1,005 research outputs found
Early death or retransplantation in adults after orthotopic liver transplantation: Can outcome be predicted?
Early, reliable outcome prediction after a liver transplant would help improve organ use by minimizing unnecessary retransplantations. At the same time, early intervention in those cases destined to fail may ameliorate the high morbidity and mortality associated with retransplantation. The purpose of this study was to analyze several parameters that have been identified in the past as being associated with patient and graft outcome, and to try to develop a model that would allow us to make predictions based on data available in the early postoperative period. A total of 148 patients were followed in a prospective, observational study. Graft failure was defined as patient death or retransplantation within 3 months of surgery. Preoperative variables studied included patient demographics, need for life support, presence of ascites, serum bilirubin, serum albumin, prothrombin time, serum creatinine, and the results of the cytotoxic crossmatch. During the first 5 postoperative days, standard measurements included serum transaminases, serum bilirubin, ketone body ratio, prothrombin time, factor V, and serum lactate. Oxygen consumption was measured shortly after surgery, once the patients had rewarmed to 36°C. There were 131 successful transplants (88.5%) and 17 failures (11.5%). Most of the variables studied were found to be associated with outcome (by univariate analysis) at different points in the early postoperative period. However, receiver operating characteristic curve analysis showed that the predictive ability of even the best parameter was not adequate to make decisions on individual patients. Multivariate analysis, using stepwise logistic regression, yielded a model with an overall accuracy of 92.7%. Again, receiver operating characteristic curve analysis suggested that this model did not achieve the discriminating power needed for routine clinical use. We are still not able to accurately predict outcome in the early posttransplant period. We must be very careful when evaluating parameters, or scoring systems, that are said to accomplish this. It is especially important in this era of cost containment, with its renewed pressures to guide therapy based on our perceived understanding of a patient’s future clinical course. © 1994 by Williams & Wilkins
The protective effect of FK506 pretreatment against renal ischemia/reperfusion injury in rats
The effect of pretreatment with FK506 on renal ischemia and reperfusion (I/R) injury was investigated using a rat model. Animals were assigned to one of two groups (20 rats each). Group 1 animals (controls) received 0.5 ml saline while group 2 animals received FK506 (0.3 mg/kg), administered intravenously 24 hr prior to the induction of renal ischemia. A 60-min period of ischemia of the right kidney was induced, and upon reperfusion a left nephrectomy was performed. Blood samples for estimation of BUN, creatinine, and tumor necrosis factor were collected on days 0 (preischemia), 1, 2, 3, 5, 7, and 10 (postischemia). Rats were sacrificed after day 10 and renal tissue was examined histologically. All animals survived the ischemic episode. FK506 pretreatment significantly reduced the serum levels of BUN (P<0.02), creatinine (P<0.02), and TNF (P<0.05) as compared with that seen in controls. Histologically, at day 10, the kidneys showed the expected sequelae of prior renal I/R with various degrees of tubular damage. However, no objective differences were evident between the two groups. Based upon these data, it can be concluded that (1) FK506 pretreatment ameliorates the functional renal injury associated with I/R, (2) renal ischemia induces the release of TNF, and (3) FK506 pretreatment results in a significant inhibition of TNF production. These data suggest that the release of TNF may be responsible for the increasing of BUN and creatinine levels seen after renal I/R and that pretreatment of renal donors with FK506 may improve renal function in the immediate post-transplant period. © 1992 by Williams and Wilkins
Fascículo IV. Vertebrata
El presente trabajo, como su nombre lo indica, responde al propósito de los que promovieron su realización desde la Comisión Científica de la Provincia de Buenos Aires, es decir, ofrecer fundamentalmente a los geólogos que trabajan en el campo un elemento bibliográfico con buena iconografía, que les hiciera accesible una primera determinación de los vertebrados fósiles para los fines estratigráficos que ellos manejan. No obstante, los autores han querido aprovechar la oportunidad de un trabajo de esta envergadura para ampliar un poco las diagnosis y llegar en casi todos los casos a categorías sistemáticas superiores al género, con el fin de transformar el trabajo en algo más que una simple Paleontografía ; la intención es facilitar el desarrollo de alguna vocación, o simplemente proveer un mayor número de elementos para aquéllos que no sólo se contentan con saber cuán antiguas son las rocas que contienen determinados fósiles, sino que desean adentrarse en el conocimiento y problemática de la paleozoología de los Vertebrados. Por otro lado, pocos —por no decir ninguno— son los libros en castellano donde pueden encontrarse condensados los datos aquí consignados, y bien valió esta ocasión para hacerlo. Aun los trabajos generales en otros idiomas difícilmente incluyen una documentación tan amplia como la que se ha conden- sado en éste, y bien podemos decir que mucha es absolutamente original, producto de la investigación personal de los autores.
De acuerdo al convenio oportunamente tratado, esta parte dedicada a los Vertebrados sólo ha llegado hasta las diagnosis de los géneros. Intentar profundizar más hubiera sido tarea de muy largo aliento, difícilmente concretable en unos pocos años, puesto que prácticamente imponía la revisión crítica de todo lo hecho hasta el momento en el campo de los Vertebrados fósiles.
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FK 506 pre-treatment is associated with reduced levels of tumor necrosis factor and interleukin 6 following hepatic ischemia/reperfusion
Using a rat model, the effect of pre-treatment with FK 506 on hepatic ischemia/reperfusion injury was investigated. All control animals died within 72 h of the ischemia/reperfusion injury. Pre-treatment of the animals with FK 506 (0.3 mg/kg in 0.5 ml saline) administered intravenously improved survival. The most striking protection against fatal ischemia/reperfusion injury was achieved in rats that were given FK 506 6 and 24 h prior to the induction of the hepatic ischemic insult (70% and 80% 10-day survival rates, respectively). The hepatoprotective effect of FK 506 was assessed further in a second experiment in which the serum levels of tumor necrosis factor (TNF) and interleukin 6 (IL-6) were measured. These results suggest that a 60-min period of hepatic ischemia and subsequent reperfusion triggers the release of both TNF and IL-6, and that FK 506 pre-treatment (6 h before the ischemic episode) significantly inhibits the production and/or release of these two cytokines compared to untreated controls. These data provide additional information concerning the immunosuppressive and hepatoprotective activities of FK 506. Based upon these data, it is probable that FK 506 attenuates hepatic ischemia/reperfusion injury, at least in part, by reducing TNF and IL-6 levels. © 1993 Elsevier Scientific Publishers Ireland Ltd. All rights reserved
The silicon-strip tracker of the Gamma ray Large Area Space Telescope
Abstract The Gamma ray Large Area Space Telescope (GLAST) is an astro-particle mission that will study the mostly unexplored, high energy ( 20 MeV – 1 TeV ) spectrum of photons coming from active sources in the universe. Construction of the GLAST silicon tracker, by far the largest ever built for a space mission, is now well on the way, as it is scheduled for launch by NASA in autumn 2006. We report on the basic technology adopted for the silicon detectors, particularly in connection to their use in space, on the first results of sensors testing and on the status of tracker assembly
A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab
We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the
creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c
s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at
sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron
collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi
K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) =
(1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from
psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)
Search for charged Higgs decays of the top quark using hadronic tau decays
We present the result of a search for charged Higgs decays of the top quark,
produced in collisions at 1.8 TeV. When the charged
Higgs is heavy and decays to a tau lepton, which subsequently decays
hadronically, the resulting events have a unique signature: large missing
transverse energy and the low-charged-multiplicity tau. Data collected in the
period 1992-1993 at the Collider Detector at Fermilab, corresponding to
18.70.7~pb, exclude new regions of combined top quark and charged
Higgs mass, in extensions to the standard model with two Higgs doublets.Comment: uuencoded, gzipped tar file of LaTeX and 6 Postscript figures; 11 pp;
submitted to Phys. Rev.
Inclusive jet cross section in collisions at TeV
The inclusive jet differential cross section has been measured for jet
transverse energies, , from 15 to 440 GeV, in the pseudorapidity region
0.10.7. The results are based on 19.5 pb of data
collected by the CDF collaboration at the Fermilab Tevatron collider. The data
are compared with QCD predictions for various sets of parton distribution
functions. The cross section for jets with GeV is significantly
higher than current predictions based on O() perturbative QCD
calculations. Various possible explanations for the high- excess are
discussed.Comment: 8 pages with 2 eps uu-encoded figures Submitted to Physical Review
Letter
Measurement of the p\bar{p}\sqrt{s}$ = 1.8 TeV
We update the measurement of the top production cross section using the CDF
detector at the Fermilab Tevatron. This measurement uses decays to
the final states +jets and +jets. We search for quarks from
decays via secondary-vertex identification or the identification of
semileptonic decays of the and cascade quarks. The background to the
production is determined primarily through a Monte Carlo simulation.
However, we calibrate the simulation and evaluate its uncertainty using several
independent data samples. For a top mass of 175 , we measure
pb and pb using
the secondary vertex and the lepton tagging algorithms, respectively. Finally,
we combine these results with those from other decay channels and
obtain pb.Comment: The manuscript consists of 130 pages, 35 figures and 42 tables in
RevTex. The manuscript is submitted to Physical Review D. Fixed typo in
author lis
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