Multimodal assessment in polymicrobial infective endocarditis with silent spondylodiscitis and cerebral embolism / Evaluación multimodal en endocarditis infecciosa polimicrobiana con espondilodiscitis silenciosa y embolia cerebral

Abstract Infective endocarditis (IE) is a rare but severe disease, due to an infection of the endocardial surface of the heart. The annual incidence ranging from 3 to 7 per 100 000 person-years, with an overall mortality rates of 25%. Staphylococci and Streptococci accounted for approximately 80% of IE cases. Enterococci are the third leading cause accounted for approximately 5-18% of all cases and are increasingly linked to health-care contact. The increasing number of cardiovascular electronic devices, prosthetic valves implants along with frequent invasive diagnostic or therapeutic procedures performed in elderly, may also contribute to the rise of IE in this population. Blood cultures and echocardiographic findings are the cornerstone of the IE diagnosis, confirmed or rejected according to modified Duke criteria. Other imaging modalities as Cardiac Computed Tomography, Cardiac Magnetic Resonance Imaging and 18Ffluorodeoxyglucose Positron Emission Tomography - Computed Tomography (18FDG-PET/CT) can determine a more correct diagnosis and identify many of the endocarditis-related complications. Here, we describe a patient with aortic prosthetic valve and Enterococcus faecalis (EF) IE. Cerebral and spinal MRI and 18FDG-PET/CT, performed during the hospitalization, showed multi-organ silent periferic embolization. Furthermore, the cultural examination of the valvular surgical specimen revealed a methicillin-sensitive Staphylococcus aureus suggestive for polymicrobial endocarditis. Some Authors demonstrated a possible false-positive valve culture due to a postoperative contamination. Since contaminated cultures usually yield microorganisms compatible with endocarditis, such as coagulase-negative Staphylococci, viridans group Streptococcus species, may be difficult for the physician not to treat the patient. This case represents need for high level of suspicion to diagnose IE. Multimodality assessment improves the diagnosis and allows the detection of the complications. Moreover, a multidisciplinary team and specialized centers determine a better patient’s outcome.

Resumen La endocarditis infecciosa (EI) es una enfermedad poco frecuente pero severa, dada por una infección del endocardio. La incidencia anual oscila entre 3 y 7 por cada 100 000 personas-año, con una tasa de mortalidad general del 25%. Los estafilococos y los estreptococos representaron aproximadamente un 80% de los casos de EI. Los enterococos son la tercera causa, aportando aproximadamente 5% a 18% de todos los casos, y se vinculan cada vez más al contacto con la atención médica. El número creciente de dispositivos electrónicos cardiovasculares e implantes de válvulas protésicas, junto con los frecuentes procedimientos invasivos diagnósticos o terapéuticos en las personas ancianas, también podrían contribuir al incremento de EI en esta población. Los hemocultivos y los hallazgos ecocardiográficos son la piedra angular del diagnóstico de EI, confirmado o rechazado de acuerdo con los criterios modificados de Duke. Otras modalidades de imagenología tales como la Tomografía Computarizada Cardíaca (TCC), la Resonancia Magnética Cardíaca (RMC) y la Tomografía por Emisión de Positrones - Tomografía Computarizada con 18F-fluorodeoxiglucosa (18F-FDG PET/TC) pueden determinar un diagnóstico más preciso e identificar muchas de las complicaciones asociadas a la endocarditis. Aquí describimos un paciente con una válvula aórtica protésica y EI por EF. Una RM del cerebro y la columna vertebral y una 18F-FDG PET/TC practicadas durante la hospitalización evidenciaron embolia periférica multiorgánica silenciosa. Además, el examen por cultivo de la muestra quirúrgica valvular reveló Staphylococcus aureus sensible a la meticilina (SASM), sugestivo de endocarditis polimicrobiana. Algunos autores demostraron un posible falso positivo del cultivo valvular dado por contaminación postoperatoria. Ya que los cultivos contaminados generalmente producen microorganismos compatibles con la endocarditis, tales como estafilococos coagulasa negativos y estreptococos del grupo viridans, le puede resultar difícil al médico no tratar al paciente. Este caso representa la necesidad de tener un alto nivel de sospecha para diagnosticar la EI. La valoración multimodal mejora el diagnóstico y permite detectar complicaciones. Además, un equipo multidisciplinario y los centros especializados determinan un mejor desenlace para el paciente.

Comportamiento dosimétrico de un sistema de planificación mediante curvas de calibración de densidades electrónicas relativas / Dosimetric behaviour of a planning system through calibration curves of relative electron density

En esta investigación se planteó como objetivo la verificación del comportamiento dosimétrico del Sistema de Planificación de Tratamiento (TPS) de Radioterapia mediante las curvas de calibración de Densidades Electrónicas Relativas (DER). Este estudio se realizó en el Hospital de la Sociedad de Lucha Contra el Cáncer (SOLCA) Núcleo Loja, usando un fantoma antropomorfo CIRS 062M y un tomógrafo Toshiba Activion 16. Para determinar la nueva curva de calibración DER se tomaron los valores de densidades electrónicas especificadas en el manual del fantoma y las Unidades Hounsfield de la imagen tomográfica. Se realizó controles de calidad dosimétricos y verificación dosimétrica en tres casos clínicos: tórax, pelvis y cráneo; para realizar las pruebas dosimétricas se utilizó un acelerador CLINAC CX, cámara de ionización PTW tipo Farmer con volumen sensible de 0,6 cm3 y un electrómetro PTW UNIDOS E. Los resultados mostraron que las medidas para cada inserto del fantoma en ningún caso excedieron los límites establecidos de ± 20 UH, para el tomógrafo y el TPS; las pruebas de control de calidad no superaron el límite máximo de desviaciones en el cálculo de dosis absorbida por el TPS y la obtenida por medición de ± 4 % establecida por la IAEA y las verificaciones dosimétricas en tórax, pelvis y cráneo, determinaron que las desviaciones en el cálculo de la dosis absorbida por el TPS y la obtenida por medición no superaban la tolerancia del ± 5 % establecida por la ICRU.

In this research, the aim was to verify the dosimetric behavior of the Radiotherapy Treatment Planning System (TPS) using the Relative Electron Density (DER) calibration curves. This study was carried out at the SOLCA (Society of Fight Against Cancer) hospital in Loja, using an CIRS model 062M anthropomorphic phantom and a Toshiba Activion 16 tomograph. To determine the new DER calibration curve, the values of the electron densities specified in the manual of the phantom and the Hounsfield Units of the tomographic image were taken. Dosimetric quality controls were made in the location of three clinical cases: thorax pelvis and skull; used a CLINAC CX accelerator was used to perform the dosimetric tests, PTW ionization chamber type Farmer with sensitive volume of 0.6 cm3 and a PTW UNIDOS E electrometer. The results showed that the measurements for each insert of the phantom in no case exceeded the established limits of ± 20 UH, for the tomograph and the TPS; the quality control tests did not exceed the maximum limit of deviations in the calculation of dose absorbed by the TPS and the one obtained by measurement of ± 4% established by the IAEA and the clinical planning in the thorax, pelvis and skull, determine that the deviations in the calculation of the dose absorbed by the TPS and that obtained by measurement, they do not exceed the tolerance of ± 5% established by the ICR.

Mamografía por emisión de positrones (PEM) / Positron emission mammography (PEM)

La mamografía por emisión de positrones (PEM) es un estudio de medicina nuclear molecular que utiliza radios trazadores administrados de forma intravenosa, adquiriendo imágenes para localización de la lesión tumoral, así como la valoración de su metabolismo. El pequeño tamaño del detector en estos equipos facilita el uso de componentes de alta resolución y permite una mayor cercanía a la fuente, aumentando la sensibilidad para los fotones de aniquilación. PEM es una modalidad de imagen que utiliza el mismo posicionamiento que la imagen de mamografía. Los resultados del PEM nos son afectados por la densidad mamaria, llegando a obtenerse valores con alta sensibilidad y especificidad para la detección de tumores más pequeños, en etapas más tempranas que el resto de los métodos convencionales de imagen, es de gran utilidad en la estadificación y planeación quirúrgica de la enfermedad, también disminuye el número de procedimientos innecesarios, así como la morbimortalidad en el cáncer de mama.

The PEM is a molecular nuclear medicine study that uses radiotracer administered intravenously, acquiring images to locate the tumor lesion, as well as the assessment of its metabolism. The small size of the detector in these devices facilitates the use of high resolution components and allows a closer proximity to the source, increasing the sensitivity for annihilation photons. Positron emission mammography (PEM) is an image modality that uses the same positioning as the mammography image. The results of the PEM are affected by mammary density, reaching values with high sensitivity and specificity for detection of smaller tumors, in earlier stages than the rest of conventional imaging methods, it is very useful in staging and planning Surgical disease and decreases the number of unnecessary procedures, as well as morbidity and mortality in breast cancer.

Structural and mechanical characterization of custom design cranial implant created using additive manufacturing

Background: Reconstruction of customized cranial implants with a mesh structure using computer-assisted design and additive manufacturing improves the implant design, surgical planning, defect evaluation, implant-tissue interaction and surgeon's accuracy. The objective of this study is to design, develop and fabricate cranial implant with mechanical properties closer to that of bone and drastically decreases the implant failure and to improve the esthetic outcome in cranial surgery with precision fitting for a better quality of life. A customized cranial mesh implant is designed digitally, based on the Digital Imaging and Communication in Medicine files and fabricated using state of the Art-Electron Beam Melting an Additive Manufacturing technology. The EBM produced titanium implant was evaluated based on their mechanical strength and structural characterization. Results: The result shows, the produced mesh implants have a high permeability of bone ingrowth with its reduced weight and modulus of elasticity closer to that the natural bone thus reducing the stress shielding effect. Scanning electron microscope and micro-computed tomography (CT) scanning confirms, that the produced cranial implant has a highly regular pattern of the porous structure with interconnected channels without any internal defect and voids. Conclusions: The study reveals that the use of mesh implants in cranial reconstruction satisfies the need of lighter implants with an adequate mechanical strength, thus restoring better functionality and esthetic outcomes for the patients.

A dose-response curve for biodosimetry from a 6 MV electron linear accelerator

Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates.

Titanium alloy orthodontic mini-implants: scanning electron microscopic and metallographic analyses

Anchorage control is one of the determining factors of successful orthodontic mechanics. In mini-implants, fractures due to placement and removal have been related to implant design and titanium alloy quality. This study assessed the topography and microstructure of five brands of mini-implants (Neodent, SIN, Morelli, Conexao, Foresta Dent). Scanning electron microscopic analyses of the head, transmucosal neck, threaded body, and tip were performed to assess implant design and manufacturing defects (n=3/group). Metallographic analysis of longitudinal sections (n=15) and cross-sections (n=15) was performed under conventional light microscopy according to international standards of "American Society for Testing and Materials". The results showed significant differences in miniimplant design. Surface irregularities in the threaded body and tip were observed. Microstructural analyses revealed an alpha/beta-phase grain structure, in compliance with the ETTC-2 ("Technical Committee of European Titanium Producers" -2nd edition). No structural defects were detected. We conclude that differences in mini-implant design and the presence of surface irregularities may influence the effectiveness of orthodontic anchorage.

O controle da ancoragem e um dos fatores decisivos no sucesso da mecanica ortodontica. Fraturas devido ao estresse de insercao e remocao de mini-implantes sao associadas ao design das pecas e a qualidade da liga de titanio. O presente estudo analisou a topografia e a microestrutura de cinco marcas de mini-implantes (Neodent, SIN, Morelli, Conexao, Foresta Dent). Analise ao microscopio eletronico de varredura da cabeca e perfil transmucoso, porcao rosqueavel e ponta ativa foi realizada com o proposito de avaliar o design e defeitos de fabricacao (n=3/grupo). A analise metalografica baseou-se nas normas internacionais da "American Society for Testing and Materials" e revelou a microestrutura em cortes longitudinais (n=15) e transversais (n=15) por meio do microscopio optico. Os resultados demostraram que os mini-implantes apresentam diferencas significativas no design. Irregularidades superficiais na porcao rosqueavel e na ponta ativa foram tambem observadas. A analise da microestrutura revelou uma estrutura de graos fases alfa e beta distribuidas de acordo com os padroes definidos pelas normas ETTC-2 ("Technical Committee of European Titanium Producers" - 2a edicao). Alem disso, nao foram detectados defeitos na estrutura interna das ligas. Conclui-se que diferencas no design dos mini-implantes e a presenca de irregularidades superficiais podem influenciar na efetividade da ancoragem durante o tratamento ortodontico.

The role of electron-emitting radiopharmaceuticals in the palliative treatment of metastatic bone pain and for radiosynovectomy: applications of conversion electron emitter Tin-117m

A variety of radionuclides continue to be investigated and/or clinically used for different therapeutic applications in nuclear medicine. The choice of a particular radionuclide with regard to appropriate emissions, linear energy transfer (LET), and physical half-life, etc., is dictated to a large extent by the character of the disease (e.g., solid tumor or metastatic disease), and by the carrier to selectively transport the radionuclide to the desired site. An impressive body of information has appeared in the recent literature that addresses many of these considerations. This article summarizes and discusses the role of high-LET electron emitters and their advantage in the treatment of cancer or for other disorders in specific situations. Areas such as bone pain palliation, bone malignancy therapy, and radiation synovectomy are covered in greater detail. Projections are made as to the future directions and progress in these areas. A discussion of the various issues related to the selection criteria that are useful for choosing the appropriate radionuclide for a particular application is included. Use of high-LET electron emitters is discussed in greater detail, with particular emphasis on the use of conversion electron emitter tin-117m for various therapeutic applications.

Uma variedade de radionuclídeos continua a ser investigada e/ou clinicamente utilizada para diferentes aplicações terapêuticas em medicina nuclear. A escolha de um radionuclídeo, considerando-se sua emissão apropriada, transferência linear de energia (LET) e meia-vida física é determinada na maior parte pelo caráter da doença (p.ex., tumor sólido ou doença metastática), e pelo carreador que transporta o radionuclídeo seletivamente para o sítio desejado. Um notável conjunto de informações voltadas para essas considerações tem aparecido na literatura recente. Esse trabalho resume e discute o papel de emissores de elétrons de alta-LET e sua vantagem no tratamento do câncer ou para outras doenças em situações específicas. Abordagens relacionadas com o alívio da dor óssea, a terapia da doença óssea e a sinovectomia por radiação são apresentadas detalhadamente. Projeções para o futuro e os progressos nessas áreas são indicadas. Uma profunda discussão relacionada aos critérios de seleção que são úteis para escolher o radionuclídeo apropriado para que uma aplicação particular seja incluída. O uso de emissores de elétrons de alta-LET é discutido em grande detalhe, com particular ênfase no uso do estanho-117m, um emissor de elétron de conversão, para várias aplicações terapêuticas.

Radioterapia complementar em dose única intra-operatória no tratamento conservador do câncer de mama / Full-dose intra operative radiotherapy in the breast cancer conserving treatment

A radioterapia complementar na cirurgia consrvadora do câncer de mama inicial visa reduzir a chance de recidiva local, que ocorre quase sempre no mesmo quadrante do tumor primário. A eletronterapia intra-operatória (ETI)ministrada através de aparelho portátil especial durante a cirurgia é procedimento novo, desenvolvido na Itália, com várias vantagens teóricas e práticas sobre a radioterapia pós-operatória convencional. Porém, este aparelho não está disponível em países em desenvolvimento. Apresentamos nossa experiência com o método, mas ministrando a dose de 21 Gy através de acelerador linear comum. De maio de 2004 a abril de 2006 tratamos 49 pacientes com carcinoma ductal infiltrativo de mama unifocal, medindo até 3 cm de diâmetro, as quais foram submetidas a ressecção segmentar de mama, monitorização intra-operatória das margens cirúrgicas, biópsia de linfonodo sentinela e ETI. As cirurgias foram realizadas em centro cirúrgico anexo à sala de radioterapia, para a qual as pacientes foram transferidas anestesiadas. Após a colocação de disco de chumbo e alumínio na face anterior do músculo peitoral maior e atrás do tecido a ser irradiado, procedeu-se de rotina à radiografia para confirmar a correção da posição do colimador e a seguir a radiação foi administrada intra-operatoriamente. Depois de período médio de 13,4 meses (I-23) nenhuma recidiva local foi detectada e a taxa de complicações foi muito baixa. O aspecto estético final foi excelente ou bom. A ETI ainda é um procedimento em fase investigacional, muito prático, e bem aceito. O método é promissor, podendo ser realizado com aparelhos aceleradores lineares convencionais.

La Tomografía por emisión de positrones: nuevo paradigma para la evaluación y el manejo del cáncer / Positron Emission Tomography: a new Paradigma in Cancer Management

El Instituto Nacional de Cancerología (INC) está construyendo actualmente una instalación para hacer tomografía por emisión de positrones (PET, por sus siglas en inglés), que consta de un ciclotrón y un escáner que fusiona la imagen funcional (PET) con una imagen anatómica de escáner convencional. Este proyecto estará en operación en diciembre de 2007. Por ser una institución de referencia de carácter nacional, dedicada al manejo del cáncer, el INC planea ofrecer a todo el país tanto servicios de distribución de radiofármacos emisores de positrones como servicios médicos relacionados con esta tecnología. La tecnología PET provee información metabólica útil en el manejo de los pacientes. Las propiedades del decaimiento de positrones permiten realizar imágenes muy precisas de la distribución in vivo de un radiofármaco emisor de positrones. Diversos radiofármacos emisores de positrones se han usado para caracterizar múltiples estados fisiológicos y patológicos. La principal aplicación clínica se da en oncología, con la utilización de la 18 fluor flurodesoxiglucosa (FDG), un análogo de la glucosa capaz de acumularse en muchos tumores con mayor avidez que el tejido normal. La PET se está usando para el diagnóstico y seguimiento de muchas neoplasias, y la lista de artículos publicados continúa creciendo. Aquí se incluyen aspectos de instrumentación de PET y muchas de las aplicaciones clínicas en oncología.

The National Cancer Institute (NCI) is currently building a Positron emission tomography facility that will house a cyclotron and a PET FUSION scanner. It should be operational as of december 2007. Being a cancer dedicated national referral center, the NCI should provide both positron-emitting radiopharmaceuticals and medical services to institutions and patients nationwide. PET technology provides metabolic information that has been documented to be useful in patient care. The properties of positron decay allow accurate imaging of the in vivo distribution of positron-emitting radiopharmaceuticals. A wide array of positron-emitting radiopharmaceuticals has been used to characterize multiple physiologic and pathologic states. The major clinical PET applications are in cancer patients using fluorine-18 fluorodeoxyglucose (FDG). FDG, an analogue of glucose, accumulates in most tumors in a greater amount than it does in normal tissue. PET is being used in diagnosis and follow-up of several malignancies, and the list of articles supporting its use continues to grow. In this article, the instrumentation aspects of PET are described and most of the clinical applications in oncology are described.

Evaluación de la Microcirculación: rol del SPECT y de la Tomografía por Emisión de Positrones / Evaluation of coronary microcirculation: Role of Spect and positron emission tomography

This investigation was designed to evaluate the coronary microcirculation and the role of single-photon emission computed tomography (SPECT) and positron emission tomografhy, for the detection of coronary artery stenosis and the evaluation of the physiological significance. Nuclear cardiology allows a not invasive manner of evaluation of the complete spectrum of the severity of the coronary artery disease (CAD). The study of the coronary microcirculation through the evaluation of the endothelial function and the coronary flow reserve permits the early detection of patients at risk for CAD. The evaluation of the coronary flow reserve associated to myocardial perfusion could have a potential role in patients with obstructive CAD, because is detects with higher precision the presence of CAD

Atividade das fosfodiesterases em tecido de granulaçäo submetido a irradiaçäo de elétrons - estudo experimental em ratos / Activity of phosphodiesterases in granulation tissue submitted to electron irradiation - experimental study in rats

Os autores estudaram o efeito de baixas doses de radiaçäo de elétrons na atividade de fosfodiesterases presentes no tecido de granulaçäo, induzido por esponja de PVC, subcutaneamente, na regiäo dorsal de 84 ratos Wistar, divididos em dois grupos, controle e irradiado. A atividade enzimática foi avaliada segundo a evoluçäo do tecido de granulaçäo aos 5, 7, 10, 14, 17, 20 e 24 dias. Os animais foram irradiados com um feixe de elétrons de 6 MeV, dose de 1 Gy, 3 dias após a implantaçäo da esponja, sendo que no momento da irradiaçäo, foram protegidos por uma lâmina de 4mm de chumbo, tendo sido irradiada somente a área correspondente ao local onde encontrava-se a esponja. Considerando-se a dose e o tipo de radiaçäo empregada, pode-se concluir que houve influência direta da radiaçäo na atividade da enzima 5'-nucleotidase e da ATPase no início do precesso de reparaçäo tecidual, aos 5 e 7 dias. Já a enzima fosfatase alcalina näo sofreu a açäo direta da radiaçäo. É possível que o principal fator tenha sido danos nos constituintes celulares que säo responsáveis pela formaçäo do tecido de granulaçäo, determinando a produçäo enzimática conforme a necessidade

Nitrate levels and stages of growth in hypernodulating mutants pf Lupinus Albus. I. N2 fixation potential

This work aimed to evaluate physiological parameters, nodulation response and N2 fixation rate in mutants of Lupinus albus in comparison with the standard Multolupa cultivar. Two nitrate levels (0 and 5mM) and two evaluation periods (7 and 10 weeks) were used. Significant differences were observed among genotypes, in relation to fresh nodule weight, nitrate levels and growth stages. The overall average for nitrate level differed between them where 5mM severely inhibieted the number of nodules, reaching a 49.5 (per cent) reduction in relation to treatment without nitrate. There were no behaviour differences among genotypes, nor among evaluation periods. Although the level of nitrate did not influence the production of shoot dry matter in relation to the average among levels applied, the L-135 genotype, being an inefficient mutant, reached very low values. There were no significant differences in electron allocation coefficient (EAC) among nitrate levels, nor among genotypes studied. However , the evaluation periods revealed differences, where the EAC for the seventh week had a higher value than that for the tenth week, when a 5mM aplication was evaluated. The N2 fixation rate (N2FIX) showed the existence of the nitrate interference in fixation, given that the application of 5mM severely reduced. However, there were no differences among the genotypes and it was noted that the fixation rate was much higher in those that received nitrate. The L-88 and L-62 genotypes were the ones that have shown best adaptability in this experiment, thus being able to be recommended for new studies with higher nitrate levels and different evaluation periods. The nitrate (5mM) interferes in the nitrogen fixation rate, given that all the genotypes were affected by the level applied.