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Dive into the research topics where P. Sirigu is active.

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Featured researches published by P. Sirigu.


European Journal of Clinical Investigation | 2003

Tumor vascularity and tryptase‐positive mast cells correlate with a poor prognosis in melanoma

Domenico Ribatti; Maria Grazia Ennas; Angelo Vacca; F. Ferreli; Beatrice Nico; S. Orru; P. Sirigu

See commentary on page 361.


Cancer | 2005

The predictive value of CD8, CD4, CD68, and human leukocyte antigen-D-related cells in the prognosis of cutaneous malignant melanoma with vertical growth phase.

Franca Piras; Romano Colombari; Luigi Minerba; Daniela Murtas; Carlo Floris; Cristina Maxia; Arianna Corbu; M. Teresa Perra; P. Sirigu

To establish the prognostic value of immune system cells that infiltrate melanoma, the authors evaluated the distribution and density of T lymphocyte subsets, macrophages, and dendritic cells in samples of primary cutaneous melanoma from 47 patients with Stage I and II melanoma according to the American Joint Committee on Cancer staging system.


British Journal of Ophthalmology | 2003

Detection of human papillomavirus DNA in pterygia from different geographical regions

Franca Piras; Ps Moore; J Ugalde; Maria Teresa Perra; Aldo Scarpa; P. Sirigu

Background/aims: The aetiology and pathogenesis of pterygia remain unclear and the involvement of human papillomavirus (HPV) is controversial. 41 pterygia from two geographic locations were evaluated for the presence of HPV DNA. Methods: 41 pterygium biopsies (17 from Italy and 24 from Ecuador) were analysed using the L1C1 and PU-1ML primer sets by polymerase chain reaction (PCR) and DNA sequence analysis. Results: 22 of the 41 pterygia (54%) were positive for HPV, including all 17 Italian cases and 5/24 (21%) Ecuadorean cases. DNA sequencing of the 22 positive cases showed that 11 were HPV type 52, four were type 54, five were candHPV90, and two of unknown genotype. Conclusions: The major differences in the frequency of HPV in geographically distant populations might suggest a possible explanation for the vast differences in the reported detection rates. Three subtypes of HPV were found in this sample of pterygia. None the less, these results suggest that HPV may have a pathogenic role in pterygium.


Histopathology | 2007

Nuclear survivin is associated with disease recurrence and poor survival in patients with cutaneous malignant melanoma

Franca Piras; Daniela Murtas; Luigi Minerba; J Ugalde; C Floris; Cristina Maxia; R Colombari; Maria Teresa Perra; P. Sirigu

Aims:u2002 Survivin is expressed in neoplastic cells and appears to be associated with resistance to therapy and shorter survival in various types of tumours. The aim of the present study was to determine whether nuclear or cytoplasmic expression of survivin is related to disease recurrence and overall survival of patients with Stage I and II melanoma according to the American Joint Committee on Cancer (AJCC) staging system.


Virology Journal | 2011

Prevalence of human papillomavirus infection in women in Benin, West Africa

Franca Piras; Michela Piga; Antonella De Montis; Ahissou Rf Zannou; Luigi Minerba; Maria Teresa Perra; Daniela Murtas; Manuela Atzori; Marco Pittau; Cristina Maxia; P. Sirigu

BackgroundCervical cancer ranks as the first most frequent cancer among women in Benin. The major cause of cervical cancer now recognized is persistent infection of Human Papillomavirus (HPV). In Benin there is a lack of screening programs for prevention of cervical cancer and little information exists regarding HPV genotype distribution.MethodsCervical cells from 725 women were examined for the presence of viral DNA by means of a polymerase chain reaction (PCR) multiplex-based assay with the amplification of a fragment of L1 region and of E6/E7 region of the HPV genome, and of abnormal cytology by Papanicolaou method. The association between HPV status and Pap test reports was evaluated. Socio-demographic and reproductive characteristics were also related.ResultsA total of 18 different HPV types were identified, with a prevalence of 33.2% overall, and 52% and 26.7% among women with and without cervical lesions, respectively. Multiple HPV infections were observed in 40.2% of HPV-infected women. In the HPV-testing group, the odds ratio for the detection of abnormal cytology was 2.98 (95% CI, 1.83-4.84) for HPV positive in comparison to HPV negative women. High risk types were involved in 88% of infections, most notably HPV-59, HPV-35, HPV-16, HPV-18, HPV-58 and HPV-45. In multiple infections of women with cytological abnormalities HPV-45 predominated.ConclusionsThis study provides the first estimates of the prevalence of HPV and type-specific distribution among women from Benin and demonstrates that the epidemiology of HPV infection in Benin is different from that of other world regions. Specific area vaccinations may be needed to prevent cervical cancer and the other HPV-related diseases.


Journal of Cellular and Molecular Medicine | 2007

Neovascularization and mast cells with tryptase activity increase simultaneously in human pterygium.

Domenico Ribatti; Beatrice Nico; Cristina Maxia; Vito Longo; Daniela Murtas; Domenica Mangieri; M. Teresa Perra; Michela De Giorgis; Franca Piras; Enrico Crivellato; P. Sirigu

Mast cells (MC) have been implicated in both normal and pathological angiogenesis, such as that in chronic inflammatory diseases and tumors. This assumption is partially supported by the close structural association between MC and blood vessels and the recruitment of these cells during tumor growth. MC release a number of angiogenic factors among which tryptase, a serine protease stored in MC granules, is one of the most active. In this study, we correlate the extent of angiogenesis with the number of tryptase‐reactive MC in tissue fragments from pterygium and normal bulbar conjunctiva investigated by immunohistochemistry, using two murine monoclonal antibodies against the endothelial cell marker CD31 and the MC marker tryptase. Angiogenesis, measured as microvessel density, was highly correlated with MC tryptase‐positive cell count in pterygium tissues. These results suggest that the characteristic neovascularization observed in pterygium may be sustained, at least in part, by MC angiogenic mediators, in particular tryptase.


European Journal of Histochemistry | 2011

Nestin expression associates with poor prognosis and triple negative phenotype in locally advanced (T4) breast cancer

Franca Piras; Mt Ionta; S Lai; Maria Teresa Perra; Francesco Atzori; Luigi Minerba; Pusceddu; Cristina Maxia; Daniela Murtas; Paolo Demurtas; B. Massidda; P. Sirigu

Nestin, an intermediate filament protein, has traditionally been noted for its importance as a neural stem cell marker. However, in recent years, expression of nestin has shown to be associated with general proliferation of progenitor cell populations within neoplasms. There is no reported study addressing nestin expression in T4 breast cancer patients. Thus, the aim of the present study was to investigate, through immunohistochemistry, the expression and distribution of nestin in T4 breast cancer, in order to determine its association with clinical and pathological parameters as well as with patients outcome. Nestin was detectable in tumoral cells and in endothelial cells of blood microvessels, and it is significantly expressed in triple-negative and in inflammatory breast cancer (IBC) subgroups of T4 breast tumours. The Kaplan-Meier analysis showed that the presence of nestin in tumoral cells significantly predicted poor prognosis at 5-years survival (P=0.02) and with borderline significance at 10-years of survival (P=0.05) in T4 breast cancer patients. On the basis of these observations, we speculate that nestin expression may characterize tumours with an aggressive clinical behavior, suggesting that the presence of nestin in tumoral cells and vessels may be considered an important factor that leads to a poor prognosis. Further studies are awaited to define the biological role of nestin in the etiology of these subgroups of breast cancers.


Journal of Cellular and Molecular Medicine | 2008

Expression of survivin protein in pterygium and relationship with oxidative DNA damage

Cristina Maxia; Maria Teresa Perra; Paolo Demurtas; Luigi Minerba; Daniela Murtas; Franca Piras; Arianna Corbu; Dc Gotuzzo; Rg Cabrera; Domenico Ribatti; P. Sirigu

Ultraviolet radiation is known to cause oxidative DNA damage and is thought to be a major factor implicated in the pathogenesis of pterygium. Among all the photo‐oxidative DNA products, the 8‐hydroxydeoxyguanosine (8‐OHdG) is regarded a sensitive and stable biomarker for evaluating the degree of DNA damage. The protein p53 is a major cell stress regulator that acts to integrate signals from a wide range of cellular stresses. UV radiation has a carcinogenic effect resulting in DNA damaged cells with loss of normal growth control. This assumption is supported by the association between UV‐B exposure and activation of survivin, a member of the inhibitor of apoptosis protein family (IAP), highly up‐regulated in almost all types of human malignancy. In this study we demonstrate, for the first time in pterygium, the immunohistochemical presence of survivin, and investigate the correlation between survivin, p53 and 8‐OHdG. Our results demonstrate that oxidative stress could lead to a significant activation of survivin expression, suggesting that this might be an important event in the development of pterygium, inducing and supporting a hyperproliferative condition. Survivin expression in pterygium would counteract UV‐B‐induced apoptosis and would cooperate with loss of p53. The co‐operation between survivin and functional loss of p53 might provide a general mechanism for aberrant inhibition of apoptosis that could be responsible for the development of pterygium and its possible progression to neoplasia.


International Journal of Experimental Pathology | 2010

Erythropoietin is involved in angiogenesis in human primary melanoma

Domenico Ribatti; Beatrice Nico; Maria Teresa Perra; Vito Longo; Cristina Maxia; Tiziana Annese; Franca Piras; Daniela Murtas; P. Sirigu

In this study, the extent of angiogenesis, evaluated as microvascular volume density, immunoreactivity of tumour cells to erythropoietin (Epo) and of endothelial cells to Epo receptor (EpoR) have been correlated in human primary melanoma specimens. Results showed that Epo/EpoR expression correlate with angiogenesis and tumour thickness. These findings suggest that Epo is secreted by tumour cells and it affects vascular endothelial cells via its receptor and promotes angiogenesis in a paracrine manner, playing an important role in melanoma angiogenesis.


Microscopy Research and Technique | 1997

Local immune response in the skin of the external auditory meatus: An immunohistochemical study

P. Sirigu; Maria Teresa Perra; Caterina Ferreli; Cristina Maxia; F. Turno

Cerumen plays an important role in the protection of the external auditory meatus against several kinds of damage. Its hydrophobic properties, due to the high concentration of lipids, shelter the canal from physical damages, while other components probably protect against certain microbial strains. Nevertheless there has been considerable dispute in the literature with regard to the antibacterial activity of cerumen. Because of the importance of the role of immunoglobulins (Ig) in local defense mechanisms, we attempted to study, by immunohistochemical methods, the presence and localization of the cells necessary to activate an Ig‐mediated immune response and the epithelial expression of immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) in order to obtain information about a local immune response in those areas of the skin that take part in cerumen production. Our findings indicate that in the human skin of the external auditory canal the cells necessary to activate an antibody‐mediated immune response were localized in the different layers of the epidermis and/or in the dermis surrounding the sebaceous and ceruminous glands and the piliary follicle, while an intense immunoreactivity for IgA and IgG was observed in the epithelial layers of the skin. The results suggest that the external auditory canal is protected from the insults of pathogens by an antibody‐mediated local immune response, because all the effector components of an active local immune system are present. Microsc. Res. Tech. 38:329–334, 1997.

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S Lai

University of Cagliari

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