ObjectiveTo systematically evaluate the relationship between the-2548G/A polymorphism in the leptin gene and antipsychotic-induced weight gain (AIWG). MethodsLiterature for the relationship between the-2548G/A polymorphism in the leptin gene and AIWG was retrieved in electronic databases including PubMed, EMbase, CNKI and WanFang Data from establishment dates to June, 2013. Two reviewers independently screened studies according to the inclusion and exclusion criteria, extracted data and evaluated the methodological quality of the included studies. Then meta-analysis was performed using RevMan 5.2 software. ResultsA total of 7 case-control studies were included, involving 404 AIWG cases and 508 controls (patients with no significant changes of weight after taking antipsychotic drugs). The results of meta-analysis showed that, regarding the total population, the-2548G/A polymorphism of the leptin gene was not associated with AIWG (OR=1.16, 95%CI 0.70 to 1.93, P=0.57). After stratification analysis, according to Chinese or non-Chinese origin, the results showed that significant association was found between the-2548G/A polymorphism of leptin gene and AIWG for Chinese (OR=2.15, 95%CI 1.41 to 3.26, P=0.000 4) but not for non-Chinese (OR=0.69, 95%CI 0.45 to 1.07, P=0.10). ConclusionThe current evidence suggests that the-2548G/A polymorphism in the leptin gene is associated with increased risk of AIWG for Chinese. Due to limited quantity of the included studies, the aforementioned conclusion needs to be further validate by more high-quality and large-scale studies.
The AC impedance of human hepatoma SMMC-7721 cells were measured in our laboratory by Agilent 4294A impedance analyzer in the frequency range of 0.01-100 MHz. And then the effect of hematocrit on electrical impedance characteristics of hepatoma cells was observed by electrical impedance spectroscopy, Bode diagram, Nyquist diagram and Nichols diagram. The results showed that firstly, there is a frequency dependence, i.e., the increment of real part and the imaginary part of complex electrical impedance (ΔZ', ΔZ″), the increment of the amplitude modulus of complex electrical impedance (Δ|Z*|) and phase angle (Δθ) were all changed with the increasing frequency. Secondly, it showed cell volume fraction (CVF) dependence, i.e., the increment of low-frequency limit (ΔZ'0, Δ|Z*|0), peak (ΔZ″p, Δθp), area and radius (Nyquist diagram, Nichols diagram) were all increased along with the electric field frequency. Thirdly, there was the presence of two characteristic frequencies: the first characteristic frequency (fC1) and the second characteristic frequency (fC2), which were originated respectively in the polarization effects of two interfaces that the cell membrane and extracellular fluid, cell membrane and cytoplasm. A conclusion can be drawn that the electrical impedance spectroscopy is able to be used to observe the electrical characteristics of human hepatoma cells, and therefore this method can be used to investigate the electrophysiological mechanisms of liver cancer cells, and provide research tools and observation parameters, and it also has important theoretical value and potential applications for screening anticancer drugs.