RESUMO
The aim of our study was to conduct a case-control study in a Chinese postmenopausal population to evaluate the roles of the IGF-1 rs35767 and rs972936 polymorphisms on bone mineral density (BMD) levels and osteoporosis risk. A total of 272 consecutive postmenopausal women with a primary diagnosis of osteoporosis and 272 controls were enrolled in the study between 2012 and 2014. The polymerase chain reaction-restriction fragment length polymorphism method was used to genotype the rs35767 and rs972936 IGF-1 polymorphisms. By comparing the demographic characteristics between patients and controls, patients with osteoporosis were found to be more likely to have a habit of alcohol drinking (P = 0.023). Furthermore, the BMD levels of the L1-L4 vertebrae, femoral necks, total hips, and trochanters in patients with osteoporosis were significantly lower than those in controls. By conditional regression analysis, we found that the IGF-1 rs2288377 and rs972936 gene polymorphisms were not associated with the risk of osteoporosis (P < 0.05). However, the CT+TT genotype of rs35767 and the AG+GG genotype of rs972936 were significantly associated with lower BMD levels in the femoral neck. Overall, our study suggests that IGF-1 rs2288377 and rs972936 gene polymorphisms do not influence the risk osteoporosis.
Assuntos
Fator de Crescimento Insulin-Like I/genética , Osteoporose Pós-Menopausa/genética , Idoso , Povo Asiático/genética , Densidade Óssea/genética , Estudos de Casos e Controles , China , Feminino , Colo do Fêmur , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Genética Populacional , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Pós-Menopausa/genéticaRESUMO
The lateral film growth rate of CH4, C2H4, CO2, CH4 + C2H4, and CH4 + C3H8 hydrates in pure water were measured at four fixed temperatures of 273.4, 275.4, 277.4, and 279.4 K by means of suspending a single gas bubble in water. The results showed that the lateral growth rates of mixed-gas CH4 + C2H4 hydrate films were slower than that of pure gas (CH4 or C2H4) for the same driving force and that of mixed-gas CH4 + C3H8 hydrate film growth was the slowest. The dependence of the thickness of hydrate film on the driving force was investigated, and it was demonstrated that the thickness of hydrate film was inversely proportional to the driving force. It was found that the convective heat transfer control model reported in the literature could be used to formulate the lateral film growth rate v(f) with the driving force DeltaT perfectly for all systems after introduction of the assumption that the thickness of hydrate films is inversely proportional to the driving force DeltaT; i.e., v(f) = psiDeltaT(5/2) is correct and independent of the composition of gas and the type of hydrate. The thicknesses of different gas hydrate films were estimated, and it is demonstrated that the thicknesses of mixed-gas hydrate films were thicker than those of pure gases, which was qualitatively consistent with the experimental result.
