Molecular dynamics and principal components analysis of human telomeric quadruplex multimers.

Guanine-rich DNA repeat sequences located at the terminal ends of chromosomal DNA can fold in a sequence-dependent manner into G-quadruplex structures, notably the terminal 150–200 nucleotides at the 3' end, which occur as a single-stranded DNA overhang. The crystal structures of quadruplexes with two and four human telomeric repeats show an all-parallel-stranded topology that is readily capable of forming extended stacks of such quadruplex structures, with external TTA loops positioned to potentially interact with other macromolecules. This study reports on possible arrangements for these quadruplex dimers and tetramers, which can be formed from 8 or 16 telomeric DNA repeats, and on a methodology for modeling their interactions with small molecules. A series of computational methods including molecular dynamics, free energy calculations, and principal components analysis have been used to characterize the properties of these higher-order G-quadruplex dimers and tetramers with parallel-stranded topology. The results confirm the stability of the central G-tetrads, the individual quadruplexes, and the resulting multimers. Principal components analysis has been carried out to highlight the dominant motions in these G-quadruplex dimer and multimer structures. The TTA loop is the most flexible part of the model and the overall multimer quadruplex becoming more stable with the addition of further G-tetrads. The addition of a ligand to the model confirms the hypothesis that flat planar chromophores stabilize G-quadruplex structures by making them less flexible.

Estrogen Receptor-beta Affects the Prognosis of Human Malignant Mesothelioma

Malignant pleural mesothelioma is an asbestos-related neoplasm with poor prognosis, refractory to current therapies, the incidence of which is expected to increase in the next decades. Female gender was identified as a positive prognostic factor among other clinical and biological prognostic markers for malignant mesothelioma, yet a role of estrogen receptors (ERs) has not been studied. Our goal was to investigate ERs expression in malignant mesothelioma and to assess whether their expression correlates with prognosis. Immunohistochemical analysis revealed intense nuclear ER beta staining in normal pleura that was reduced in tumor tissues. Conversely, neither tumors nor normal pleura stained positive for ER alpha. Multivariate analysis of 78 malignant mesothelioma patients with pathologic stage, histologic type, therapy, sex, and age at diagnosis indicated that FRO expression is an independent prognostic factor of better survival. Moreover, studies in vitro confirmed that treatment with 17 beta-estradiol led to an ER beta-mediated inhibition of malignant mesothelioma cell proliferation as well as p21(CIP1) and p27(KIP1) up-regulation. Consistently cell growth was suppressed by ER beta overexpression, causing a G(2)-M-phase cell cycle arrest, paralleled by cyclin B1 and survivin down-regulation. Our data support the notion that ER beta acting as a tumor suppressor is of high potential relevance to prediction of disease progression and to therapeutic response of malignant mesothelioma patients. [Cancer Res 2009;69(11):4598-604]

Realising political equality: the European Court of Human Rights and positive obligations in a democracy'

The European Convention on Human Rights (ECHR) speaks of the importance of an “effective political democracy” in its Preamble, though it is only in Article 3 of Protocol 1 (P1-3) that we find a right to free elections. This paper discusses the role of “positive obligations” under P1-3. This paper outlines the positive obligations in P1-3 focusing on obligations where the state is required to do more than just change the law. This may mean providing resources or facilities, adopting regulatory frameworks or creating new institutions. The paper highlights specific positive obligations that need to be further developed in the jurisprudence of the European Court of Human Rights (ECtHR). Sometimes these can be developed by analogy with positive obligations recognised in other areas of ECtHR jurisprudence. However, beyond these cases, states should ensure that members of vulnerable and disadvantaged minorities are able to participate in the electoral process and should ensure that dominant political groups cannot abuse their political power to exclude other parties unfairly. This is necessary to realise equal political rights. The second section of this paper sketches some preliminary points about the Strasbourg institutions’ approach to P1-3. After that, the third section identifies circumstances where the ECtHR should apply a more intense scrutiny in P1-3 cases. The fourth, fifth and sixth sections look at positive obligations relating to the right to vote, the right to run for election and the regulation of political parties.

ADP can induce aggregation of human platelets via both P2Y(1) and P-2T receptors

1 In the present study we have investigated the roles of P2Y(1) and P-2T receptor subtypes in adenosine 5'-diphosphate (ADP)-induced aggregation of human platelets in heparinized platelet rich plasma.

Human Dignity and judicial Interpretation of Human Rights

The Universal Declaration on Human Rights was pivotal in popularizing the use of 'dignity' or 'human dignity' in human rights discourse. This article argues that the use of 'dignity', beyond a basic minimum core, does not provide a universalistic, principled basis for judicial decision-making in the human rights context, in the sense that there is little common understanding of what dignity requires substantively within or across jurisdictions. The meaning of dignity is therefore context-specific, varying significantly from jurisdiction to jurisdiction and (often) over time within particular jurisdictions. Indeed, instead of providing a basis for principled decision-making, dignity seems open to significant judicial manipulation. increasing rather than decreasing judicial discretion. That is one of its significant attractions to both judges and litigators alike. Dignity provides a convenient language for the adoption of substantive interpretations of human rights guarantees which appear to be intentionally, not just coincidentally. highly contingent on local circumstances. Despite that, however, I argue that the concept of 'human dignity' plays an important role in the development of human rights adjudication, not in providing an agreed content to human rights but in contributing to particular methods of human rights interpretation and adjudication.

In vivo and in vitro function of human UDP-galactose 4 '-epimerase variants

Type III galactosemia results from reduced activity of the enzyme UDP-galactose 4'-epimerase. Five disease-associated alleles (G90E, V94M, D103G, N34S and L183P) and three artificial alleles (Y105C, N268D, and M284K) were tested for their ability to alleviate galactose-induced growth arrest in a Saccharomyces cerevisiae strain which lacks endogenous UDP-galactose 4'-epimerase. For all of these alleles, except M284K, the ability to alleviate galactose sensitivity was correlated with the UDP-galactose 4'-epimerase activity detected in cell extracts. The M284K allele, however, was able to substantially alleviate galactose sensitivity, but demonstrated near-zero activity in cell extracts. Recombinant expression of the corresponding protein in Escherichia coil resulted in a protein with reduced enzymatic activity and reduced stability towards denaturants in vitro. This lack of stability may result from the introduction of an unpaired positive charge into a bundle of three alpha-helices near the surface of the protein. The disparities between the in vivo and in vitro data for M284K-hGALE further suggest that there are additional, stabilising factors present in the cell. Taken together, these results reinforce the need for care in the interpretation of in vitro, enzymatic diagnostic tests for type III galactosemia. (C) 2011 Elsevier Masson SAS. All rights reserved.

Increased Promiscuity of Human Galactokinase Following Alteration of a Single Amino Acid Residue Distant from the Active Site

Galactokinase catalyses the site-and stereospecific phosphorylation of galactose at the expense of ATP. The specificity of bacterial galactokinase enzymes can be broadened by alteration of a tyrosine residue to a histidine. The effects of altering the equivalent residue in human galactokinase (Tyr379) were investigated by testing all 19 possible variants. All of these alterations, except Y379P, resulted in soluble protein on expression in Escherichia coli and all the soluble variants could catalyse the phosphorylation of galactose, except Y379A and Y379E. The variants Y379C, Y379K, Y379R, Y379S and Y379W were all able to catalyse the phosphorylation of a variety of monosaccharides, including ones that are not acted on by the wild-type enzyme. Novel substrates for these variant galactokinases included D-mannose and D-fructose. The latter monosaccharide is presumed to react in the pyranose configuration. Molecular modelling suggested that the alterations do not cause changes to the overall structure of the enzyme. However, alteration of Tyr379 increases the flexibility of the peptide backbone in regions surrounding the active site. Therefore, it is proposed that alteration of Tyr379 affects the substrate specificity by the propagation of changes in flexibility to the active site, permitting a broader range of compounds to be accommodated.

The Development of Entrepreneurial Leadership: The Role of Human, Social and Institutional Capital

This paper contributes to the literature on entrepreneurial leadership development. Leadership studies are characterized by an increasing emphasis given to an individual leader's social and organizational domain. Within the context of human capital and social capital theory, the paper reflects on the emergence of a social capital theory of leadership development. Using a retrospective, interpretivist research method, the authors present the experience of a cohort of business leaders on an executive development programme to uncover the everydayness of leadership development in practice. Specifically, they explore how entrepreneurial leadership develops as a social process and what the role of social capital is in this. The findings suggest that the enhancement of leaders’ human capital only occurred through their development of social capital. There is not, as extant literature suggests, a clear separation between leader development and leadership development. Further, the analysis implies that the social capital theory of leadership is limited in the context of the entrepreneurial small firm, and the authors propose that it should be expanded to incorporate institutional capital, that is, the formal structures and organizations which enhance the role of social capital and go beyond enriching the human capital stock of individual leaders

AM1- receptor dependent protection by intermedin of human vascular and cardiac non-vascular cells from ischaemia-reperfusion injury

Intermedin (IMD) protects rodent heart and vasculature from oxidative stress and ischaemia. Less is known about distribution of IMD and its receptors and the potential for similar protection in man. Expression of IMD and receptor components were studied in human aortic endothelium cells (HAECs), smooth muscle cells (HASMCs), cardiac microvascular endothelium cells (HMVECs) and fibroblasts (v-HCFs). Receptor subtype involvement in protection by IMD against injury by hydrogen peroxide (H2O2, 1 mmol l?¹) and simulated ischaemia and reperfusion were investigated using receptor component-specific siRNAs. IMD and CRLR, RAMP1, RAMP2 and RAMP3 were expressed in all cell types.When cells were treated with 1 nmol l?¹ IMD during exposure to 1 mmol l?¹ H2O2 for 4 h, viability was greater vs. H2O2 alone (P<0.05 for all cell types). Viabilities under 6 h simulated ischaemia differed (P<0.05) in the absence and presence of 1 nmol l?¹ IMD: HAECs 63% and 85%; HMVECs 51% and 68%; v-HCFs 42% and 96%. IMD 1 nmol l?¹ present throughout ischaemia (3 h) and reperfusion (1 h) attenuated injury (P<0.05): viabilities were 95%, 74% and 82% for HAECs, HMVECs and v-HCFs, respectively, relative to those in the absence of IMD (62%, 35%, 32%, respectively). When IMD 1 nmol l?¹ was present during reperfusion only, protection was still evident (P<0.05, 79%, 55%, 48%, respectively). Cytoskeletal disruption and protein carbonyl formation followed similar patterns. Pre-treatment (4 days) of HAECs with CRLR or RAMP2, but not RAMP1 or RAMP3, siRNAs abolished protection by IMD (1 nmol l?¹) against ischaemia-reperfusion injury. IMD protects human vascular and cardiac non-vascular cells from oxidative stress and ischaemia-reperfusion,predominantly via AM1 receptors.