Evaluation of 3 different methods for determining triiodothyronine (T-3) and thyroxine (T-4)

The authors compare three methodologies based on the immunology (RIA, FPIA, LIA) in the determination of two important parameters of the so-called thyroid outline: triiodothyronine (T-3) and thyroxine (T-4). The correlations between the analytic systems examined are presented and discussed.     

Mycobacterium tuberculosis subverts the differentiation of human monocytes into dendritic cells

Intracellular pathogens have developed strategies for evading elimination by the defenses of the host immune system. Here we describe an escape mechanism utilized by Mycobacterium tuberculosis that involves the interference with the generation of fully competent DC from monocytes. We show that monocytes infected with live M. tuberculosis differentiated into mature, CD83+ and CCR7+ DC (Mt-MoDC), but were characterized by a selective failure in the expression of the family of CD1 molecules. These cells also showed levels of MHC class II and CD80 (B7.1) that were reduced in comparison with LPS-matured DC. In addition, Mt-MoDC produced TNF-alpha and IL-10, but were unable to secrete IL-12. The generation of Mt-MoDC required the infection of monocytes with live M. tuberculosis, since infection with heat-killed bacteria partially abrogated the effects on monocyte differentiation. Interestingly, Mt-MoDC revealed an impaired antigen-presentation function as assessed by the reduced capability to induce proliferation of cord blood T lymphocytes. Further, naive T lymphocytes expanded by Mt-MoDC were unable to secrete cytokines, in particular IL-4 and IFN-gamma, suggesting that they could be ineffective in helping the macrophage-mediated killing of intracellular mycobacteria. Our results suggest that the interference with monocyte differentiation into fully competent DC is an evasion mechanism of M. tuberculosis that could contribute to its intracellular persistence by avoiding immune recognition.     

Microenvironment and tumor cell plasticity: An easy way out

Cancer cells undergo genetic changes allowing their adaptation to environmental changes, thereby obtaining an advantage during the long metastatic route, disseminated of several changes in the surrounding environment. In particular, plasticity in cell motility, mainly due to epigenetic regulation of cancer cells by environmental insults, engage adaptive strategies aimed essentially to survive in hostile milieu, thereby escaping adverse sites. This review is focused on tumor microenvironment as a collection of structural and cellular elements promoting plasticity and adaptive programs. We analyze the role of extracellular matrix stiffness, hypoxia, nutrient deprivation, acidity, as well as different cell populations of tumor microenvironment.     

Speckle tracking echocardiography in heart failure development and progression in patients with apneas

Heart Failure Reviews - Obstructive (OA) and central apneas (CA) are highly prevalent breathing disorders that have a negative impact on cardiac structure and function; while OA promote the...     

EphA2-mediated mesenchymal–amoeboid transition induced by endothelial progenitor cells enhances metastatic spread due to cancer-associated fibroblasts

Tumor progression is deeply influenced by epigenetic changes induced by tumor stroma. Cancer-associated fibroblasts (CAFs) have been reported to promote epithelial–mesenchymal transition in cancer cells, thereby enhancing their aggressiveness and stem-like properties. As CAFs are able to recruit endothelial progenitor cells (EPCs) to tumor site, we aim to investigate their interplay for prostate carcinoma progression. Both prostate CAFs and cancer cells actively recruit EPCs, known to affect tumor progression through increased vasculogenesis. EPCs synergize with CAFs to further promote epigenetic plasticity of cancer cells, through a mesenchymal-to-amoeboid transition. Indeed, after fibroblasts have engaged epithelial–mesenchymal transition in cancer cells, a further shift towards amoeboid motility is promoted by EPCs through contact-mediated triggering of the bidirectional ephrinA1/EphA2 signaling. The activation of ephrinA1 reverse pathway enhances EPC-induced neo-vascularization, thus promoting tumor growth, while EphA2 forward signaling elicits mesenchymal–amoeboid transition in cancer cells, favoring their adhesion to endothelium, transendothelial migration, and lung metastatic colonization. We therefore underscore that the metastatic advantage given by tumor microenvironment embraces different motility strategies and propose EphA2-targeted tools as useful adjuvants in anti-metastatic treatments.     

Design of donecopride,a dual serotonin subtype 4 receptor agonist/acetylcholinesterase inhibitor with potential interest for Alzheimer's disease treatment

RS67333 is a partial serotonin subtype 4 receptor (5-HT₄R) agonist that has been widely studied for its procognitive effect. More recently, it has been shown that its ability to promote the nonamyloidogenic cleavage of the precursor of the neurotoxic amyloid-β peptide leads to the secretion of the neurotrophic protein sAPPα. This effect has generated great interest in RS67333 as a potential treatment for Alzheimer’s disease (AD). We show herein that RS67333 is also a submicromolar acetylcholinesterase (AChE) inhibitor and therefore, could contribute, through this effect, to the restoration of the cholinergic neurotransmission that becomes altered in AD. We planned to pharmacomodulate RS67333 to enhance its AChE inhibitory activity to take advantage of this pleiotropic pharmacological profile in the design of a novel multitarget-directed ligand that is able to exert not only a symptomatic but also, a disease-modifying effect against AD. These efforts allowed us to select donecopride as a valuable dual (h)5-HT₄R partial agonist (K_i = 10.4 nM; 48.3% of control agonist response)/(h)AChEI (IC₅₀ = 16 nM) that further promotes sAPPα release (EC₅₀ = 11.3 nM). Donecopride, as a druggable lead, was assessed for its in vivo procognitive effects (0.1, 0.3, 1, and 3 mg/kg) with an improvement of memory performances observed at 0.3 and 1 mg/kg on the object recognition test. On the basis of these in vitro and in vivo activities, donecopride seems to be a promising drug candidate for AD treatment.Among the large family of serotonin receptors (5-HTR), some of them, such as the subtype 4 (5-HT₄R), are of particular interest in improving memory performance and therefore, decreasing memory deficits, such as those that occur in Alzheimer''s disease (AD). In the CNS, they are located in structures that are primarily involved in cognitive functions, like the olfactory tubercles, basal ganglia, septum, substantia nigra, superior colliculi, hippocampus, and cortex. Several compounds act as agonists to 5-HT₄R (BIMU1, BIMU8, RS17017, SL65.0155, VRX-03011, prucalopride, RS67333, and RS67506). One of the most affine (pK_i = 7.88) and selective vs. other receptors is RS67333, which acts as a partial agonist (1). With respect to the potential therapeutic modulation of 5-HT₄R with RS67333 and excluding its putative antidepressant-like activity (2–4), most studies focused on the promnesic or antiamnesic actions of this compound. These effects on cognitive functions that concern learning and memory are probably, in part, because of the fact that the pharmacological stimulation of these receptors increases the release of ACh in the hippocampus and cortex, and it also increases serotonin, dopamine, and GABA release (5–13). Concerning the selective aspects of memory functions, RS67333 has been shown to improve object recognition in adult (14, 15) and aged animals (16, 17) and place recognition (10) in rodents. It also increases spatial learning on the Morris water maze task in rodents, and it even reverses the deleterious effect of atropine (18) or scopolamine during this same task.Based on the structural analogy existing between RS67333 and donepezil (Fig. 1), we postulated that RS67333 could improve learning and memory by not only activating 5-HT₄R but also, inhibiting acetylcholinesterase (AChE) activity. Indeed, several early studies reported that the inhibition of AChE improved cognition and that this effect is the main reason for the initial use of donepezil, galantamine, and rivastigmine as cognitive enhancers in AD (19, 20). AChE inhibition has also been reported to improve performances in healthy rodents or animal models of memory deficiency (21). The hypothesis of an involvement of AChE inhibition by RS67333 in memory improvement is an issue that has never been tested.Open in a separate windowFig. 1.RS67333 and donepezil are chemically close.Furthermore, such a pharmacological profile could be also exploited to lead to pleiotropic compounds that are theoretically useful in AD treatment. Indeed, today, it is well-established that 5-HT₄R activation not only favors ACh release but also, is involved in the nonamyloidogenic cleavage of amyloid precursor protein (APP) in the neurotrophic sAPPα fragment, with secretion that is detrimental to amyloid-β peptide (Aβ) production (22–24). However, inhibiting the catalytic activity of AChE is widely used to restore cholinergic neurotransmission in AD, and interacting with the peripheral anionic site (PAS) of this enzyme could also reduce amyloid aggregation, for which AChE would be responsible (25). These activities seem to be synergistic when they are associated in an AD animal model, which we have recently shown in mice (26). A second pharmacological approach based on the fact that a single compound may be able to hit multiple targets is now emerging. This concept, called multitarget-directed ligands (MTDLs) (27, 28), would have inherent advantages over a combination of drugs called multiple medication therapy. It would specially obviate the problems linked to the complexity of the pharmacokinetic profile of the combined drugs and the risk of drug–drug interactions. Moreover, MTDL could also alleviate compliance difficulties associated with multiple medication therapy. It has also been shown that MTDLs generally show a higher synergistic effect than that observed with a combination of drugs. Numerous examples of MTDL against AD have been recently described (27). Most of them associate an AChE inhibitory effect with another activity hitting another molecular target of AD, such as antioxidant effect, monoamine oxidase inhibition, calcium channel blocking effect, metal chelating activity, etc. However, no MTDLs associating an inhibition of AChE and 5-HT₄R agonist effect have been hitherto described. Among the different ways to synthesize such MTDLs, one of them is to merge the frameworks of two selective starting compounds, each one exerting an activity toward a sole target (28). This goal is even more easily reached if the starting compounds are structurally close, and it is the reason why we considered the structural analogy between donepezil and RS67333 as a good starting point to design MTDLs displaying both activities (AChE inhibition and 5-HT₄R agonist activities). We will, thus, provide proof of this concept with the synthesis and biological evaluation of MR31147 (donecopride) as conceived from the pharmacomodulation of RS67333.     

Improved survival in limited scleroderma-related pulmonary artery hypertension

Reportedly, patients with scleroderma-related pulmonary hypertension (SSc-PAH) respond poorly to new vasoactive drugs (NVD). Forty-nine SSc-PAH patients underwent right heart catheterization (RHC) and, according to NVD availability, divided as follows: Group 1 (n = 23, from 1999 to 2004, poor availability), and Group 2 (n = 26, from 2005 to 2010, good availability). Before diagnostic RHC, NVD had been given to 30 % of the patients in Group 1, and 58 % of those in Group 2 (p = 0.049). At diagnosis, patients in Group 1 had greater heart dilatation (p < 0.01), higher mean pulmonary artery pressure (p < 0.05), lower pulmonary artery capacitance (p < 0.05), and lower carbon monoxide lung diffusing capacity (DLco, p < 0.05) than those in Group 2. At a median follow-up time of 15.5 months, DLco further decreased in Group 1 (p < 0.05), whereas cardiac index increased in Group 2 (p < 0.05). At 36 months of follow-up, 72.4 % of the patients in Group 2 were still alive as opposed to 30.4 % in Group 1 (p = 0.02). In multivariate analysis, DLco and mixed venous oxygen saturation (SvO₂) were independent predictors of survival. A value of DLco <7.2 mL/mmHg/min was associated with a hazard ratio (HR) of 5.3 (p < 0.001); for SvO₂ <63.8 %, the HR was 3.7 (p < 0.01).NVD have beneficial effects in patients with SSc-PAH. Both DLco and SvO₂ are predictors of survival and may assist in planning treatment.     

A tissue engineering approach to bone repair in large animal models and in clinical practice

The repair of large segmental bone defects due to trauma, inflammation and tumor surgery remains a major clinical problem. Animal models were developed to test bone repair by tissue engineering approaches, mimicking real clinical situations. Studies differed with regard to animals (dog, sheep, goat), treated bone (femur, tibia, mandible), chemistry and structure of the scaffolds. Still, an advantage in the bone formation and in the healing of the segmental defect was always observed when scaffolds were seeded with bone marrow derived stromal cells (BMSCs). In the year 1998 was performed the first implantation of a porous ceramic construct in a bone segmental defect of a patient; it was the first construct seeded with cultured autologous osteogenic cells. Since then, only few other similar cases were treated by the same approach. However, in other fields, such as oral and maxillofacial surgery, injectable cells/platelet-rich plasma composites have been used as grafting materials for maxillary sinus floor augmentation and/or onlay plasty. More recently, the reconstruction of a human mandible was also reported by means of a bone-muscle-flap in vivo prefabrication technique, where the patient served as his own bioreactor. Indeed continuous implementations test and provide new means of defects treatment and cure. However, based on results so far obtained in animal models and pilot clinical studies, one can affirm that the bone tissue engineering approaches, although successful in most cases, need further validation before a wide application in clinics. In particular, the supply of oxygen and nutrients to the cells in the inner part of the implanted scaffolds remains a major concern, requiring additional investigations.     

Five-year retrospective clinical study of indirect composite restorations luted with a light-cured composite in posterior teeth

Objectives

The purpose of this study was to evaluate the clinical performance of indirect composite onlays–overlays bonded with a light-cured composite on vital molars.

Materials and methods

Forty-one patients were restored with 79 indirect composite restorations. The restorations were studied for an observation time of 5 years. Marginal adaptation, marginal discolouration, secondary caries, colour match and anatomic form were clinically examined following modified United States Public Health Service criteria. Each restoration was also examined for fractures and debonding. Endodontic complications were registered. Survival rate, based just on failures that required a replacement, and success rate that included also failures that required a repair intervention were statistically determined using a restoration and a patient-related analysis.

Results

After 5 years, using each restoration as a statistical unit, the survival rate was 91.1 % and the success rate 84.8 %, with a high Kaplan–Meier estimated success probability of 0.852. Using the patient as the statistical unit, the survival rate was 90.2 % and the success rate 85.4 %, corresponding to a Kaplan–Meier estimated success probability of 0.857. On the basis of the criteria used, most of the restorations rated Alpha. Regarding marginal adaptation and marginal discolouration, 5 and 10.1 % of the restorations, respectively, revealed Bravo ratings

Conclusions

Indirect composite restorations offer a predictable and successful treatment modality giving an optimal preservation of sound tooth tissue.

Clinical relevance

The preparation, cementation and finishing procedures are considered key factors for the long-term success of the indirect composite restorations.