Combining Contrast Invariant L1 Data Fidelities with Nonlinear Spectral Image Decomposition

This paper focuses on multi-scale approaches for variational methods and corresponding gradient flows. Recently, for convex regularization functionals such as total variation, new theory and algorithms for nonlinear eigenvalue problems via nonlinear spectral decompositions have been developed. Those methods open new directions for advanced image filtering. However, for an effective use in image segmentation and shape decomposition, a clear interpretation of the spectral response regarding size and intensity scales is needed but lacking in current approaches. In this context, $L^1$ data fidelities are particularly helpful due to their interesting multi-scale properties such as contrast invariance. Hence, the novelty of this work is the combination of $L^1$-based multi-scale methods with nonlinear spectral decompositions. We compare $L^1$ with $L^2$ scale-space methods in view of spectral image representation and decomposition. We show that the contrast invariant multi-scale behavior of $L^1-TV$ promotes sparsity in the spectral response providing more informative decompositions. We provide a numerical method and analyze synthetic and biomedical images at which decomposition leads to improved segmentation.Comment: 13 pages, 7 figures, conference SSVM 201

Production of a Discrete, Infectious, Double-stranded DNA by Reverse Transcription in Virions of Moloney Murine Leukemia Virus

One of the most unique viral replication schemes is that of the retroviruses (a class that includes the RNA tumor viruses). These viruses synthesize a double-stranded (DS) DNA copy of their single-stranded (SS) RNA genome as the initial event following infection of susceptible cells (see Weinberg 1977). The details of this process—called reverse transcription—are still obscure, but the general outlines have become clear during the last few years

Light with tunable non-Markovian phase imprint

We introduce a simple and flexible method to generate spatially non-Markovian light with tunable coherence properties in one and two dimensions. The unusual behavior of this light is demonstrated experimentally by probing the far field and recording its diffraction pattern after a double slit: In both cases we observe instead of a central intensity maximum a line or cross shaped dark region, whose width and profile depend on the non-Markovian coherence properties. Since these properties can be controlled and easily reproduced in experiment, the presented approach lends itself to serve as a testbed to gain a deeper understanding of non-Markovian processes

Improving results of pediatric renal transplantation

BACKGROUND: Outcome after renal transplantation in children has been variable. We undertook a retrospective study of our experience over the past five years. STUDY DESIGN: From January 1, 1988, to October 15, 1992, 60 renal transplantations were performed upon 59 children at the Children's Hospital of Pittsburgh. Twenty-eight (47 percent) of the kidneys were from cadaveric donors, and 32 (53 percent) were from living donors. The recipients ranged in age from 0.8 to 17.4 years, with a mean of 9.8 ± 4.8 years. Forty-six (77 percent) recipients were undergoing a first transplant, while 14 (23 percent) received a second or third transplant. Eight (13 percent) of the patients were sensitized, with a panel reactive antibody of more than 40 percent. Eleven of the 14 patients undergoing retransplantation and seven of the eight patients who were sensitized received kidneys from cadaveric donors. Thirty- three (55 percent) patients received cyclosporine-based immunosuppression, and 27 (45 percent) received FK506 as the primary immunosuppressive agent. RESULTS: The median follow-up period was 36 months, with a range of six to 63 months. The one- and four-year actuarial patient survival rate was 100 and 98 percent. The one- and four-year actuarial graft survival rate was 98 and 83 percent. For living donor recipients, the one- and four-year actuarial patient survival rate was 100 and 100 percent; for cadaveric recipients, it was 100 and 96 percent. Corresponding one- and four-year actuarial graft survival rates were 100 and 95 percent for the living donor recipients and 96 and 69 percent for the cadaveric recipients. Patients on cyclosporine had a one- and four-year patient survival rate of 100 and 97 percent, and patients on FK506 had a one- and three-year patient survival rate of 100 and 100 percent. Corresponding one- and four-year actuarial graft survival rates were 100 and 85 percent in the cyclosporine group, while one- and three-year actuarial graft survival rates were 96 and 84 percent in the FK506 group. The mean serum creatinine level was 1.24 ± 0.64 mg per dL; the blood urea nitrogen level was 26 ± 13 mg per dL. The incidence of rejection was 47 percent; 75 percent of the rejections were steroid-responsive. The incidence of cytomegalovirus was 10 percent. The incidence of post-transplant lymphoproliferative disorder was 8 percent. None of the patients on cyclosporine were able to be taken off prednisone; 56 percent of the patients receiving FK506 were taken off prednisone successfully. Early growth and development data suggest that the patients receiving FK506 off prednisone had significant gains in growth. CONCLUSIONS: These results support the idea that renal transplantation is a successful therapy for end-stage renal disease in children. They also illustrate the potential benefits of a new immunosuppressive agent, FK506

FK506 IN PEDIATRIC KIDNEY-TRANSPLANTATION - PRIMARY AND RESCUE EXPERIENCE

Between December 14, 1989, and December 17, 1993,43 patients undergoing kidney transplantation alone at the Children’s Hospital of Pittsburgh received FK506 as the primary immunosuppressive agent. The mean recipient age was 10.2 ± 4.8 years (range 0.7–17.4), with 7 (16%) children under 5 years of age and 2 (5%) under 2 years of age. Fifteen (35%) children underwent retransplantation, and 5 (12%) had a panel reactive antibody level greater than 40%. Twenty-two (51%) cases were with cadaveric donors, and 21 (49%) were with living donors. The mean follow-up is 25 ± 14 months. There were no deaths. One and three year actuarial graft survival was 98% and 85%. The mean serum creatinine and BUN were 1.2 ± 0.6 mg/dl and 26 ± 11 mg/dl; the calculated creatinine clearance was 75 ± 23 ml/min/1.73 m(2). Twenty-four (62%) patients have been successfully withdrawn from steroids, and 24 (62%) require no anti-hypertensive medication. Improved growth was seen, particularly in pre-adolescent children off steroids. Between July 28, 1990, and December 2, 1993, 24 children were referred for rescue therapy with FK506, 14.6 ± 16.4 months (range 1.1–53.2) after transplantation. Nineteen (79%) were referred because of resistant rejection; 4 (17%) were referred because of proteinuria; 1 (4%) was switched because of steroid-related obesity. There were no deaths. One and two year graft survival was 75% and 68%. Seventeen (71%) patients were successfully rescued, including 1 of 2 patients who arrived on dialysis. Four (24%) of the successfully rescued patients were weaned off steroids. While not without side effects, which include nephrotoxicity, neurotoxicity, diabetogenicity, and viral complications, FK506 appears to be an effective immunosuppressive agent for both primary and rescue therapy after kidney transplantation. Its steroid-sparing qualities may be of particular importance in the pediatric population

Tacrolimus in pediatric renal transplantation

Tacrolimus was used as the primary immunosuppressive agent in 69 pediatric renal transplantations between December 17, 1989, and June 30, 1995. Children undergoing concomitant or prior liver and/or intestinal transplantation were excluded from analysis. The mean recipient age was 10.3±5.0 years (range, 0.7-17.5 years). Seventeen (24.6%) children were undergoing retransplantation, and six (8.7%) had a panel reactive antibody level of 40% or higher. Thirty-nine (57%) cases were with cadaveric kidneys, and 30 (43%) were with living donors. The mean donor age was 28.0±14.7 years (range, 1.0-50.0 years), and the mean cold ischemia time for the cadaveric kidneys was 27.0±9.4 hr. The antigen match was 2.7±1.2, and the mismatch was 3.1±1.2. All patients received tacrolimus and steroids, without antibody induction, and 26% received azathioprine as well. The mean follow-up was 32±20 months. One- and 4-year actuarial patient survival rates were 100% and 95%. One- and 4-year actuarial graft survival rates were 99% and 85%. The mean serum creatinine level was 1.2±0.8 mg/dl, and the calculated creatinine clearance was 82±26 ml/min/1.73 m2. The mean tacrolimus dose was 0.22±0.14 mg/kg/day, and the level was 9.5±4.8 ng/ml. The mean prednisone dose was 2.1±4.9 mg/day (0.07±0.17 mg/kg/day), and 73% of successfully transplanted children were off prednisone. Seventy-nine percent were not taking any antihypertensive medications. The mean serum cholesterol level was 158±54 mg/dl. The incidence of delayed graft function was 4.3%. The incidence of rejection was 49%, and the incidence of steroid-resistant rejection was 6%. The incidence of rejection decreased to 27% in the most recent 26 cases (January 1994 through June 1995). The incidence of new-onset diabetes was 10.1%; six of the seven affected children were able to be weaned off insulin. The incidence of cytomegalovirus disease was 13%, and that of posttransplant lymphoproliferative disorder was 10%; the incidence of posttransplant lymphoproliferative disorder in the last 40 transplants was 5% (two cases). All of the children who developed posttransplant lymphoproliferative disorder are alive and have functioning allografts. Based on this data, we believe that tacrolimus is a superior immunosuppressive agent in pediatric renal transplant patients, with excellent short- and medium-term patient and graft survival, an ability to withdraw steroids in the majority of patients, and, with more experience, a decreasing rate of rejection and vital complications

Which trial do we need? How to treat Pseudomonas aeruginosa bacteraemia—proposal for an umbrella randomized controlled trial

Pseudomonas aeruginosa bacteraemia is a common and severe condition. The prevalence of P. aeruginosa bacteraemia varies depending on the population and setting. In hospital settings, estimations show that it is the cause of approximately 6% of all bloodstream infections and 24% of gram-negative bloodstream infections. In intensive care units, the prevalence is even higher, with estimates ranging from 10% to 15%. The mortality rate associated with P. aeruginosa bacteraemia is high, estimated at approximately 30%, and is higher than that associated with other bacteria causing bloodstream infections