Fluorescent organic particle doped polymer-based gel dosimeter for neutron detection.

The purpose of this work is to develop a material capable of detecting neutrons produced by photodisintegration in a linear accelerator for its medical use. In this study, we have developed a gel-like material doped with fluorescent organic particles. PPO at 1 wt% is used as primary dopant and POPOP as secondary one at 0.03 wt%. A set of four samples is produced, with boric acid concentrations of 0, 400, 800 and 1200 ppm. The viscoelastic properties of the material are characterized with rheological measurements, finding a gel-like behavior, i.e., a material that can keep its original shape if no stresses are applied, but can also be deformed by applying a moderate shear rate. Furthermore, the material was irradiated with gamma, electron, and neutron emission sources from 137Cs, 22Na, 60Co, 210Po, 90Sr and 241AmBe, and its response was measured in two different experimental settings, in two different institutions, for comparative purposes. From these measurements, one can clearly establish that the new material detects neutrons, electrons, and gammas within the MeV regions and below. Thus, our findings show that the developed material and its properties make it a promising technology for its use in a neutron detector.

Incidence and predictors of cardiovascular events in a cohort of patients with rheumatoid arthritis.

INTRODUCTION: An excess in cardiovascular (CV) morbidity and mortality has been recognized in Rheumatoid Arthritis (RA) patients when compared to the general population. Given the paucity of prospective data, our aim was to estimate the incidence of CV events and the contribution of traditional CVD risk factors and RA-related parameters to future events. METHODS: Incident fatal and non-fatal CV events (hospitalizations due to unstable angina, myocardial infarction, coronary artery revascularization procedures, stroke, or CV death) were assessed in a prospective cohort of RA women followed since 2007 and without CV events at cohort entry. The presence of traditional CV risk factors, disease characteristics, medication, carotid ultrasound, and biomarkers of inflammation and endothelial activation were evaluated at baseline. Univariate Cox proportional hazard models were used to identify risk factors for CV events. RESULTS: Among 106 women followed over 565 patient-years we identified 4 CV events (1 fatal stroke, 2 myocardial infarction and 1 unstable angina), which contributed to an incidence rate of 7 per 1000 person-years (95%CI 2.0- 13.9). Patients who developed CV events were older, but the distribution of other traditional CV risk factors was otherwise similar in both groups. Also, corticosteroid dosage and proportion of patients with carotid atherosclerotic plaques was higher in those with CV events. Erythrocyte sedimentation rate (ESR) (HR 1.036; 95%CI 1.005-1.067) and soluble intercellular adhesion molecule-1 (sICAM-1) serum levels (HR 1.002; 95%CI 1.000-1.003) significantly contributed to CV events. These results remained significant after adjusting for patients' age. CONCLUSION: We found an incidence of cardiovascular events in women with RA of 7 per 1000 patent-years. This value is similar to that found in other Portuguese cohort of RA patients1 and much higher than the incidence reported for the general Portuguese population. Markers of inflammation and endothelial activation contributed significantly to CV events, but the limited number of events prevents further analysis.

[Atheroma plaque of the carotid bifurcation: how to identify an "active" lesion?]. / Placa de ateroma da bifurcação carotídea: como identificar a lesão "activa"?

UNLABELLED: The identification of carotid atheromatous plaques associated to a higher neurologic risk may be important in therapeutic decision making for asymptomatic patients and symptomatic patients with 50%-70% stenosis. The introduction of high-definition ultrasonography (HDU) and computer-assisted image analysis provides the possibility of a standard, objective and detailed characterization of the structure of the carotid plaque. The aim of this study is to analyse the relationship between the ultrasonographic characteristics of a group of plaques and the risk of associated cerebrovascular events and cerebral infarction. MATERIAL: One hundred carotid bifurcation plaques (in 68 patients) were studied for the presence of ipsilateral cerebrovascular events. In 61 patients (87 plaques), a correlation with CT scan for the presence of cerebral infarction was possible. METHOD: The lesions were studied by HDU (ATL-HDI 3000) and digitalized for computer-assisted standardization of the image. The analysis included the appreciation of the histogram of the image gray-scale pixel distribution by use of commercial software Adobe Photoshop 3.0. The parameters analysed for global echogenicity were the median of the histogram and the percentage of percentile 40 hypoechogenic pixels (40). Statistical analysis was made with STATA 4.0 software with categorical variables analysed by chi-square and Fisher's exact test and continuous variables analysed by variance analysis and Student's t test. RESULTS: Thirty eight (38%) plaques were symptomatic and 34 (39.1%) were associated to cerebral infarction. The degree of stenosis was > 70% in 51%; between 50 and 69% in 27% and < 50% in 22%. The mean of the median and P40 values was 33.9 and 60.3% in the symptomatic and 46.8 (p = 0.005) and 46.6% (p = 0.001) in the asymptomatic plaques respectively. In the plaques associated to cerebral infarction, it was 32.7 and 61.6% respectively, and in the ones with negative CT scan, it was 44.6 (p = 0.005) and 48.1% (p = 0.002). The mean of the median in the plaques vs. degree of stenosis was: > 70%--33.3; 50-69%--45.1; < 49%--57.7 (p < 0.001). In the series the cut-off point for the median value was 32 and for P40 it was 43 (for any degree of stenosis): G1--plaques < 32 (echolucent); G2--plaques > 32 (echogenic). In G1 symptoms occurred in 60% of the plaques and in 26% of the plaques in G2 (p = 0.0001). CT scan was positive in 66% of the echolucent plaques and in 25% of the echogenic plaques (p = 0.0238). CONCLUSION: 1. The more echolucent plaques are associated with a significantly higher neurological risk. 2. The plaques associated with higher degrees of stenosis are more echolucent. 3. The use of a standard and objective methodology in the analysis of the echographic structure of carotid plaques is important and limits the known intra and inter-observer variability of subjective appreciation.

[Assessment of arterial occlusive disease with Duplex sonography. Prospective study]. / Avaliação da doença oclusiva das artérias renais com Triplex Scan. Estudo prospectivo.

Occlusive disease involving the renal arteries represent a major cause of curable hypertension and improvement of renal dysfunction. Angiography is still the major diagnostic procedure. Isotopic methods with Captopril and split-function studies have shown high incidence of false-positive and false-negative results. Colour flow Duplex-Scan renders possible the visualization of the aorta and renal arteries, is noninvasive and combines morphologic and hemodynamic evaluation. To assess its efficacy in the diagnosis of renal artery occlusive disease, a prospective blind study was undertaken in 24 patients, 48 renal arteries, 15 women and 9 men, with mean age of 44 years. Scans of the aorta and renal arteries at the origin, along its extension and at the renal hilum were obtained using and ATL Ultrmark 9 with 3.0 MHZ probe Velocity measurements were obtained at the aorta and along the renal arteries. Criteria for a positive examination were: focal acceleration with a reduction of the flow velocity at the hilum. Absence of flow in a properly visualized renal artery was considered as occlusion. All patients had digital subtraction arteriography. In 1 patient the non-invasive examination was inadequate. In the remain 23 patients the exam was considered adequate. False-positives were 4.8%; false-negatives 8.7%. Sensitivity, specificity and accuracy were respectively 91.7%, and 95.7% and 93.5%. These results suggest that non-invasive assessment of renal artery occlusive disease is feasible and accurate when compared to angiography, thus providing a useful tool for screening hypertensive patients.

[Endovascular treatment of aneurysms of the descending thoracic aorta--a new therapeutic perspective]. / Tratamento endovascular de aneurisma da aorta torácica descendente--uma nova perspectiva terapêutica.

Endovascular treatment of aneurysmal disease of descending thoracic aorta and infra-renal abdominal aorta, has become an accepted technique, in selected cases due to the reduction of neurological morbidity, paraparesis or paraplegic and renal ischemia, associated with conventional surgery. The authors describe the first case performed in Portugal of a 75-year-old female with an expanding thoracic aneurysm managed by endovascular exclusion of the aneurysm with an EXCLUDER endoprosthesis, without any complications or evidence of endoleak, achieving complete exclusion of the aneurysm.

[Neodymium--Yag laser in the recanalization of arterial occlusions]. / Neodymium--Yag Laser na recanalização das oclusões arteriais.

Failure of the guide-wire to recanalize some arterial total occlusion does not preclude balloon angioplasty. Nowadays there are recanalization devices such as the mechanical atherectomy and Lasers. The following report describes the successful use of the Nd: YG Laser in the recanalization of a common iliac artery total occlusion in a patient with claudication, rendering possible balloon angioplasty and a Palmaz Stent implantation, which is the first case performed in our country.

[Carotid artery surgery in extracranial occlusive disease and cerebral ischemia. Early and late results]. / Cirurgia carotídea na doença oclusiva extracraneana e isquemia cerebral. Resultados precoces e tardios.

Carotid artery surgery became an established procedure for the treatment of cerebrovascular insufficiency associated with carotid artery stenosis and for the prevention of Stroke. 180 patients were consecutively treated because of occlusive disease of the carotid arteries: 152 (84%) had TIA's or reversible deficits, 11 (6.1%) had strokes with partial recovery, 16 (8.8%) asymptomatic carotid disease and 1 patient (0.5%) had global cerebral ischemia. The severity of occlusive disease was assessed by ECHO-DOPPLER, with or without colour mapping and by angiography: 21 had minimal lesions (less than 20%), 58 stenosis between 21-75%, 92 stenosis between 76-99% and 7 had complete occlusion of the carotid artery; 2 patients had aneurysmal disease 196 operations were performed; early mortality (less than 30 days) was 2.2% (4/180) and neurological morbidity 1.6% (3/180), the operative risk being 3.8%. Longterm results were assessed during a follow-up period extending to 132 months and were assessed by life-table analysis. Survival was 52.5%, 79.3% of the patients were fully asymptomatic during the follow-up but 89.2% were stroke-free, the incidence of stroke being 0.97%/year. These results compare favorably with data available from the natural history and confirm the efficacy of carotid artery reconstructive surgery for the prevention of stroke.

[Prevalence of extracranial carotid occlusive disease. Non-invasive study]. / Prevalência da doença carotídea oclusiva extracraneana. Estudo não-invasivo.

Cerebrovascular disease is the most important cause of mortality and morbility in some European Countries, but the prevalence of carotid occlusive disease has not been adequately assessed. From 1985 to 1987, 1,143 patients were consecutively evaluated in the Vascular Laboratory in order to determine the presence of extracranial carotid occlusive disease. 638 (55.8%) were males and 505 (44.2%) females and mean age was 58 years (16-87). 509 had previously focal brain ischemia, ocular and/or hemispheric (Group I), 78 had assymptomatic cervical bruit (Group II), 55 non-hemispheric neurologic dysfunction (Group III) and 501 had atypical symptoms for cerebrovascular disease (Group IV). Diagnostic criteria for carotid disease: were peak frequency greater than 4.0 KHz; spectral broadening greater than 40% and late sysstolic turbulence. Global prevalence of carotid disease was 31.8% and the results in each group were: Gr. I-37.2%; Gr. II-57.7%; Gr. III-43.6%; Gr. IV-21.2%. 49% of the patients had hypertension, 22.8% dyslipidemia, 22.4% evidence of coronary disease and 13.6% had diabetes. Hypertension, diabetes, coronary disease and the coexistence of two risk factors were significantly more prevalent in the group of patients with carotid disease. These results confirm a high prevalence of carotid disease in this population, which is comparable to the one is northern european populations.

["Off pump" coronary surgery and simultaneous carotid endarterectomy]. / Cirurgia coronária sem cec e endarterectomia carotídea simultânea.

The occurrence of significant carotid artery disease in patients requiring coronary artery bypass grafting (CABG), results in a dilemma regarding the best surgical management. Our philosophy has been to perform simultaneous carotid endarterectomy and CABG off-pump. We reviewed the efficacy of this therapy in six patients treated in our hospital between January 2001 and December 2002. The result was satisfactory and there was no hospital mortality.

Barley ß-glucans extraction and partial characterization.

Barley is rarely used in the food industry, even though it is a main source of ß-glucans, which have important health benefits and a technological role in food. This work evaluated the humid extraction of barley ß-glucans and partially characterized them. The extraction was studied using surface response methodology with both temperature and pH as variables. The extracted ß-glucans were characterized by chemical and rheological analysis, infrared spectroscopy and scanning electron microscopy. The effect on extraction of linear and quadratic terms of pH and temperature corresponding to the regression model was significant, and we obtained a maximum concentration of 53.4% at pH 7.56 and temperature 45.5°C, with protein and mainly starch contamination. The extracted ß-glucans presented a higher apparent viscosity than the commercial ones, the behavior of the commercial and extracted samples can be described as Newtonian and pseudoplastic, respectively. The results of infrared spectroscopy and scanning electron microscopy were characteristic of commercial ß-glucans, indicating that this method is efficient for extracting ß-glucans.

Atherosclerotic plaque tissue characterization in 2D ultrasound longitudinal carotid scans for automated classification: a paradigm for stroke risk assessment.

In the case of carotid atherosclerosis, to avoid unnecessary surgeries in asymptomatic patients, it is necessary to develop a technique to effectively differentiate symptomatic and asymptomatic plaques. In this paper, we have presented a data mining framework that characterizes the textural differences in these two classes using several grayscale features based on a novel combination of trace transform and fuzzy texture. The features extracted from the delineated plaque regions in B-mode ultrasound images were used to train several classifiers in order to prepare them for classification of new test plaques. Our CAD system was evaluated using two different databases consisting of 146 (44 symptomatic to 102 asymptomatic) and 346 (196 symptomatic and 150 asymptomatic) images. Both these databases differ in the way the ground truth was determined. We obtained classification accuracies of 93.1 and 85.3 %, respectively. The techniques are low cost, easily implementable, objective, and non-invasive. For more objective analysis, we have also developed novel integrated indices using a combination of significant features.

Chemical characterization of candy made of Erva-Mate (Ilex paraguariensis A. St. Hil.) residue.

The aim of this work was to evaluate the chemical properties of the residues from erva-mate processing and also to determine the candy-making performance with addition of residues from erva-mate on consumers' acceptance and purchase intent of this new product. The candies containing different amounts of mate powder were evaluated through overall acceptability test and purchase intent. Mate powder showed high contents of dietary fiber, total ash, and total polyphenols. The total dietary fiber content of the mate candies ranged from 5.7 to 6.29% on a dry matter basis. Supplementation with mate powder caused significant increases in polyphenol and mineral contents of mate candies. The incorporation of mate powder increased the hardness of the candies and produced desirable results in their nutritional characteristics. The sensory tests indicated that mate candies were acceptable and approved in relation to purchase intent.

Carotid plaque 3D compound imaging and echo-morphology analysis: a Bayesian approach.

This paper describes a method for volume reconstruction of the carotid plaque and presents a novel local characterization of its echo-morphology. The data is composed by a series of nearly parallel ultrasound images (3D Compound Imaging) and the acquisition is performed using traditional non-invasive ultrasound equipment available in most medical facilities, without need of a spatial locator device. The reconstruction algorithm uses the observed pixels inside the plaque, which were obtained in a pre-segmentation stage performed under medical guidance [1]. The paper proposes a Bayesian algorithm which estimates the underlying volume inside the plaque, by filtering and interpolating the data in order to remove speckle noise and fill non-observed regions, respectively. This volume is further used in plaque echo-morphology analysis. The observation model is based on the Rayleigh distribution, commonly used to model speckle noise in ultrasound images. A prior model based on the edge preserving Total Variation Gibbs distribution is also used to fill the gaps on non-evenly spaced observations. An energy function is derived from these models and an iterative algorithm computes its minimizer. The estimated function, defined in a given volume of interest, is used in global and local plaque characterization, namely to estimate its average levels of stenosis, echo-morphology and to identify vulnerable foci inside the plaque. The goal is to make atherosclerosis diagnosis more accurate and complete than using traditional 2D ultrasound analysis.

Echolucency of carotid plaques correlates with plaque cellularity.

OBJECTIVE: To analyse the relationship between carotid plaque echolucency and cellularity. METHODS: Carotid plaques (14 symptomatic and 16 asymptomatic) were snap frozen after endarterectomy and defined on the basis of their grey-scale-median (GSM), obtained from pre-operative high-definition ultrasonography, as either echolucent (<32) or echogenic (>or=32). DNA and total soluble protein were determined to assess cellularity. RESULTS: After correcting for wet weight, symptomatic plaques had significantly more DNA (0.400 +/- 0.07 vs 0.335 +/- 0.07 mg/g; p = 0.03) and soluble protein (34.1 +/- 6.6 vs 29.7 +/- 3.4 mg/g; p = 0.03) than asymptomatic plaques. Predominantly echolucent (Grey-Weale classification) plaques had more DNA (0.404 +/- 0.06 vs 0.332 +/- 0.08 mg/g; p = 0.03) than echogenic plaques. Plaques with GSM < 32 also had more DNA (0.386 +/- 0.08 vs 0.319 +/- 0.06 mg/g; p = 0.04) and soluble protein (34.7 +/- 7.3 vs 29.6 +/- 4.2 mg/g; p = 0.03) than those with GSM >or= 32. Inverse relations were found between GSM and plaque DNA (r = -0.47; p = 0.02) and soluble protein (r = -0.45; p = 0.02) as well as between age and DNA (r = 0.39; p = 0.04) and soluble protein (r = -0.50; p = 0.003). CONCLUSIONS: Echolucency of carotid plaques as assessed by ultrasonography reflects plaque cellularity. This observation support the notion that ultrasonography can be used to identify high-risk plaques and evaluate effect of interventions on plaque structure.

Ultrasonographic risk score of carotid plaques.

OBJECTIVE: to determine the relative significance of ultrasonographic parameters of carotid plaques to develop an Activity Index (AI) which could correlate with clinical findings. METHOD: two hundred and fifteen plaques in 141 patients underwent ultrasonography and computer-assisted structural analysis. In half the patients (group 1), plaques were classified as either homogeneous and heterogeneous and ultrasonographic appearances related symptomatic (SP) or asymptomatic (AP) station. The probability of SP for each ultrasound parameter was used to define an Activity Index (AI). The AI was then applied the second half of patients (Group 2) to assess the value of AI in determining symptomatic station. RESULTS: the parameters with highest morbility were surface disruption, severe stenosis and low grey scale median and, additionally in heterogenous plaques heterogeneity and the presence of a juxta-luminal echolucent area. The power in group 2 of AI to identify symptomatic plaques was determined. Mean AI was for SP-75 (41-100) and for AP-43 (22-100); 78% of SP have AI>60 and 70% of AP have AI<50. The cut-off point between the two groups was 52. ROC curve analysis of the AI were obtained to determine its diagnostic accuracy. CONCLUSION: Activity Index is an objective parameter of plaque echostructure that positively correlates with symptoms. AI may contribute to better selection for treatment of patients with carotid artery disease.

Computer-assisted carotid plaque analysis: characteristics of plaques associated with cerebrovascular symptoms and cerebral infarction.

OBJECTIVE: to correlate the echostructural characteristics of carotid plaques with neurological symptoms and cerebral infarcts. MATERIALS: one hundred and five plaques were studied in 74 patients by colour-flow duplex ultrasound: 39 were symptomatic and 37 were associated with brain infarction on CT scanning. METHODS: the images were digitalised for computer-assisted image standardisation and divided in homogenous (n=67) and heterogenous (n=38) groups. Parameters of the plaque image were analysed. RESULTS: global echogenicity was significantly lower in symptomatic and in CT(+)plaques (p<0.05). For homogenous plaques, an echogenic cap (EC) was visualised in 8.3% of symptomatic vs. 33.9% of asymptomatic (p<0. 05) and in 7.7% for plaques that were CT(+)vs. 37.7% for CT(-)(p<0. 05). Surface disruption was visualised in 50% of symptomatic vs. 8. 5% of asymptomatic (p=0.002) and in 46% of CT(+)vs. 9.4% of CT(-)plaques (p=0.002). For heterogenous plaques, the echolucent region was juxtaluminal in 67% of symptomatic and CT(+)plaques vs. 33% in asymptomatic and CT(-)(p<0.01). CONCLUSION: echolucent plaques are associated with a higher neurological risk. In homogenous plaques the absence of an echogenic cap and disruption of the plaque surface also correlates with symptoms. In heterogenous plaques, juxtaluminal location of the echolucent region is an additional marker of increased risk.