Transmissão do glioma de um doador de múltiplos órgãos para o enxerto pancreático

INTRODUÇÃO: A disparidade entre a oferta e a demanda de órgãos para transplanteimpulsiona a inclusão de doadores com tumores primários do sistema nervosocentral (SNC) no programa de transplantes. OBJETIVO: reportar um caso de um paciente que desenvolveu um glioma no enxerto pancreático proveniente de um doador de múltiplos órgãos cuja causa mortis foi um glioma maligno. RELATO DE CASO: paciente, branca, 11anos de idade, portadora de glioma maligno evolui a morte encefálica, sendo doadora de múltiplos órgãos. Havia sido submetida a 4 craniotomias com a finalidade de ressecar a massa tumoral. Sem sucesso, apresentou hipertensão intra-crâniana. No entanto, a derivação ventrículo-peritoneal não foi empregada em nenhum momento de sua evolução.Durante a captação do órgão, anormalidades intra-torácicas ou intra-abdominais não foram encontradas. Coração, fígado, pâncreas e um rim foram utilizados para transplante em diferentes receptores. Um rim não foi utilizado devido a problemas anatômicos. Um transplante de pâncreas isolado foi realizado um paciente masculino, 21 anos de idade, diabético tipo I há 19 anos. Não ocorreram complicações pós-operatórias e o paciente teve alta hospitalar livre de insulina. No quarto mês pós-operatório, foi encontrada uma tumoração na cabeça do pâncreas transplantado em exames de imagem. Optou-se, então, pela pancreatectomia. À histologia, demonstrou-se o mesmo tipo histológico do glioma malignodo doador. Atualmente, o paciente tem sido rigorosamente acompanhado, estando no 12ºmês pós-transplante, numa boa evolução clínica, sem imunossupressão, fazendo, novamente,uso de insulina e sem sinais de recidiva tumoral.INTRODUCTION: The disparity between the supply of and the demand fortrans plantable organs has led to an acceptance of donors with primary central nervous system(CNS) tumors. PURPOSE: Face the rarity, the authors report the case of a patient who developed a glioma on a pancreatic graft received from a donor with a malignant glioma as cause of brain death. CASE REPORT: A 11-years-old white female who had died in a local hospital from a malignant glioma was the organ donor. She had been submitted to 4 craniotomies to resect tumoral mass. By the time of organ retrieval, no intra-abdominal or intra-thoracic abnormalities were noticed. Heart, liver, one kidney and pancreas were used for transplant in different recipients. One kidney was not used due to anatomical problems.A pancreas transplant alone was performed in a 21-years-old male, diabetic for 19 years.Postoperative recovery was uneventful and patient was discharged insulin-free. Four months later the patient developed a pancreatic mass and was submitted to graft pancreatectomy.Histology confirmed the same malignant glioma of the donor. Currently the patient has been strictly followed, on his 12th month post-transplant, with a good clinical evolution, off immunosupression and again on insulin, without signs of malignancy

Pancreas-kidney simultaneous transplant with graft derived from previously transplanted dead donor

O aumento das listas de espera por órgãos para transplante faz com que cada vez mais se procure meios de aumentar o “pool” de doadores de órgãos. Para tanto, tem-se utilizado doadores vivos, limítrofes ou sem batimentos cardíacos. Uma outra forma de se  aumentar o número de doadores utilizados é através do uso de órgãos provenientes de doadores previamente transplantados, população que tende a crescer, dado o aumento do número de transplantes realizados no mundo. Os resultados obtidos com esse tipo de doador são favoráveis ao seu uso, demonstrando resultados semelhantes aos obtidos com doadores convencionais. Apresenta-se a seguir o primeiro caso em nosso meio de transplante depâncreas e rim simultâneo com órgãos provenientes de doador que fora submetido a transplante cardíaco.Nota: No vol. 84, n.3-4 de 2005, está publicado a Carta contendo os nomes dos autores deste artigo. O pdf anexo foi corrigido.The raising increase in the patient’s waiting list leaves us search for ways to increase the pool of organ donors. Looking at this, there is the use of living donors, of adjoining donors or non-heart beating donors. Another way to increase the number of donors is through the use of organs that came from previously transplanted donors, a group that is becoming larger, because of the rise of the number of transplants all around the world. The results obtained with this kind of donor are suitable to its use, showing similar results to the obtained with usual donors. We present the first case in our ambience of a simultaneous pancreas and kidney transplant with grafts derived from a heart transplanted donor

À Revista de Medicina do Departamento Científico do Centro Acadêmico Oswaldo Cruz da Faculdade de Medicina da Universidade de São Paulo

Carta retificando o nome correto dos autores, o trabalho completo e corrigido está publicado no v.84, n.2, p.90-93, 2005

Nanoscale transient polarization gratings

We present the generation of transient polarization gratings at the nanoscale, achieved using a tailored accelerator configuration of the FERMI free electron laser. We demonstrate the capabilities of such a transient polarization grating by comparing its induced dynamics with the ones triggered by a more conventional intensity grating on a thin film ferrimagnetic alloy. While the signal of the intensity grating is dominated by the thermoelastic response of the system, such a contribution is suppressed in the case of the polarization grating. This exposes helicity-dependent magnetization dynamics that have so-far remained hidden under the large thermally driven response. We anticipate nanoscale transient polarization gratings to become useful for the study of any physical, chemical and biological systems possessing chiral symmetry

FEL stochastic spectroscopy revealing silicon bond softening dynamics

Time-resolved X-ray Emission/Absorption Spectroscopy (Tr-XES/XAS) is an informative experimental tool sensitive to electronic dynamics in materials, widely exploited in diverse research fields. Typically, Tr-XES/XAS requires X-ray pulses with both a narrow bandwidth and sub-picosecond pulse duration, a combination that in principle finds its optimum with Fourier transform-limited pulses. In this work, we explore an alternative xperimental approach, capable of simultaneously retrieving information about unoccupied (XAS) and occupied (XES) states from the stochastic fluctuations of broadband extreme ultraviolet pulses of a free-electron laser. We used this method, in combination with singular value decomposition and Tikhonov regularization procedures, to determine the XAS/XES response from a crystalline silicon sample at the L2,3-edge, with an energy resolution of a few tens of meV. Finally, we combined this spectroscopic method with a pump-probe approach to measure structural and electronic dynamics of a silicon membrane. Tr-XAS/XES data obtained after photoexcitation with an optical laser pulse at 390 nm allowed us to observe perturbations of the band structure, which are compatible with the formation of the predicted precursor state of a non-thermal solid-liquid phase transition associated with a bond softening phenomenon

Femtosecond polarization shaping of free-electron laser pulses

We demonstrate the generation of extreme-ultraviolet (XUV) free-electron laser (FEL) pulses with time-dependent polarization. To achieve polarization modulation on a femtosecond timescale, we combine two mutually delayed counterrotating circularly polarized subpulses from two cross-polarized undulators. The polarization profile of the pulses is probed by angle-resolved photoemission and above-threshold ionization of helium; the results agree with solutions of the time-dependent Schrödinger equation. The stability limit of the scheme is mainly set by electron-beam energy fluctuations, however, at a level that will not compromise experiments in the XUV. Our results demonstrate the potential to improve the resolution and element selectivity of methods based on polarization shaping and may lead to the development of new coherent control schemes for probing and manipulating core electrons in matter

Electron Beam Transport in Plasma-Accelerator-Driven Free-Electron Lasers in the Presence of Coherent Synchrotron Radiation and Microbunching Instability

Laser- and beam-driven plasma accelerators promise electron beam brightness at the exit of plasma cells suitable for X-ray free-electron lasers. Beam transport from the accelerator to the undulator may include a multi-bend, energy-dispersive switchyard, in which energy collimators can be installed to protect the undulator or to serve multiple photon beamlines. Coherent synchrotron radiation and microbunching instability in the switchyard can seriously degrade the brightness of the accelerated beam, reducing the lasing eciency. We present a semi-analytical analysis of those collective eects for beam parameters expected at the exit of state-of-the-art plasma accelerators. Prescriptions for the linear optics design used to minimize transverse and longitudinal beam instability are discussed

Impact of the Electrons Dynamics on the Free-electron Lasers Radiation Coherence

Modern science advancements rely on the possibility of producing short laser-like coherent pulses in the XUV and in the X-rays wavelength ranges to probe electronic structure in atoms, molecules and solid-state matter. For this reason, light-sources including synchrotrons, inverse Compton scattering, high harmonic generation in gas (HHG) and free electron lasers (FELs) are invaluable tools for research in these fields. In particular, they all have in common the exploitation of the radiating process resulting from electrons’ acceleration under the influence of an electromagnetic field. The aim of this thesis is to explore the impact of electrons’ dynamics on the coherence of FELs seeded by an external laser. In this thesis I demonstrate that electrons’ dynamics plays a major role in the conversion and transformation of light’s features, such as coherence, which can be transmitted to electrons and "inherited" from the re-emitted light. To fulfill this purpose, both the theoretical and the experimental approaches have been used. Most of the models presented, derived or extended in this work are, in fact, supported by experimental evidence. The interplay between electrons and light’s properties is investigated using both classical and quantum dynamics. While the former is routinely adopted to describe the FEL dynamics and collective phenomena in an electron bunch, the latter becomes mandatory to fully achieve a faithful description of the varieties of phenomena that involve the emission of photons. From the classical point of view, a comprehensive analytical model for electron beam longitudinal dynamics is derived by including a new phenomenon, known as intrabeam scattering, and by investigating its effect on the electrons’ distribution. The predictions of this model can be directly compared with both beam and FEL measurements, showing a good agreement with both. From the quantum-dynamical point of view, we start to explore the possibility to answer the following question: "is it possible to introduce quantum features, such as coherence, in any process of harmonic generation from a coherent light pulse?" In order to do so, we focus our attention on the characterization of quantum coherence via photon number distribution and the quantum electrodynamics of an electron in a laser field. The practical aspect of my investigation is threefold: the prediction and characterization of electron beam quality; the optimization of seeded and unseeded FELs performances, that is possible through the mitigation of instabilities originated in the electron bunch; the investigation of unexplored FELs features and configurations that could be exploited for novel experiments. Finally, although the results and discussions are directly applied to the FEL case, some of the theoretical results regarding the coherence can be applied, without loss of generality, to any process of electrons-light interaction.Modern science advancements rely on the possibility of producing short laser-like coherent pulses in the XUV and in the X-rays wavelength ranges to probe electronic structure in atoms, molecules and solid-state matter. For this reason, light-sources including synchrotrons, inverse Compton scattering, high harmonic generation in gas (HHG) and free electron lasers (FELs) are invaluable tools for research in these fields. In particular, they all have in common the exploitation of the radiating process resulting from electrons’ acceleration under the influence of an electromagnetic field. The aim of this thesis is to explore the impact of electrons’ dynamics on the coherence of FELs seeded by an external laser. In this thesis I demonstrate that electrons’ dynamics plays a major role in the conversion and transformation of light’s features, such as coherence, which can be transmitted to electrons and "inherited" from the re-emitted light. To fulfill this purpose, both the theoretical and the experimental approaches have been used. Most of the models presented, derived or extended in this work are, in fact, supported by experimental evidence. The interplay between electrons and light’s properties is investigated using both classical and quantum dynamics. While the former is routinely adopted to describe the FEL dynamics and collective phenomena in an electron bunch, the latter becomes mandatory to fully achieve a faithful description of the varieties of phenomena that involve the emission of photons. From the classical point of view, a comprehensive analytical model for electron beam longitudinal dynamics is derived by including a new phenomenon, known as intrabeam scattering, and by investigating its effect on the electrons’ distribution. The predictions of this model can be directly compared with both beam and FEL measurements, showing a good agreement with both. From the quantum-dynamical point of view, we start to explore the possibility to answer the following question: "is it possible to introduce quantum features, such as coherence, in any process of harmonic generation from a coherent light pulse?" In order to do so, we focus our attention on the characterization of quantum coherence via photon number distribution and the quantum electrodynamics of an electron in a laser field. The practical aspect of my investigation is threefold: the prediction and characterization of electron beam quality; the optimization of seeded and unseeded FELs performances, that is possible through the mitigation of instabilities originated in the electron bunch; the investigation of unexplored FELs features and configurations that could be exploited for novel experiments. Finally, although the results and discussions are directly applied to the FEL case, some of the theoretical results regarding the coherence can be applied, without loss of generality, to any process of electrons-light interaction

Matrix model for collective phenomena in electron beam\u2019s longitudinal phase space

The possibility to predict, characterize and minimize the presence of spurious harmonic content in the longitudinal profile of high brightness electron beams, namely the microbunching instability, has become vital to ensure accurate modeling and reliable operation of radiofrequency and plasma-based linear accelerators such as those driving free-electron lasers. Recently, the impact of intrabeam scattering (IBS) on the instability has been experimentally demonstrated by the authors. This work complements that experimental study by extending existing theories in a self-consistent, piece-wise calculation of IBS in single pass linacs and multi-bend transfer lines. New expressions for the IBS are introduced in two different semi-analytical models of microbunching. The accuracy of the proposed models and the range of beam parameters to which they apply is discussed. The overall modeling turns out to be a fast comprehensive tool for the optimization of linac-driven free-electron lasers

Half-wavelength velocity bunching: non-adiabatic temporal focusing of charged particle beams

X-ray free-electron lasers (XFELs) and megaelectronvolt ultrafast electron diffractometers (MeV UEDs) are revolutionary scientific instruments that allow visualizing the dynamics of elementary excitations in a wide range of systems from atoms and molecules to phonons, magnons and plasmons. Femtosecond (fs) electron beams are at the heart of XFELs and MeV UEDs, and the formation of fs electron beams with ultrahigh brightness is the subject of active research. We report an interesting regime of non-adiabatic temporal compression of electron beams by two orders of magnitude. Via analytical calculations and numerical simulations, we show that few MeV electron bunches can be trapped and compressed by a strong electromagnetic field within a half of the field wavelength. Furthermore, in a multi-cell accelerating cavity, the bunch is first compressed and then accelerated, thus allowing one to preserve very short bunch duration. For example, a 3 ps 16 pC 1 MeV electron bunch is compressed to 21 fs rms and accelerated to 12 MeV in a TESLA superconducting cavity. Another example is the production of 1.2 fs 16 fC 3.3 MeV bunches with a coherence length of 20 nm and and an energy spread less than 3 keV. The discovered mechanism of compression, which is another mode of velocity bunching, opens the door for obtaining very high electron brightness