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.

Apoptosis in human ejaculated sperm cells (notulae seminologicae 9).

Abstract: In this work we apply the Hoechst 33258 DNA staining, the TUNEL procedure and conventional electron microscopy to study the ejaculate of fertile and infertile men, in order to detect apoptosis in human sperm cells. We have observed that apoptosis is abnormally frequent in the sperm cells of the ejaculate of sterile men, and that it shows the classical biochemical and ultrastructural pattern in spermatozoa, spermatids and apoptotic bodies. These characteristics, involving the chromatin, the nuclear envelope, the plasma membrane, the presence of cytoplasmic vacuoles and the status of mitochondria, are consistent whatever the pathology of the patient is. What is varying is the percentage of the apoptotic sperm cells, that is about 0.1% in fertile controls, and increases up to about 10% in varicocele, infected (including AIDS), "round headed' patients, to 20% in cryptorchid men, to 25% in immature patients, and to 50% in testicular seminoma carriers. Obviously in each category the frequence of apoptotic cells increases concomitantly with the degree of the affection. The present demonstration not only extends to human spermiogenetic epithelium the natural presence of apoptosis, which starts in the testis and is revealed in the ejaculate, but also explains many abnormal ultrastructural sperum patterns hitherto unexplained in fertile and infertile individuals.

Binding of an ankyrin-1 isoform to obscurin suggests a molecular link between the sarcoplasmic reticulum and myofibrils in striated muscles

Abstract: Assembly of specialized membrane domains, both of the plasma membrane and of the ER, is necessary for the physiological activity of striated muscle cells. The mechanisms that mediate the structural organization of the sarcoplasmic reticulum with respect to the myofibrils are, however, not known. We report here that ank1.5, a small splice variant of the ank1 gene localized on the sarcoplasmic reticulum membrane, is capable of interacting with a sequence of 25 aa located at the COOH terminus of obscurin. Obscurin is a giant sarcomeric protein of ∼800 kD that binds to titin and has been proposed to mediate interactions between myofibrils and other cellular structures. The binding sites and the critical aa required in the interaction between ank1.5 and obscurin were characterized using the yeast two-hybrid system, in in vitro pull-down assays and in experiments in heterologous cells. In differentiated skeletal muscle cells, a transfected myc-tagged ank1.5 was found to be selectively restricted near the M line region where it colocalized with endogenous obscurin. The M line localization of ank1.5 required a functional obscurin-binding site, because mutations of this domain resulted in a diffused distribution of the mutant ank1.5 protein in skeletal muscle cells. The interaction between ank1.5 and obscurin represents the first direct evidence of two proteins that may provide a direct link between the sarcoplasmic reticulum and myofibrils. In keeping with the proposed role of obscurin in mediating an interaction with ankyrins and sarcoplasmic reticulum, we have also found that a sequence with homology to the obscurin-binding site of ank1.5 is present in the ank2.2 isoform, which in striated muscles has been also shown to associate with the sarcoplasmic reticulum. Accordingly, a peptide containing the COOH terminus of ank2.2 fused with GST was found to bind to obscurin. Based on reported evidence showing that the COOH terminus of ank2.2 is necessary for the localization of ryanodine receptors and InsP 3 receptors in the sarcoplasmic reticulum, we propose that obscurin, through multiple interactions with ank1.5 and ank2.2 isoforms, may assemble a large protein complex that, in addition to a structural function, may play a role in the organization of specific subdomains in the sarcoplasmic reticulum.

Patterns and meanings in discourse : theory and practice in corpus-assisted discourse studies (CADS)

Abstract: This work is designed, firstly, to both provoke theoretical discussion and serve as a practical guide for researchers and students in the field of corpus linguistics and, secondly, to offer a wide-ranging introduction to corpus techniques for practitioners of discourse studies. It delves into a wide variety of language topics and areas including metaphor, irony, evaluation, (im)politeness, stylistics, language change and sociopolitical issues. Each chapter begins with an outline of an area, followed by case studies which attempt both to shed light on particular themes in this area and to demonstrate the methodologies which might be fruitfully employed to investigate them. The chapters conclude with suggestions on activities which the readers may wish to undertake themselves. An Appendix contains a list of currently available resources for corpus research which were used or mentioned in the book.

Comparison of two dosing frequencies of subcutaneous interferon beta-1a in patients with a first clinical demyelinating event suggestive of multiple sclerosis (REFLEX): a phase 3 randomised controlled trial

Abstract: Summary Background In patients presenting with a first clinical demyelinating event that is suggestive of multiple sclerosis (MS), treatment with interferon beta can delay the occurrence of further attacks and the onset of MS. We investigated the effects of two dosing frequencies of subcutaneous interferon beta-1a in patients with a first clinical demyelinating event. Methods We undertook a multicentre phase 3 study (REbif FLEXible dosing in early MS [REFLEX]) that included patients (aged 18–50 years) with a single clinical event suggestive of MS, and at least two clinically silent T2 lesions on brain MRI. Participants were randomly assigned in a 1:1:1 ratio by use of a centralised interactive voice response system to receive the serum-free formulation of subcutaneous interferon beta-1a 44 μg three times a week or once a week (plus placebo twice a week for masking), or placebo three times a week for up to 24 months. Patients and physicians were masked to group allocation. The primary endpoint was time to a diagnosis of MS as defined by the 2005 McDonald criteria and the main secondary endpoint was time to clinically definite MS (CDMS) as defined by the Poser criteria. Analysis was by intention to treat. The study is registered with ClinicalTrials.gov, number NCT00404352. Findings 517 patients were randomly assigned (171 to subcutaneous interferon beta-1a three times a week, 175 to subcutaneous interferon beta-1a once a week, and 171 to placebo) and 515 were treated. The 2-year cumulative probability of McDonald MS was significantly lower in patients treated with subcutaneous interferon beta-1a (three times a week 62·5%, p Interpretation Both regimens of subcutaneous interferon beta-1a delayed clinical relapses and subclinical disease activity. The potential differences between the regimens warrant longer-term study. Funding Merck Serono SA, Geneva, Switzerland.