High-resolution spatial mapping of changes in the neurochemical profile after focal ischemia in mice.

After ischemic stroke, the ischemic damage to brain tissue evolves over time and with an uneven spatial distribution. Early irreversible changes occur in the ischemic core, whereas, in the penumbra, which receives more collateral blood flow, the damage is more mild and delayed. A better characterization of the penumbra, irreversibly damaged and healthy tissues is needed to understand the mechanisms involved in tissue death. MRSI is a powerful tool for this task if the scan time can be decreased whilst maintaining high sensitivity. Therefore, we made improvements to a (1) H MRSI protocol to study middle cerebral artery occlusion in mice. The spatial distribution of changes in the neurochemical profile was investigated, with an effective spatial resolution of 1.4 μL, applying the protocol on a 14.1-T magnet. The acquired maps included the difficult-to-separate glutamate and glutamine resonances and, to our knowledge, the first mapping of metabolites γ-aminobutyric acid and glutathione in vivo, within a metabolite measurement time of 45 min. The maps were in excellent agreement with findings from single-voxel spectroscopy and offer spatial information at a scan time acceptable for most animal models. The metabolites measured differed with respect to the temporal evolution of their concentrations and the localization of these changes. Specifically, lactate and N-acetylaspartate concentration changes largely overlapped with the T(2) -hyperintense region visualized with MRI, whereas changes in cholines and glutathione affected the entire middle cerebral artery territory. Glutamine maps showed elevated levels in the ischemic striatum until 8 h after reperfusion, and until 24 h in cortical tissue, indicating differences in excitotoxic effects and secondary energy failure in these tissue types. Copyright © 2011 John Wiley & Sons, Ltd.

Predicting trabecular bone microdamage initiation and accumulation using a non-linear perfect damage model

Studies evaluating the mechanical behavior of the trabecular microstructure play an important role in our understanding of pathologies such as osteoporosis, and in increasing our understanding of bone fracture and bone adaptation. Understanding of such behavior in bone is important for predicting and providing early treatment of fractures. The objective of this study is to present a numerical model for studying the initiation and accumulation of trabecular bone microdamage in both the pre- and post-yield regions. A sub-region of human vertebral trabecular bone was analyzed using a uniformly loaded anatomically accurate microstructural three-dimensional finite element model. The evolution of trabecular bone microdamage was governed using a non-linear, modulus reduction, perfect damage approach derived from a generalized plasticity stress-strain law. The model introduced in this paper establishes a history of microdamage evolution in both the pre- and post-yield regions

Schistosoma mansoni: structural damage after treatment with oxamniquine

The effects of a single dose (100 mg/kg-body weight of mouse) of oxamniquine on the worm's tegument and paranchyma in relation to the process of immunological granulomatous reaction of the host's liver are described under light and electron microscopy (EM). The lesions caused by the drug are sequentially and simultaneously described in form of swelling, surface bulble and disruption with erosions. Ulceration in the tubercules with loss of spines is often more extensive and severe in male worms and concentration of host's mononuclear cells is observed. The possible role of host's immune response is discussed.

Uric acid is a danger signal activating NALP3 inflammasome in lung injury inflammation and fibrosis.

RATIONALE: Lung injury leads to pulmonary inflammation and fibrosis through myeloid differentiation primary response gene 88 (MyD88) and the IL-1 receptor 1 (IL-1R1) signaling pathway. The molecular mechanisms by which lung injury triggers IL-1beta production, inflammation, and fibrosis remain poorly understood. OBJECTIVES: To determine if lung injury depends on the NALP3 inflammasome and if bleomycin (BLM)-induced lung injury triggers local production of uric acid, thereby activating the NALP3 inflammasome in the lung. Methods: Inflammation upon BLM administration was evaluated in vivo in inflammasome-deficient mice. Pulmonary uric acid accumulation, inflammation, and fibrosis were analyzed in mice treated with the inhibitor of uric acid synthesis or with uricase, which degrades uric acid. MEASUREMENTS AND MAIN RESULTS: Lung injury depends on the NALP3 inflammasome, which is triggered by uric acid locally produced in the lung upon BLM-induced DNA damage and degradation. Reduction of uric acid levels using the inhibitor of uric acid synthesis allopurinol or uricase leads to a decrease in BLM-induced IL-1beta production, lung inflammation, repair, and fibrosis. Local administration of exogenous uric acid crystals recapitulates lung inflammation and repair, which depend on the NALP3 inflammasome, MyD88, and IL-1R1 pathways and Toll-like receptor (TLR)2 and TLR4 for optimal inflammation but are independent of the IL-18 receptor. CONCLUSIONS: Uric acid released from injured cells constitutes a major endogenous danger signal that activates the NALP3 inflammasome, leading to IL-1beta production. Reducing uric acid tissue levels represents a novel therapeutic approach to control IL-1beta production and chronic inflammatory lung pathology.

Endoscopic mucosal resection in the esophagus with a new rigide device : an animal study

Résumé: Introduction : L'utilisation de méthodes endoscopiques peu invasives est en constante augmentation pour le traitement des lésions tumorales précoces de l'oesophage. Le but du traitement comprend l'éradication complète de tous les foyers de dysplasie ou de carcinome in situ, notamment dans les métaplasies intestinales de l'oesophage de Barrett, qui peuvent dégénérer en adénocarcinome. Plusieurs techniques d'ablation de la muqueuse oesophagienne (laser, argon plasma, electrocoagulation, photothérapie dynamique, résection endoscopique) ont été utilisées jusqu'à présent, mais aucune n'a vraiment donné entière satisfaction. Les techniques actuelles de résections endoscopiques par fibroscopie sont entre autres limitées par le grand nombre de séances nécessaires à l'éradication complète de la lésion et par la petite taille des fragments de muqueuse obtenus, ce qui rend l'analyse histologique difficile. Dans notre étude animale, nous avons évalué la faisabilité, l'efficacité et la sécurité d'une méthode de résection endoscopique à l'aide d'un nouvel oesophagoscope rigide. Matériel et méthode : Le résectoscope est formé d'un oesophagoscope rigide avec une fenêtre distale transparente à travers laquelle la muqueuse et une partie de la sous-muqueuse sont aspirées et ensuite réséquées avec une anse thermique. Les diverses fenêtres utilisées ont une taille comprise entre 2.2 et 4.4 cm. Le mouton a été choisi en raison de la ressemblance de son oesophage avec celui de l'humain en ce qui concerne l'épaisseur de son oesophage et sa structure histologique. Nous avons effectué 55 résections hémi-circonférentielles sur 21 animaux et 11 résections circonférentielles sur 11 autres. La Mitomycine-C, une substance qui inhibe la prolifération fibroblastique, a été utilisée dans 8 résections circonférentielles à différents intervalles de temps afin d'empêcher la survenue de sténoses oesophagiennes. Résultats : Toutes les résections hémi-circonférentielles ont permis d'obtenir des fragments compacts de tissu avec des bords nets, ce qui permet une excellente étude histologique. La surface du tissu prélevé était en corrélation avec la taille de la fenêtre du resectoscope. Nous avons ainsi pu obtenir des fragments avec des dimensions comprises entre 6 et 12 cm2. Pour les résections circonférentielles, les tissus étaient obtenus en 2 parties, en inversant de 180° la position de l'appareil. La profondeur de la résection a été optimale dans 58 cas sur 65 avec une découpe précise au niveau de la sous-muqueuse sans lésion de la couche musculaire sous- jacente. Il n'y a pas eu de complications après les résections hémi-circonférentielles. Les complications engendrées par les résections circonférentielles (sténose, perforation) n'ont plus été rencontrées après application locale de Mitomycine-C administrée à des intervalles de temps bien précis. Conclusion : Notre méthode de résection endoscopique de la muqueuse oesophagienne offre une nouvelle approche très prometteuse par rapport aux options déjà disponibles. Elle apparaît supérieure en ce qui concerne la taille de tissu prélevé, la précision et régularité de la profondeur de résection, ainsi que la facilité et sûreté du diagnostic histologique et des marges de sécurité. Les résections hémi-circonférentielles se sont révélées sûres chez le modèle animal. Cette nouvelle technique mérite de plus amples investigations pour les résections circonférentielles avant son utilisation chez l'humain. Abstract: Background and Study Aims: We undertook this retrospective study to evaluate the frequency and prognosis of endoscopic treatment of laterally spreading tumors (LSTs) in the rectum. The recurrence rate for lesions of the lower rectum was compared with that of the upper rectum. Patients and Methods: During the period from July 1989 to June 2002, a total of 1237 rectal tumors were detected. LSTs accounted for 6.9% (85/1237) of all rectal tumors. A total of 224 tumors of the lower rectum were detected among the 1237 rectal tumors. LSTs accounted for 16.1 % (36/224) of all the lower rectal tumors. From 85 LST lesions, 67 were evaluated for their prognosis after endoscopic mucosal resection (EMR). Patients whose LSTs had been resected were followed up by endoscopy at the following frequencies: once 15 (22.4%); twice (more than 1 year), 20 (29.9%); three times (more than 3 years), 21(31.3%); and four times or more (more than 5 years), 11 (16.4%). Results: A total of 67 patients with endoscopically treated LSTs were followed up by endoscopy. We observed recurrences in two lesions of the upper rectum (2/38, 5.3%) and five lesions of the lower rectum (5/29, 17.2%) (P = 0.2364); all seven lesions were resected piecemeal. LSTs whose horizontal margin reached the pectinate line frequently recurred in the lower rectum, at a rate of 80% (4/5). However, all patients were completely cured by additional endoscopic resections, the greatest number of treatments being four. Conclusion: For early detection of recurrence and successful endoscopic cure, further colonoscopic examination within a few months after the first treatment is necessary.

Potentiel des liposomes pour l'injection intravitréenne de molécules thérapeutiques [Potential of liposomes for the intravitreal injection of therapeutic molecules].

Intravitreal administration has been widely used since 20 years and has been shown to improve the treatment of diseases of the posterior segment of the eye with infectious origin or in edematous maculopathies. This route of administration allows to achieve high concentration of drug in the vitreous and avoids the problems resulting from systemic administration. However, two basic problems limit the use of intravitreal therapy. Many drugs are rapidly cleared from the vitreous humor; therefore, to reach and to maintain effective therapy repeated injections are necessary. Repeated intravitreal injections increase the risk of endophthalmitis, damage to lens, retinal detachment. Moreover, some drugs provoke a local toxicity at their effective dose inducing side-effects and possible retinal lesions. In this context, the development and the use of new drug delivery systems for intravitreal administration are necessary to treat chronic ocular diseases. Among them, particulate systems such as liposomes have been widely studied. Liposomes are easily injectable and permit to reduce the toxicity and to increase the residence time of several drugs in the eye. They are also able to protect in vivo poorly-stable molecules from degradation such as peptides and nucleic acids. Some promising results have been obtained for the treatment of retinitis induced by cytomegalovirus in human and more recently for the treatment of uveitis in animal. Finally, the fate of liposomes in ocular tissues and fluids after their injection into the vitreous and their elimination routes begin to be more known.

Translation of biomechanical concepts in bone tissue engineering: from animal study to revision knee arthroplasty.

Bone defects in revision knee arthroplasty are often located in load-bearing regions. The goal of this study was to determine whether a physiologic load could be used as an in situ osteogenic signal to the scaffolds filling the bone defects. In order to answer this question, we proposed a novel translation procedure having four steps: (1) determining the mechanical stimulus using finite element method, (2) designing an animal study to measure bone formation spatially and temporally using micro-CT imaging in the scaffold subjected to the estimated mechanical stimulus, (3) identifying bone formation parameters for the loaded and non-loaded cases appearing in a recently developed mathematical model for bone formation in the scaffold and (4) estimating the stiffness and the bone formation in the bone-scaffold construct. With this procedure, we estimated that after 3 years mechanical stimulation increases the bone volume fraction and the stiffness of scaffold by 1.5- and 2.7-fold, respectively, compared to a non-loaded situation.

Acanthocefalan eggs in animal coprolites from archaeological sites from Brazil

An important point in paleoparasitology is the correct diagnosis of the origin of coprolites found in archaelogical sites. The identification of human and animal coprolites, through the study of the shape, size, charactheristics after rehydration, alimentary contents, and the presence of parasites, has proved to be accurate for human coprolites. For non-human ones we compared coprolites with recent faeces of animals collected near the archaeological sites, following the methodology above mentioned. In this paper anteaters coprolites (Tamandua tetradactyla; Mymecophaga tridactyla) with eggs of Gigantorhynchus echinodiscus (Archiancanthocephala; Gigantorynchidae) were identified.

A peptide inhibitor of C-jun N-terminal kinase modulates hepatic damage and the inflammatory response after hemorrhagic shock and resuscitation

Hemorrhage and resuscitation (H/R) leads to phosphorylation of mitogen-activated stress kinases, an event that is associated with organ damage. Recently, a specific, cell-penetrating, protease-resistant inhibitory peptide of the mitogen-activated protein kinase c-JUN N-terminal kinase (JNK) was developed (D-JNKI-1). Here, using this peptide, we tested if inhibition of JNK protects against organ damage after H/R. Male Sprague-Dawley rats were treated with D-JNKI-1 (11 mg/kg, i.p.) or vehicle. Thirty minutes later, rats were hemorrhaged for 1 h to a MAP of 30 to 35 mmHg and then resuscitated with 60% of the shed blood and twice the shed blood volume as Ringer lactate. Tissues were harvested 2 h later. ANOVA with Tukey post hoc analysis or Kruskal-Wallis ANOVA on ranks, P < 0.05, was considered significant. c-JUN N-terminal kinase inhibition decreased serum alanine aminotransferase activity as a marker of liver injury by 70%, serum creatine kinase activity by 67%, and serum lactate dehydrogenase activity by 60% as compared with vehicle treatment. The histological tissue damage observed was blunted after D-JNKI-1 pretreatment both for necrotic and apoptotic cell death. Hepatic leukocyte infiltration and serum IL-6 levels were largely diminished after D-JNKI-1 pretreatment. The extent of oxidative stress as evaluated by immunohistochemical detection of 4-hydroxynonenal was largely abrogated after JNK inhibition. After JNK inhibition, activation of cJUN after H/R was also reduced. Hemorrhage and resuscitation induces a systemic inflammatory response and leads to end-organ damage. These changes are mediated, at least in part, by JNK. Therefore, JNK inhibition deserves further evaluation as a potential treatment option in patients after resuscitated blood loss.