Angiotensin II-induced cardiac hypertrophy is associated with different mitogen-activated protein kinase activation in normotensive and hypertensive mice.

OBJECTIVE: In addition to its haemodynamic effects, angiotensin II (AngII) is thought to contribute to the development of cardiac hypertrophy via its growth factor properties. The activation of mitogen-activated protein kinases (MAPK) is crucial for stimulating cardiac growth. Therefore, the present study aimed to determine whether the trophic effects of AngII and the AngII-induced haemodynamic load were associated with specific cardiac MAPK pathways during the development of hypertrophy. Methods The activation of the extracellular-signal-regulated kinase (ERK), the c-jun N-terminal kinase (JNK) and the p38 kinase was followed in the heart of normotensive and hypertensive transgenic mice with AngII-mediated cardiac hypertrophy. Secondly, we used physiological models of AngII-dependent and AngII-independent renovascular hypertension to study the activation of cardiac MAPK pathways during the development of hypertrophy. RESULTS: In normotensive transgenic animals with AngII-induced cardiac hypertrophy, p38 activation is associated with the development of hypertrophy while ERK and JNK are modestly stimulated. In hypertensive transgenic mice, further activation of ERK and JNK is observed. Moreover, in the AngII-independent model of renovascular hypertension and cardiac hypertrophy, p38 is not activated while ERK and JNK are strongly stimulated. In contrast, in the AngII-dependent model, all three kinases are stimulated. CONCLUSIONS: These data suggest that p38 activation is preferentially associated with the direct effects of AngII on cardiac cells, whereas stimulation of ERK and JNK occurs in association with AngII-induced mechanical stress.

A morphometric study of mechanotransductively induced dermal neovascularization.

BACKGROUND:: Mechanical stretch has been shown to induce vascular remodeling and increase vessel density, but the pathophysiologic mechanisms and the morphologic changes induced by tensile forces to dermal vessels are poorly understood. METHODS:: A custom computer-controlled stretch device was designed and applied to the backs of C57BL/6 mice (n = 38). Dermal and vascular remodeling was studied over a 7-day period. Corrosion casting and three-dimensional scanning electron microscopy and CD31 staining were performed to analyze microvessel morphology. Hypoxia was assessed by immunohistochemistry. Western blot analysis of vascular endothelial growth factor (VEGF) and mRNA expression of VEGF receptors was performed. RESULTS:: Skin stretching was associated with increased angiogenesis as demonstrated by CD31 staining and vessel corrosion casting where intervascular distance and vessel diameter were decreased (p < 0.01). Immediately after stretching, VEGF dimers were increased. Messenger RNA expression of VEGF receptor 1, VEGF receptor 2, neuropilin 1, and neuropilin 2 was increased starting as early as 2 hours after stretching. Highly proliferating epidermal cells induced epidermal hypoxia starting at day 3 (p < 0.01). CONCLUSIONS:: Identification of significant hypoxic cells occurred after identification of neovessels, suggesting an alternative mechanism. Increased expression of angiogenic receptors and stabilization of VEGF dimers may be involved in a mechanotransductive, prehypoxic induction of neovascularization.

Mechanisms of proteasome inhibitor-induced cytotoxicity in malignant glioma.

The 26S proteasome constitutes an essential degradation apparatus involved in the consistent recycling of misfolded and damaged proteins inside cells. The aberrant activation of the proteasome has been widely observed in various types of cancers and implicated in the development and progression of carcinogenesis. In the era of targeted therapies, the clinical use of proteasome inhibitors necessitates a better understanding of the molecular mechanisms of cell death responsible for their cytotoxic action, which are reviewed here in the context of sensitization of malignant gliomas, a tumor type particularly refractory to conventional treatments.

The aldosterone-mineralocorticoid receptor pathway exerts anti-inflammatory effects in endotoxin-induced uveitis.

We have previously shown that the eye is a mineralocorticoid-sensitive organ and we now question the role of mineralocorticoid receptor (MR) in ocular inflammation. The endotoxin-induced uveitis (EIU), a rat model of human intraocular inflammation, was induced by systemic administration of lipopolysaccharide (LPS). Evaluations were made 6 and 24 hours after intraocular injection of aldosterone (simultaneous to LPS injection). Three hours after onset of EIU, the MR and the glucocorticoid metabolizing enzyme 11-beta hydroxysteroid dehydrogenase type 2 (11β-HSD2) expression were down-regulated in iris/ciliary body and the corticosterone concentration was increased in aqueous humor, altering the normal MR/glucocorticoid receptor (GR) balance. At 24 hours, the GR expression was also decreased. In EIU, aldosterone reduced the intensity of clinical inflammation in a dose-dependent manner. The clinical benefit of aldosterone was abrogated in the presence of the MR antagonist (RU26752) and only partially with the GR antagonist (RU38486). Aldosterone reduced the release of inflammatory mediators (6 and 24 hours: TNF-α, IFN-γ, MIP-1α) in aqueous humor and the number of activated microglia/macrophages. Aldosterone partly prevented the uveitis-induced MR down-regulation. These results suggest that MR expression and activation in iris/ciliary body could protect the ocular structures against damages induced by EIU.

Influence of Apion sp. (Brentidae, Apioninae) stem-galls on induced resistance and leaf area of Diospyros hispida (Ebenaceae)

We addressed the influence of the stem galls induced by an unidentified species of Apion sensu lato (Brentidae, Apioninae) on the host plant, Diospyros hispida (Ebenaceae) leaf area and induced resistance against a Cecidomyiidae (Diptera) leaf galls. The study was performed in a cerrado vegetation in Serra do Cipó, southeastern Brazil. Although the number of leaves produced on galled and ungalled shoots did not differ statically (p>0.05), the presence of the apionid galls influenced the area of the leaves on the attacked shoots of D. hispida. Leaves on galled stems were approximately 50% smaller compared to leaves in healthy stems. The average of the cecidomyiid leaf galls successfully induced on healthy shoots was higher compared to galls successfully induced on shoots galled by the apionid. The same pattern was found for the abundance of hypersensitive reactions against the cedidomyiid gall induction. Therefore, the ability of the cecidomyiid to successfully induce galls was not influenced by the apionid galler.

Alvéolite aux isocyanates chez une couturière [Isocyanate-induced alveolitis in a furniture manufacture worker]

A 41-year-old woman who worked in a furniture plant was admitted to hospital for acute dyspnea that had developed a few hours she marked pieces of "Alcantara" material with a heated metallic blade. The chest x-ray showed a restrictive syndrome. The lymphocyte count was high in the bronchioalveolar lavage fluid with a CD4/CD8 ratio of 0.11, leading to the diagnosis of alveolitis. Investigations at the work place allowed identification and evaluation of the causal agent. Alcantara is a synthetic fabric composed of 70% polyurethane fibers, which when burned produces isocyanate monomers. After eliminating exposure and institution of corticosteroid therapy, the outcome was good with complete recovery. The risk was eliminated by changing the work procedure. This risk has not been reported earlier for furniture manufacture.

Retrovirus-induced target cell activation in the early phases of infection: the mouse mammary tumor virus model.

Mouse mammary tumor virus (MMTV) infects B lymphocytes and expresses a superantigen on the cell surface after integration of its reverse-transcribed genome. Superantigen-dependent B- and T-cell activation becomes detectable 2 to 3 days after infection. We show here that before this event, B cells undergo a polyclonal activation which does not involve massive proliferation. This first phase of B-cell activation is T cell independent. Moreover, during the first phase of activation, when only a small fraction of B cells is infected by MMTV(SW), viral DNA is detected only in activated B cells. Such a B-cell activation is also seen after injection of murine leukemia virus but not after injection of vaccinia virus, despite the very similar kinetics and intensity of the immune response. Since retroviruses require activated target cells to induce efficient infection, these data suggest that the early polyclonal retrovirus-induced target cell activation might play an important role in the establishment of retroviral infections.

Late Onset Cystoid Macular Oedema Following Surgery for Radiation Induced Cataract in Patient With Retinoblastoma

Purpose: Cystoid macular oedema (CMO) is a very rare condition following cataract surgery in paediatric population. Nevertheless, we report a case series of patients with radiation induced cataract after retinoblastoma (Rb) treatment that underwent cataract surgery and developed subsequently late onset CMO. Methods: Between January 1984 and December 2009, 25 consecutive eyes (25 patients) with Rb presented with radiation induced cataract surgery at the Jules Gonin Eye Hospital. Sixteen eyes (16 patients) had prior radiation induced retinopathy and maculopathy (IRM). Out of these, 3 eyes (3 patients) developed CMO after cataract surgery. Results: One eye had Rb stage B, and 2 eyes had stage D International classification. All of them developed IRM following brachytherapy and/or external beam irradiation. Patients underwent phako-aspiration and in bag intraocular lens implantation after IRM had resolved. Mean age at cataract surgery was 10.7 ± 2.8 (SEM) (range 5-14) years old. Mean time between resolution of IRM and cataract surgery was 76.0 ± 27.2 (SEM) (range 24-116) months. Mean time of onset CMO after cataract surgery was 81.0 ± 34.4 (SEM) (range 13-124) months. There was no other underlying vascular or tractional factor for CMO development. All of them were treated with a combination of oral carbonic anhydrase inhibitor, topical steroid and topical non-steroid. Mean macular thickness pre-, during-, and post CMO were 134.0 ± 10.3, 298.0 ± 37.1, and 154.0 ± 4.0 (SEM) µm, respectively. Mean best corrected visual acuity pre-, during-, and post CMO were 0.31 ± 0.19, 0.46 ± 0.12, and 0.34 ± 0.18 (SEM) LogMAR, respectively. Mean time for CMO reabsorption was 17.0 ± 9.8 (SEM) months. Conclusions: To the best of our knowledge, CMO following paediatric cataract surgery is a very uncommon condition. Moreover, late onset CMO after phako-aspiration for radiation induced cataract in Rb patients has never been described. It is a rare complication but can be treated successfully.

Time-Lapse AFM Imaging of DNA Conformational Changes Induced by Daunorubicin.

Cancer is a major health issue that absorbs the attention of a large part of the biomedical research. Intercalating agents bind to DNA molecules and can inhibit their synthesis and transcription; thus, they are increasingly used as drugs to fight cancer. In this work, we show how atomic force microscopy in liquid can characterize, through time-lapse imaging, the dynamical influence of intercalating agents on the supercoiling of DNA, improving our understanding of the drug's effect.

Predicting adverse events in children with fever and chemotherapy-induced neutropenia: the prospective multicenter SPOG 2003 FN study.

PURPOSE To develop a score predicting the risk of adverse events (AEs) in pediatric patients with cancer who experience fever and neutropenia (FN) and to evaluate its performance. PATIENTS AND METHODS Pediatric patients with cancer presenting with FN induced by nonmyeloablative chemotherapy were observed in a prospective multicenter study. A score predicting the risk of future AEs (ie, serious medical complication, microbiologically defined infection, radiologically confirmed pneumonia) was developed from a multivariate mixed logistic regression model. Its cross-validated predictive performance was compared with that of published risk prediction rules. Results An AE was reported in 122 (29%) of 423 FN episodes. In 57 episodes (13%), the first AE was known only after reassessment after 8 to 24 hours of inpatient management. Predicting AE at reassessment was better than prediction at presentation with FN. A differential leukocyte count did not increase the predictive performance. The score predicting future AE in 358 episodes without known AE at reassessment used the following four variables: preceding chemotherapy more intensive than acute lymphoblastic leukemia maintenance (weight = 4), hemoglobin > or = 90 g/L (weight = 5), leukocyte count less than 0.3 G/L (weight = 3), and platelet count less than 50 G/L (weight = 3). A score (sum of weights) > or = 9 predicted future AEs. The cross-validated performance of this score exceeded the performance of published risk prediction rules. At an overall sensitivity of 92%, 35% of the episodes were classified as low risk, with a specificity of 45% and a negative predictive value of 93%. CONCLUSION This score, based on four routinely accessible characteristics, accurately identifies pediatric patients with cancer with FN at risk for AEs after reassessment.

Twitch and M-wave potentiation induced by intermittent maximal voluntary quadriceps contractions: Differences between direct quadriceps and femoral nerve stimulation.

Introduction: To investigate differences in twitch and M-wave potentiation in the quadriceps femoris when electrical stimulation is applied over the quadriceps muscle belly versus the femoral nerve trunk. Methods: M-waves and mechanical twitches were evoked using direct quadriceps muscle and femoral nerve stimulation between 48 successive isometric maximal voluntary contractions (MVC) from 10 young, healthy subjects. Potentiation was investigated by analyzing the changes in M-wave amplitude recorded from the vastus medialis (VM) and vastus lateralis (VL) muscles and in quadriceps peak twitch force. Results: Potentiation of twitch, VM M-wave, and VL M-wave were greater for femoral nerve than for direct quadriceps stimulation (P<0.05). Despite a 50% decrease in MVC force, the amplitude of the M-waves increased significantly during exercise. Conclusions: In addition to enhanced electrogenic Na(+) -K(+) pumping, other factors (such as synchronization in activation of muscle fibers and muscle architectural properties) might significantly influence the magnitude of M-wave enlargement. © 2013 Wiley Periodicals, Inc.

Variations in IB1/JIP1 expression regulate susceptibility of beta-cells to cytokine-induced apoptosis irrespective of C-Jun NH2-terminal kinase signaling.

We previously reported that interleukin-1beta (IL-1beta) alone does not cause apoptosis of beta-cells, whereas when combined with gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), it exerts a distinct apoptotic effect. Studies in beta-cell lines indicated that IL-1beta reduced expression of islet brain (IB)-1/JNK interacting protein (JIP)-1, a JNK scaffold protein with antiapoptotic action. We examined whether variations in IB1/JIP-1 expression in purified primary beta-cells affect their susceptibility to cytokine-induced apoptosis. Exposure to IL-1beta for 24 h decreased cellular IB1/JIP-1 content by 66 +/- 17%; this IL-1beta effect was maintained in the presence of TNF-alpha + IFN-gamma, which did not influence IB1/JIP-1 levels by themselves. Addition of IL-1beta to TNF-alpha + IFN-gamma increased apoptosis from 20 +/- 2% to 59 +/- 5%. A similar increase in TNF-alpha + IFN-gamma-induced apoptosis was produced by adenoviral expression of antisense IB1/JIP-1 and was not further enhanced by addition of IL-1beta, indicating that IL-1beta-mediated suppression of IB1/JIP-1 in beta-cells increases their susceptibility to cytokine-induced apoptosis. However, adenovirally mediated overexpression of IB1/JIP-1 also potentiated TNF-alpha + IFN-gamma-induced apoptosis, suggesting that the antiapoptotic effect of IB1/JIP-1 depends on well-defined cellular levels. We conclude that the IB1/JIP-1 level in beta-cells can control their susceptibility to apoptosis independent of JNK signaling.

Assessment of vaccine-induced CD4 T cell responses to the 119-143 immunodominant region of the tumor-specific antigen NY-ESO-1 using DRB1*0101 tetramers.

Abstract: Purpose: NY-ESO-1 (ESO), a tumor-specific antigen of the cancer/testis group, is presently viewed as an important model antigen for the development of generic anticancer vaccines. The ESO119-143 region is immunodominant following immunization with a recombinant ESO vaccine. In this study, we generated DRB1*0101/ESO119-143 tetramers and used them to assess CD4 T-cell responses in vaccinated patients expressing DRB1*0101 (DR1). Experimental Design: We generated tetramers of DRB1*0101 incorporating peptide ESO119-143 using a previously described strategy. We assessed ESO119-143-specific CD4 T cells in peptide-stimulated post-vaccine cultures using the tetramers. We isolated DR1/ESO119-143 tetramer(+) cells by cell sorting and characterized them functionally. We assessed vaccine-induced CD4(+) DR1/ESO119-143 tetramer(+) T cells ex vivo and characterized them phenotypically. Results: Staining of cultures from vaccinated patients with DR1/ESO119-143 tetramers identified vaccine-induced CD4 T cells. Tetramer(+) cells isolated by cell sorting were of T(H)1 type and efficiently recognized full-length ESO. We identified ESO123-137 as the minimal optimal epitope recognized by DR1-restricted ESO-specific CD4 T cells. By assessing DR1/ESO119-143 tetramer(+) cells using T cell receptor (TCR) beta chain variable region (V beta)-specific antibodies, we identified several frequently used V beta. Finally, direct ex vivo staining of patients' CD4 T cells with tetramers allowed the direct quantification and phenotyping of vaccine-induced ESO-specific CD4 T cells. Conclusions: The development of DR1/ESO119-143 tetramers, allowing the direct visualization, isolation, and characterization of ESO-specific CD4 T cells, will be instrumental for the evaluation of spontaneous and vaccine-induced immune responses to this important tumor antigen in DR1-expressing patients

Resistance to diet-induced obesity and associated metabolic perturbations in haploinsufficient monocarboxylate transporter 1 mice

The monocarboxylate transporter 1 (MCT1 or SLC16A1) is a carrier of short-chain fatty acids, ketone bodies, and lactate in several tissues. Genetically modified C57BL/6J mice were produced by targeted disruption of the mct1 gene in order to understand the role of this transporter in energy homeostasis. Null mutation was embryonically lethal, but MCT1 (+/-) mice developed normally. However, when fed high fat diet (HFD), MCT1 (+/-) mice displayed resistance to development of diet-induced obesity (24.8% lower body weight after 16 weeks of HFD), as well as less insulin resistance and no hepatic steatosis as compared to littermate MCT1 (+/+) mice used as controls. Body composition analysis revealed that reduced weight gain in MCT1 (+/-) mice was due to decreased fat accumulation (50.0% less after 9 months of HFD) notably in liver and white adipose tissue. This phenotype was associated with reduced food intake under HFD (12.3% less over 10 weeks) and decreased intestinal energy absorption (9.6% higher stool energy content). Indirect calorimetry measurements showed ∼ 15% increase in O2 consumption and CO2 production during the resting phase, without any changes in physical activity. Determination of plasma concentrations for various metabolites and hormones did not reveal significant changes in lactate and ketone bodies levels between the two genotypes, but both insulin and leptin levels, which were elevated in MCT1 (+/+) mice when fed HFD, were reduced in MCT1 (+/-) mice under HFD. Interestingly, the enhancement in expression of several genes involved in lipid metabolism in the liver of MCT1 (+/+) mice under high fat diet was prevented in the liver of MCT1 (+/-) mice under the same diet, thus likely contributing to the observed phenotype. These findings uncover the critical role of MCT1 in the regulation of energy balance when animals are exposed to an obesogenic diet.

Mechanisms of the anti-obesity effects of oxytocin in diet-induced obese rats.

Apart from its role during labor and lactation, oxytocin is involved in several other functions. Interestingly, oxytocin- and oxytocin receptor-deficient mice develop late-onset obesity with normal food intake, suggesting that the hormone might exert a series of beneficial metabolic effects. This was recently confirmed by data showing that central oxytocin infusion causes weight loss in diet-induced obese mice. The aim of the present study was to unravel the mechanisms underlying such beneficial effects of oxytocin. Chronic central oxytocin infusion was carried out in high fat diet-induced obese rats. Its impact on body weight, lipid metabolism and insulin sensitivity was determined. We observed a dose-dependent decrease in body weight gain, increased adipose tissue lipolysis and fatty acid β-oxidation, as well as reduced glucose intolerance and insulin resistance. The additional observation that plasma oxytocin levels increased upon central infusion suggested that the hormone might affect adipose tissue metabolism by direct action. This was demonstrated using in vitro, ex vivo, as well as in vivo experiments. With regard to its mechanism of action in adipose tissue, oxytocin increased the expression of stearoyl-coenzyme A desaturase 1, as well as the tissue content of the phospholipid precursor, N-oleoyl-phosphatidylethanolamine, the biosynthetic precursor of the oleic acid-derived PPAR-alpha activator, oleoylethanolamide. Because PPAR-alpha regulates fatty acid β-oxidation, we hypothesized that this transcription factor might mediate the oxytocin effects. This was substantiated by the observation that, in contrast to its effects in wild-type mice, oxytocin infusion failed to induce weight loss and fat oxidation in PPAR-alpha-deficient animals. Altogether, these results suggest that oxytocin administration could represent a promising therapeutic approach for the treatment of human obesity and type 2 diabetes.