Impact of Extracellular DNA on Architectural Parameters of Leptospira biflexa Biofilm.

Extracellular DNA (eDNA) is a major component of bacterial biofilms. In this study, we performed a three-dimensional analysis of Leptospira biofilm using advanced imaging by confocal laser scanning microscopy (CLSM) and multi-parameter analysis by COMSTAT 2 software, with quantification of Leptospira and eDNA fluorescence. To investigate the role of eDNA in Leptospira biofilm, we treated Leptospira biflexa biofilms with DNase I enzyme (DNase), which digested eDNA, and compared DNase treated biofilms and controls. There was a significant reduction of the biomass of biofilms treated with DNase, by spectrophotometry and COMSTAT analysis. The multiparameter analysis evidenced for DNase-treated biofilms a significant decrease in the surface area and the average thickness; opposing to a significant augmentation of the surface/biovolume ratio and the roughness coefficient (Ra*), when compared to controls. We analyzed the parameters of DNase-treated biofilms by Pearson's correlation coefficient and found significant positive correlations between biomass and average thickness; biomass and surface area; surface area and average thickness. On the other hand, there were significant negative correlations between Ra* and biomass; Ra* and average thickness; Ra* and surface area. These findings suggest that eDNA digestion results in biofilm instability and alteration of the three-dimensional architecture, justifying the negative correlation between Ra* and the above-mentioned parameters. In conclusion, our study showed that eDNA digestion produced a massive structural loss, instability, and dramatic changes in the three-dimensional architecture of Leptospira biflexa biofilm. These findings contribute to a better understanding of the role of eDNA and highlight the importance of eDNA as a key component in Leptospira biofilms.

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers.

Copper nitride, a metastable semiconductor material with high stability at room temperature, is attracting considerable attention as a potential next-generation earth-abundant thin-film solar absorber. Moreover, its non-toxicity makes it an interesting eco-friendly material. In this work, copper nitride films were fabricated using reactive radio frequency (RF) magnetron sputtering at room temperature, 50 W of RF power, and partial nitrogen pressures of 0.8 and 1.0 on glass and silicon substrates. The role of argon in both the microstructure and the optoelectronic properties of the films was investigated with the aim of achieving a low-cost absorber material with suitable properties to replace the conventional silicon in solar cells. The results showed a change in the preferential orientation from (100) to (111) planes when argon was introduced in the sputtering process. Additionally, no structural changes were observed in the films deposited in a pure nitrogen environment. Fourier transform infrared (FTIR) spectroscopy measurements confirmed the presence of Cu-N bonds, regardless of the gas environment used, and XPS indicated that the material was mainly N-rich. Finally, optical properties such as band gap energy and refractive index were assessed to establish the capability of this material as a solar absorber. The direct and indirect band gap energies were evaluated and found to be in the range of 1.70-1.90 eV and 1.05-1.65 eV, respectively, highlighting a slight blue shift when the films were deposited in the mixed gaseous environment as the total pressure increased.

[Experience with 4 clinical cases. Traumatic encephalopathy may be associated with a single traumatic brain injury?] / Experiencia con cuatro casos clínicos, ¿puede la encefalopatía traumática crónica estar asociada a un traumatismo craneoencefálico único?

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that affects people who had repetitive head trauma. Also, in single traumatic brain injury (TBI), changes may be found during the follow-up visits. We present four clinical cases of patients visited at the Institut Guttmann clinic between 2017 and 2019. They were affected by mild sequelae of severe and unique TBI who have subsequently developed a neurodegenerative disease without a specific diagnosis, and who could meet clinical criteria for chronic traumatic encephalopathy syndrome. Rehabilitation doctors are the professionals with the greatest possibility of identifying a suggestive clinic of this pathology, they can order the appropriate studies and indicate the new rehabilitation goals according to the new neurological situation.

Fetal Hemodynamic Parameters in Low Risk Pregnancies: Doppler Velocimetry of Uterine, Umbilical, and Middle Cerebral Artery.

Objective. To elaborate curves of longitudinal reference intervals of pulsatility index (PI) and systolic velocity (SV) for uterine (UtA), umbilical (UA), and middle cerebral arteries (MCA), in low risk pregnancies. Methods. Doppler velocimetric measurements of PI and SV from 63 low risk pregnant women between 16 and 41 weeks of gestational age. Means (±SD) for intervals of gestational age and percentiles 5, 50, and 95 were calculated for each parameter. The Intraclass Correlation Coefficients (ICC) were also estimated for assessing intra- and intervariability of measurements. Results. Mean PI of UtA showed decreasing values during pregnancy, but no regular pattern was identified for mean SV. For UA, PI decreased and SV increased along gestation. MCA presented PI increasing values until 32-35 weeks. SV showed higher levels with increasing gestation. High ICC values indicated good reproducibility. Conclusions. Reference intervals for the assessment of SV and PI of UtA, UA, and MCA were established. These reference intervals showed how a normal pregnancy is expected to progress regarding these Doppler velocimetric parameters and are useful to follow high risk pregnancies. The comparison between results using different curves may provide insights about the best patterns to be used.

Leptospira in breast tissue and milk of urban Norway rats (Rattus norvegicus).

Leptospirosis is a zoonosis caused by bacteria of the genus Leptospira. The disease is globally distributed and a major public health concern. The Norway rat (Rattus norvegicus) is the main reservoir of the pathogen in urban slums of developing and developed countries. The potential routes of intra-specific leptospire transmission in rats are largely unknown. Herein, we identified pathogenic Leptospira spp. in breast tissue and milk of naturally infected rats. We examined kidney, breast tissue and milk from 24 lactating rats for the presence of leptospires using immunofluorescence, immunohistochemistry, polymerase chain reaction (PCR) and scanning electronic microscopy. All 24 rats had evidence for Leptospira in the kidneys, indicating chronic carriage. The majority of kidney-positive rats had detectable leptospires in milk (18, 75%) and breast tissue (16, 67%), as evidenced by immunofluorescence assay and immunohistochemistry. Four (17%) milk samples and two (8%) breast tissue samples were positive by quantitative real-time PCR. Scanning electron microscopy confirmed the presence of leptospires in breast tissue. No major pathological changes in breast tissue were found. This study, for the first time, identified leptospires in the milk and breast tissue of wild Norway rats, suggesting the possibility of milk-borne transmission of leptospirosis to neonates.

Determination of backscatter factors in breast tomosynthesis using MCNPX simulations and measurements.

The perspective of adding digital breast tomosynthesis (DBT) to standard mammography in screening raises concerns regarding the dose absorbed by the fibroglandular breast tissue. Thus, it is important to estimate accurately the mean glandular dose (MGD), although there are no standard protocols for dosimetry, concerning DBT. This study aims at introducing backscatter factors (BSF) to calculate the entrance surface air kerma (ESAK), directly on patients or phantoms, in order to be introduced in the formalism proposed by Dance et al. MCNPX simulations were performed, to mimic a DBT acquisition, for a wide range of X-ray spectra. A homogeneous breast phantom with 50 % of glandular tissue was considered and several thicknesses were evaluated. Dose measurements were performed, to validate and support the simulation results. The BSF may indicate a real MGD estimation in vivo for DBT examinations and contribute for the improvement of the current guidelines used in these applications.

Assessment of the occupational exposure in real time during interventional cardiology procedures.

Interventional cardiology (IC) procedures can be complex, requiring the operators to work near the patient, during long exposure times. Owing to scattered radiation in the patient and the fluoroscopic equipment, the medical staff are exposed to a non-uniform radiation field and can receive high radiation doses. In this study, it is proposed to analyse staff doses obtained in real time, during IC procedures. A system for occupational dosimetry in real time was used. In order to identify some parameters that may affect the staff doses, Monte Carlo (MC) calculations, using MCNPX v.2.7.0 code and voxel phantoms, were performed. The data obtained from measurements, together with MC simulations, allowed the identification of actions and behaviours of the medical staff that could be considered a risk under routine working conditions. The implementation of this monitoring system for exposure of personnel may have a positive effect on optimisation of radiological protection in fluoroscopically guided cardiac procedures.

Paediatric CT exposures: comparison between CTDI vol and SSDE methods using measurements and Monte Carlo simulations.

Computed tomography (CT) is one of the most used techniques in medical diagnosis, and its use has become one of the main sources of exposure of the population to ionising radiation. This work concentrates on the paediatric patients, since children exhibit higher radiosensitivity than adults. Nowadays, patient doses are estimated through two standard CT dose index (CTDI) phantoms as a reference to calculate CTDI volume (CTDI vol) values. This study aims at improving the knowledge about the radiation exposure to children and to better assess the accuracy of the CTDI vol method. The effectiveness of the CTDI vol method for patient dose estimation was then investigated through a sensitive study, taking into account the doses obtained by three methods: CTDI vol measured, CTDI vol values simulated with Monte Carlo (MC) code MCNPX and the recent proposed method Size-Specific Dose Estimate (SSDE). In order to assess organ doses, MC simulations were executed with paediatric voxel phantoms.

Assessment of patient dose reduction by bismuth shielding in CT using measurements, GEANT4 and MCNPX simulations.

This work reports on the use of two different Monte Carlo codes (GEANT4 and MCNPX) for assessing the dose reduction using bismuth shields in computer tomography (CT) procedures in order to protect radiosensitive organs such as eye lens, thyroid and breast. Measurements were performed using head and body PMMA phantoms and an ionisation chamber placed in five different positions of the phantom. Simulations were performed to estimate Computed Tomography Dose Index values using GEANT4 and MCNPX. The relative differences between measurements and simulations were <10 %. The dose reduction arising from the use of bismuth shielding ranges from 2 to 45 %, depending on the position of the bismuth shield. The percentage of dose reduction was more significant for the area covered by the bismuth shielding (36 % for eye lens, 39 % for thyroid and 45 % for breast shields).

Medical staff extremity dosimetry in CT fluoroscopy: an anthropomorphic hand voxel phantom study.

This work aims to contribute to the study of the radiation dose distribution delivered to the hands of medical staff members during a general computed tomographic (CT) fluoroscopic guided procedure. In this study, both Monte Carlo simulations and measurements were performed. For free-in-air and computed tomography dose index (CTDI) body phantom measurements, a standard pencil ionization chamber (IC) 100 mm long was used. The CT scanner model was implemented using MCNPX (Monte Carlo N-Particle eXtended) and was successfully validated by comparing the simulated results with measurements. Subsequently, CT images of a hand, together with an anthropomorphic phantom, were voxelized and used with the MCNPX code for dose calculations. The hand dose distribution study was performed both by using thermo-luminescent detector measurements and Monte Carlo simulations. The validated simulation tool provides a new perspective for detailed investigations of CT-irradiation scenarios. Simulations show that there is a strong dose gradient, namely the even zones of the hand that are in precise vicinity to the x-ray beam only receive about 4% of the maximum dose delivered to adjacent areas which are directly exposed to the primary x-ray beam. Finally, the scatter contribution of the patient was also studied through MC simulations. The results show that for directly exposed parts of the hand surface, the dose is reduced by the body of the patient (due to the shielding), whereas the dose is increased by scattered radiation from the patient for parts of the skin that receive scattered radiation only.

Ultrasonido endoscópico y puncion aspiración con aguja fina en tumores del páncreas: experiencia de 2 años. Servicio oncológico hospitalario del IVSS 2010 / Endoscopic ultrasound and fine needle aspiration puncture in tumors of the pancreas: 2 years experience. Hospital oncology service IVSS 2010

La punción aspiración guiada por ultrasonido endoscópico (PAAF-USE) se ha convertido en una herramienta fundamental en el diagnóstico de los tumores de páncreas. Es un procedimiento con baja tasa de complicaciones que además provee información determinante que puede modificar la conducta terapéutica. Métodos: Estudio retrospectivo, descriptivo. Se incluyeron pacientes con diagnóstico de tumor de páncreas referidos para la realización PAAF-USE en el período comprendido entre 2008-2009. Resultados: 36 pacientes fueron estudiados, 58.30% (n=21) del sexo femenino. Se evidenciaron tumores sólidos en el 80.5%. Según la histología, fueron reportados adenocarcinoma en el 47.05% (n=16), cistoadenoma mucinoso en el 8.88% (n=3), cistoadenocarcinoma en el 5.88% (n=2), linfoma no Hodgkin en el 5.88% (n=2), tumor neuroendocrino (insulinoma) en el 2.94 % (n=1), cistodenoma seroso en el 2.94% (n=1), tumor sólido pseudopapilar en el 2.94% (n=1), tumor metastásico a páncreas en el 2.94% (n=1) y el 17.64% (n=6) fueron reportados negativos para malignidad. No hubo complicaciones asociadas al procedimiento. Conclusiones: Los hallazgos obtenidos por PAAF-USE permiten establecer el diagnóstico en un alto porcentaje de las lesiones tumorales del páncreas, con una baja tasa de complicaciones, permitiendo seleccionar conductas terapéuticas adecuadas.

Endoscopic ultrasound-guided fine-needle-aspiration (EUS-FNA) has become an essential tool for the diagnosis and staging of pancreatic neoplasms. It is a procedure with low complication rates and also provides crucial information which could alter the therapeutic management. Methods: A retrospective analysis of patients referred for USE-FNA with presumed pancreatic neoplasms between January 2008 and December 2009. Results: 36 patients were studied, 58.30% (n = 21) were females. Solid tumors were evident in 80.5%. According to their histology, adenocarcinoma were reported in 47.05% (n = 16), mucinous cystadenoma in 8.88% (n = 3), cystadenocarcinoma in 5.88% (n = 2), non-Hodgkin lymphoma in 5.88% (n = 2), neuroendocrine tumor (insulinoma) in 2.94% (n = 1), serous cystoadenoma in 2.94% (n = 1), solid pseudopapillary tumor in 2.94% (n = 1), metastatic tumor 2.94 % (n = 1) and 17.64% (n = 6) were reported negative for malignancy. There were no complications associated with the procedure. Conclusions: The fi ndings obtained by EUS-FNA make diagnosis possible in a high percentage of tumoral lesions of the pancreas, with no procedural complication rates overall in this study. Consequently, the accurate histological diagnosis will have the potential to affect the selection of an appropriate treatment.

Marsh deer (Blastocerus dichotomus) reintroduction in the Jataí Ecological Station (Luís Antônio, SP): spatial preferences.

Throughout the latter half of the twentieth century, wildlife habitat destruction and species extinctions have greatly increased. As the number of endangered species grows, the use of reintroduction as a conservation tool against species extinction increases. This study focuses on a 16-month study on marsh deer reintroduced in the Jataí Ecological Station. The animals were radio tagged and tracked daily between December 1998 and April 2000. Displacement activity and spatial preferences were monitored by triangulation. The animals wandered the floodplains inside the protected area and also a floodplain that is part of privately owned property on the western edge of the Jataí Ecological Station. During the study, most of the reintroduced marsh deer preferred the private floodplain area more than the floodplains inside the protected area. This preference revealed the ecological importance of the area and the necessity of its incorporation into the Jataí Ecological Station.

Marsh deer (Blastocerus Dichotomus) reintroduction in the Jataí Ecological Station (Luís Antônio, SP): spatial preferences

A destruição dos habitats naturais e a extinção de espécies têm crescido muito a partir da última metade do século XX. Nesse contexto, o aumento do número de espécies ameaçadas tem proporcionado maior uso da reintrodução como estratégia de conservação no combate à atual taxa de extinção. O presente trabalho focaliza um estudo de 16 meses realizado com cervos-do-pantanal reintroduzidos na Estação Ecológica de Jataí. Os animais foram marcados com rádio-colares e monitorados diariamente entre dezembro de 1998 e abril de 2000, tendo suas atividades de deslocamento e uso do espaço acompanhadas por triangulação. Os animais exploraram várzeas dentro da unidade de conservação e também uma área de várzea pertencente a uma propriedade particular localizada na fronteira oeste da estação. Durante o período de estudo, a maioria dos cervos reintroduzidos utilizou a área de várzea particular mais intensivamente que as várzeas da unidade de conservação. A preferência demonstrada por essa área confirmou sua importância ecológica, evidenciando a necessidade de proteção por meio de sua incorporação aos limites da Estação Ecológica de Jataí. .

Predictive value of the acid fast smear for detection of Mycobacterium tuberculosis in respiratory specimens in a reference center of HIV/AIDS in Rio de Janeiro, Brazil.

In order to evaluate the predictive value of acid fast bacilii (AFB) smear for the diagnosis of Mycobacterium tuberculosis in respiratory specimens in a setting with a high prevalence of AIDS and an unknown prevalence of nontuberculous mycobacteria (NTM), we retrospectively examined specimens cultured for mycobacteria between 1 September 1993 and 30 September 1994 and medical records of patients with positive culture in a General Hospital, AIDS reference in Rio de Janeiro, Brazil. Seventy three per cent (1517/2077) of samples were respiratory specimens and mycobacteria were recovered from 20.6% (313/1517) of these. M. tuberculosis was identified in 94.2% (295/313) and NTM in 5.8% (18/313). The yield of positive AFB smear and of positive culture was 6.1% (93/1517) and 20.6% (313/1517), respectively. The positive predictive value (PPV) of AFB for M. tuberculosis was 98.4% in expectorated sputum and 96.4% in bronchoalveolar lavage. Forty four percent (130/295) of specimens with positive culture for M. tuberculosis and 66.7% (12/18) for NTM were from patients HIV positive. The conclusion was that in our study population, the PPV of AFB for M. tuberculosis in respiratory specimens was high and the prevalence of NTM was low despite the high prevalence of HIV positive.