Metástase Hematogênica: Uma Atualização do Problema

O A. faz uma atualização dos conhecimentos no que se refere ao estudo da metástase hematogênica. Divide o assunto em duas etapas: o da invasão e o da Nidação e Crescimento. Estuda minuciosamente os fatores que condicionam a metastatização, tanto os ligados à célula tumoral como os que dependem do hospedeiro. Nos fatôres ligados à célula, estuda a adesividade, o ameboidismo, a liberação de enzimas proteolíticos, a natureza da membrana celular e o índice mitótico. Quanto ao fator hospedeiro, faz considerações em tôrno do estroma, a estrutura e anatomia do leito vascular, os fatôres bormoniais e principalmente o estado da coagulação sangüínea, estrutura do endotélio vascular, fatores imunológicos específicos e inespecíficos e por fim, fatôres hormonais

Video monitoring of neovessel occlusion induced by photodynamic therapy with verteporfin (Visudyne®), in the CAM model

The aim of the present study was to monitor photodynamic angioocclusion with verteporfin in capillaries. Details of this process were recorded under a microscope in real-time using a high-sensitivity video camera. A procedure was developed based on intravenous (i.v.) injection of a light-activated drug, Visudyne®, into the chorioallantoic membrane (CAM) of a 12-day-old chicken embryo. The effect of light activation was probed after 24h by i.v. injection of a fluorescent dye (FITC dextran), and analysis of its fluorescence distribution. The angioocclusive effect was graded based on the size of the occluded vessels, and these results were compared with clinical observations. The time-resolved thrombus formation taking place in a fraction of the field of view was video recorded using a Peltier-cooled CCD camera. This vessel occlusion in the CAM model was reproducible and, in many ways, similar to that observed in the clinical use of verteporfin. The real-time video recording permitted the monitoring of platelet aggregation and revealed size-selective vascular closure as well as some degree of vasoconstriction. Platelets accumulated at intravascular junctions within seconds after verteporfin light activation, and capillaries were found to be closed 15min later at the applied conditions. Larger-diameter vessels remained patent. Repetition of these data with a much more sensitive camera revealed occlusion of the treated area after 5min with doses of verteporfin and light similar to those used clinically. Consequently, newly developed light-activated drugs can now be studied under clinically relevant condition

Preformed expression of defense is a hallmark of partial resistance to rice blast fungal pathogen Magnaporthe oryzae

Background: Partial resistance to plant pathogens is extensively used in breeding programs since it could contribute to resistance durability. Partial resistance often builds up during plant development and confers quantitative and usually broad-spectrum resistance. However, very little is known on the mechanisms underlying partial resistance. Partial resistance is often explained by poorly effective induction of plant defense systems. By exploring rice natural diversity, we asked whether expression of defense systems before infection could explain partial resistance towards the major fungal pathogen Magnaporthe oryzae. The constitutive expression of 21 defense-related genes belonging to the defense system was monitored in 23 randomly sampled rice cultivars for which partial resistance was measured. Results: We identified a strong correlation between the expression of defense-related genes before infection and partial resistance. Only a weak correlation was found between the induction of defense genes and partial resistance. Increasing constitutive expression of defense-related genes also correlated with the establishment of partial resistance during plant development. Some rice genetic sub-groups displayed a particular pattern of constitutive expression, suggesting a strong natural polymorphism for constitutive expression of defense. Constitutive levels of hormones like salicylic acid and ethylene cannot explain constitutive expression of defense. We could identify an area of the genome that contributes to explain both preformed defense and partial resistance. Conclusion: These results indicate that constitutive expression of defense-related genes is likely responsible for a large part of partial resistance in rice. The finding of this preformed defense system should help guide future breeding programs and open the possibility to identify the molecular mechanisms behind partial resistance. ( Résumé d'auteur

Analogies de méthodes et différences d'appareillage dans l'enregistrement d'informations corrélées

L'enregistrement des énergies de particules corrélées : expériences (α, γ), (3He, dγ), (d, pγ), (p, p' γ), expériences de polarisation [4, 6,12], a été effectué indépendamment avec des appareillages de conceptions différentes. L'un est un système d'acquisition et de contrôle utilisant une logique câblée, l'autre un ordinateur en temps réel. L'examen critique de ces appareillages et de leur utilisation conduit à des conclusions voisines

Autologous tooth graft after endodontical treated used for socket preservation: A multicenter clinical study.

The aim of the study was to evaluate the tooth extracted use as autologous tooth graft after endodontic root canal therapies used for socket preservation. To this purpose, the Tooth Transformer shredding and decontamination machine has been used. The graft obtained in this way, was inserted at the time of the extraction or at a second surgery altogether with the chosen regenerative therapy. This clinical trial enrolled patients with post-estractive defects requiring the restoration bone dimension and shape in the maxillary and mandibular zone. In addition, 98 patients with 119 extraction sockets were enrolled across 10 standardized centers. An innovative preparation method, using the dedicated automated device Tooth Transformer, able to transform autologous teeth in suitable grafting material, has been used. The extracted tooth was cleaned and treated using a Tooth Transformer and made a socket preservation. Thirteen Biopsies were realized to analyze the histologic outcomes at the average time of four months to demonstrate that the autologous tooth graft made from root after endodontic therapy should be used in human bone regeneration as graft for dental implant placement

Uptake and localisation of mTHPC (Foscan®) and its14C-labelled form in normal and tumour tissues of the hamster squamous cell carcinoma model: a comparative study

The aim of this study was to evaluate the pharmacokinetics of meta(tetrahydroxyphenyl)chlorin (mTHPC) on different tissues of interest in a hamster tumour model and to confirm our earlier animal studies on semi-quantitative fluorescence microscopy. The results obtained by three different evaluation methods were compared: in vivo spectrofluorometry, ex vivo fluorescence microscopy and chemical extraction of 14C-labelled mTHPC. Following intracardiac injection of 0.5 mg kg−1 mTHPC, groups of five tumour-bearing animals were used for in situ light-induced fluorescence spectroscopy. Afterwards, the biopsies were taken and snap frozen for fluorescence microscopy. The presence of radioactivity in serum and tissues was determined after chemical digestion in scintillation fluid using a scintillation counter. For each analysed tissue, a good correlation was observed between the three evaluation methods. The highest fluorescence intensity and quantities of mTHPC were observed between 12 and 24 h in liver, kidney, serum, vascular endothelium and advanced neoplasia. The majority of mTHPC was found at around 48 h in smooth muscle and at 96 h in healthy cheek pouch mucosa and early malignant lesions. The lowest level of mTHPC was noted in striated muscle at all times. No selectivity in dye localisation was observed between early squamous cell carcinoma and healthy mucosa. Soon after the injection, a significant selectivity was noted for advanced squamous cell carcinoma as compared to healthy cheek pouch mucosa or striated muscle. A significant difference in mTHPC localisation and quantity was also observed between striated and smooth muscle during the first 48 h following the injection. Finally, this study demonstrated the usefulness of non-invasive in situ spectroscopic measurements to be performed systematically prior to photodynamic therapy as a real-time monitoring for each treated patient in order to individualise and adapt the light dosimetry and avoid over or under treatments

International lower limb collaborative (INTELLECT) study: a multicentre, international retrospective audit of lower extremity open fractures

Trauma remains a major cause of mortality and disability across the world1, with a higher burden in developing nations2. Open lower extremity injuries are devastating events from a physical3, mental health4, and socioeconomic5 standpoint. The potential sequelae, including risk of chronic infection and amputation, can lead to delayed recovery and major disability6. This international study aimed to describe global disparities, timely intervention, guideline-directed care, and economic aspects of open lower limb injuries