Development of CBCT-based prostate setup correction strategies and impact of rectal distension.

BACKGROUND: Cone-beam computed tomography (CBCT) image-guided radiotherapy (IGRT) systems are widely used tools to verify and correct the target position before each fraction, allowing to maximize treatment accuracy and precision. In this study, we evaluate automatic three-dimensional intensity-based rigid registration (RR) methods for prostate setup correction using CBCT scans and study the impact of rectal distension on registration quality. METHODS: We retrospectively analyzed 115 CBCT scans of 10 prostate patients. CT-to-CBCT registration was performed using (a) global RR, (b) bony RR, or (c) bony RR refined by a local prostate RR using the CT clinical target volume (CTV) expanded with 1-to-20-mm varying margins. After propagation of the manual CT contours, automatic CBCT contours were generated. For evaluation, a radiation oncologist manually delineated the CTV on the CBCT scans. The propagated and manual CBCT contours were compared using the Dice similarity and a measure based on the bidirectional local distance (BLD). We also conducted a blind visual assessment of the quality of the propagated segmentations. Moreover, we automatically quantified rectal distension between the CT and CBCT scans without using the manual CBCT contours and we investigated its correlation with the registration failures. To improve the registration quality, the air in the rectum was replaced with soft tissue using a filter. The results with and without filtering were compared. RESULTS: The statistical analysis of the Dice coefficients and the BLD values resulted in highly significant differences (p<10(-6)) for the 5-mm and 8-mm local RRs vs the global, bony and 1-mm local RRs. The 8-mm local RR provided the best compromise between accuracy and robustness (Dice median of 0.814 and 97% of success with filtering the air in the rectum). We observed that all failures were due to high rectal distension. Moreover, the visual assessment confirmed the superiority of the 8-mm local RR over the bony RR. CONCLUSION: The most successful CT-to-CBCT RR method proved to be the 8-mm local RR. We have shown the correlation between its registration failures and rectal distension. Furthermore, we have provided a simple (easily applicable in routine) and automatic method to quantify rectal distension and to predict registration failure using only the manual CT contours.

Peritoneal fluid changes in horses subjected to small colon distension

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Local and remote lesions in horses subjected to small colon distension and decompression

The purpose of this study was to observe and characterize colonic and lung lesions in horses subjected to experimental distension and decompression of the small colon. Sixteen healthy adult horses were divided into 2 groups: 9 horses that were subjected to distension of the small colon by means of a latex balloon surgically implanted in the lumen and inflated to a pressure of 40 mm Hg for 4 h, and 7 horses in which the balloon was implanted but not inflated. Colonic biopsy specimens were collected before balloon implantation, at the end of the period of obstruction, and 1.5 and 12 h after decompression and were examined for hemorrhage, edema, and neutrophil infiltration; myeloperoxidase (MPO) activity and hemoglobin concentration were measured as well. At the end of the experiment, lung samples were also collected and examined for neutrophil accumulation and MPO activity. The mucosa was not affected by luminal distension; lesions were restricted to the seromuscular layer. Neutrophil accumulation and edema were observed in the samples from both groups of horses but were greater in those from the distension group, in which there was also hemorrhage, fibrin deposition, and increased MPO activity in the seromuscular layer. Similarly, there was greater accumulation of neutrophils in the lung samples from the distension group than in those from the sham-operated group, as determined by histologic evaluation and MPO assay. These findings provide new evidence of reperfusion injury and a systemic inflammatory response, followed by remote lesions, in horses with intestinal obstruction.

An experimental study to compare inflammatory response due to liquid or gas joint distension in horses submitted to arthroscopy

PURPOSE: To assess comparatively the inflammatory response that follows CO2 or Ringer's lactate joint capsular distension of horses submitted to experimental arthroscopy METHODS: Each animal was submitted to a bilateral tarsocrural arthroscopy employing gas distention in one joint and fluid distention in the contralateral joint. Synovial fluid was evaluated at 0, six, 12, 24 and 48 hours post-operative. RESULTS: The use of CO2 for arthroscopy causes an acute and mild synovitis alike to the liquid capsular distension, showing similar synovial fluid increase of leukocytes, TP, and TNF-alpha. Although synovial fluid PGE(2) content was higher in joints submitted to CO2 distension, lower levels of hemoglobin and leukocytes oxidative burst after surgery indicates that CO2 arthroscopy decreased intra-articular bleeding and activation of infiltrating leukocytes. CONCLUSIONS: The use of CO2 for arthroscopic examination causes acute and mild synovitis that is similar to the effects caused by the liquid capsular distension. CO2 also seems to decrease intra-articular bleeding and activation of leukocytes.

Retaining perivascular tissue of human saphenous vein grafts protects against surgical and distension-induced damage and preserves endothelial nitric oxide synthase and nitric oxide synthase activity

OBJECTIVE: Conventional harvesting of saphenous vein used for coronary artery bypass surgery induces a vasospasm that is overcome by high-pressure distension. Saphenous vein harvested with its cushion of perivascular tissue by a "no touch" technique does not undergo vasospasm and distension is not required, leading to an improved graft patency. The aim of this study is to investigate the effect of surgical damage and high-pressure distension on endothelial integrity and endothelial nitric oxide synthase expression and activity in saphenous vein harvested with and without perivascular tissue. METHODS: Saphenous veins from patients (n = 26) undergoing coronary artery bypass surgery were prepared with and without perivascular tissue. We analyzed the effect of 300 mm Hg distension on morphology and endothelial nitric oxide synthase/nitric oxide synthase activity using a combination of immunohistochemistry, Western blot analysis, reverse transcriptase polymerase chain reaction, and enzyme assay in distended (with and without perivascular tissue) compared with nondistended (with and without perivascular tissue) segments. RESULTS: Distension induced substantial damage to the luminal endothelium (assessed by CD31 staining) and vessel wall. Endothelial nitric oxide synthase expression and activity were significantly reduced by high-pressure distension and removal of, or damage to, perivascular tissue. The effect of distension was significantly less for those with perivascular tissue than for those without perivascular tissue in most cases. CONCLUSION: The success of the saphenous vein used as a bypass graft is affected by surgical trauma and distension. Veins removed with minimal damage exhibit increased patency rates. We show that retention of perivascular tissue on saphenous vein prepared for coronary artery bypass surgery by the "no touch" technique protects against distension-induced damage, preserves vessel morphology, and maintains endothelial nitric oxide synthase/nitric oxide synthase activity.

True four-dimensional analysis of thoracic aortic displacement and distension using model-based segmentation of computed tomography angiography.

Previous analyses of aortic displacement and distension using computed tomography angiography (CTA) were performed on double-oblique multi-planar reformations and did not consider through-plane motion. The aim of this study was to overcome this limitation by using a novel computational approach for the assessment of thoracic aortic displacement and distension in their true four-dimensional extent. Vessel segmentation with landmark tracking was executed on CTA of 24 patients without evidence of aortic disease. Distension magnitudes and maximum displacement vectors (MDV) including their direction were analyzed at 5 aortic locations: left coronary artery (COR), mid-ascending aorta (ASC), brachiocephalic trunk (BCT), left subclavian artery (LSA), descending aorta (DES). Distension was highest for COR (2.3 ± 1.2 mm) and BCT (1.7 ± 1.1 mm) compared with ASC, LSA, and DES (p < 0.005). MDV decreased from COR to LSA (p < 0.005) and was highest for COR (6.2 ± 2.0 mm) and ASC (3.8 ± 1.9 mm). Displacement was directed towards left and anterior at COR and ASC. Craniocaudal displacement at COR and ASC was 1.3 ± 0.8 and 0.3 ± 0.3 mm. At BCT, LSA, and DES no predominant displacement direction was observable. Vessel displacement and wall distension are highest in the ascending aorta, and ascending aortic displacement is primarily directed towards left and anterior. Craniocaudal displacement remains low even close to the left cardiac ventricle.

Irritable bowel syndrome : the role of gut neuroendocrine peptides

Irritable bowel syndrome (IBS) is a common chronic disorder with a prevalence ranging from 5 to 10 % of the world's population. This condition is characterised by abdominal discomfort or pain, altered bowel habits, and often bloating and abdominal distension. IBS reduces quality of life in the same degree of impairment as major chronic diseases such as congestive heart failure and diabetes and the economic burden on the health care system and society is high. Abnormalities have been reported in the neuroendocrine peptides/amines of the stomach, small- and large intestine in patients with IBS. These abnormalities would cause disturbances in digestion, gastrointestinal motility and visceral hypersensitivity, which have been reported in patients with IBS. These abnormalities seem to contribute to the symptom development and appear to play a central role in the pathogenesis of IBS. Neuroendocrine peptides/amines are potential tools in the treatment and diagnosis of IBS. In particular, the cell density of duodenal chromogranin A expressing cells appears to be a good histopathological marker for the diagnosis of IBS with high sensitivity and specificity.

Release of β-galactosidase from poloxamine/α-cyclodextrin hydrogels

All mammals lose their ability to produce lactase (β-galactosidase), the enzyme that cleaves lactose into galactose and glucose, after weaning. The prevalence of lactase deficiency (LD) spans from 2 to 15% among northern Europeans, to nearly 100% among Asians. Following lactose consumption, people with LD often experience gastrointestinal symptoms such as abdominal pain, bowel distension, cramps and flatulence, or even systemic problems such as headache, loss of concentration and muscle pain. These symptoms vary depending on the amount of lactose ingested, type of food and degree of intolerance. Although those affected can avoid the uptake of dairy products, in doing so, they lose a readily available source of calcium and protein. In this work, gels obtained by complexation of Tetronic 90R4 with α-cyclodextrin loaded with β-galactosidase are proposed as a way to administer the enzyme immediately before or with the lactose-containing meal. Both molecules are biocompatible, can form gels in situ, and show sustained erosion kinetics in aqueous media. The complex was characterized by FTIR that evidenced an inclusion complex between the polyethylene oxide block and α-cyclodextrin. The release profiles of β-galactosidase from two different matrices (gels and tablets) of the in situ hydrogels have been obtained. The influence of the percentage of Tetronic in media of different pH was evaluated. No differences were observed regarding the release rate from the gel matrices at pH 6 (t50 = 105 min). However, in the case of the tablets, the kinetics were faster and they released a greater amount of 90R4 (25%, t50 = 40–50 min). Also, the amount of enzyme released was higher for mixtures with 25% Tetronic. Using suitable mathematical models, the corresponding kinetic parameters have been calculated. In all cases, the release data fit quite well to the Peppas–Sahlin model equation, indicating that the release of β-galactosidase is governed by a combination of diffusion and erosion processes. It has been observed that the diffusion mechanism prevails over erosion during the first 50 minutes, followed by continued release of the enzyme due to the disintegration of the matrix.

Étude d’impact de l’alimentation entérale précoce sur la durée de séjour hospitalier pour la chirurgie colique

Introduction: La réinstitution de l’alimentation entérale en deçà de 24h après une chirurgie digestive semble a priori conférer une diminution du risque d’infections de plaie, de pneumonies et de la durée de séjour. Le but de cette étude est de vérifier l’effet de la reprise précoce de l’alimentation entérale sur la durée de séjour hospitalier suite à une chirurgie colique. Méthodes: Il s’agit d’une étude prospective randomisée dans laquelle 95 patients ont été divisés aléatoirement en deux groupes. Dans le groupe contrôle, la diète est réintroduite lorsque le patient passe des gaz ou des selles per rectum, et qu’en plus il n’est ni nauséeux ni ballonné. Les patients du groupe expérimental reçoivent pour leur part une diète liquide dans les 12 heures suivant la chirurgie, puis une diète normale aux repas subséquents. L’objectif primaire de cette étude est de déterminer si la réinstitution précoce de l'alimentation entérale post chirurgie colique diminue la durée de séjour hospitalier lorsque comparée au régime traditionnel de réintroduction de l’alimentation. Les objectifs secondaires sont de quantifier l’effet de la réintroduction précoce de la diète sur les morbidités periopératoires et sur la reprise du transit digestif. Résultats: La durée de séjour hospitalier a semblé être légèrement diminuée dans le groupe expérimental (8,78±3,85 versus 9,41±5,22), mais cette difference n’était pas statistiquement significative. Des nausées ou des vomissements furent rapportés chez 24 (51%) patients du bras experimental et chez 30 (62.5%) patients du groupe contrôle. Un tube nasogastrique a du être installé chez un seul patient du groupe experimental. La morbidité périopératoire fut faible dans les deux groupes. Conclusion: Il semble sécuritaire de nourrir précocément les patients suite à une chirurgie colique. Cependant cette étude n’a pu démontrer un impact significatif de la reintroduction précoce de l alimentation per os sur la durée de séjour hospitalier.

Approches arthroscopiques et description de l'anatomie articulaire normale du carpe et du tarse chez le bovin adulte

Les approches arthroscopiques et l’anatomie normale des articulations antébrachiocarpienne, carpienne moyenne et tarsocrurale n’ont jamais été décrites spécifiquement chez les bovins. Notre étude avait pour buts de définir les abords chirurgicaux et de décrire l’anatomie arthroscopique de ces trois articulations. Deux carpes et deux tarses issus du cadavre frais d’une vache adulte ont été injectés avec un mélange de latex, puis disséqués afin de déterminer les sites arthroscopiques d’intérêt. Par la suite, l’arthroscopie des articulations antébrachiocarpienne et carpienne moyenne (approche dorsale) et de l’articulation tarsocrurale (approches dorsale et plantaire) a été réalisée sur six cadavres frais de vaches adultes ne présentant ni boiterie ni distension articulaire avant leur euthanasie. Les approches dorsolatérale et dorsomédiale des articulations antébrachiocarpienne et carpienne moyenne ont été réalisées de part et d’autre de l’extenseur radial du carpe. Les structures observées étaient le radius distal, les os radial, intermédiaire, ulnaire, II et III fusionnés et IV du carpe, ainsi que des ligaments palmaires. Les approches dorsolatérale et dorsomédiale de l’articulation tarsocrurale ont été réalisées latéralement au long extenseur des doigts et médialement au troisième péronier respectivement. Les approches plantarolatérale et plantaromédiale ont été réalisées latéralement au fléchisseur latéral des doigts et latéralement au fléchisseur médial des doigts respectivement. Les structures observées étaient le tibia distal, les trochlées proximale et plantaire du talus, le processus coracoïde du calcanéus, l’articulation fibulo-calcanéenne et des ligaments articulaires. Quelle que soit l’articulation, l’approche latérale était préférée à l’approche médiale. L’arthroscopie du carpe et du tarse pourra être proposée dans un contexte hospitalier comme outil diagnostique, thérapeutique et pronostique des maladies articulaires bovines.

La zona de distensión del Caguán: un análisis de los factores económicos, políticos y sociales a partir del concepto de Estado Fallido

La presente Monografía pretende describir los diferentes sucesos que se dieron al interior de la zona de distensión del Caguán, durante el gobierno de Andrés Pastrana (1998-2002). Cabe mencionar, que ésta era la primera vez en la cual se despejaba una parte del territorio nacional, para que un grupo al margen de la ley se acentuara allí. A raíz de esto, se establecerá porque la zona de distensión puede considerarse como un Estado al interior de Colombia si ésta nunca lo llegó a ser. Finalmente, se describirá la administración realizada por las FARC en dicha zona, teniendo como base el concepto de Estado fallido, y se determinará si la gestión llevada a cabo por los guerrilleros puede considerarse como fallida.

Desmite dos Ligamentos Colaterais da Articulação Interfalângica Distal em Equinos

Os objectivos deste estudo basearam-se na análise dos aspectos clínicos de cavalos de desporto, aos quais foi diagnosticado através de ecografia, desmite dos Ligamentos Colaterais (LCs) da articulação Interfalângica Distal (IFD). Os cavalos incluídos na amostra foram examinados entre Setembro de 2011 e Junho de 2012 tendo sido selecionados aqueles que apresentaram os critérios de inclusão requeridos, nomeadamente o diagnóstico de desmite em pelo menos um dos LCs da articulação IFD. Foram incluídos 8 animais no estudo, sendo que o diagnóstico foi feito através de um cuidadoso exame ortopédico e de ecografia, tendo-se verificado as lesões nos membros anteriores. O LC Lateral foi o mais afectado (5 cavalos) seguido do Medial (2 cavalos). Apenas em 1 dos casos as lesões eram bilaterais. A maioria dos animais apresentavam distensão da articulação IFD confirmada ecograficamente. A claudicação foi invariavelmente exacerbada em círculo no piso duro, sendo que 7 dos 8 (87.5%) animais aumentaram o grau de claudicação quando o membro afectado estava no interior do círculo. Após o bloqueio digital palmar a claudicação foi atenuada em 7 dos 8 animais (87.5%) sendo totalmente abolida em 3 (37.5%) deles. O bloqueio da articulação IFD foi positivo em todos os animais, e o bloqueio da bursa podotroclear negativa em 7 dos 8 cavalos. Metade dos animais (50%) apresentaram alterações radiográficas como osteoartrite da articulação IFD, remodelação óssea da origem/inserção do LC afectado e um deles apresentava ossificação de uma cartilagem ungular. Todos os animais apresentaram sinais evidentes de lesão na ecografia, sendo que alguns demostraram sinais de desmite crónica e outros aguda. Os tratamentos instituídos variaram de acordo com a história, sinais clínicos, sinais radiográficos e severidade das lesões ecográficas. A desmite dos LC da articulação IFD deve ser considerada como uma causa de claudicação que afecta a performance dos cavalos de desporto. Mais estudos são necessários, de modo a caraterizar melhor estas lesões e avaliar as melhorias após a terapia por forma a determinar os factores que mais influenciam o prognóstico. Palavras-Chave: Equinos, Ligamentos colaterais, Desmite, articulação Interfalângica distal

Microbiology of the human intestinal tract and approaches for its dietary modulation

Gut bacteria can be categorised as being either beneficial or potentially pathogenic due to their metabolic activities and fermentation end-products. Health-promoting effects of the microflora may include immunostimulation, improved digestion and absorption, vitamin synthesis, inhibition of the growth of potential pathogens and lowering of gas distension. Detrimental effects are carcinogen production, intestinal putrefaction, toxin production, diarrhoea/constipation and intestinal infections. Certain indigenous bacteria such as bifidobacteria and lactobacilli are considered to be examples of health-promoting constituents of the microflora. They may aid digestion of lactose in lactose-intolerant individuals, reduce diarrhoea, help resist infections and assist in inflammatory conditions. Probiotics, prebiotics and synbiotics are functional foods that fortify the lactate producing microflora of the human or animal gut.

O Programa Nuclear e a construção da democracia : análise da oposição ao Programa Nuclear Brasileiro (1975-1990)

O recorte analítico deste trabalho percorre os anos entre 1975 e 1990, fazendo uma análise sobre diferentes instâncias de oposição doméstica ao Programa Nuclear Brasileiro. A aludida oposição é entendida dentro do contexto político que o Brasil atravessava neste período, que coincide com a distensão do regime militar, a transição para governos civis e, depois, democraticamente eleitos. Nesse sentido, para além de construir uma narrativa sobre oposições domésticas ao programa nuclear e contribuir para as recentes interpretações historiográficas sobre a energia nuclear no Brasil, este trabalho busca situar estes atores dentro do contexto histórico do Brasil, avaliando seu impacto tanto na política nuclear quanto no contexto mais amplo da longa transição que encerrou o regime militar e trouxe o poder de volta para os civis.