RESUMO
INTRODUCTION: Medullary thyroid carcinoma (MTC) is observed in nearly 100 % of patients with multiple endocrine neoplasia type 2A (MEN2A). The gene responsible for MEN2A is the RET proto-oncogene and about 95 % of MEN2A patients have germline mutations in five specific cysteine codons (609, 611, 618, 620 and 634). MATERIALS AND METHODS: A retrospective study of children from families with MEN2A in our geographic area was performed. Variables analyzed included demographic data, kinship relations, age at genetic screening, age at prophylactic thyroidectomy, genetic mutation subtype and histological findings. The genetic study consisted in direct molecular analysis by automatic sequencing of RET mutated exon in the studied family. RESULTS: We performed 13 prophylactic total thyroidectomies from 1997 to 2013, 8 females and 5 males. The mean age at genetic diagnosis was 3.8 years (range 2-5.9). All children belonged to four interconnected families living in the same geographic area and presenting C634Y mutation in all the cases. The mean age at prophylactic thyroidectomy was 5.6 years (range 4-8.5). Histopathological findings demonstrated seven cases of C-cells nodular hyperplasia, one lymphocytic thyroiditis, two without evidence of disease, two micro-carcinomas and one multicentric carcinoma. CONCLUSION: The mutation found in the RET proto-oncogene responsible for MEN2A in pediatric patients in the south of Spain is the C635Y. It is considered a high-risk mutation, associated with an earlier malignant transformation and development of MTC.
Assuntos
Carcinoma Medular/congênito , Neoplasia Endócrina Múltipla Tipo 2a/genética , Neoplasia Endócrina Múltipla Tipo 2a/patologia , Proteínas Proto-Oncogênicas c-ret/genética , Neoplasias da Glândula Tireoide/genética , Carcinoma Medular/genética , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Mutação , Linhagem , Proto-Oncogene Mas , EspanhaRESUMO
Dioctadecyldimethylammonium bromide (DODAB) dispersions obtained by simply mixing the amphiphile in water, and by bath-sonication, were investigated by electron spin resonance (ESR) of stearic acids and their methyl ester derivatives, labeled at the 5th and 16th carbons of the acyl chain. The ESR spectra indicate that the non-sonicated dispersions are formed mainly by one population of DODAB vesicles, either in the gel (T
Assuntos
Compostos de Amônio Quaternário/química , Espectroscopia de Ressonância de Spin Eletrônica , Bicamadas Lipídicas/química , Lipossomos/química , Micelas , Estrutura Molecular , Sonicação , Marcadores de Spin , TermodinâmicaRESUMO
Similar to melanocyte stimulating hormone (alpha-MSH), its potent and long-acting analogue, [Nle(4), D-Phe(7)]alpha-MSH, when labeled with the paramagnetic amino acid probe 2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid (Toac), maintains its full biological potency, thus validating any comparative structural investigations between the two labeled peptides. Correlation times, calculated from the electron paramagnetic resonance signal of Toac bound to the peptides, and Toac-Trp distances, estimated from the Toac fluorescence quenching of the Trp residue present in the peptides, indicate a more rigid and folded structure for the potent analogue as compared to the hormone, in aqueous medium.
Assuntos
Óxidos N-Cíclicos/química , alfa-MSH/química , Animais , Bioensaio , Relação Dose-Resposta a Droga , Espectroscopia de Ressonância de Spin Eletrônica , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Conformação Proteica , Dobramento de Proteína , Estrutura Terciária de Proteína/fisiologia , Rana catesbeiana , Pigmentação da Pele/efeitos dos fármacos , Espectrometria de Fluorescência , Espectrofotometria , Triptofano/química , alfa-MSH/análogos & derivados , alfa-MSH/farmacologiaRESUMO
The cationic tridecapeptide alpha-melanocyte stimulating hormone (alpha-MSH) is known to interact with anionic vesicles of 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG), partially penetrating the lipid membrane. In the lipid liquid crystal phase, phospholipid derivatives spin labeled at the different C-atoms along the acyl chain, show that the peptide increases the bilayer packing at all depths. Parallel to that, there is an increase in the probe's isotropic hyperfine splittings, indicating that the peptide significantly decreases the membrane hydrophobic barrier. Accordingly, it is suggested that the increase in membrane packing yielded by alpha-MSH is partly due to a greater level of interchain hydration. This result is compared to the increase in packing and decrease in polarity yielded by cholesterol, and the absence of structural or polar alterations with Na+. The latter result shows that the peptide effect is not related to an increase of positive charges at the anionic vesicle surface. Alterations on the lipid bilayer polar profile measured by the nitroxide hyperfine splitting z component in frozen samples are shown to be different from those obtained at room temperature. However, it is shown here that a certain correlation can be drawn between the increase in polarity measured in frozen samples and the packing effect caused by the different molecules in the lipid gel phase.
Assuntos
Bicamadas Lipídicas/química , alfa-MSH/farmacologia , Ânions/química , Cátions/química , Fenômenos Químicos , Físico-Química , Colesterol/química , Espectroscopia de Ressonância de Spin Eletrônica , Técnicas In Vitro , Fluidez de Membrana/efeitos dos fármacos , Fosfatidilgliceróis/química , Sódio/química , Marcadores de Spin , alfa-MSH/químicaRESUMO
Recent literature reports an apparent decline in the incidence of neural tube defects throughout the world. A revision of stillbirth certificates and surgical reports of closure procedures for open neural tube defects was done in order to establish the incidence and its trend during a nine year period in Puerto Rico. The current prevalence of the syndrome was estimated using the death certificates in addition to the fore-mentioned surgical reports. Our results indicate that Puerto Rico carries probably the highest incidence of the US territories and that the trend is not declining one.