Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review.

Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.

Temperature-driven growth of Legionella in lab-scale activated sludge systems and interaction with protozoa.

The occurrence of Legionella pneumophila in activated sludge systems has been reported in the literature. However, the factors triggering its growth are not yet well understood. This knowledge is needed to develop strategies to minimize the risk of the spread of Legionnaires' disease that originates in these systems. In the present study, L. pneumophila multiplied exponentially at 35 °C in activated sludge, but lower temperatures (24 °C and 15 °C) did not favour the growth of the pathogen despite the presence of its protozoan hosts (free-living amoeba and ciliates). L. non-pneumophila species, which are adapted to low temperature, prevailed at 15 °C. Legionella was found dispersed in the activated sludge, forming clusters of different sizes and also inside protozoa. This study shows that temperature is a key parameter triggering the growth of L. pneumophila in activated sludge. The detection of infected protozoa suggests that these are important vehicles for the multiplication of Legionella. However, in this study it was not possible to exclude the growth of Legionella directly on the substrate or on the activated sludge matrix.

Occurrence of Legionella in wastewater treatment plants linked to wastewater characteristics.

In recent years, the occurrence of Legionella in wastewater treatment plants (WWTP) has often been reported. However, until now there is limited knowledge about the factors that promote Legionella's growth in such systems. The aim of this study was to investigate the chemical wastewater parameters that might be correlated to the concentration of Legionella spp. in WWTP receiving industrial effluents. For this purpose, samples were collected at different processes in three WWTP. In 100 % of the samples taken from the activated sludge tanks Legionella spp. were detected at varying concentrations (4.8 to 5.6 log GU/mL) by the quantitative real-time polymerase chain reaction method, but not by the culture method. Statistical analysis with various parameters yielded positive correlations of Legionella spp. concentration with particulate chemical oxygen demand, Kjeldahl nitrogen and protein concentration. Amino acids were quantified in wastewater and activated sludge samples at concentrations that may not support the growth of Legionella, suggesting that in activated sludge tanks this bacterium multiplied in protozoan hosts.

[(18)F-FDG PET/CT in the evaluation of patients suspected of paraneoplastic neurological syndrome]. / PET/TC con (18)F-FDG en la valoración de pacientes con sospecha de síndrome paraneoplásico neurológico.

OBJECTIVE: This study aimed to determine the diagnostic impact of (18)F-FDG PET/CT based on the clinical features of paraneoplastic neurological syndrome (PNS). MATERIAL AND METHODS: Multicenter retrospective and longitudinal study of patients with suspicion of PNS. The clinical picture was classified into classic (CS) and non-classic syndrome (NCS). After the follow-up, the definitive or possible diagnosis of PNS was established. The pictures that did not match any of the previous criteria were categorized as non-classifiable. The state of the onco-neural antibodies was studied. The PET/CT was classified as positive or negative for the detection of malignancy. The relationship between PET/CT findings and the final diagnosis was determined. The differences between variables (Pearson test X(2)) and the relationship between the results of the PET/CT and the final diagnosis were analyzed. RESULTS: A total of 64 patients were analyzed, classifying 30% as CS and 42% as NCS. After the follow-up, 20% and 16% of subjects were diagnosed as possible and definitive PNS, respectively. Positive onco-neural antibodies were found in 13% of the patients. A definitive diagnosis of PNS was associated with a positive PET/CT (P=.08). A significant relation between antibodies expression and final diagnosis of neoplasia (P=.04) was demonstrated. The PET/CT correctly localized malignancy in 5/7 cases of invasive cancer. CONCLUSIONS: The PET/CT showed a higher percentage of positive results in patients with definitive diagnosis of PNS. Despite the low prevalence of malignancy in our series, the PET/CT detected malignancy in a significant proportion of patients with invasive cancer.

Impact of initial FDG PET/CT in the management plan of patients with locally advanced head and neck cancer

Objective. To determine the impact of initial FDG PET/CT staging on clinical stage and the management plan in patients with locally advanced head and neck cancer (LAHNC). Materials and methods. We retrospectively reviewed the records of 72 consecutive patients (2007–2010) staged with PET/CT and conventional CT with tumours of hypopharynx/larynx (26 patients, 36 %), oral cavity (17 patients, 24 %), oropharynx (16 patients, 22 %), nasopharynx (12 patients, 17 %), and others (2 %). The impact of PET/CT on management plans was considered high when PET/CT changed the planned treatment modality or treatment intent, and intramodality changes were considered as minor changes with low impact. Results. FDG PET/CT changed the stage in 27 patients and had high impact on the management plan in 12 % of patients (detection of distant metastases in 6 patients and stage II in 2 patients). Intramodality changes were more frequent: FDG PET/CT altered the TNM stage in 18/72 (25 %) of patients, upstaging N stage in 90 % of patients with low impact. Conclusions. Initial FDG PET/CT staging not only improves stage but also affects the management plan in LAHNC patients (AU)

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Impact of initial FDG PET/CT in the management plan of patients with locally advanced head and neck cancer.

OBJECTIVE: To determine the impact of initial FDG PET/CT staging on clinical stage and the management plan in patients with locally advanced head and neck cancer (LAHNC). MATERIALS AND METHODS: We retrospectively reviewed the records of 72 consecutive patients (2007-2010) staged with PET/CT and conventional CT with tumours of hypopharynx/larynx (26 patients, 36 %), oral cavity (17 patients, 24 %), oropharynx (16 patients, 22 %), nasopharynx (12 patients, 17 %), and others (2 %). The impact of PET/CT on management plans was considered high when PET/CT changed the planned treatment modality or treatment intent, and intramodality changes were considered as minor changes with low impact. RESULTS: FDG PET/CT changed the stage in 27 patients and had high impact on the management plan in 12 % of patients (detection of distant metastases in 6 patients and stage II in 2 patients). Intramodality changes were more frequent: FDG PET/CT altered the TNM stage in 18/72 (25 %) of patients, upstaging N stage in 90 % of patients with low impact. CONCLUSIONS: Initial FDG PET/CT staging not only improves stage but also affects the management plan in LAHNC patients.

Radiomarcaje y estudios de biodistribución de nanopartículas poliméricas como adyuvantes para la vacunación oftálmica frente a la brucelosis / Radiolabeling and biodistribution studies of polymeric nanoparticles as adjuvants for ocular vaccination against brucellosis

Objetivo. Optimizar el radiomarcaje con 99mTc de nanopartículas de Gantrez® manosiladas y cargadas con el antígeno de Brucella ovis (Man-NP-HS) y llevar a cabo estudios de biodistribución en un ratón tras la administración de las nanopartículas por vía ocular. Material y métodos. Las Man-NP-HS se obtuvieron por el método de desplazamiento del disolvente. Se purificaron, liofilizaron y caracterizaron. A continuación, se marcaron con 74MBq de 99mTcO4− previamente reducido con una disolución ácida de cloruro de estaño, trabajando en ausencia de oxígeno y con un pH final de 4. El rendimiento del marcaje se evaluó mediante TLC. Los estudios de biodistribución se llevaron a cabo en ratones tras la administración oftálmica de la formulación y de un control de 99mTcO4− libre. Para ello, se sacrificaron los animales a las 2 y a las 24h tras la administración ocular y se contaron los órganos en un contador gamma. Resultados. Se obtuvo un rendimiento de marcaje superior al 90%. Los estudios de biodistribución de 99mTc-Man-NP-HS permitieron detectar la actividad concentrada en la mucosa nasal y ocular y el tracto gastrointestinal tanto a las 2 como a las 24h frente a la biodistribución de 99mTcO4− libre que permaneció concentrado en la piel alrededor del ojo y en el tracto gastrointestinal. Conclusión. Los estudios de biodistribución de 99mTc-Man-NP-HS tras la administración oftálmica han permitido demostrar su biodistribución en las mucosas y el tracto gastrointestinal, característica indispensable como sistema de liberación de antígenos a través de la mucosa ocular. Esto, junto con su elevada respuesta inmune, efectiva protección y no virulencia, convierte a estas nanopartículas en una vacuna ideal antibrucelosis (AU)

Purpose. To optimize radiolabeling with 99mTc of mannosylated Gantrez® nanoparticles loaded with the Brucella Ovis antigen (Man-NP-HS) and to carry out biodistribution studies in mice after ocular administration of the nanoparticles. Material and methods. Man-NP-HS nanoparticles were prepared by the solvent displacement method. They were purified, lyophilized and characterized. Following this, they were radiolabeled with 74 MBq of 99mTcO4− previously reduced with an acidic stannous chloride solution, working in absence of oxygen and at a final pH of 4. Radiolabeling yield was evaluated by TLC. Biodistribution studies were carried out in mice after ocular administration of the formulation and control of free 99mTcO4−. To do so, the animals were humanely killed at 2 and 24hours after the ocular administration and activity in organs was measured in a Gamma counter. Results. Radiolabeling yield obtained was greater than 90%. Biodistribution studies of 99mTc-Man-NP-HS showed radioactivity accumulated at 2 and 24hours in nasal and ocular mucosa and gastrointestinal tract, in contrast to biodistribution of free 99mTcO4− that remained concentrated in the skin around the eye and gastrointestinal tract. Conclusion. Biodistribution studies of 99mTc-Man-NP-HS after ocular instillation have made it possible to demonstrate its biodistribution in nasal mucosa and gastrointestinal tract. This characteristic is essential as an antigenic delivery system throughout the ocular mucosa. This, together with its elevated immune response, effective protection and intrinsic avirulence make them a suitable anti-Brucella vaccine candidate (AU)

Aportación del tiempo de vuelo y de la modelización de la respuesta a una fuente puntual a las características de funcionamiento del tomógrafo PET/TAC Biograph mCT / Contribution of time of flight and point spread function modeling to the performance characteristics of the PET/CT Biograph mCT scanner

Objetivo. Caracterizar el funcionamiento del tomógrafo PET/TAC Biograph mCT TrueV que incorpora el tiempo de vuelo (TOF) y modeliza la respuesta a una fuente puntual (PSF). Material y métodos. El tomógrafo combina un TAC de 64 cortes y un PET que reconstruye tomográficamente con TOF y PSF. Las características de funcionamiento PET se evaluaron siguiendo el estándar NEMA NU-2-2007, ampliando algunas pruebas. Adicionalmente se evaluaron diferentes algoritmos de reconstrucción y se midieron la radiación intrínseca y la uniformidad tomográfica. Resultados. La resolución espacial (FWHM) a 1 y 10cm del eje fue de 4,4 y 5,3mm, mejorando al introducir la PSF a 2,6 y 2,5mm. La sensibilidad fue de 10,9 y 10,2 kcps/MBq a 0 y 10cm del eje. La fracción de dispersión fue inferior al 34% a bajas concentraciones y la tasa de sucesos equivalentes al ruido (NECR) fue máxima en 182 kcps a 27,8 kBq/mL. La radiación intrínseca produjo 4,42 coincidencias verdaderas por segundo. El coeficiente de variación de la uniformidad del volumen y del sistema fue del 4,7 y 0,8%. La prueba de calidad de imagen mostró mejores resultados al incluir conjuntamente PSF y TOF. Específicamente, la PSF mejoró el contraste de las esferas calientes y la variabilidad del fondo, mientras que el TOF aumentó el contraste de las esferas frías. Conclusiones. El tomógrafo tiene muy buenas características de funcionamiento, además la calidad de la imagen mejora al incorporar la información de la PSF y del TOF en la reconstrucción tomográfic (AU)

Objective. To characterize the performance of the Biograph mCT PET/CT TrueV scanner with time of flight (TOF) and point spread function (PSF) modeling. Material and methods. The PET/CT scanner combines a 64-slice CT and PET scanner that incorporates in the reconstruction the TOF and PSF information. PET operating characteristics were evaluated according to the standard NEMA NU 2-2007, expanding some tests. In addition, different reconstruction algorithms were included, and the intrinsic radiation and tomographic uniformity were also evaluated. Results. The spatial resolution (FWHM) at 1 and 10cm was 4.4 and 5.3mm, improving to 2.6 and 2.5mm when PSF is introduced. Sensitivity was 10.9 and 10.2 Kcps/MBq at 0 and 10cm from the axis. Scatter fraction was less than 34% at low concentrations and the noise equivalent count rate (NECR) was maximal at 27.8 kBq/mL with 182 Kcps, the intrinsic radiation produced a rate of 4.42 true coincidences per second. Coefficient of variation of the volume and system uniformity were 4.7 and 0.8% respectively. The image quality test showed better results when PSF and TOF were included together. PSF improved the hot spheres contrast and background variability, while TOF improved the cold spheres contrast. Conclusions. The Biograph mCT TrueV scanner has good performance characteristics. The image quality improves when the information from the PSF and the TOF is incorporated in the reconstruction (AU)

[Radiolabeling and biodistribution studies of polymeric nanoparticles as adjuvants for ocular vaccination against brucellosis]. / Radiomarcaje y estudios de biodistribución de nanopartículas poliméricas como adyuvantes para la vacunación oftálmica frente a la brucelosis.

PURPOSE: To optimize radiolabeling with (99m)Tc of mannosylated Gantrez(®) nanoparticles loaded with the Brucella Ovis antigen (Man-NP-HS) and to carry out biodistribution studies in mice after ocular administration of the nanoparticles. MATERIAL AND METHODS: Man-NP-HS nanoparticles were prepared by the solvent displacement method. They were purified, lyophilized and characterized. Following this, they were radiolabeled with 74 MBq of (99m)TcO4(-) previously reduced with an acidic stannous chloride solution, working in absence of oxygen and at a final pH of 4. Radiolabeling yield was evaluated by TLC. Biodistribution studies were carried out in mice after ocular administration of the formulation and control of free (99m)TcO4(-). To do so, the animals were humanely killed at 2 and 24hours after the ocular administration and activity in organs was measured in a Gamma counter. RESULTS: Radiolabeling yield obtained was greater than 90%. Biodistribution studies of (99m)Tc-Man-NP-HS showed radioactivity accumulated at 2 and 24hours in nasal and ocular mucosa and gastrointestinal tract, in contrast to biodistribution of free (99m)TcO4(-) that remained concentrated in the skin around the eye and gastrointestinal tract. CONCLUSION: Biodistribution studies of (99m)Tc-Man-NP-HS after ocular instillation have made it possible to demonstrate its biodistribution in nasal mucosa and gastrointestinal tract. This characteristic is essential as an antigenic delivery system throughout the ocular mucosa. This, together with its elevated immune response, effective protection and intrinsic avirulence make them a suitable anti-Brucella vaccine candidate.

[Contribution of time of flight and point spread function modeling to the performance characteristics of the PET/CT Biograph mCT scanner]. / Aportación del tiempo de vuelo y de la modelización de la respuesta a una fuente puntual a las características de funcionamiento del tomógrafo PET/TAC Biograph mCT.

OBJECTIVE: To characterize the performance of the Biograph mCT PET/CT TrueV scanner with time of flight (TOF) and point spread function (PSF) modeling. MATERIAL AND METHODS: The PET/CT scanner combines a 64-slice CT and PET scanner that incorporates in the reconstruction the TOF and PSF information. PET operating characteristics were evaluated according to the standard NEMA NU 2-2007, expanding some tests. In addition, different reconstruction algorithms were included, and the intrinsic radiation and tomographic uniformity were also evaluated. RESULTS: The spatial resolution (FWHM) at 1 and 10cm was 4.4 and 5.3mm, improving to 2.6 and 2.5mm when PSF is introduced. Sensitivity was 10.9 and 10.2 Kcps/MBq at 0 and 10cm from the axis. Scatter fraction was less than 34% at low concentrations and the noise equivalent count rate (NECR) was maximal at 27.8 kBq/mL with 182 Kcps, the intrinsic radiation produced a rate of 4.42 true coincidences per second. Coefficient of variation of the volume and system uniformity were 4.7 and 0.8% respectively. The image quality test showed better results when PSF and TOF were included together. PSF improved the hot spheres contrast and background variability, while TOF improved the cold spheres contrast. CONCLUSIONS: The Biograph mCT TrueV scanner has good performance characteristics. The image quality improves when the information from the PSF and the TOF is incorporated in the reconstruction.

Relación entre el tamaño de los tumores renales y el estado de extensión evidenciado luego de manejo quirurgico / Size renal tumors and extension condition evidencing after surgical handle

Objetivos: Determinar si el tamaño tumoral renal, es predictivo de compromiso vascular de los tumores renales, así como determinar la utilidad de la Tomografía Axial Computarizada (TAC) en establecer el tamaño tumoral. Materiales y Métodos: Estudio retrospectivo, revisión de 34 Historias Clínicas de dos centros asistenciales, con diagnóstico de Tumor renal a quienes se les realizó Nefrectomía Radical, entre enero de 1992 y junio del 2001, mediante la realización de TAC. Se evaluaron los síntomas, tratamiento y estado clínico de la enfermedad. Resultados: 34 pacientes con edad promedio de 58,27 años. 52/8 por ciento de sexo masculino y 47,2 por ciento de sexo femenino. 69 por ciento sin metástasis en los estudios de extensión, 11,1 por ciento con adenopatías retroperitoneales, 2,8 por ciento con metástasis a Sistema Nervioso Central y 16/1 por ciento a pulmón. 63,9 por ciento de los pacientes consultaron por hematuria, 16,7 por ciento por dolor lumbar, 16,7 por ciento como hallazgo incidental y 2,8 por ciento por presencia de masa. El seguimiento en promedio fue de 30 meses. 13,8 por ciento de los pacientes requirieron trombectomía además de la Nefrectomía. El promedio de tamaño en la TAC fue de 10,63 cm. y en el espécimen quirúrgico de 9,72. A la inversa, los pacientes con menor tamaño en la TAC, mostraron diferencia de 1cm el 66,7 por ciento, y de 2 cm el 33,3 por ciento (p<0,001). 6 pacientes con tamaño > a 7cm mostraron compromiso vascular, ninguno con menos de 7cm; 15 sin compromiso vascular mostraron masa de más de 7cm, y 13 pacientes sin compromiso vascular mostraron masa de menos de 7cm. Conclusiones: Sensibilidad 28,57 por ciento de compromiso vascular con volúmenes tumorales de más de 7cm. Valor predictivo negativo de 46,4 por ciento. En general la variación del tamaño del espécimen patológico no es mayor de un centímetro relacionado con el tamaño encontrado en la TAC

Correlación clínico-urodinámica de la incontinencia urinaria en mujeres / Urodinamycs clinical correlation of the urinary incontinence in women

Objetivos. Determinar la utilidad del estudio urodinámico, en la valoración de las mujeres con incontinencia urinaria de esfuerzo (IUE), que van a ser llevadas a manejo quirúrgico. Metodología. Se revisaron las historias clínicas de las pacientes llevadas a cirugía para IUE, desde enero de 1998 hasta diciembre del 2000, clasificando clínicamente el tipo de incontinencia. Igualmente, se estableció a que pacientes se les realizó urodinamia, como parte de la evaluación prequirúrgica, valorando si este estudio corroboró o modificó el diagnóstico clínico o la conducta terapéutica. Resultados. Se estudiaron 80 pacientes con promedio de edad de 50 años. Se realizó urodinamia en 39 pacientes (48.8 por ciento), realizándose diagnóstico clínico de incontinencia urinaria de esfuerzo pura (IUEP), en 55 pacientes (68.8 por ciento), incontinencia urinaria mixta (IUM) en 24 pacientes (30 por ciento) y sospecha de incontinencia urinaria de esfuerzo tipo III (SIUE III), en 1 paciente (1.3 por ciento). Se realizó urodinamia en 16 mujeres con IUEP, en 22 con IUM, y en 1 con SIUE III. En las pacientes a quienes se les realizó urodinamia se corroboró el diagnóstico clínico en el 89.7 por ciento y se modificó el diagnóstico clínico en 10.3 por ciento. La conducta quirúrgica sólo se modificó en 2 pacientes (5.1 por ciento). Al hacer el análisis por tipo de incontinencia, se corroboró el diagnóstico clínico en el 100 por ciento de los casos de IUEP y en el 86.4 por ciento de las pacientes con IUM, modificando la conducta terapéutica en 1 caso (4.5 por ciento), difiriendo el tratamiento quirúrgico definitivo. La urodinamia modificó el diagnóstico clínicoy la conducta quirúrgica definitiva en 1 caso de las pacientes con IUE grado III. Conclusión. En el presente estudio, la urodinamia modificó la conducta quirúrgica definitiva en solo 1 caso de IUE grado III (sospecha de IUE tipo III), representando la mayor importancia clínica, el examen de las pacientes en el estudio de las mujeres con IUE, que van a ser llevadas a cirugía, dada la gran correlación clínico-urodinámica evidenciada

Densidad del PSA de la zona transicional como predictor de cáncer de próstata / PSA density of the transitional zone as prostate cancer predictor

Determinar la utilidad de la densidad del PSA de la zona de transición (PSAD ZT) como predictor de adenocarcinoma de próstata en la biopsia transrectal ecodirigida, en pacientes con PSA entre 4 y 10 ng/ml. Se llevó un registro prospectivo, de los pacientes que asisten a consulta de Urología del Hospital Militar Central, sometidos a biopsia transrectal de próstata, durante un período determinado de tiempo, especificando el PSA, volumen prostático, volumen de la ZT, calculando la densidad del PSA y la densidad del PSA de la ZT y revisando posteriormente el reporte de la patología de la biopsia. Se estudiaron 78 pacientes, con edad promedio de 63 años. Se encontró adenocarcinoma en la biopsia en 8 pacientes (10.25 por ciento ) y patología benigna en 70 pacientes (89.75 por ciento ). El PSA promedio de los pacientes con cáncer fue de 6.87 ng/ml y el de los pacientes con patología benigna de 6.78 ng/ml. El volumen de la ZT promedio de los pacientes con cáncer fue de 15.37 ce representando el 35 por ciento del volumen prostático y en patología benigna fue 31.25 ce y 55.34 por ciento respectivamente. La PSAD ZT promedio para los pacientes con cáncer fue de 0.492 ng/ml/cc y para los pacientes con patología benigna de 0.244 ng/ml/ce. Tomando como punto de corte 0.350 ng/ml/ce se encontró una sensibilidad del 100 por ciento y una especificidad del 97.2 por ciento , así como valor predictivo positivo del 80 por ciento y un valor predictivo negativo del 100 por ciento para la PSAD ZT en la predicción de adenocarcinoma de próstata en la biopsia