HELENA PANTELIOU LIMA VALASSI
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Clínica Médica, Faculdade de Medicina
LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina
LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina
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conferenceObject Simple method for Mitotane determination in plasma samples by LC-DAD(2023) MARQUES, Anna Sylvia Ferreira; ALVES, Atecla Nunciata Lopes; MENDONCA, Berenice Bilharinho; LIMA-VALASSI, Helena Pantelilou- Role of the Mevalonate Pathway in Adrenocortical Tumorigenesis(2021) LIMA-VALASSI, Helena Panteliou; LERARIO, Antonio Marcondes; MONTENEGRO, Luciana Ribeiro; FRAGOSO, Maria Candida Barisson Villares; ALMEIDA, Madson Queiroz; MENDONCA, Berenice Bilharinho; LIN, Chin Jia3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) is the rate-limiting enzyme of the mevalonate pathway, which generates cholesterol and non-sterol compounds such as isoprenoid, which are involved in key steps of tumorigenesis such as cell growth and proliferation. Our aim was to evaluate the role of the mevalonate pathway in adrenocortical tumors (ACTs). Expression pattern of HMGCR , FDFT1 , LDLR , SCARB1 , StAR , TSPO , CYP11A1 , CYP11B1 , CYP17A1 , CYP21A1 , and HSD3B1 genes , involved in the mevalonate pathway and steroidogenesis, was quantified by real-time RT-PCR in 46 ACT [14 adenomas (ACA) and 11 carcinomas (ACC) from adults and 13 ACA and 8 ACC from pediatric patients]. Effects of the mevalonate pathway inhibition on NCI-H295A cell viability was assessed by colorimetric assay. HMGCR was overexpressed in most adult ACT. The expression of TSPO , STAR , CYP11B1 , CYP21A1 , and HSD3B1 in adult ACC was significantly lower than in ACA (p<0.05). Regarding pediatric ACT, the expression of genes involved in steroidogenesis was not different between ACA and ACC. Inhibition of isoprenoid production significantly decreased the viability of NCI-H295A cells (p<0.05). However, cholesterol synthesis blockage did not show the same effect on cell viability. Low expression of TSPO,StAR , CYP11B1 , CYP21A1 , and HSD3B1 characterized a signature of adult ACCs. Our data suggest that HMGCR overexpression in adult ACC might lead to intracellular isoprenoid accumulation and cell proliferation. Therefore, the mevalonate pathway is a potential target for ACC treatment.
- Validation of an immunoassay for anti-Mullerian hormone measurements and reference intervals in healthy Brazilian subjects(2015) WOLOSZYNEK, Renata Reis; BRITO, Luciana Pinto; BATISTA, Marcelo Cidade; VALASSI, Helena Panteliou Lima; MENDONCA, Berenice Bilharinho; BRITO, Vinicius NahimeBackground Anti-Mullerian hormone is marker of ovarian and testicular reserve. The clinical use of this hormone requires proper standardization of reference intervals. The aims of this study were to validate the Anti-Mullerian hormone Gen II immunoassay, to establish Anti-Mullerian hormone reference intervals in healthy subjects, and to evaluate the influence of hormonal contraceptives, smoking, and body mass index on Anti-Mullerian hormone. Methods The validation of the Anti-Mullerian hormone Gen II assay (Beckman Coulter Company, TX, USA) was performed using a simplified protocol recommended by Clinical Laboratory Standard Institute. One-hundred and thirty-three healthy females and 120 males were prospectively selected for this study. Results The analytical and functional sensitivities of the Anti-Mullerian hormone Gen II immunoassay were 0.02 and 0.2ng/mL, respectively. Intra-assay coefficients ranged from 5.2 to 9.0%, whereas inter-assay precision ranged from 4.6 to 7.8% at different concentrations. In females, Anti-Mullerian hormone showed progressive decline with increasing age (r=-0.4, p<0.001), whereas in males, age showed no influence on Anti-Mullerian hormone concentrations. In females, Anti-Mullerian hormone concentrations did not differ between users and non-users of hormonal contraceptives, smokers, and non-smokers and obese and lean individuals. However, there was a negative and significant correlation between Anti-Mullerian hormone and body mass index in males (r=-0.3, p=0.008). Conclusions Anti-Mullerian hormone Gen II assay was reliable for determining serum Anti-Mullerian hormone concentrations. Anti-Mullerian hormone concentrations declined with aging and presented a wide inter-individual variability. The lack of influence of hormonal contraceptives, smoking, and obesity on Anti-Mullerian hormone in both sexes allowed us to refine the normative concentrations for the Brazilian population.