英语论文网

Body composition was analyzed using dual-energy X-ray absorptiometry (DEXA), a method that can accurately and rapidly assess body fat analysis. DEXA scan series was conducted using General Electric's Lunar Digital Prodigy Advance at the beginning and end of each phase in order to assess body composition including overall body fat and lean mass.

Analyses

Blood lipid analysis

Plasma T-C, TG, and HDL-C were analysed using a VITROS 350 autoanalyser. Plasma LDL-C concentrations were calculated using the Friedewald equation as described below:

LDL-C (mmol/L) =T-C-HDL-C-(TG/2.2) (Friedewald et al., 1972) (1)

Total apolipoprotein B (apoB-48 and apoB-100) was measured by the human apoB EIA kit (Cayman Chemical). This assay is based on the quantitative sandwich enzyme immunoassay technique. In summary, each well is pre-coated with a monoclonal antibody specific to apoB. Any apoB from serum introduced to the kit binds to this antibody. Serum samples were diluted 5000x using the sample diluent buffer provided.

To each well 100 ml of standard or sample was added and the plate was incubated at room temperature on an orbital shaker for 2 hrs to allow binding. The plate was then rinsed 4 times with the provided wash buffer and 100 ml of goat polyclonal apoB antibody was added. The plate was incubated at room temperature and shaken for another hour to detect the captured apoB. Following this, the plate was washed once again (4 times) and 100 ml of donkey anti-goat IgG/HRP-conjugated antibody was added to allow for ‘sandwich' recognition. After a third incubation on an orbital shaker for 1 hr at room temperature, the plate was washed for the final time (4 times) and 100 ml of chromogenic substrate TMB was added. The apoB concentration of the samples was determined by the enzymatic activity of the HRP. After 25 minutes, the plate was stopped with the 100 ml of the provided acidic stop solution, which changes the well colour from blue to yellow. This colour was then measured spectrophotometrically at 450 nm, using a microplate reader. The intensity of the colour is proportional to concentration of apoB in the wells (Absorbance μ [donkey a-goat HRP] μ [apoB]).

The absorbance of the plate blanks was subtracted from the absorbance of the standards and samples. The standards were plotted using linear regression and the samples concentration were determined by:

apoB (ng/mL) in sample = [A450- (Y-intercept)/Slope] x Dilution (2)

Concentrations were then multiplied by the dilution factor (5000x) and expressed as g/L.

Cholesterol fractional synthesis rate analysis

The rate of deuterium from body water incorporated into RBC membrane free cholesterol over day 42 to day 43 of each phase was taken as an indicator of cholesterol fractional synthesis rate (FSR). Therefore, deuterium enrichments were measured in both RBCs and plasma water. The deuterium enrichment of free cholesterol extracted from RBCs was analyzed in samples obtained at day 42 and day 43 o本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。