Aim To summarize the principles, applications and future development in oxygen radical absorbance capacity (ORAC) assay. Methods The ORAC assay method use Sodium Fluorescein as fluorescent probe, AAPH as free radical initiator, and results are expressed as Trolox equivalents. Results This method has several advantages compared with other methods in linear responses with concentration, specificity, precision, accuracy and ruggedness. Conclusion The ORAC assay has been widely accepted and largely applied to the assessment of free radical scavenging capacity of pure compounds, biological samples, plant and food extracts.

Objective To evaluate the effects of enteral immunonutrition on cell immunity level and clinical efficacy in patients with severe tuberculosis. Methods Sixty patients with severe tuberculosis were admitted to the department of tuberculosis intensive care unit of Hangzhou Red Cross Hospital from June 2015 to June 2017, and they were randomly divided into a conventional enteral nutrition group (EN group) and a enteral immunonutrition group (EIN group), each group 30 cases. Based on the patients' gastrointestinal tolerance condition, the EN group was treated with therapies of normal nutrition support, anti-tuberculosis, anti-infection, etc.; the EIN group was treated with enteral immunonutrition (TPF-T), and simultaneously with anti-tuberculosis, anti-infection, etc. therapies according to the disease situation. The target energy maintained at 104.6 kJ·d-1·kg-1and the therapeutic course was 14 days in the two groups. The levels of interleukins (IL-6, IL-10) and interferon-γ (IFN-γ), white blood cell count (WBC), C-reactive protein (CRP), procalcitonin (PCT), cell immune indexes (T cell subgroup CD4+, CD8+) were observed before treatment and on day 14 after treatment in the patients of two groups; the changes of acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score before treatment and after treatment and 28-day mortality rate were recorded in the two groups. Results After treatment, the levels of WBC, CRP, PCT were obviously lower than those before treatment, while the levels of IL-6, IFN-γ, CD4+in the two groups were significantly higher than those before treatment, and the changes of the EIN group were more significant than those in the EN group [WBC (×109/L): 8.0±3.1 vs. 10.0±2.4, CRP (mg/L): 30.3±9.1 vs. 45.8±6.6, PCT (μg/L): 2.2±1.8 vs. 4.3±2.2, IL-6 (mg/L): 182.53±8.52 vs. 168.42±7.62, IFN-γ (mg/L): 32.52±3.5 vs. 25.41±2.6, CD4+: 0.56±0.06 vs. 0.45±0.08, all P < 0.05]. The level of CD8+after treatment in the two groups was higher than that before treatment (the EN group: 0.28±0.06 vs. 0.27±0.07, the EIN group: 0.27±0.08 vs. 0.26±0.09), the APACHE Ⅱ scores in the two groups were lower than those before treatment (the EN group: 11±6 vs. 18±4, the EIN group: 10±3 vs. 17±6), the 28-day mortality in the EIN group was lower than that in the EN group [13.3% (4/30) vs. 16.7% (5/30)], no statistical significant difference in CD8+, APACHE Ⅱscore, 28-day mortality between the two groups being found (all P > 0.05). Conclusion Enteral immunonutrition can improve the level of cell immunity and decrease the degree of inflammatory response, and increase the clinical curative effect in patients with severe tuberculosis.