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Sergio Chimenti

Publications and source records attributed to Sergio Chimenti.

At least 37 records · Page 2Linked to original sources
PubMed2005

Fate of UVB-induced p53 mutations in SKH-hr1 mouse skin after discontinuation of irradiation: relationship to skin cancer development.

Chronic exposure to ultraviolet (UV) radiation causes skin cancer in humans and mice. We have previously shown that in hairless SKH-hr1 mice, UVB-induced p53 mutations arise very early, well before tumor development. In this study, we investigated whether discontinuation of UVB exposure before the onset of skin tumors results in the disappearance of p53 mutations in the skin of hairless SKH-hr1 mice. Irradiation of mice at a dose of 2.5 kJ/m2 three times a week for 8 weeks induced p53 mutations in the epidermal keratinocytes of 100% of the mice. UVB irradiation was discontinued after 8 weeks, but p53 mutations at most hotspot codons were still present even 22 weeks later. During that period, the percent of mice carrying p53(V154A/R155C), p53(H175H/H176Y), and p53R275C mutant alleles remained at or near 100%, whereas the percentage of mice with p53R270C mutation decreased by 45%. As expected, discontinuation of UVB after 8 weeks resulted in a delay in tumor development. A 100% of tumors carried p53(V154A/R155C) mutant alleles, 76% carried p53(H175H/H176Y) mutants, and 24 and 19% carried p53R270C and p53R275C mutants, respectively. These results suggest that different UVB-induced p53 mutants may provide different survival advantages to keratinocytes in the absence of further UVB exposure and that skin cancer development can be delayed but not prevented by avoidance of further exposure to UVB radiation.

Alleles↗
PubMed2005

A p38-dependent pathway regulates DeltaNp63 DNA binding to p53-dependent promoters in UV-induced apoptosis of keratinocytes.

The p53 protein plays a pivotal role in determining the quality of the response to DNA damage through its transcriptional activity. Upon DNA damage, p53 is activated by post-translational modifications, binds its cognate sequences on the promoters of its target genes and stimulates transcription. In proliferating keratinocytes, the activity of p53 is blunted by its inhibitor DeltaNp63alpha. Here, we describe a novel mechanism through which DeltaNp63 functions in order to prevent the survival and propagation of ultraviolet (UV)-damaged keratinocytes. We found that UVB stimulation induces the rapid phosphorylation of DeltaNp63, which precedes DeltaNp63 transcriptional downregulation and protein degradation, which is mediated by the p38 MAPK. Phosphorylated DeltaNp63 has a lower affinity for p53REs and detaches from cell cycle arrest and apoptotic promoters, thus allowing the rapid activation of p53-dependent transcriptional apoptotic program.

Apoptosis↗
PubMed2005

WHO-EORTC classification for cutaneous lymphomas.

Primary cutaneous lymphomas are currently classified by the European Organization for Research and Treatment of Cancer (EORTC) classification or the World Health Organization (WHO) classification, but both systems have shortcomings. In particular, differences in the classification of cutaneous T-cell lymphomas other than mycosis fungoides, Sezary syndrome, and the group of primary cutaneous CD30+ lymphoproliferative disorders and the classification and terminology of different types of cutaneous B-cell lymphomas have resulted in considerable debate and confusion. During recent consensus meetings representatives of both systems reached agreement on a new classification, which is now called the WHO-EORTC classification. In this paper we describe the characteristic features of the different primary cutaneous lymphomas and other hematologic neoplasms frequently presenting in the skin, and discuss differences with the previous classification schemes. In addition, the relative frequency and survival data of 1905 patients with primary cutaneous lymphomas derived from Dutch and Austrian registries for primary cutaneous lymphomas are presented to illustrate the clinical significance of this new classification.

Humans↗
PubMed2005

The spectrum of Spitz nevi: a clinicopathologic study of 83 cases.

OBJECTIVE: To achieve a clinicopathologic classification of Spitz nevi by comparing their clinical, dermoscopic, and histopathologic features. DESIGN: Eighty-three cases were independently reviewed by 3 histopathologists and preliminarily classified into classic or desmoplastic Spitz nevus (CDSN, n = 11), pigmented Spitz nevus (PSN, n = 14), Reed nevus (RN, n = 16), or atypical Spitz nevus (ASN, n = 14); the remaining 28 cases were then placed into an intermediate category (pigmented Spitz-Reed nevus, PSRN) because a unanimous diagnosis of either PSN or RN was not reached. SETTING: University dermatology and pathology departments and general hospital pathology departments. PATIENTS: A sample of subjects with excised melanocytic lesions. MAIN OUTCOME MEASURE: Frequency of dermoscopic patterns within the different histopathologic subtypes of Spitz nevi. RESULTS: Overlapping clinical, dermoscopic, and histopathologic findings were observed among PSN, RN, and PSRN, thereby justifying their inclusion into the single PSRN diagnostic category. Asymmetry was the most frequent indicator of histopathologic ASN (79%; n = 11); in only 4 cases did dermoscopic asymmetry show no histopathologic counterpart, and in those cases the discrepancy was probably the result of an artifact of the gross sampling technique carried out with no attention to the dermoscopic features. CONCLUSIONS: Among Spitz nevi, histopathologic distinction between PSN and RN is difficult, not reproducible, and may be clinically useless. A simple clinicopathologic classification of these neoplasms might therefore be structured as CDSN, PSRN, and ASN. Asymmetry should be assessed using both dermoscopic and histopathologic analysis, and reliability in histopathologic diagnosis may be enhanced by the simultaneous evaluation of the corresponding dermoscopic images.

Adolescent↗
PubMed2005

WHO/EORTC classification of cutaneous lymphomas 2005: histological and molecular aspects.

UNLABELLED: The new WHO/EORTC classification for cutaneous lymphomas comprises mature T-cell and natural killer (NK)-cell neoplasms, mature B-cell neoplasms, and immature hematopoietic malignancies. It reflects the unique features of lymphoproliferative diseases of the skin, and at the same time it is as compatible as possible with the concepts underlying the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. This article reviews the histological, phenotypical, and molecular genetic features of the various nosological entities included in this new classification. These findings always have to be interpreted in the context of the clinical features and biologic behavior. AIM: To review the histological, phenotypical and molecular genetic features of the various nosological entities of the new WHO/EORTC classification for cutaneous lymphomas. METHODS: Extensive review of the literature cited in Medline and own data of the authors. RESULTS: The WHO/EORTC classification of cutaneous lymphomas comprises mature T-cell and NK-cell neoplasms, mature B-cell neoplasms and immature hematopoietic malignancies. It reflects the unique features of primary cutaneous lymphoproliferative diseases. CONCLUSION: This classification is as much as possible compatible with the concept of the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. The histological, phenotypical and molecular genetic features always have to be interpreted in the context of the clinical features and biologic behavior.

Europe↗
PubMed2005

Imiquimod treatment of superficial and nodular basal cell carcinoma: 12-week open-label trial.

BACKGROUND: Imiquimod is an immune response modifier shown to be effective in basal cell carcinoma (BCC). OBJECTIVE: To evaluate the efficacy, tolerability, and response durability of imiquimod 5% cream in selected patients with superficial and/or nodular BCCs. METHODS: Seventy-five superficial and 19 nodular BCCs in 49 patients were treated with imiquimod once daily three times a week for up to 12 weeks. RESULTS: Of the 49 enrolled patients, 1 discontinued the study and 1 was lost to follow-up. After 12 weeks of treatment, a complete response occurred in 70 of 75 (93.3%) superficial BCCs and a partial response in 4 of 75 (5.3%) superficial BCCs. Ten of 19 (52.6%) nodular BCCs cleared after 12 weeks, whereas 7 (36.8%) showed partial remission. Adverse side effects were limited to local skin reactions. Recurrence was observed in 2 of 70 (2.9%) successfully treated superficial BCCs 6 and 8 months after treatment discontinuation. No recurrence was detected in 68 of 70 (97.1%) superficial BCCs and in 10 successfully treated nodular BCCs after 12 to 34 months of follow-up (mean 23 months). CONCLUSIONS: In our patient population, treatment of superficial BCCs with topical imiquimod for 12 weeks produced an excellent clinical response overall, with complete remission maintained after a mean of 23 months.

Adjuvants, Immunologic↗
PubMed2005

Teledermatology: just cool or a real tool?

Telemedicine is the practice of healthcare using interactive audio, visual and data communication. This includes healthcare delivery, diagnoses, consultation and treatment as well as education and transfer of medical data. The transmission of multimedia streams has remained a major challenge. Although the Internet remains basically insecure, technology allows today to define and implement complete security profiles for specific (medical) communities. Data security is a must as in all other areas of applied medicine. Teledermatology offers possibilities in consulting, continuous medical education or teleteaching. In the future, consulting and asking for a second opinion will be the gold standard of medical care. The quality of healthcare will be improved without saving direct costs. However, indirect costs such as time and effort for the patient and the citizen will be reduced.

Dermatology↗
PubMed2004

Treatment of lentigo maligna with tazarotene 0.1% gel.

We report 2 elderly patients with facial lentigo maligna who experienced complete regression, both clinically and histopathologically, after once-daily topical treatment with tazarotene 0.1% gel for 6 to 8 months. After a follow-up period of 18 and 30 months, no recurrence was observed. We believe that tazarotene might be considered as an alternative medical approach in selected patients with lentigo maligna.

Aged↗
PubMed2004

Constitutional and environmental risk factors for cutaneous melanoma in an Italian population. A case-control study.

The aim of this study was to determine the relative risk for cutaneous melanoma associated with phenotypic and environmental variables in a population in central Italy and to assess how the combination of the different risk factors contributes to the overall risk for melanoma. We performed a case-control study of 100 patients with sporadic cutaneous melanoma and 200 controls matched for sex, age, ethnicity and residential area. Individuals were interviewed concerning pigmentary traits and sun exposure, and underwent a total body skin examination. Logistic regression models were used to evaluate the association between cutaneous melanoma and constitutional and environmental variables. The strongest risk factors were prolonged recreational sun exposure (odds ratio [OR] 5.010, 95% confidence interval [CI] 2.110-11.891), the presence of clinically atypical naevi (OR 4.916, 95% CI 2.496-9.995) and the presence of >50 common melanocytic naevi (OR 4.684, 95% CI 2.442-9.231). In addition, occupational sun exposure (OR 2.573, 95% CI 1.399-4.732), light brown hair (OR 2.336, 95% CI 1.328-4.138), high density of solar lentigos and/or actinic keratoses (OR 1.824, 95% CI 1.0-3.510) and type II, fair skin (OR 1.815, 95% CI 1.031-3.193) and blue eyes (OR 1.757, 95% CI 1.0-3.477) were each significantly associated with cutaneous melanoma risk. The combination of individual strong risk factors was associated with up to a 46-fold increase in the risk for cutaneous melanoma. Selected pigmentary traits, sun exposure and melanocytic naevi, individually and in combination, are important risk factors for cutaneous melanoma in an Italian population.

Adolescent↗
PubMed2004

Evidence of increased apoptosis and reduced proliferation in basal cell carcinomas treated with tazarotene.

A preliminary clinical experience suggested tazarotene, a new acetylenic retinoid, as an effective alternative topical treatment of basal cell carcinomas (BCC). The mechanisms of action of this synthetic retinoid, however, have not been yet clarified. In this work we assessed the in vivo effects of daily application of tazarotene for 24 wk, on 30 small superficial and nodular BCC, and the in vitro effects of tazarotene on immortalized basal and squamous tumor epidermal cells. Cellular proliferation, apoptosis and changes in expression of retinol and retinoic acid receptors (RAR), p53, bcl-2, and bax were studied by immunohistochemistry, western blotting and PCR. Overall, 76.7% of treated tumors showed >50% regression. Complete healing was observed in 46.7% of all treated BCC, without recurrences at 2-y observation. Regression was associated with reduced proliferation and increased apoptosis, demonstrated by Ki-67- and TdT-mediated dUTP-biotin nick-end labelling-positive nuclear staining, and with enhanced RAR-beta and bax expression, with RAR-alpha and -gamma expression unchanged. In vitro, tazarotene induced a concentration-dependent increase of RAR-beta and bax associated with a greater rate of apoptosis and growth inhibition in basaloid tumor cells compared with squamous tumor cells. Our studies provide convincing evidence that tazarotene induces BCC regression possibly by synergistic RAR-beta-dependent anti-proliferative and pro-apoptotic pathways.

Adult↗
PubMed2004

Psoriatic arthritis and CARD15 gene polymorphisms: no evidence for association in the Italian population.

Psoriatic arthritis (PsA) has been defined as an inflammatory arthritis associated with psoriasis that may affect as many as 30% of psoriasis patients. Epidemiological study reported strong familial clustering of PsA although the precise etiology of PsA is poorly understood. Recently, a genomewide linkage scan in PsA revealed a LOD score of 2.17 on chromosome 16q and provided strong evidence for a paternal imprinting effect. That region surrounds a psoriasis susceptibility locus including the CARD15 gene which has convincingly been shown to confer susceptibility to Crohn's disease. The existence of a common susceptibility gene for psoriasis/PsA and Crohn disease was recently demonstrated by evidence of association of CARD15 polymorphisms with PsA. To confirm these results in an independent population, we analyzed a data set of 193 Italian PsA patients and 150 controls for CARD15 polymorphisms (R702W, G908R and leu1007finsC) previously demonstrated associated with PsA. Here we report no evidence for association in the examined population for CARD15 polymorphisms, suggesting that the positive association previously reported in a genetically isolated population was the result of a linkage disequilibrium due to a founder effect.

Arthritis, Psoriatic↗
PubMed2004

The p73 gene is an anti-tumoral target of the RARbeta/gamma-selective retinoid tazarotene.

Tazarotene, a member of the new class of acetylenic retinoids, has been shown to be effective in the treatment of several hyperproliferative skin diseases, including non-melanoma skin cancer. Its effectiveness is thought to rely on the ability to activate retinoic acid receptors beta and gamma and to induce a number of downstream anti-proliferative genes. Here, we show that the p53-related gene p73 is a target of tazarotene. Indeed, tazarotene modulates the expression of the p73 gene in immortalized keratinocyte cell lines by inducing the pro-apoptotic and anti-proliferative TAp73 isoforms and by repressing the anti-apoptotic and pro-proliferative DeltaNp73 isoforms. This occurs at the transcriptional level through a coordinated action on P1p73 and P2p73 promoters that control the expression of TA and DeltaN isoforms, respectively. The selective downregulation of DeltaNp73 expression by small interfering RNA led to an enhancement of tazarotene-induced bax activation and apoptosis, whereas the downregulation of both TA and DeltaN isoforms impairs tazarotene-mediated apoptosis. These results indicate the relevance of p73 gene products in tazarotene-induced growth inhibition and effectiveness in the treatment of skin tumors.

Animals↗
PubMed2004

Three-point checklist of dermoscopy. A new screening method for early detection of melanoma.

BACKGROUND: Dermoscopy used by experts has been demonstrated to improve the diagnostic accuracy for melanoma. However, little is known about the diagnostic validity of dermoscopy when used by nonexperts. OBJECTIVE: To evaluate the diagnostic performance of nonexperts using a new 3-point checklist based on a simplified dermoscopic pattern analysis. METHODS: Clinical and dermoscopic images of 231 clinically equivocal and histopathologically proven pigmented skin lesions were examined by 6 nonexperts and 1 expert in dermoscopy. For each lesion the nonexperts assessed 3 dermoscopic criteria (asymmetry, atypical network and blue-white structures) constituting the 3-point method. In addition, all examiners made an overall diagnosis by using standard pattern analysis of dermoscopy. RESULTS: Asymmetry, atypical network and blue-white structures were shown to be reproducible dermoscopic criteria, with a kappa value ranging from 0.52 to 0.55. When making the overall diagnosis, the expert had 89.6% sensitivity for malignant lesions (tested on 68 melanomas and 9 pigmented basal cell carcinomas), compared to 69.7% sensitivity achieved by the nonexperts. Remarkably, the sensitivity of the nonexperts using the 3-point checklist reached 96.3%. The specificity of the expert using overall diagnosis was 94.2% compared to 82.8 and 32.8% achieved by the nonexperts using overall diagnosis and 3-point checklist, respectively. CONCLUSION: The 3-point checklist is a valid and reproducible dermoscopic algorithm with high sensitivity for the diagnosis of melanoma in the hands of non-experts. Thus it may be applied as a screening procedure for the early detection of melanoma.

Adult↗