Role of dendrimers in advanced drug delivery and biomedical applications: a review.

AIM: Dendrimers dendritic structural design holds vast promises, predominantly for drug delivery, owing to their unique properties. Dendritic architecture is widespread topology found in nature and offers development of specific properties of chemical substances. Dendrimers are an ideal delivery vehicle candidate for open study of the effects of polymer size, charge, and composition on biologically relevant properties such as lipid bilayer interactions, cytotoxicity, bio-distribution, internalization, blood plasma retention time, and filtration. This article reviews role of dendrimers in advanced drug delivery and biomedical applications.

Microengineered cancer-on-a-chip platforms to study the metastatic microenvironment.

More than 90% of cancer-related deaths can be attributed to the occurrence of metastatic diseases. Recent studies have highlighted the importance of the multicellular, biochemical and biophysical stimuli from the tumor microenvironment during carcinogenesis, treatment failure, and metastasis. Therefore, there is a need for experimental platforms that are able to recapitulate the complex pathophysiological features of the metastatic microenvironment. Recent advancements in biomaterials, microfluidics, and tissue engineering have led to the development of living multicellular microculture systems, which are maintained in controllable microenvironments and function with organ level complexity. The applications of these "on-chip" technologies for detection, separation, characterization and three dimensional (3D) propagation of cancer cells have been extensively reviewed in previous works. In this contribution, we focus on integrative microengineered platforms that allow the study of multiple aspects of the metastatic microenvironment, including the physicochemical cues from the tumor associated stroma, the heterocellular interactions that drive trans-endothelial migration and angiogenesis, the environmental stresses that metastatic cancer cells encounter during migration, and the physicochemical gradients that direct cell motility and invasion. We discuss the application of these systems as in vitro assays to elucidate fundamental mechanisms of cancer metastasis, as well as their use as human relevant platforms for drug screening in biomimetic microenvironments. We then conclude with our commentaries on current progress and future perspectives of microengineered systems for fundamental and translational cancer research.

[Conductive disorders following open-heart valvular surgery. Concerning 230 operated patients]. / Les troubles conductifs après chirurgie cardiaque valvulaire sous circulation extracorporelle. A propos de 230 malades opérés.

AIMS: Conductive disorders following open-heart valvular surgery represent serious complications that may require definitive pacemaker implantation. The natural history of these troubles is not well established thus, controversy persist concerning the timing of pacemaker implantation. In this study we identify the predictive factors of permanent conductive disorders in order to assess the optimal time of pacing. METHODS AND RESULTS: Two hundred thirty valvular replacements were done between 1993 and 2003. The mean age of our patients was 42 +/- 13.4 years. Rheumatic valvulopathies accounted for 76% of cases, with 54% of multiple valvulopathies. Twenty-two patients (9,5%) had an early postoperative conductive disorder, 9 of them (4%) were definitively implanted after a mean delay of 31.8 days. Preoperative bifascicular bloc and early installation of postoperative high-grade conduction disturbances and its persistence for more than 48 hours are significantly associated with permanent postoperative conductive disorders (respectively P = 0.04 and = 0.03). Aortic valve surgery and infective endocarditis were more frequent in the implanted group but the difference was not significant. CONCLUSION: After open-heart valvular surgery; predictive factors of definitive conductive troubles justify an earlier pacemaker implantation. This attitude may accelerate the hospital discharge and decrease the disease cost effectiveness.

[Brucella endocardititis: clinical particularities and therapeutic modalities]. / Endocardite brucellienne: particularités cliniques et modalités thérapeutiques.

Brucella infective endocarditis is an uncommon, but serious complication of brucellosis. The aortic valve is the most commonly affected cardiac valve. Due to characteristics of the infection, medical therapy alone is not sufficient in treating the disease and best results are obtained with surgery combination. We describe a case of Brucella endocarditis involving the aortic valve suspected in front of the clinical data and the results of serology, confirmed by the culture of the native valves. In association with the medical treatment, management valve replacement lead to a favorable medium-term evolution.