Identification of differentially expressed genes in aflatoxin B1- treated cultured primary rat hepatocytes and Fischer 344 rats

Aflatoxin B1 (AFB1), a mutagen and hepatocarcinogen in rats and humans, is a contaminant of the human food supply, particularly in parts of Africa and Asia. AFB1-induced changes in gene expression may play a part in the development of the toxic, immunosuppressive and carcinogenic properties of this fungal metabolite. An understanding of the-role of AFB1 in modulating gene regulation should provide insight regarding mechanisms of AFB1-induced carcinogenesis. We used three PCR- based subtractive techniques to identify AFB1-responsive genes in cultured primary rat hepatocyte RNA: differential display PCR (DD-PCR), representational difference analysis (RDA) and suppression subtractive hybridization (SSH). Each of the three techniques identified AFB1- responsive genes, although no individual cDNA was isolated by more than one technique. Nine cDNAs isolated using DD-PCR, RDA or SSH were found to represent eight genes that are differentially expressed as a result of AFB1 exposure. Genes whose mRNA levels were increased in cultured primary rat hepatocytes after AFB1 treatment were corticosteroid binding globulin (CBG), cytochrome P450 4F1 (CYP4F1), alpha-2 microglobulin, C4b-binding protein (C4BP), serum amyloid A-2 and glutathione S-transferase Yb2 (GST). Transferrin and a small CYP3A-like cDNA had reduced mRNA levels after AFB1 exposure. Full-length CYP3A mRNA levels were increased. When liver RNA from AFB1-treated male F344 rats was evaluated for transferrin, CBG, GST, CYP3A and CYP4F1 expression, a decrease in transferrin mRNA and an increase in CBG, GST, CYP3A and CYP4F1 mRNA levels was also seen. Analysis of the potential function of these genes in maintaining cellular homeostasis suggests that their differential expression could contribute to the toxicity associated with AFB1 exposure.      

Antiangiogéniques et métastases cérébrales: plus de peur que de mal ?

Brain metastases occur in 5% to 20% of cancer patients, depending on the primary tumor type. Several angiogenesis inhibitors have shown clinical efficacy in numerous tumors that frequently metastasize to the brain. However, clinical trials of such angiogenesis inhibitors have excluded patients with brain metastases owing to the theoretical risk of cerebral hemorrhage. Therefore, the available safety data are mainly retrospective: cerebral hemorrhage incidence is estimated to affect 0.1% to 3% of patients treated with angiogenesis inhibitors. Efficacy data are scarce, but case reports of brain metastases with complete and partial responses have been published. Few retrospective reports with few patients suggest that radiation therapy or radiosurgery could be safe. Therefore, available safety data suggest that angiogenesis inhibitor can be used to treat cancer patients with brain metastases. Prospective evaluation is warranted, and cancer patients who harbor brain metastases should not be systematically excluded from prospective clinical trials evaluating angiogenesis inhibitors.     

Total elbow arthroplasty is moving forward: Review on past,present and future

The elbow joint is a complex joint, which, when impaired in function, leads to severe disability. In some cases however, an arthroplasty might be an appropriate treatment. In the past four decades, large steps havebeen taken to optimize this treatment in order to achieve better post-operative outcomes. To understand these progresses and to discover aspects for upcoming improvements, we present a review on the past developments, the present state of affairs and future developments which may improve patient care further.     

EFAS Score —Validation of Persian Version by the Score Committee of the European Foot and Ankle Society (EFAS)

BackgroundThe Score Committee of the European Foot and Ankle Society (EFAS) developed, validated, and published the EFAS Score in nine European languages (English, German, French, Italian, Polish, Dutch, Swedish, Finnish, Turkish). From other languages under validation, the Persian version finished data acquisition and underwent further validation.MethodsThe Persian version of the EFAS Score was developed and validated in three stages: 1) item (question) identification (completed during initial validation study), 2) item reduction and scale exploration (completed during initial validation study), 3) confirmatory analyses and responsiveness of Persian version (completed during initial validation study in nine other languages). The data were collected pre-operatively and post-operatively at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using classical test theory and item response theory.ResultsThe internal consistency was confirmed in the Persian version (Cronbach’s Alpha 0.82). The Standard Error of Measurement (SEM) was 0.38 and is similar to other language versions. Between baseline and follow-up, 97% of patients showed an improvement on their EFAS score, with excellent responsiveness (effect size 1.93).ConclusionsThe Persian EFAS Score version was successfully validated in patients with a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.co.     

Quantitative frame by frame analysis of regional contraction and lengthening on left ventricular cineangiograms: application to the study of normal left ventricles and left ventricles with mitral valve prolapse

This work attempted to study the segmental wall motion on left ventriculograms, in terms of segmental shortening, velocity of segmental shortening, and temporal sequences of various events in systole as well as in diastole. The ability of such a method to characterize patterns of normal regional wall motion and to detect mild abnormalities such as isolated asynchronisms, was tested on two groups of patients. Group I included 25 patients presenting evidence of a normal left ventricle (LV) after left heart catheterization. Group II consisted of 21 patients suffering from an isolated pure idiopathic mitral valve prolapse (MVP), with no mitral insufficiency and with an unaffected global LV function. In all patients left ventriculography was filmed in the right anterior oblique view at a rate of 50 frames/s. For each patient a cycle was chosen, distant from any premature beat, with acceptably contrasted outlines, and a quantitative frame by frame study of the motion of 10 segments was performed using a semiautomated method derived from the Stanford method. In the control group (Group I), analysis of the segmental motion by means of this method demonstrates a mild nonuniformity of the normal wall motion. This is principally marked by a stronger and faster contraction in anterolateral segments (segments 7, 8, 9) and by a shorter duration of the contraction in this region. In contrast the MVP group (Group II), exhibited a frank asynergy of the anterolateral region occurring from end systole to early diastole.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enhancement of chemotactic factor-stimulated neutrophil oxidative metabolism by leukotriene B4

Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation, and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with f-Met-Leu-Phe (fMLP, 10(-7) mol/L), opsonized zymosan (OZ, 250 micrograms/mL), or phorbol myristate acetate (PMA, 32 nmol/L). Superoxide (O2-) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O2- production in concentrations below 10(-7) mol/L and had no effect on the O2- assay. In the concentration range of 10(-12) to 10(-8) mol/L, LTB4 did not alter O2- release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced O2- production following exposure to fMLP, and in the presence of 10 nmol/LLTB4, generated 180% +/- 41% of O-2 quantities produced by control cells (n = 23). Enhancement was LTB4 dose-dependent, was maximal in the range of 1 to 10 nmol/L LTB4, was not reversed by removal of the lipid from the medium prior to fMLP stimulation, and was not dependent on the presence of Ca++ or Mg++ in the suspending medium. Chemiluminescence of fMLP-stimulated neutrophils was increased to 323% of controls in neutrophils preincubated with 10 nmol/L LTB4. Unlike augmentation of oxidative responses to fMLP seen with other degranulating stimuli, enhancement by LTB4 was not correlated with an increase in 3H-fMLP receptor binding. These results indicate that, in addition to its primary effects on neutrophil function, LTB4 modulates PMN oxidative responses to the chemotactic peptide and, thus, may amplify the release of oxygen metabolites at inflammatory foci.     

Thrombospondin mediates the cytoadherence of Plasmodium falciparum- infected red cells to vascular endothelium in shear flow conditions

Cerebral malaria is thought to involve specific attachment of Plasmodium falciparum-infected knobby red cells to venular endothelium. The nature of surface ligands on host endothelial cells that may mediate cytoadherence is poorly understood. We have investigated the effects of soluble thrombospondin, rabbit antiserum raised against thrombospondin, and human immune serum on cytoadherence of parasitized erythrocytes in ex vivo mesocecum vasculature. Preincubation of infected red cells with soluble thrombospondin or human immune serum inhibits binding of infected red cells to rat venular endothelium. Infusion of the microcirculatory preparation with rabbit antithrombospondin antibodies before perfusion of parasitized erythrocytes also resulted in decreased cytoadherence. In addition, incubation of infected cells with human immune sera obtained from malaria patients significantly inhibited the observed cytoadherence. Our results indicate that thrombospondin mediates binding of infected red cells to venular endothelium and may thus be involved in the pathogenesis of cerebral malaria.