Study on the dose profile in CT-fluoroscopy.

This work aims to contribute to the description of the dose profile in Computed Tomography Fluoroscopy (CTF). Our approach uses a function model to fit the single slice dose profiles (SSDP) for any point inside the gantry of the CT unit, with special attention to points off the rotation axis. The function model was successfully tested with measurements performed using GafChromic film. The parameters of the SSDP at the rotation axis (isocenter) and at 8 cm and 16 cm off the isocenter were determined. The model allows an estimation of the slice thickness at the isocenter and for points at 8 cm and 16 cm off the isocenter. The differences between the slice thicknesses results in overestimation of the Computed Tomography Dose Index, CTDI, by values as high as 20% if the nominal slice thickness instead of the model estimated value is used. The results obtained in this work provided a good description of the dose profiles, which can be used in further studies such as comparisons with measurements performed with phantoms and patients.

Ventilation distribution as a contributor to the functional exercise capacity in patients with systemic sclerosis-associated interstitial lung disease without pulmonary hypertension.

Phenotypic differences have been described between patients with systemic sclerosis (SSc)-associated interstitial lung disease (ILD) and SSc-associated pulmonary hypertension, including performance differences in the 6-min walk test (6MWT). Moreover, the correlations between the 6MWT and traditional pulmonary function tests (PFTs) are weak, indicating the need to search for new parameters that explain exercise performance. Thus, our objective was to evaluate the impact of ventilation distribution heterogeneity assessed by the nitrogen single-breath washout (N2SBW) test and peripheral muscle dysfunction on the exercise capacity in patients with SSc-ILD and limited involvement of the pulmonary parenchyma. In this cross-sectional study, 20 women with SSc-ILD and 20 matched controls underwent PFTs (including spirometry, diffusing capacity for carbon monoxide (DLco), and the N2SBW test) and performed the 6MWT and knee isometric dynamometry. The 6-min walking distance (6MWD, % predicted) was strongly correlated with the phase III slope of the single-breath nitrogen washout (phase III slopeN2SBW) (r=-0.753, P<0.0001) and reasonably correlated with the forced vital capacity (FVC) (r=0.466, P=0.008) and DLco (r=0.398, P=0.011). The peripheral oxygen saturation (SpO2) during exercise was not significantly correlated with any of the pulmonary or muscle function parameters. The phase III slopeN2SBW was the only predictive variable for the 6MWD, whereas quadriceps strength and FVC/DLco were predictive variables for SpO2. Ventilation distribution heterogeneity is one factor that contributes to a lower 6MWD in SSc-ILD patients. In addition, muscle dysfunction and abnormal lung diffusion at least partly explain the decreased SpO2 of these patients.

Dose to the interventional radiologist in CTF-guided procedures.

The aim of this work was to assess the occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures; to identify the most exposed areas of the body including the hands and fingers; to suggest recommendations for individual monitoring; and to improve radiation safety of the practice. A total of 53 CTF-guided procedures were studied. Twelve whole-body dosimeters were worn by the IR in each procedure for the assessment of the personal dose equivalent, Hp(10), on the chest, waist, and back, both over and under the lead apron, as well as the personal dose equivalent, Hp(0.07), on both arms, knees, and feet. Special gloves with casings to fit extremity dosimeters were prepared to assess Hp(0.07) to the fingers. The measured chest dose values were higher than those on the waist and back; the dominant hand or the left side was the most exposed. In general, the ring, middle, and index fingers of the dominant hand were the most exposed (maximum in the 36-39 mSv range), while wrist dose was negligible compared to finger doses. Based on the results obtained the following recommendations are suggested: protective devices (lead aprons, thyroid shield, and goggles) should be worn; Hp(10) should be assessed at the chest level both above and below the lead apron; finger doses can be measured on the basis of each middle finger; the arm closer to the beam should be monitored; and finally, a wrist dosimeter will not provide useful information.

Ventilation distribution as a contributor to the functional exercise capacity in patients with systemic sclerosis-associated interstitial lung disease without pulmonary hypertension

Phenotypic differences have been described between patients with systemic sclerosis (SSc)-associated interstitial lung disease (ILD) and SSc-associated pulmonary hypertension, including performance differences in the 6-min walk test (6MWT). Moreover, the correlations between the 6MWT and traditional pulmonary function tests (PFTs) are weak, indicating the need to search for new parameters that explain exercise performance. Thus, our objective was to evaluate the impact of ventilation distribution heterogeneity assessed by the nitrogen single-breath washout (N2SBW) test and peripheral muscle dysfunction on the exercise capacity in patients with SSc-ILD and limited involvement of the pulmonary parenchyma. In this cross-sectional study, 20 women with SSc-ILD and 20 matched controls underwent PFTs (including spirometry, diffusing capacity for carbon monoxide (DLco), and the N2SBW test) and performed the 6MWT and knee isometric dynamometry. The 6-min walking distance (6MWD, % predicted) was strongly correlated with the phase III slope of the single-breath nitrogen washout (phase III slopeN2SBW) (r=−0.753, P<0.0001) and reasonably correlated with the forced vital capacity (FVC) (r=0.466, P=0.008) and DLco (r=0.398, P=0.011). The peripheral oxygen saturation (SpO2) during exercise was not significantly correlated with any of the pulmonary or muscle function parameters. The phase III slopeN2SBW was the only predictive variable for the 6MWD, whereas quadriceps strength and FVC/DLco were predictive variables for SpO2. Ventilation distribution heterogeneity is one factor that contributes to a lower 6MWD in SSc-ILD patients. In addition, muscle dysfunction and abnormal lung diffusion at least partly explain the decreased SpO2 of these patients.

Biomedical applications of glyconanoparticles based on quantum dots.

BACKGROUND: Quantum dots (QDs) are outstanding nanomaterials of great interest to life sciences. Their conjugation versatility added to unique optical properties, highlight these nanocrystals as very promising fluorescent probes. Among uncountable new nanosystems, in the last years, QDs conjugated to glycans or lectins have aroused a growing attention and their application as a tool to study biological and functional properties has increased. SCOPE OF REVIEW: This review describes the strategies, reported in the literature, to conjugate QDs to lectins or carbohydrates, providing valuable information for the elaboration, improvement, and application of these nanoconjugates. It also presents the main applications of these nanosystems in glycobiology, such as their potential to study microorganisms, the development of diseases such as cancer, as well as to develop biosensors. MAJOR CONCLUSIONS: The development of glyconanoparticles based on QDs emerged in the last decade. Many works reporting the conjugation of QDs with carbohydrates and lectins have been published, using different strategies and reagents. These bioconjugates enabled studies that are very sensitive and specific, with potential to detect and elucidate the glycocode expressed in various normal or pathologic conditions. GENERAL SIGNIFICANCE: Produce a quick reference source over the main advances reached in the glyconanotechnology using QDs as fluorescent probes.

A new antitumoral Heteroarylaminothieno[3,2-b]pyridine derivative: its incorporation into liposomes and interaction with proteins monitored by fluorescence.

The fluorescence properties of the new potent antitumoral methyl 3-amino-6-(benzo[d]thiazol-2-ylamino)thieno[3,2-b]pyridine-2-carboxylate in solution and when encapsulated in several different nanoliposome formulations were investigated. The compound exhibits very reasonable fluorescence quantum yields and a solvent sensitive emission in several polar and non-polar media, despite not being fluorescent in protic solvents. Fluorescence anisotropy measurements of the compound incorporated into liposomes revealed that this thienopyridine derivative can be carried in the hydrophobic region of the lipid membrane. Liposome formulations including this antitumor compound are nanometric in size, with a diameter lower than 130 nm and generally low polydispersity, and are promising for future drug delivery developments. The interaction of the compound with bovine serum albumin (BSA) and the multidrug resistance protein MDR1 was monitored by FRET, the compound acting as an energy acceptor. It was observed that the drug had a lower interaction with the MDR1 protein than with the native form of BSA, which is an important result regarding applications of this antitumoral drug.

Heart rate variability and cardio-respiratory coupling during sleep in patients prior to bariatric surgery.

Obesity is associated with increased cardiac risk of morbidly and mortality and for the development and progression of obstructive sleep apnea (OSA). Severity of obesity negatively affects the heart rate variability (HRV) in patients with indication for bariatric surgery (BS). The purpose of this study is to determine if the severity of obesity alters the autonomic cardiac regulation and the cardio-respiratory coupling during sleep using spectral analysis of HRV and respiration variability signals (RS) in patients prior to BS. Twenty-nine consecutive preoperative BS and ten subjects (controls) underwent polysomnography. The spectral and cross-spectral parameters of the HRV and RS were computed during different sleep stages (SS). Spectral analysis of the HRV and RV indicated lower respiration regularity during sleep and a lower HRV in obese patients (OP) during all SS when compared with controls (p < 0.05). Severely (SO) and super-obese patients (SOP) presented lower values of low frequency/high frequency (LF/HF) ratio and LF power during REM sleep and higher HF power (p < 0.05), while morbidly obese (MO) patients presented lower LF/HF ratio and LF power in SS-S2 and higher HF power when compared to controls (p < 0.05). The cross-spectral parameters showed that SOP presented lower percentage of tachogram power coherent with respiration in SS-S3 when compared to controls (p < 0.05). Patients prior to BS presented altered HRV and RV in all SS. SO, MO, and SOP presented altered cardio-respiratory coupling during sleep, and these alterations are related with severity of obesity and OSA parameters.

Preliminary assessment of the dose to the interventional radiologist in fluoro-CT-guided procedures.

A preliminary assessment of the occupational dose to the intervention radiologist received in fluoroscopy computerised tomography (CT) used to guide the collection of lung and bone biopsies is presented. The main aim of this work was to evaluate the capability of the reading system as well as of the available whole-body (WB) and extremity dosemeters used in routine monthly monitoring periods to measure per procedure dose values. The intervention radiologist was allocated 10 WB detectors (LiF: Mg, Ti, TLD-100) placed at chest and abdomen levels above and below the lead apron, and at both right and left arms, knees and feet. A special glove was developed with casings for the insertion of 11 extremity detectors (LiF:Mg, Cu, P, TLD-100H) for the identification of the most highly exposed fingers. The H(p)(10) dose values received above the lead apron (ranged 0.20-0.02 mSv) depend mainly on the duration of the examination and on the placement of physician relative to the beam, while values below the apron are relatively low. The left arm seems to receive a higher dose value. H(p)(0.07) values to the hand (ranged 36.30-0.06 mSv) show that the index, middle and ring fingers are the most highly exposed. In this study, the wrist dose was negligible compared with the finger dose. These results are preliminary and further studies are needed to better characterise the dose assessment in CT fluoroscopy.

Uso de pinças ópticas para avaliação do potencial zeta de hemácias em EDTA, CPD-SAGM e estocadas / Use of optical tweezers for evaluation of szeta potential of red blood cells in EDTA, CPD-SAGM and stored in blood banks

A hemácia é carregada negativamente, principalmente devido ao ácido siálico que gera um potencial elétrico denominado Potencial Zeta que impede a aglutinação intravascular. Os testes de hemaglutinação na rotina transfusional, necessitam de substâncias potencializadoras, das quais muitas agem diminuindo o Potencial Zeta para se ter maior sensibilidade. Através da pinça óptica, ferramenta capaz de capturar células utilizando a luz, foi proposta uma metodologia para quantificar o potencial zeta e aplicar em hemácias coletadas com EDTA e estocadas em CPD-SAGM (visando avaliar alterações de cargas da membrana relacionadas a lesões de armazenamento. Os potenciais zeta em CPD-CAGM foram superiores (-14,8 mV) aos em EDTA (-7,9 mV) e decrescentes a partir do primeiro dia de armazenamento, estabilizando-se a partir da terceira semana com potencial zeta -7,6 mV. Hemácias com CPD-SAGM apresentaram potencial zeta maior, pois possivelmente este conservante evitou lesões mais significativas da membrana que poderiam alterar as cargas. A redução do potencial zeta no armazenamento pode ser consequência de enzimas liberadas de leucócitos lisados que tenham alterado as glicoforinas da membrana. A metodologia permitiu avaliar o potencial zeta em diferentes condições e poderá contribuir na padronização de técnicas de hemaglutinação com diferentes meios potencializadores e no melhor conhecimento das lesões de estocagem para fins transfusionais.

Impact of Forpus xanthopterygius (Spix, 1824) (Aves, Psittacidae) on flowers of Handroanthus serratifolius (Vahl.) S. O. Grose (Bignoniaceae).

Handroanthus serratifolius produces flowers during the dry season in the Cerrado biome, and it may be an important food source to some bird species. For Psittacidae species, like Forpus xanthopterygius, flowers are important in their diet. This study intended to characterize the behavior of F.xanthopterygius and evaluate the damage to the flowering and in the reproduction of H. serratifolius. Four individuals of H. serratifolius were observed for 60 hours to register size of groups, the time and duration of visit, and the number of flowers predated by F.xanthopterygius. The groups that visited the plants had between 2 and 12 individuals. The mean time of visits was 60.31 minutes (+/-22.29). The size of groups was correlated to number of flowers predated and was influenced by number of flowers offered. During the flowering, each H. serratifolius individual loses approximately 1,052 flowers per week.

Degradabilidade ruminal e digestibilidade intestinal da proteína de capim-elefante com três idades de corte / Rumen degradability and intestinal digestibility of protein of elephant-grass at three cutting ages

Determinaram-se a degradabilidade potencial (DP) e a digestibilidade intestinal da proteína não degradada no rúmen (DIPNDR) do capim-elefante em diferentes idades de rebrote (30, 45 e 60 dias) e comparou-se a técnica do saco de náilon móvel (in situ) com o método de três estádios (in vitro). Para tanto, utilizaram-se seis novilhos mestiços canulados no rúmen e duodeno alimentados exclusivamente com capim-elefante picado. O ensaio de degradabilidade foi realizado com amostras do capim incubadas no rúmen por 3, 6, 9, 12, 24, 48, 72, 96 e 120h. A digestibilidade intestinal foi determinada utilizando-se os resíduos de incubação por 24 horas. Na técnica in situ os resíduos em sacos de náilon foram colocados no duodeno e recuperados nas fezes. No método in vitro, os resíduos foram submetidos à digestão com HCl-pepsina-pancreatina. Em amostras de capim com idades de 30, 45 e 60 dias foram observados valores de DP da proteína de 87,5; 87,8 e 83,8 por cento, respectivamente. A DIPNDR variou com a idade do capim e foi semelhante entre os métodos in situ e in vitro somente para o capim com 60 dias. O método in situ apresentou estimativa de digestibilidade intestinal mais coerente com as mudanças na composição química do capim-elefante decorrentes do envelhecimento.

The potential degradability (PD) and intestinal digestibility of ruminal escape protein (IDREP) of elephant-grass at 30, 45, and 60 days of regrowth were determined and the mobile bag technique (in situ) was compared to the three-stage method (in vitro). Thus, six cross-bred steers with rumen and duodenum canulas were used and fed exclusively with chopped elephant grass. The degradability trial was carried out with grass samples incubated in rumen by 3, 6, 9, 12, 24, 48, 72, 96, and 120 h. The intestinal digestibility was determined using 24-h ruminal incubation residue. In the in situ technique, residues in nylon bags were placed in duodenum and recovered in feces. In the in vitro method, residues were digested with solution of HCl-pepsin-pancreatin. In samples of grass at 30, 45, and 60 days of age, the values of protein PD were 87.5, 87.8, and 83.8 percent, respectively. The IDREP ranged with grass age and it was similar between in situ and in vitro methods only for 60-day old grass. Considering the changes in elephant-grass chemical composition due to aging, the in situ method supplied a more coherent estimative of intestinal digestibility.

Comparison of deterministic and Monte Carlo methods in shielding design.

In shielding calculation, deterministic methods have some advantages and also some disadvantages relative to other kind of codes, such as Monte Carlo. The main advantage is the short computer time needed to find solutions while the disadvantages are related to the often-used build-up factor that is extrapolated from high to low energies or with unknown geometrical conditions, which can lead to significant errors in shielding results. The aim of this work is to investigate how good are some deterministic methods to calculating low-energy shielding, using attenuation coefficients and build-up factor corrections. Commercial software MicroShield 5.05 has been used as the deterministic code while MCNP has been used as the Monte Carlo code. Point and cylindrical sources with slab shield have been defined allowing comparison between the capability of both Monte Carlo and deterministic methods in a day-by-day shielding calculation using sensitivity analysis of significant parameters, such as energy and geometrical conditions.

Photon track evolution.

Given the time scale of biological, biochemical, biophysical and physical effects in a radiation exposure of living tissue, the first physical stage can be considered to be independent of time. All the physical interactions caused by the incident photons happen at the same starting time. From this point of view it would seem that the evolution of photon tracks is not a relevant topic for analysis; however, if the photon track is considered as a sequence of several interactions, there are several steps until the total degradation of the energy of the primary photon. We can characterise the photon track structure by the probability p(E,j), that is, the probability that a photon with energy E suffers j secondary interactions. The aim of this work is to analyse the photon track structure by considering j as a step of the photon track evolution towards the total degradation of the photon energy. Low energy photons (<150 keV) are considered, with water phantoms and half-extended geometry. The photon track evolution concept is presented and compared with the energy deposition along the track and also with the spatial distribution of the several steps in the photon track.

[Sport as integration factor of the physically handicapped in our society]. / Esporte como fator de integração do deficiente físico na sociedade.

The objective of this study was to make use of sports as a rehabilitation method, as well as to assess the physical, psychological, and social aspects of those present some physical handicap, particularly those who have some kind of chronic disease and are no longer taking part in any rehabilitation program. Thirty handicapped people were evaluated: fifteen started with basketball and fifteen with swimming, according either to the specific preference of each one of them or to the degree and kind of physical impairment. They were submmited to the following evaluations: clinical examination, physiotherapy assessment, social interview and use of the Rivermead Social Scale, functional classification of the sport, use of the Barthel and Rivermead Functional Scales, and the psychological profile test (POMS). After two years, no relevant change in the moving evolution of the athletes were reported. Concerning the POMS psychological test, both basketball and swimming groups presented with high vigor and low depression levels. Considering the social aspects, both groups presented substantial improvement, specially regarding their relationship to one person or more people and also in the everyday activities (be it social, leisure, or domestic), thus leading them to better social integration. This essay shows that sport can bring people who are physically impaired a better social integration and physical conditions.

[Blood pressure in school children and adolescents - The Belo Horizonte study] / Pressão arterial em escolares e adolescentes - O estudo de Belo Horizonte.

OBJECTIVE: To investigate epidemiological aspects of blood pressure (BP) levels, and the prevalence of arterial hypertension in a representative sample of the whole elementary and high school population of the city of Belo Horizonte (state of Minas Gerais, southeastern Brazil). To describe the blood pressure levels found and the prevalence of BP levels above the 90th and 95th percentiles in the first and second measurements. To evaluate prevalence using four different normality references separately to assess the impact of choice of reference. To study the frequency at which the students blood pressure has been evaluated.METHODS: In an observational cross-sectional epidemiological study, we studied a sample of 1005 students, aged 6 to 18 year, randomized from an universe of 486,166 students from the 521 public and private elementary and high schools in the city. Each student was evaluated by means of a personal interview, anthropometric measurements, and two blood pressure measurements in a single visit and at a 10-minute interval.RESULTS: The systolic and diastolic blood pressure levels, by age and gender, were slightly lower than those described by the Task Force Report (1987) and by Rosner et al. (1993). The prevalence of BP levels (systolic or diastolic) over the 95th percentile were, according to the reference used: 8.7% - Task Force Report (1987); 5.5% - Rosner et al. (1993); 6.5% - Update on the Task Force Report (1996); and 9.8% - the 95th percentile from our own study. In the second measurement these prevalence rates dropped to 4.9%; 2.4%; 3.5% and 5.8%, respectively.CONCLUSIONS: We present a detailed description (mean values and standard deviations, and the 90th, 95th and 99th percentiles by age and gender) of the BP levels found in both measurements. Mean values and upper percentiles found in this study are very close to those found in the American references, which validates the current use of these references in Brazil. The prevalence of 9.0% of BP levels above the 90th percentile in two measurements made at random hints at the number of children who should be monitored for hypertension, and reinforces the importance of routine evaluation of blood pressure at every pediatric examination.

[Hepatoportal sclerosis associated with portal vein thrombosis in children: report of 3 cases]. / Esclerose hepatoportal associada à trombose de veia porta em crianças: relato de três casos.

Hepatoportal sclerosis is the term used to name a clinicopathological condition responsible for non-chirrotic portal hypertension. A three cases report of children with hepatoportal sclerosis is presented associated with portal vein thrombosis. The first two patients presented as main complaint upper digestive hemorrhage and the third one was admitted for investigation of hepatosplenomegaly. The ultrasonographic exam revealed alterations indicative of extrahepatic portal vein thrombosis in the three cases. The patients underwent liver biopsy for they had presented altered liver enzymes. The main histological findings were: subintimal sclerosis, portal fibrosis and telangiectases of the intrahepatic venous branches, consistent with the diagnosis of hepatoportal sclerosis. The three patients showed good evolution, being the hemorrhage controlled in the first two cases through esclerotherapy of esophageal varices.

Cirurgia reconstrutiva de lábio superior com recuperaçäo estético-funcional / Reconstructive surgery of the upper lip with esthetic-functional recovery

Este artigo relata dois casos de cirurgia reconstrutiva de lábio superior em pacientes que apresentavam carcinoma espinocelular, aplicando a técnica de Bürrow. Esta técnica é mais usada em lábio inferior, pois nao invade unidade estética. Optamos por utilizar esta técnica também em lábio superior aplicando uma variaçao da incisao na comissura labial, conseguindo, assim, um resultado estético e funcional significativo.

[Knowledge about AIDS prevention among professionals and students in health care]. / Conhecimentos sobre prevenção da SIDA entre profissionais e acadêmicos da área de saúde.

This work is a exploratory research based on the analysis of the answers to the questionnaires of 52 students and health care professionals knowledge about AIDS sexual prevention, biosecurity, diagnosis tests, patients and workers rights and the modifications of nursing and medical care to this kind of disease.

[Reconstructive surgery of the upper lip with esthetic-functional recovery]. / Cirurgia reconstrutiva de lábio superior com recuperação estético-functional.

Two cases are reported of reconstructive surgery of the upper lip in patients who had squamous cell carcinoma, using the Bürrow technique. This technique is more used in lower lips because it does not involve esthetic unity. We have opted for it in the upper lip also, using a variation in the lip commissure incision, getting a significant functional and esthetic result.