University of Siena

About: University of Siena is a education organization based out in Siena, Italy. It is known for research contribution in the topics: Population & Cancer. The organization has 12179 authors who have published 33334 publications receiving 1008287 citations. The organization is also known as: Università degli studi di Siena & Universita degli studi di Siena.

Patterns of Link Reciprocity in Directed Networks

Abstract: We address the problem of link reciprocity, the nonrandom presence of two mutual links between pairs of vertices. We propose a new measure of reciprocity that allows the ordering of networks according to their actual degree of correlation between mutual links. We find that real networks are always either correlated or anticorrelated, and that networks of the same type (economic, social, cellular, financial, ecological, etc.) display similar values of the reciprocity. The observed patterns are not reproduced by current models. This leads us to introduce a more general framework where mutual links occur with a conditional connection probability. In some of the studied networks we discuss the form of the conditional connection probability and the size dependence of the reciprocity.

Clinical and imaging assessment of cognitive dysfunction in multiple sclerosis

Abstract: In patients with multiple sclerosis (MS), grey matter damage is widespread and might underlie many of the clinical symptoms, especially cognitive impairment. This relation between grey matter damage and cognitive impairment has been lent support by findings from clinical and MRI studies. However, many aspects of cognitive impairment in patients with MS still need to be characterised. Standardised neuropsychological tests that are easy to administer and sensitive to disease-related abnormalities are needed to gain a better understanding of the factors affecting cognitive performance in patients with MS than exists at present. Imaging measures of the grey matter are necessary, but not sufficient to fully characterise cognitive decline in MS. Imaging measures of both lesioned and normal-appearing white matter lend support to the hypothesis of the existence of an underlying disconnection syndrome that causes clinical symptoms to trigger. Findings on cortical reorganisation support the contribution of brain plasticity and cognitive reserve in limiting cognitive deficits. The development of clinical and imaging biomarkers that can monitor disease development and treatment response is crucial to allow early identification of patients with MS who are at risk of cognitive impairment.

Proteins as biomarkers of oxidative/nitrosative stress in diseases: The contribution of redox proteomics

Abstract: I. Introduction 00 II. Reactive Oxygen and Nitrogen Species 00 III. Biological Markers of Oxidative/Nitrosative Stress 00 IV. Oxidative/Nitrosative Stress and Protein Modifications 00 A. Oxidative/Nitrosative Modification of Protein Thiols 00 B. Oxidative/Nitrosative Modification of Tyrosine 00 C. Oxidative Modification of Methionine 00 D. Protein Carbonylation 00 E. Oxidative Modification of Histidine and Tryptophan 00 V. MS Approaches for the Molecular Characterization of Oxidatively/Nitrosatively Modified Proteins 00 A. Analysis of Oxidized/Nitrosated Products of Protein Thiols 00 B. Analysis of Oxidized/Nitrated Products of Tyrosine Residues 00 C. Analysis of Oxidized Products of Methionine Residues 00 D. Analysis of Protein Carbonylation Products 00 E. Analysis of Oxidized Products of Tryptophan Residues 00 F. Analysis of Oxidized Products of Histidine Residues 00 VI. Proteomic Strategies for the Identification of ROS/RNS Targets in Complex Protein Mixtures 00 VII. Selected Human Diseases Associated with Oxidative/Nitrosative Stress 00 A. Acute (Adult) Respiratory Distress Syndrome 00 B. Alzheimer's Disease 00 C. Amyotrophic Lateral Sclerosis 00 D. Asthma 00 E. Atherosclerosis 00 F. Chronic Obstructive Pulmonary Diseases 00 G. Diabetes Mellitus 00 H. HIV Infection 00 I. Preeclampsia 00 J. Rheumatoid Arthritis 00 K. Transmissible Spongiform Encephalopathies 00 VIII. Oxidatively Modified Proteins in Human Diseases 00 IX. Concluding Remarks and Future Perspectives 00 Acknowledgments 00 Abbreviations 00 References 00 Reactive oxygen species (ROS) and reactive nitrogen species (RNS) contribute to the pathogenesis and/or progression of several human diseases. Proteins are important molecular signposts of oxidative/nitrosative damage. However, it is generally unresolved whether the presence of oxidatively/nitrosatively modified proteins has a causal role or simply reflects secondary epiphenomena. Only direct identification and characterization of the modified protein(s) in a given pathophysiological condition can decipher the potential roles played by ROS/RNS-induced protein modifications. During the last few years, mass spectrometry (MS)-based technologies have contributed in a significant way to foster a better understanding of disease processes. The study of oxidative/nitrosative modifications, investigated by redox proteomics, is contributing to establish a relationship between pathological hallmarks of disease and protein structural and functional abnormalities. MS-based technologies promise a contribution in a new era of molecular medicine, especially in the discovery of diagnostic biomarkers of oxidative/nitrosative stress, enabling early detection of diseases. Indeed, identification and characterization of oxidatively/nitrosatively modified proteins in human diseases has just begun. © 2004 Wiley Periodicals, Inc., Mass Spec Rev