Protective Effect of Spin Trap Agent,N - tert -butyl-α-phenylnitrone on Hyperoxia-induced Oxidative Stress and Its Potential As a Nitric Oxide Donor

We have previously suggested that the spin trap agent, N - tert -butyl- &#102 -phenylnitrone (PBN) can function not only as an antioxidant but also as a nitric oxide (NO) donor. To characterize the pharmacological activities of PBN against oxidative damage, we examined the effect of PBN on NO generation under hyperoxic conditions. The formation of NO in mice exposed to 95% oxygen was determined using a NOx analyzer and electron spin resonance (ESR). Levels of NOx, an oxidative product of NO, increased in the blood of mice under these conditions. However, the increase was returned to a normal level by the NOS (nitric oxide synthase) inhibitor, L-NMMA, indicating that the NO was formed via a biosynthetic pathway. In addition, ESR spectra of the liver and brain of control and experimental mice that were measured using Fe(DETC) 2 as an NO trap reagent showed strong ESR signals from NO complexes in the livers of mice exposed to 95% oxygen. When examining the effect of PBN in mice, PBN reduced the NOx formation in the blood under the same hyperoxic conditions. In addition, the ESR intensity of the NO complex was weaker in the PBN-treated mice than in the non-treated mice, showing that PBN possess anti-inflammatory properties. However, under a normal atmosphere, NOx and ESR analyses showed that NO levels increased in PBN-treated mice but not in control mice. These findings suggested that PBN functions as an NO donor under specific physiological conditions. PBN appears to protect against hyperoxia-induced NO toxicity by anti-inflammatory action rather than by serving as an NO donor.     

OrthoGNC:A Software for Accurate Identi?cation of Orthologs Based on Gene Neighborhood Conservation

Orthology relations can be used to transfer annotations from one gene(or protein) to another. Hence, detecting orthology relations has become an important task in the post-genomic era. Various genomic events, such as duplication and horizontal gene transfer, can cause erroneous assignment of orthology relations. In closely-related species, gene neighborhood information can be used to resolve many ambiguities in orthology inference. Here we present Ortho GNC, a software for accurately predicting pairwise orthology relations based on gene neighborhood conservation.Analyses on simulated and real data reveal the high accuracy of Ortho GNC. In addition to orthology detection, Ortho GNC can be employed to investigate the conservation of genomic context among potential orthologs detected by other methods. Ortho GNC is freely available online at http://bs.ipm.ir/softwares/orthognc and http://tinyurl.com/ortho GNC.     

TNF-α-308G/A Polymorphism Contributes to Obstructive Sleep Apnea Syndrome Risk: Evidence Based on 10 Case-Control Studies

Objective

The aim of our study was to investigate the association between the TNF-α-308G/A polymorphism and obstructive sleep apnea syndrome (OSAS).

Method

The Medline, Web of Science, EMBASE, Chinese National Knowledge Infrastructure (CNKI), and Cochrane Central Register of Controlled Trials were searched. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to study TNF-α-308G/A polymorphism and risk of OSAS.

Result

10 case-control studies were included in our meta-analysis. The results from our study showed that the TNF-α-308G/A polymorphism was significantly associated with risk of OSAS (A vs. G: OR = 1.67, 95% CI = 1.43–1.95). In the subgroup analysis by ethnicity, the statistical similar results were observed both in European (A vs. G: OR = 1.68, 95% CI = 1.35–2.08) and Asian population (A vs. G: OR = 2.02, 95% CI = 1.50–2.71). When stratified by age, a significantly increased risk was observed in adult carries A allele compared with G allele (OR = 1.79, 95% CI = 1.50–2.13), whereas no association was found in children (OR = 1.09, 95% CI = 0.70–1.69).

Conclusion

Our study suggested that the TNF-α- 308G/A polymorphism contributed to the susceptibility to the risk of OSAS. Additional well-designed large studies are needed to validate our findings.     

A Sensitive Pulse Scheme for Measuring the Backbone Dihedral Angle ψ Based on Cross-correlation Between 13Cα-1Hα Dipolar and Carbonyl Chemical Shift Anisotropy Relaxation Interactions

A pulse scheme for measuring cross-correlation between 13C-1H dipolar and carbonyl chemical shift anisotropy relaxation mechanisms is presented from which the protein backbone dihedral angle is measured. The method offers significant sensitivity gains relative to our recently published scheme for measuring based on this cross-correlation effect [Yang et al. (1997) J. Am. Chem. Soc., 119, 11938-11940]. The utility of the method is demonstrated with an application to a 42 kDa complex of 15N,13C-labeled maltose binding protein and -cyclodextrin.     

Computer Aided Identification of Small Molecules Disrupting uPAR/α5β1- Integrin Interaction: A New Paradigm for Metastasis Prevention

Background

Disseminated dormant cancer cells can resume growth and eventually form overt metastases, but the underlying molecular mechanism responsible for this change remains obscure. We previously established that cell surface interaction between urokinase receptor (uPAR) and α5β1-integrin initiates a sequel of events, involving MAPK-ERK activation that culminates in progressive cancer growth. We also identified the site on uPAR that binds α5β1-integrin. Disruption of uPAR/integrin interaction blocks ERK activation and forces cancer cells into dormancy.

Methods and Principle Findings

Using a target structure guided computation docking we identified 68 compounds from a diversity library of 13,000 small molecules that were predicted to interact with a previously identified integrin-binding site on uPAR. Of these 68 chemical hits, ten inhibited ERK activation in a cellular assay and of those, 2 compounds, 2-(Pyridin-2-ylamino)-quinolin-8-ol and, 2,2′-(methylimino)di (8-quinolinol) inhibited ERK activation by disrupting the uPAR/integrins interaction. These two compounds, when applied in vivo, inhibited ERK activity and tumor growth and blocked metastases of a model head and neck carcinoma.

Conclusions/Significance

We showed that interaction between two large proteins (uPAR and α5β1-integrin) can be disrupted by a small molecule leading to profound downstream effects. Because this interaction occurs in cells with high uPAR expression, a property almost exclusive to cancer cells, we expect a new therapy based on these lead compounds to be cancer cell specific and minimally toxic. This treatment, rather than killing disseminated metastatic cells, should induce a protracted state of dormancy and prevent overt metastases.     

Structure-activity relationship studies on 1-(5-carboxyindol-1-yl)-propan-2-one inhibitors of human cytosolic phospholipase A2α: variation of the activated ketone moiety

Indole-5-carboxylic acids with 3-aryloxy-2-oxopropyl residues in position 1 have been found to be potent inhibitors of human cytosolic phospholipase A₂α (cPLA₂α). In course of structure-activity relationship studies, we investigated the effect of the substitution of the electrophilic ketone group in the middle part of the molecule by other polar residues, such as hydroxyimino, azido, acyloxy, acylamino, urea and carbamate, on enzyme inhibition. With an IC₅₀ of 1.7 μM against cPLA₂α from human platelets, the 4-fluorophenylcarbamate derivative 23f was the most active of the compounds tested.     

Effectiveness and Complications of Ultrasound Guided Fine Needle Aspiration for Primary Liver Cancer in a Chinese Population with Serum α-Fetoprotein Levels ≤200 ng/ml - A Study Based on 4,312 Patients

Background

Hepatocellular carcinoma (HCC) can be diagnosed by noninvasive approaches with serum α-fetoprotein (AFP) levels >200 ng/ml and/or a radiological imaging study of tumor mass >2 cm in patients with chronic liver disease. Percutaneous fine needle aspiration (FNA) under ultrasound (US) guidance has a diagnostic specificity of 95% and is superior to radiological imaging studies.

Aim

The aim of this study is to elucidate the effectiveness and complications of fine needle aspiration in a Chinese population with primary liver cancer and AFP levels ≤200 ng/ml.

Materials and Methods

A retrospective study was conducted over a period of 28 years. This selection period included patients with a suspected diagnosis of primary liver cancer whose AFP levels were ≤200 ng/ml and who underwent US-FNA. This data was then analyzed with cytomorphological features correlating with medical history, radiological imaging, AFP, and follow-up information.

Results

Of the 1,929 cases with AFP ≤200 mg/ml, 1,756 underwent FNA. Of these, 1,590 cases were determined malignant and the remaining 166 were determined benign. Further, 1,478 malignant cases were diagnosed by FNA alone, and of these, 1,138 were diagnosed as PLC. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the diagnoses were 92.96%, 100%, 100%, 59.71%, and 93.62% respectively. There was no significant difference in the sensitivity, specificity, PPV and NPV between the subgroups with tumor size<2 cm and ≥2 cm. Major complications included implantation metastasis and hemorrhage.

Conclusion

Patients with PLC, especially those who present with an AFP ≤200 ng/ml, should undergo FNA. If negative results are obtained by FNA, it still could be HCC and repeated FNA procedure may be needed if highly suspicious of HCC on imaging study. The superiority of FNA in overall accuracy may outweigh its potential complications, such like hemorrhage and implantation metastasis.     

A reevaluation of an agent proposed for imaging oestrogen receptors: 17α-[125I]-iodovinyl-11β-methoxyoestradiol-3-methyl ether ([125I]VMEME)

The metabolism of an iodinated steroid, 17α-[¹²⁵I]iodovinyl-11β-methoxyoestradiol-3-methyl ether ([¹²⁵I]VMEME), previously proposed as a potential agent for imaging oestrogen receptor-containing tissues, has been studied and the conditions for synthesis and labelling redefined. It is confirmed that, although the compound does not itself have significant receptor-binding affinity, a metabolite is active. Because of its high solubility in fat and the consequential low contrast of small receptor-containing tumours, there is little prospect of successful early imaging of small axillary or internal mammary lymph node metastases from human breast cancer with this compound. Some more general implications of this finding are considered.     

Structure activity relationship studies of 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6α-(isoquinoline-3′-carboxamido)morphinan (NAQ) analogues as potent opioid receptor ligands: Preliminary results on the role of electronic characteristics for affinity and function

17-Cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6α-(isoquinoline-3′-carboxamido)morphinan (NAQ) was previously designed following the ‘message-address’ concept and was identified as a potent and highly selective mu opioid receptor (MOR) ligand based on its pharmacological profile. We here report the preliminary structure activity relationship (SAR) studies of this novel lead compound. For the new ligands synthesized as NAQ analogues, their binding assay results showed that a longer spacer and a saturated ring system of the side chain were unfavorable for their MOR selectivity over the kappa and delta opioid receptors. In contrast, substitutions with different electronic properties at either 1′- or 4′-position of the isoquinoline ring of the side chain were generally acceptable for reasonable MOR selectivity. The majority of NAQ analogues retained low efficacy at the MOR compared to NAQ in the ³⁵S-GTP[γS] binding assays while electron-withdrawing groups at 1′-position of the isoquinoline ring induced higher MOR stimulation than electron-donating groups did. In summary, the electronic characteristics of substituents at 1′- or 4′-position of the isoquinoline ring in NAQ seem to be critical and need to be further tuned up to achieve higher MOR selectivity and lower MOR stimulation.     

The extracellular domain of Bri2 (ITM2B) binds the ABri peptide (1-23) and amyloid β-peptide (Aβ1-40): Implications for Bri2 effects on processing of amyloid precursor protein and Aβ aggregation

In Alzheimer’s disease the amyloid β-peptide (Aβ) aggregates in brain tissue and arteries. Aβ is proteolytically cleaved out from amyloid precursor protein (APP) by different secretases. Recently, the transmembrane protein ITM2B/Bri2, which is expressed in neurons and associated with familial British and Danish dementia, was shown to inhibit APP processing in transfected cells as well as in transgenic mice. Several mechanisms by which Bri2 can interfere with Aβ production and aggregation have been proposed. Herein, we studied recombinant human Bri2 (residues 90-236) containing the extracellular Brichos domain without the ABri23 peptide. Bri2(90-236) binds to ABri23, which suggests that these two parts interact during Bri2 biosynthesis, in line with proposed functions of Brichos domains in other proteins. Moreover, Bri2(90-236) binds Aβ1-40 and inhibits its aggregation and fibril formation. These data suggest a model for how the processing of Bri2 and APP are interrelated.     

Different rotamer populations around the C-5C-6 bond for α- and β-d-galactopyranosides through the combined interaction of the gauche and anomeric effects: A 300-MHz 1H-n.m.r. and mndo study

A 300-MHz ¹H-n.m.r. study of methyl 2,3,4-tri-O-methyl-ga- (1) and β-d-galactopyranoside-6-(dimethyl phosphate) (3), using various solvents, shows that the gauche (gg) rotamer populations about the C-5C-6 bond are are the same in all solvents, whereas those of the gauche(trans) (gt) and trans(gauche) (tg, O-5 and O-6 trans) rotamers are solvent dependent. The tg population increases with decreasing polarity of the solvent, which is attributed to an increased electrostatic repulsion between O-5 and O-6 in apolar solvents. The tg population of 3 is larger than that of 1 and the same difference is observed in the corresponding compounds (2 and 4) which have a trigonal-bipyramidal five-coördinated phosphorus (P^v) at position 6 and which have a higher electron density at O-6. These differences in rotamer populations are due to an effect additional to that of the coulombic effect between O-5 and O-6. That these differences are caused by a combination of the gauche and anomeric effects is supported by the finding that the tg population increases with increasing pK_a of the group at C-1. The results of the n.m.r. measurements (in CCl₄) are reproduced fairly accurately by MNDO calculations on model systems. The solvent dependence of the rotamer population around the C-5ẋC-6 bond is a good criterion for the assignment of the H-6S,6R resonances since, for galactopyranosides, J_5,6S increases and J_5,6R decreases as the polarity of the solvent decreases.     

Asymmetric reduction of (4S)-(+)-carvone catalyzed by baker's yeast: A green method for monitoring the conversion based on liquid–liquid–liquid microextraction with polypropylene hollow fiber membranes

The α,β-unsaturated carbonyl compound (4S)-(+)-carvone was selectively reduced to (1R,2R,4S)-iso-dihydrocarveol using baker's yeasts. The conversion of the bioreduction reaction was monitored using a green hollow-fiber liquid–liquid–liquid microextraction (HF-LLLME) technique. Several parameters which may affect the bioreduction of (4S)-(+)-carvone, such as temperature, time, substrate/enzyme ratio, pH and buffer concentration, were evaluated. The effect of some additives, such as trehalose, DMSO and the ionic liquid [BMIm][PF₆], was also studied. The (1R,2R,4S)-iso-dihydrocarveol was recovered with 52.7% conversion and diastereoisomeric excess >99% after 48 h of reaction at 40 °C in an aqueous monophasic system, with 0.1 mol L^?1 buffer concentration (pH 7.5) and a substrate/yeast cell mass ratio of 8.0 mg g^?1. The HF-LLLME microextraction technique allowed the optimization of the reaction with a reduction of over 99.5% in relation to the use of organic solvents.