown dwarfs and isolated
planets detected per square degree for power-law mass functions with
=1.5, and 1.0. Shallower surveys covering a larger area are inefficient
because of large overheads and detector noise. Deeper surveys covering a
smaller area become more and more affected by crowding with galaxies. A survey
like the one that we propose would determine the field mass function down to a
few Jupiter masses through the identification of a large sample of brown dwarfs
and isolated planets. The proposed SIRTF survey would also allow the first
detection of ultracool substellar objects with temperatures between 700 K and
200 K. The cooling curves of substellar objects with masses less than 20
Jupiters imply that they should spend most of their lifetimes at temperatures
below 700 K. Preliminary models indicate that their atmospheres could be
dominated by water clouds, which would diminish their optical and near-infrared
fluxes. The properties of those objects are still completely unexplored.Comment: 7 pages, 6 figures, submitted to PAS
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