Untangling the ATR-CHEK1 network for prognostication, prediction and therapeutic target validation in breast cancer

Background: ATR-Chk1 signalling network is critical for genomic stability. ATR-Chk1 may be deregulated in breast cancer and have prognostic, predictive and therapeutic significance. Patients and methods: We investigated ATR and phosphorylated CHK1Ser345 protein (pChk1) expression in 1712 breast cancers (Nottingham Tenovus series). ATR and Chk1 mRNA were evaluated in 1950 breast cancers (METABRIC cohort). Pre-clinically, biological consequences of ATR gene knockdown or ATR inhibition by small molecule inhibitor (VE-821) were investigated in MCF-7 and MDA-MB-231 breast cancer cell lines and in non-tumorigenic breast epithelial cells (MCF10A). Results: High ATR and high cytoplasmic pChk1 expression was significantly associated with higher tumour stage, higher mitotic index, pleomorphism and lymphovascular invasion. In univariate analysis, high ATR and high cytoplasmic pChk1 protein expression was associated with shorter breast cancer specific survival (BCSS). In multivariate analysis, high ATR remains an independent predictor of adverse outcome. At the mRNA level, high Chk1 remains associated with aggressive phenotypes including lymph node positivity, high grade, Her-2 overexpression, triple-negative phenotype and molecular classes associated with aggressive behaviour and shorter survival.. Pre-clinically, Chk1 phosphorylation at serine 345 following replication stress (induced by gemcitabine or hydroxyurea treatment) was impaired in ATR knockdown and in VE-821 treated breast cancer cells. Doxycycline inducible knockdown of ATR suppressed growth, which was restored when ATR was re-expressed. Similarly, VE-821 treatment resulted in a dose dependent suppression of cancer cell growth and survival (MCF7 and MDA-MB-231) but had no effect on non-tumorigenic breast epithelial cells (MCF10A). Conclusions: We provides evidence that ATR and Chk1 are promising biomarkers and rational drug target for personalized therapy in breast cancer

Antibacterial 45S5 Bioglass®-based scaffolds reinforced with genipin cross-linked gelatin for bone tissue engineering

45S5 Bioglass® (BG) scaffolds with high porosity (>90%) were coated with genipin cross-linked gelatin (GCG) and further incorporated with poly(p-xylyleneguanidine) hydrochloride (PPXG). The obtained GCG coated scaffolds maintained the high porosity and well interconnected pore structure. A 26-fold higher compressive strength was provided to 45S5 BG scaffolds by GCG coating, which slightly retarded but did not inhibit the in vitro bioactivity of 45S5 BG scaffolds in SBF. Moreover, the scaffolds were made antibacterial against both Gram-positive and Gram-negative bacteria by using polyguanidine, i.e. PPXG, in this study. Osteoblast-like cells (MG-63) were seeded onto PPXG and GCG coated scaffolds. PPXG was biocompatible with MG-63 cells at a low concentration (10 μg mL−1). MG-63 cells were shown to attach and spread on both uncoated and GCG coated scaffolds, and the mitochondrial activity measurement indicated that GCG coating had no negative influence on the cell proliferation behavior of MG-63 cells. The developed novel antibacterial bioactive 45S5 BG-based composite scaffolds with improved mechanical properties are promising candidates for bone tissue engineering

Teratoma of the anterior mediastinum presenting as a cystic neck mass: a case report

<p>Abstract</p> <p>Introduction</p> <p>Teratomas of anterior mediastinum are rare tumors and are often slow growing, asymptomatic and detected incidentally on chest imaging. Results of surgical resection are very satisfactory.</p> <p>Case presentation</p> <p>A 19-years old male presented with an asymptomatic cystic neck mass. X-ray and CT scan of chest and neck showed an extrathyroidal multi-septate, predominantly cystic neck mass, that was continuous with a solid intrathoracic mass extending up to the level of right atrium and which contained areas of calcification and cystic necrosis. The mediastinal structures did not show any features of compression or infiltration. Fine needle aspiration cytology from the neck mass was suggestive of a dermoid cyst. In view of the extent and uncertain pathological nature of the tumor, it was excised via a combined cervical and trans-sternal route. Histo-pathology of the resected specimen confirmed the diagnosis of a mature cystic teratoma. The patient made an uneventful recovery, and after five years of follow-up, he has been symptom free with no clinical or radiological evidence of recurrent disease. We discuss the role of imaging and the need for surgical treatment to avoid possible catastrophic complications in patients with cervical and mediastinal masses of uncertain histological nature.</p> <p>Conclusion</p> <p>A mediastinal teratoma may rarely present as a cystic neck swelling due to its cephalad extension. This entity needs to be considered in cases where clinical and investigative work-up fail to provide a convincing clue to a primary neck pathology as cause of a cystic neck swelling.</p

Allosteric communication in class A β-lactamases occurs via cooperative coupling of loop dynamics

Understanding allostery in enzymes and tools to identify it, offer promising alternative strategies to inhibitor development. Through a combination of equilibrium and nonequilibrium molecular dynamics simulations, we identify allosteric effects and communication pathways in two prototypical class A β-lactamases, TEM-1 and KPC-2, which are important determinants of antibiotic resistance. The nonequilibrium simulations reveal pathways of communication operating over distances of 30 Å or more. Propagation of the signal occurs through cooperative coupling of loop dynamics. Notably, 50% or more of clinically relevant amino acid substitutions map onto the identified signal transduction pathways. This suggests that clinically important variation may affect, or be driven by, differences in allosteric behavior, providing a mechanism by which amino acid substitutions may affect the relationship between spectrum of activity, catalytic turnover and potential allosteric behavior in this clinically important enzyme family. Simulations of the type presented here will help in identifying and analyzing such differences

A relocatable ocean model in support of environmental emergencies

During the Costa Concordia emergency case, regional, subregional, and relocatable ocean models have been used together with the oil spill model, MEDSLIK-II, to provide ocean currents forecasts, possible oil spill scenarios, and drifters trajectories simulations. The models results together with the evaluation of their performances are presented in this paper. In particular, we focused this work on the implementation of the Interactive Relocatable Nested Ocean Model (IRENOM), based on the Harvard Ocean Prediction System (HOPS), for the Costa Concordia emergency and on its validation using drifters released in the area of the accident. It is shown that thanks to the capability of improving easily and quickly its configuration, the IRENOM results are of greater accuracy than the results achieved using regional or subregional model products. The model topography, and to the initialization procedures, and the horizontal resolution are the key model settings to be configured. Furthermore, the IRENOM currents and the MEDSLIK-II simulated trajectories showed to be sensitive to the spatial resolution of the meteorological fields used, providing higher prediction skills with higher resolution wind forcing.MEDESS4MS Project; TESSA Project; MyOcean2 Projectinfo:eu-repo/semantics/publishedVersio

On the conservation of the slow conformational dynamics within the amino acid kinase family: NAGK the paradigm

N-Acetyl-L-Glutamate Kinase (NAGK) is the structural paradigm for examining the catalytic mechanisms and dynamics of amino acid kinase family members. Given that the slow conformational dynamics of the NAGK (at the microseconds time scale or slower) may be rate-limiting, it is of importance to assess the mechanisms of the most cooperative modes of motion intrinsically accessible to this enzyme. Here, we present the results from normal mode analysis using an elastic network model representation, which shows that the conformational mechanisms for substrate binding by NAGK strongly correlate with the intrinsic dynamics of the enzyme in the unbound form. We further analyzed the potential mechanisms of allosteric signalling within NAGK using a Markov model for network communication. Comparative analysis of the dynamics of family members strongly suggests that the low-frequency modes of motion and the associated intramolecular couplings that establish signal transduction are highly conserved among family members, in support of the paradigm sequence→structure→dynamics→function © 2010 Marcos et al

Impact of seminal trace element and glutathione levels on semen quality of Tunisian infertile men

<p>Abstract</p> <p>Background</p> <p>Growing evidence indicates that oxidative stress can be a primary cause of male infertility. Non-enzymatic antioxidants play an important protective role against oxidative damages and lipid peroxidation. Human seminal plasma is a natural reservoir of antioxidants. The aim of this study was to determine glutathione (GSH) concentrations, trace element levels (zinc and selenium) and the lipid peroxidation end product, malondialdehyde (MDA), in the seminal plasma of men with different fertility potentials.</p> <p>Methods</p> <p>Semen samples from 60 fertile men (normozoospermics) and 190 infertile patients (74 asthenozoospermics, 56 oligozoospermics, and 60 teratozoospermics) were analyzed for physical and biochemical parameters. Zinc (Zn) and selenium (Se) levels were estimated by atomic absorption spectrophotometry. Total GSH (GSHt), oxidized GSH (GSSG), reduced GSH (GSHr) and MDA concentrations were measured spectrophotometrically.</p> <p>Results</p> <p>Zn and Se concentrations in seminal plasma of normozoospermics were more elevated than the three abnormal groups. Nevertheless, only the Zn showed significant differences. On the other hand, Zn showed positive and significant correlations with sperm motility (P = 0.03, r = 0.29) and count (P < 0.01, r = 0.49); however Se was significantly correlated only with sperm motility (P < 0.01, r = 0.36). GSHt, GSSG and GSHr were significantly higher in normozoospermics than in abnormal groups. We noted a significant association between seminal GSHt and sperm motility (P = 0.03). GSSG was highly correlated to sperm motility (P < 0.001) and negatively associated to abnormal morphology (P < 0.001). GSHr was significantly associated to total sperm motility (P < 0.001) and sperm count (P = 0.01). MDA levels were significantly higher in the three abnormal groups than in normozoospermics. Rates of seminal MDA were negatively associated to sperm motility (P < 0.01; r = -0.24) and sperm concentration (P = 0.003; r = -0.35) Meanwhile, there is a positive correlation between seminal lipid peroxidation and the percentage of abnormal morphology (P = 0.008).</p> <p>Conclusions</p> <p>This report revealed that decreased seminal GSH and trace element deficiencies are implicated in low sperm quality and may be an important indirect biomarker of idiopathic male infertility. Our results sustain that the evaluation of seminal antioxidant status in infertile men is necessary and can be helpful in fertility assessment from early stages.</p

Successful Shortening of Tuberculosis Treatment Using Adjuvant Host-Directed Therapy with FDA-Approved Phosphodiesterase Inhibitors in the Mouse Model

Global control of tuberculosis (TB), an infectious disease that claims nearly 2 million lives annually, is hindered by the long duration of chemotherapy required for curative treatment. Lack of adherence to this intense treatment regimen leads to poor patient outcomes, development of new or additional drug resistance, and continued spread of M.tb. within communities. Hence, shortening the duration of TB therapy could increase drug adherence and cure in TB patients. Here, we report that addition of the United Stated Food and Drug Administration-approved phosphodiesterase inhibitors (PDE-Is) cilostazol and sildenafil to the standard TB treatment regimen reduces tissue pathology, leads to faster bacterial clearance and shortens the time to lung sterilization by one month, compared to standard treatment alone, in a murine model of TB. Our data suggest that these PDE-Is could be repurposed for use as adjunctive drugs to shorten TB treatment in humans

Study on the short-term effects of increased alcohol and cigarette consumption in healthy young men's seminal quality

Many studies have reported a negative impact of lifestyle factors on testicular function, spermatozoa parameters and pituitary-gonadal axis. However, conclusions are difficult to draw, since studies in the general population are rare. In this study we intended to address the early and late short-term impact of acute lifestyle alterations on young men's reproductive function. Thirty-six healthy male students, who attended the Portuguese academic festivities, provided semen samples and answered questionnaires at three time-points. The consumption of alcohol and cigarette increased more than 8 and 2 times, respectively, during the academic festivities and resulted in deleterious effects on semen quality: one week after the festivities, a decrease on semen volume, spermatozoa motility and normal morphology was observed, in parallel with an increase on immotile spermatozoa, head and midpiece defects and spermatozoa oxidative stress. Additionally, three months after the academic festivities, besides the detrimental effect on volume, motility and morphology, a negative impact on spermatozoa concentration was observed, along with a decrease on epididymal, seminal vesicles and prostate function. This study contributed to understanding the pathophysiology underlying semen quality degradation induced by acute lifestyle alterations, suggesting that high alcohol and cigarette consumption are associated with decreased semen quality in healthy young men.publishe

A periodic boundary value problem for nonlinear singular differential systems with ‘maxima’

décembre 20052005/12 (N254)-2005/12.Appartient à l’ensemble documentaire : UnivJeun