Novel inhibitors of neuronal nitric oxide synthase with potent antioxidant properties

A series of hybrid compounds possessing an nNOS pharmacophore linked to an antioxidant fragment has been synthesized. Among them, compound 8d, a propofol derivative, displayed the greatest dual potencies against nNOS (IC(50)=0.12 microM) and lipid peroxidation (IC(50)=0.4 microM) accompanied with e/nNOS selectivity (67.5). This shows that nNOS was able to accommodate very bulky groups such as di-tert-butyl or di-iso-propyl phenol in its active site.     

Candidate Luminal B Breast Cancer Genes Identified by Genome,Gene Expression and DNA Methylation Profiling

Breast cancers (BCs) of the luminal B subtype are estrogen receptor-positive (ER+), highly proliferative, resistant to standard therapies and have a poor prognosis. To better understand this subtype we compared DNA copy number aberrations (CNAs), DNA promoter methylation, gene expression profiles, and somatic mutations in nine selected genes, in 32 luminal B tumors with those observed in 156 BCs of the other molecular subtypes. Frequent CNAs included 8p11-p12 and 11q13.1-q13.2 amplifications, 7q11.22-q34, 8q21.12-q24.23, 12p12.3-p13.1, 12q13.11-q24.11, 14q21.1-q23.1, 17q11.1-q25.1, 20q11.23-q13.33 gains and 6q14.1-q24.2, 9p21.3-p24,3, 9q21.2, 18p11.31-p11.32 losses. A total of 237 and 101 luminal B-specific candidate oncogenes and tumor suppressor genes (TSGs) presented a deregulated expression in relation with their CNAs, including 11 genes previously reported associated with endocrine resistance. Interestingly, 88% of the potential TSGs are located within chromosome arm 6q, and seven candidate oncogenes are potential therapeutic targets. A total of 100 candidate oncogenes were validated in a public series of 5,765 BCs and the overexpression of 67 of these was associated with poor survival in luminal tumors. Twenty-four genes presented a deregulated expression in relation with a high DNA methylation level. FOXO3, PIK3CA and TP53 were the most frequent mutated genes among the nine tested. In a meta-analysis of next-generation sequencing data in 875 BCs, KCNB2 mutations were associated with luminal B cases while candidate TSGs MDN1 (6q15) and UTRN (6q24), were mutated in this subtype. In conclusion, we have reported luminal B candidate genes that may play a role in the development and/or hormone resistance of this aggressive subtype.     

Accuracy of Ultrasonography and Magnetic Resonance Imaging in the Diagnosis of Placenta Accreta

Purpose

To evaluate the accuracy of ultrasonography and magnetic resonance imaging (MRI) in the diagnosis of placenta accreta and to define the most relevant specific ultrasound and MRI features that may predict placental invasion.

Material and Methods

This study was approved by the institutional review board of the French College of Obstetricians and Gynecologists. We retrospectively reviewed the medical records of all patients referred for suspected placenta accreta to two university hospitals from 01/2001 to 05/2012. Our study population included 42 pregnant women who had been investigated by both ultrasonography and MRI. Ultrasound images and MRI were blindly reassessed for each case by 2 raters in order to score features that predict abnormal placental invasion.

Results

Sensitivity in the diagnosis of placenta accreta was 100% with ultrasound and 76.9% for MRI (P = 0.03). Specificity was 37.5% with ultrasonography and 50% for MRI (P = 0.6). The features of greatest sensitivity on ultrasonography were intraplacental lacunae and loss of the normal retroplacental clear space. Increased vascularization in the uterine serosa-bladder wall interface and vascularization perpendicular to the uterine wall had the best positive predictive value (92%). At MRI, uterine bulging had the best positive predictive value (85%) and its combination with the presence of dark intraplacental bands on T2-weighted images improved the predictive value to 90%.

Conclusion

Ultrasound imaging is the mainstay of screening for placenta accreta. MRI appears to be complementary to ultrasonography, especially when there are few ultrasound signs.     

Sequence dependence of transient Hoogsteen base pairing in DNA

Hoogsteen (HG) base pairing is characterized by a 180° rotation of the purine base with respect to the Watson-Crick-Franklin (WCF) motif. Recently, it has been found that both conformations coexist in a dynamical equilibrium and that several biological functions require HG pairs. This relevance has motivated experimental and computational investigations of the base-pairing transition. However, a systematic simulation of sequence variations has remained out of reach. Here, we employ advanced path-based methods to perform unprecedented free-energy calculations. Our methodology enables us to study the different mechanisms of purine rotation, either remaining inside or after flipping outside of the double helix. We study seven different sequences, which are neighbor variations of a well-studied A⋅T pair in A₆-DNA. We observe the known effect of A⋅T steps favoring HG stability, and find evidence of triple-hydrogen-bonded neighbors hindering the inside transition. More importantly, we identify a dominant factor: the direction of the A rotation, with the 6-ring pointing either towards the longer or shorter segment of the chain, respectively relating to a lower or higher barrier. This highlights the role of DNA’s relative flexibility as a modulator of the WCF/HG dynamic equilibrium. Additionally, we provide a robust methodology for future HG proclivity studies.     

Diffusion of Ofloxacin in the Endocarditis Vegetation Assessed with Synchrotron Radiation UV Fluorescence Microspectrocopy

The diffusion of antibiotics in endocarditis vegetation bacterial masses has not been described, although it may influence the efficacy of antibiotic therapy in endocarditis. The objective of this work was to assess the diffusion of ofloxacin in experimental endocarditis vegetation bacterial masses using synchrotron-radiation UV fluorescence microspectroscopy. Streptococcal endocarditis was induced in 5 rabbits. Three animals received an unique IV injection of 150 mg/kg ofloxacin, and 2 control rabbits were left untreated. Two fluorescence microscopes were coupled to a synchrotron beam for excitation at 275 nm. A spectral microscope collected fluorescence spectra between 285 and 550 nm. A second, full field microscope was used with bandpass filters at 510–560 nm. Spectra of ofloxacin-treated vegetations presented higher fluorescence between 390 and 540 nm than control. Full field imaging showed that ofloxacin increased fluorescence between 510 and 560 nm. Ofloxacin diffused into vegetation bacterial masses, although it accumulated in their immediate neighborhood. Fluorescence images additionally suggested an ofloxacin concentration gradient between the vegetation peripheral and central areas. In conclusion, ofloxacin diffuses into vegetation bacterial masses, but it accumulates in their immediate neighborhood. Synchrotron radiation UV fluorescence microscopy is a new tool for assessment of antibiotic diffusion in the endocarditis vegetation bacterial masses.     

Covalent attachment of epoxide hydrolase to dextran

Epoxide hydrolase (EC 3.3.2.3) purified from rat liver microsomes has been immobilized by covalent linking to dextran activated by imidazolyl carbamate groups, under mild conditions. K^app_m values of free and dextran bound epoxide hydrolase toward benzo(a)pyrene-4,5-oxide were 0.5 and 0.35 μM respectively, while V^app_max was lowered from 300 to 120 nmol min^?1mg^?1protein. The activity lost upon coupling could not be restored by digestion of the support by dextranase (1,6-α-d-glucan 6-glucanohydrolase, EC 3.2.1.11) treatment. This fact, along with the similarity of the activation energy values for both native and bound epoxide hydrolase, indicated that steric hindrance effects due to the polymer support played only a minor role in this loss of activity. Evidences of changes in the conformation of epoxide hydrolase were obtained by a comparative study of u.v. circular dichroism and tryptophan fluorescence emission spectra of the native and dextran bound enzymes. On the other hand, the enzyme conjugate showed greater resistance than the free enzyme to thermal inactivation.     

A quality improvement program to improve nutritional status of children with Cystic Fibrosis aged 2-12 years old over a 3 year period at CF center Roscoff,Brittany

Background

The Cystic Fibrosis (CF) center in Roscoff (Brittany) has been involved in therapeutic education programs (TEP) since 2006 and took part in the pilot phase of the French quality improvement program (QIP) since 2011. The aim was to improve the nutritional status of children with cystic fibrosis aged 2-12 years old in order to optimize their health status as they enter adolescence.

Methods

A multidisciplinary quality team was created in order to select and address a specific health problem among our pediatric population. Following analysis of yearly indicators for our CF center, our team chose to improve quality of care concerning nutritional status of children aged 2-12 years old. Factors influencing efficacy were studied, tools were developed to implement a new nutritional program, results were analyzed on a real-time basis.

Results

Over the 3 year period, all patients from 2 years of age, were monitored with the new follow-up program (2012: N =?34; 2014: N =?44). Each patient was followed up at every clinic visit, their BMI z-score was calculated to decide their nutritional risk and personalize their follow-up program consequently. Between 1/1/2012 and 31/12/2014, the mean BMI z-score of the open cohort improved from ?0.49 to ?0.22.

Conclusions

Since 2014, focus on nutrition using the newly-adapted program has become routine practice at each follow-up visit. Patients and parents expressed a high level of satisfaction (75% very satisfied). The follow-up program aimed at improving nutritional status for children aged 2-12 years old was successfully implemented and integrated into routine practice; it was therefore extended to all children with CF (1 month - 18 years) in our center. The relationship among professional and patients and parents was strengthened.

     

LKB1 as a Gatekeeper of Hepatocyte Proliferation and Genomic Integrity during Liver Regeneration

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A missense mutation in rpoD results in an A-signalling defect in Myxococcus xanthus

The Myxococcus xanthus asg genes ( asgA, asgB , and asgC ) are necessary for production of extracellular A-signal, which is thought to function as a cell-density signal. Previous analyses of the asgA and asgB genes suggest that they perform regulatory functions. In this work, we localized asgC to a region that contains genes homologous to rpsU, dnaG , and rpoD of the Escherichia coli macromolecular synthesis (MMS) operon. Surprisingly, asgC767 was found to be a mutant allele of rpoD , the gene encoding the major sigma factor of M. xanthus . The mutation in asgC767 results in a glutamate to lysine substitution at amino acid 598, which lies within conserved region 3.1 of the major sigma factors. Previous studies have shown that the asg mutants share a number of growth and developmental phenotypes. We found that A-signal restores developmental expression of an A-signal-dependent gene (Ω4521) in the asgC767 ( rpoDEK598 ) mutant background in a manner similar to that seen in the asgA and asgB mutants. Because the asg mutants have very similar phenotypes and the asg genes encode proteins that appear to have regulatory functions, we hypothesize that the asg gene products function together in a regulatory pathway that is required for extracellular A-signal production.