3,817 research outputs found

    LONG TERM RESULTS OF HEPATIC TRANSPLANTATION DURING THE CYCLOSPORINE ERA: THE PITTSBURGH EXPERIENCE.

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    We have reviewed the long term results of the first 500 liver transplant recipients performed by our group during the cyclosporine era. Three hundred and forty-nine recipients lived (69.8%) more than 1 year and the projected 5 year actuarial survival for this sub-group of patients is 88%. The two most common causes of graft dysfunction after the first year were recurrence of the original disease, usually malignancy, and chronic rejection. Most episodes of rejection can be controlled with medical treatment; however, 16 patients of 34 patients who experienced rejection episodes after the first year required retransplantation. Eleven of these 16 are currently alive and free of jaundice. Another common cause of late graft dysfunction is biliary strictures. The recognized side effects of cyclosporine such as nephrotoxicity and lymphoproliferative disease have been lesser problems as a result of the judicious use of the drug. The quality of life of long term survivors is excellent

    Effect of 3-Dimensional Virtual Reality Models for Surgical Planning of Robotic-Assisted Partial Nephrectomy on Surgical Outcomes: A Randomized Clinical Trial.

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    Importance: Planning complex operations such as robotic-assisted partial nephrectomy requires surgeons to review 2-dimensional computed tomography or magnetic resonance images to understand 3-dimensional (3-D), patient-specific anatomy. Objective: To determine surgical outcomes for robotic-assisted partial nephrectomy when surgeons reviewed 3-D virtual reality (VR) models during operative planning. Design, Setting, and Participants: A single-blind randomized clinical trial was performed. Ninety-two patients undergoing robotic-assisted partial nephrectomy performed by 1 of 11 surgeons at 6 large teaching hospitals were prospectively enrolled and randomized. Enrollment and data collection occurred from October 2017 through December 2018, and data analysis was performed from December 2018 through March 2019. Interventions: Patients were assigned to either a control group undergoing usual preoperative planning with computed tomography and/or magnetic resonance imaging only or an intervention group where imaging was supplemented with a 3-D VR model. This model was viewed on the surgeon\u27s smartphone in regular 3-D format and in VR using a VR headset. Main Outcomes and Measures: The primary outcome measure was operative time. It was hypothesized that the operations performed using the 3-D VR models would have shorter operative time than those performed without the models. Secondary outcomes included clamp time, estimated blood loss, and length of hospital stay. Results: Ninety-two patients (58 men [63%]) with a mean (SD) age of 60.9 (11.6) years were analyzed. The analysis included 48 patients randomized to the control group and 44 randomized to the intervention group. When controlling for case complexity and other covariates, patients whose surgical planning involved 3-D VR models showed differences in operative time (odds ratio [OR], 1.00; 95% CI, 0.37-2.70; estimated OR, 2.47), estimated blood loss (OR, 1.98; 95% CI, 1.04-3.78; estimated OR, 4.56), clamp time (OR, 1.60; 95% CI, 0.79-3.23; estimated OR, 11.22), and length of hospital stay (OR, 2.86; 95% CI, 1.59-5.14; estimated OR, 5.43). Estimated ORs were calculated using the parameter estimates from the generalized estimating equation model. Referent group values for each covariate and the corresponding nephrometry score were summed across the covariates and nephrometry score, and the sum was exponentiated to obtain the OR. A mean of the estimated OR weighted by sample size for each nephrometry score strata was then calculated. Conclusions and Relevance: This large, randomized clinical trial demonstrated that patients whose surgical planning involved 3-D VR models had reduced operative time, estimated blood loss, clamp time, and length of hospital stay. Trial Registration: ClinicalTrials.gov identifiers (1 registration per site): NCT03334344, NCT03421418, NCT03534206, NCT03542565, NCT03556943, and NCT03666104

    Deterministic Sampling and Range Counting in Geometric Data Streams

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    We present memory-efficient deterministic algorithms for constructing epsilon-nets and epsilon-approximations of streams of geometric data. Unlike probabilistic approaches, these deterministic samples provide guaranteed bounds on their approximation factors. We show how our deterministic samples can be used to answer approximate online iceberg geometric queries on data streams. We use these techniques to approximate several robust statistics of geometric data streams, including Tukey depth, simplicial depth, regression depth, the Thiel-Sen estimator, and the least median of squares. Our algorithms use only a polylogarithmic amount of memory, provided the desired approximation factors are inverse-polylogarithmic. We also include a lower bound for non-iceberg geometric queries.Comment: 12 pages, 1 figur

    Impacts of Openness

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    This is the recording from the Impacts of Openness lightning talk session that was held on Friday, October 25, 2013, from 10:00 a.m. - noon in Watson Library, room 455 during the KU Libraries' celebration of Open Access Week.This event brings together several speakers from a variety of fields, each of whom will give a 10-minute presentation about the impact of openness in their work. More information about this event is available at http://openaccess.ku.edu/impacts-openness-lightning-talks-october-25

    Effect of partial portal vein ligation on hepatic regeneration

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    To evaluate the effect of portal hypertension and diminished portal venous blood flow to the liver on hepatic regeneration, male rats were subjected to partial portal vein ligation and subsequently to a two-thirds partial hepatectomy. The levels of ornithine decarboxylase activity at 6 h after partial hepatectomy were greater (p > 0.001) in the rats with prior partial portal vein ligation than in those without portal hypertension. The rats with prior partial portal vein ligation also had greater (p > 0.005) levels of thymidine kinase activity at 48 h after partial hepatectomy than did those without portal hypertension. Hepatic sex hormone receptor activity was not affected by prior partial portal vein ligation either before or after partial hepatectomy. The reductions in both estrogen and androgen receptor activity observed in the hepatic cytosol after partial hepatectomy were similar to those observed in control animals. These data indicate that animals with portal hypertension having a diminished hepatic portal blood flow have a normal capacity to regenerate hepatic mass following a hepatic resection © 1988 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted

    Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment

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    The OLYMPUS collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R2ÎłR_{2\gamma}, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ≈20°\approx 20\degree to 80°80\degree. The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved GEM and MWPC detectors at 12°12\degree, as well as symmetric M{\o}ller/Bhabha calorimeters at 1.29°1.29\degree. A total integrated luminosity of 4.5~fb−1^{-1} was collected. In the extraction of R2ÎłR_{2\gamma}, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of R2ÎłR_{2\gamma}, presented here for a wide range of virtual photon polarization 0.456<Ï”<0.9780.456<\epsilon<0.978, are smaller than some hadronic two-photon exchange calculations predict, but are in reasonable agreement with a subtracted dispersion model and a phenomenological fit to the form factor data.Comment: 5 pages, 3 figures, 2 table

    Three-Dimensional Dual-Energy Computed Tomography for Enhancing Stone/Stent Contrasting and Stone Visualization in Urolithiasis

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    The use of dual-energy computed tomography (DECT) for evaluating urinary calculi has been appreciated due to the modality's capability of differentiating between uric acid (UA) and non-UA stones, which are color coded based on a postprocessing algorithm. No other imaging modality or laboratory test is able to identify the stone composition without first attaining the stone material. Knowledge of the stone composition is clinically significant since UA calculi may be treated medically whereas non-UA calculi may require surgical removal. Regardless of the stone type, ureteral stents are often placed to prevent or treat obstruction. Recent work has demonstrated that commonly used stents are also colored based on their dual energy characteristics and may thereby either improve or obscure the identification of adjacent calculi. Herein, we report the case of a 65-year-old man who underwent percutaneous nephrolithotomy of a large staghorn stone with subsequent significant residual stone fragments noted on a follow-up scan. By using three-dimensional DECT and taking advantage of color contrasting, the stone composition, burden, shape, and boundary were clearly depicted apart from the adjacent stent, resulting in successful medical treatment and obviating the need for further surgical intervention

    Occurrence of cytomegalovirus hepatitis in liver transplant patients

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    The differential diagnosis of liver dysfunction after orthotopic liver transplantation can be difficult. Cytomegalovirus (CMV) hepatitis is one possibility. This report reviews our experience with 17 cases of pathologically proven CMV hepatitis following liver transplantation and demonstrates the need for percutaneous liver biopsies to establish the diagnosis. There were seven pediatric patients (ages 2–11 years, five males, two females) and ten adult patients (ages 17–53 years, eight males, two females). The most common symptoms were prolonged fever (15 patients, with a mean duration of 22 ± 5.5 days), elevation in total bilirubin (14 patients), and elevation in liver enzymes (15 patients); all symptoms were also found in rejection. Leukopenia and thrombocytopenia, reported to frequently occur with CMV infection, were found in only three and five patients, respectively. Twelve patients with the above symptoms underwent percutaneous biopsy on one or more occasions to differentiate CMV hepatitis from rejection. The diagnosis was made at retransplantation in five patients. CMV hepatitis followed treatment for acute rejection in 14 patients and occurred without additional immunosuppression in three patients. All patients were maintained on cyclosporine and prednisone. Acute rejection episodes were treated with a 5‐day tapering dose of steroids (17 courses in 12 patients), OKT3 monoclonal antibody [Ortho (4 patients)] antithymocyte globulin [Upjohn (2 patients)], and azathioprine (1 patient). CMV was isolated from urine (nine patients), blood (nine patients), throat (seven patients), lungs (two patients), and other organs (two patients). CMV was cultured from the liver biopsy specimens in five of the seven attempts in pediatric patients. When the diangosis was confirmed in the absence of rejection, immunosuppression was routinely lowered. When rejection occurred concomitantly with CMV hepatitis, therapy had to be individualized. Retrospectively, three patients treated for rejection were noted at retransplantation to have only CMV hepatitis, and all three paients died. A high index of suspicion and the judicioususe of liver bopsies is essential in order to differentiate CMV hepatitis from other causes of posttransplant liver dysfunction. Copyright © 1988 Wiley‐Liss, Inc., A Wiley Compan
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