[Regulatory effect of Bushenfang on the serum testosterone level of naturally aging rats and its mechanism].

OBJECTIVE: To study the regulatory effect of Bushenfang on the serum testosterone (T) level of naturally aging rats and its mechanism, in order to provide a theoretical and experimental basis for the clinical treatment of late onset hypogonadism (LOH) in males. METHODS: Thirty-two 18-month-old male SD rats were randomly divided into four groups of equal number, naturally aging model and low-, medium- and high-dose Bushenfang groups, and another eight 4-month-old rats were taken as normal controls. The rats of the aging model and normal control groups were treated with normal saline, while those of the low-, medium- and high-dose Bushenfang groups received intragastrically Bushenfang at 3.25, 7.50 and 15.00 g/kg, respectively, all for 3 weeks. Then the rats were sacrificed, the histomorphologic changes of the testis observed by HE staining, the serum T level measured by radioimmunoassay, and the expressions of the StAR protein, P450scc and 3beta-HSD I determined by RT-PCR. RESULTS: The number of Leydig cells was obviously increased after Bushenfang treatment. The levels of serum T were significantly higher in the low-, medium- and high-dose Bushenfang groups ([6.74 +/- 1.56] nmol/L, [8.50 +/- 1.99] nmol/L and [12.41 +/- 2.91] nmol/L) than in the model group ([3.48 +/- 0.75] nmol/L) (P < 0.05). The three Bushenfang groups also showed a remarkable elevation in the mRNA expressions of StAR (0.74 +/- 0.29, 0.83 +/- 0.32 and 1.35 +/- 0.50), P450scc (0.72 +/- 0.36, 1.023 +/- 0.30 and 1.41 +/- 0.37) and 3beta-HSD I (0.58 +/- 0.14, 0.72 +/- 0.07 and 0.85 +/- 0.18), as compared with the models (StAR: 0.44 +/- 0.09; P450scc: 0.33 +/- 0.05; 3beta-HSD I: 0.34 +/- 0.02), with significant differences in the StAR expression between the high-dose Bushenfang and the model groups, as well as in P450scc and 3beta-HSD I expressions between the medium- and high-dose Bushenfang and the model groups (P < 0.05). CONCLUSION: Bushenfang could improve the pathological status of testicular injury and increase the expression of testosterone synthetase, which might be the mechanism behind its regulatory effect on the serum T level of aging rats.

[Evaluation on the effects of education regarding road safety among middle school students].

OBJECTIVE: To evaluate the intervention effects for road traffic accident prevention among middle school students through understanding their knowledge, attitude and practice (KAP) on road safety. METHODS: Students in Grade 1 and Grade 2 from 7 junior and senior middle schools in Ji'nan city were selected as intervention group and students from a middle school in Hefei city served as control group. Education was provided to the intervention group and all the middle school students in Ji'nan city. Changes of KAP on road safety were measured for both groups during the follow-up period, and comparison on KAP for the two groups was carried statistically. RESULTS: The mean scores of road safety knowledge for intervention group improved significantly during the follow-up period (from 0.9 - 3.8), while these indices did not change much in the control group (from 0 - 0.2). Negative attitude on road safety was found in both groups, but less in the intervention group. More students started to admit that middle school students themselves should be responsible for most of the RTAs. Per week frequency of violating traffic rules did not improve, however during the follow-up period on both groups as still 75% to 80% of the students violating the traffic rules less than 2 times per week. Although three kinds and one kind of traffic rules violation seemed to have improved in the intervention group and in the control group, there were still two and three other kinds turned worse in the intervention and in the control group, respectively. CONCLUSION: Program on road safety education significantly improved the relative knowledge for middle school student and it exerted positive effects in road safety attitude to some extent. However, no significant effect was found in the improvement on their behavior. Education on road safety should be carried out in the early stage of childhood with newer and more effective intervention approaches.

[Risk factors on road traffic accidents in middle school students: a matched case-control study].

OBJECTIVE: To investigate the predictors of road traffic accidents (RTAs) in middle school students, a case-control study was designed to seek new clues for prevention and control on RTAs in this population. METHODS: Cases were 116 students who experienced RTAs from 2005/01/01 to 2005/12/31. 116 students were served as controls who were from the same class of the cases and matched by age and sex. Information on personal behavior, family conditions, and knowledge, attitude, practice (KAB) on road traffic of these children were collected and compared. Conditional logistic regressions were conducted to analyze the relationship between these factors and RTAs. RESULTS: Compared to the controls, the cases showed more negative attitude and risk-taking-behaviors especially in riding bicycle. However, knowledge on road safety showed less significant differences between case and control groups. The negative attitude and risk-taking-behaviors were independent risk factors for RTAs by logistic regression. In addition, distance from home to school that longer than 1000 m seemed a risk factors for RTAs, while high education levels among mothers was a protective factor. CONCLUSION: Road safety attitude and behavior, distance from home to school were the main influence factors for RTAs among middle school students. It seemed more important in improving the attitude and behavior on road safety than to enhance the knowledge for prevention and control of RTAs among middle school students.

Expression of cholera toxin B subunit and assembly as functional oligomers in silkworm.

The nontoxic B subunit of cholera toxin (CTB) can significantly increase the ability of proteins to induce immunological tolerance after oral administration, when it was conjugated to various proteins. Recombinant CTB offers great potential for treatment of autoimmune disease. Here we firstly investigated the feasibility of silkworm baculovirus expression vector system for the cost-effective production of CTB under the control of a strong polyhedrin promoter. Higher expression was achieved via introducing the partial non-coding and coding sequences (ATAAAT and ATGCCGAAT) of polyhedrin to the 5' end of the native CTB gene, with the maximal accumulation being approximately 54.4 mg/L of hemolymph. The silkworm bioreactor produced this protein vaccine as the glycoslated pentameric form, which retained the GM1-ganglioside binding affinity and the native antigenicity of CTB. Further studies revealed that mixing with silkworm-derived CTB increases the tolerogenic potential of insulin. In the nonconjugated form, an insulin : CTB ratio of 100 : 1 was optimal for the prominent reduction in pancreatic islet inflammation. The data presented here demonstrate that the silkworm bioreactor is an ideal production and delivery system for an oral protein vaccine designed to develop immunological tolerance against autoimmune diabetes and CTB functions as an effective mucosal adjuvant for oral tolerance induction.