Objective To explore the possible immunological mechanism of laminarin sulfate in the prevention of experimental atherosclerosis. Methods Serum soluble interleukin 2 receptor (sIL-2R) , circulating immuno-complex, sub units of T lymphocyte, inter leukin-6(IL-6) , in-terleukin-8(IL-8), tumor necrosis factor-a (TNF-a) and lipid metabolism were determined by ELISA, RIA in rats and quails. Results The lipid metabolism and immunologic function were prominent disturbance in animals after feeding with high-lipid food. However, Laminarin sulfate has obvious regulating effects on above-mentioned index. Conclusions The mechanism of laminarin sulfate in the prevention of atherosclerosis might be closely related to the regulation of the disturbance of lipid metabolism and to the regulation of the immunologic function of the body.

Objective:To analyse the correlation between depression and hip fracture in the middle-aged and elderly population in the Chinese community.Methods:The study data were obtained from the China Health and Retirement Longitudinal Study (CHARLS) database. A total of 16,831 respondents from 12,400 households in the fourth national follow-up data in 2018 were selected as the research sample. The samples were divided into a training set and a test set at a ratio of 7∶3, and the test set data were used for internal validation. For external validation, 2,337 subjects recruited from the Institute of Orthopaedics, the First Affiliated Hospital of Zhejiang Chinese Medical University from 2018 to 2023 were selected as the survey subjects. The Center for Epidemiological Studies Depression Scale (CESD) was used to assess depression. CESD≥16 points were defined as depression, and CESD<16 points were defined as no depression. Binary logistic regression was used to gradually analyze the correlation between depression and hip fracture after adjusting for different covariates.Results:In the training set, statistically significant differences were observed between patients with and without hip fractures in terms of depression prevalence (χ 2=16.310, P<0.001), age (χ 2=9.417, P=0.009), education level ( P<0.001), marital status ( P=0.019), and place of residence ( P=0.035). In the testing set, statistically significant differences were found in depression prevalence (χ 2=10.130, P=0.001), gender (χ 2=4.368, P=0.037), education level ( P=0.013), and smoking history (χ 2=8.804, P=0.012). In the external validation set, significant differences were noted in depression prevalence (χ 2=337.885, P<0.001), age (χ 2=29.475, P<0.001), and smoking history ( P=0.020). After controlling for demographic characteristics, exercise, smoking and drinking history, binary logistic regression showed that the risk of hip fracture in depressed patients was 1.78 times higher in the training set ( OR=1.78, P<0.001), 2.73 times higher in the testing set ( OR=2.73, P=0.002), and 15.21 times higher in the external validation set ( OR=15.21, P<0.001) than that of non-depressed patients, indicating good internal and external validation results. Conclusion:Depression is an independent risk factor for hip fractures among middle-aged and elderly populations in Chinese communities. Early identification and active intervention for depression in this population can help reduce the risk of hip fractures.

Enterokinase is a class of serine proteases that specifically recognize the cleavage DDDDK sequences. Therefore, enterokinase has been widely used as a tool enzyme in the field of biomedicine. Currently, the expression level of enterokinase in Pichia pastoris is low, which hinders related practical applications. In this study, the effects of six different signal peptides SP1, SP2, SP3, SP4, SP7 and SP8 on the secretory expression of enterokinase in Pichia pastoris were studied. Compared with α-factor, SP1 significantly increased the secretory expression of enterokinase (from 6.8 mg/L to 14.3 mg/L), and the enterokinase activity increased from (2 390±212) U/mL to (4 995±378) U/mL in shaking flask cultures. On this basis, the enterokinase activity was further enhanced to (7 219±489) U/mL by co-expressing the endogenous protein Kex2. Moreover, the activity that the mutant strain with N-terminal fusion of three amino acids of WLR was increased to (15 145±920) U/mL with a high specific activity of (1 174 600±53 100) U/mg. The efficient secretory expression of enterokinase laid a foundation for its applications in near future.