Objective:To prepare highly purified Staphylococcal enterotoxin B(SEB) by affinity chromatography and test its activities.Methods:Anti-SEB McAb(1D2) purified by precipitation method with caprylic acid was coupled to Sepharose 4B. And then the SEB was isolated using an affinity chromatography column. In addition, we analyzed the superantigen activity and antigen activity of SEB.Results:The purification efficiency of SEB was 60.71% by affinity chromatography. Its purity was higher than those of standard preparation and the SEB purified by ion change chromatography. At the same time, the purified SEB by affinity chromatography possesses favourable activities of superantigen and antigen.Conclusion:McAb affinity chromatography could be used for purification of SEB with high efficiency.

According to the results of quantum chemistry calculation and the present research status in the relationship between the structures and the functions of DT, the E154 in DT catalyzing domain was mutated to aspartic acid and arginine in order to study the effects of the alteration on the biological activities. By means of gene site-direct mutation, two mutated genes were prepared and the high performance expression was obtained in E.coli system. The results of toxcity studies indicated that the acute toxicity in guinea pig and cytotoxicities of mutant E154D increased slightly in compared with those of recombination wild toxin, and contrarily, those of E154R decreased obviously.

Objective To investigate the effects of high-fat diet on fatty acid metabolism, expression and activity of acetyl coenzyme A carboxylase (ACC) in skeletal muscle in rats. Methods Male Wistar rats aged 22-24 months were randomly divided into old control (OC) group and high-fat diet (HF) group. Male Wistar rats aged 4-5 months were selected as young control (YC) group. The rats in OC and YC groups were fed with basic diet, and the rats in HF group received high-fat diet. Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp technique. Skeletal muscle triglyceride was extracted and measured by an automated biochemistry analyzer. Long-chain acetyl coenzyme A (LCACoAs) were extracted from muscle and measured by a fluorospectrophotometer. Protein expressions of ACC and P-ACC were measured using SDS-PAGE and Western blot techniques. Results (1)Fasting blood glucose (FBG), fasting insulin (FINS) and free fatty acid were higher in OC group than in YC group and they increased significantly in HF group. Triglyceride (TG) and total cholesterol (TO levels were also elevated after high-fat feeding. (2)Glucose infusion rates (GIR) were reduced in OC group than in YC group, and decreased significantly after high-fat feeding. GIR was lower at the end of the 8th week than at the end of the 4th week in HF group. (3) Compared with YC group, skeletal muscle triglyceride and LCACoAs increased in OC group and increased significantly in HF group. (4)No alterations of protein levels of ACC in skeletal muscle were detected among three groups (P>0.05). The protein levels of P-ACC in skeletal muscle were lower in OC group, and much lower in HF group than in YC group (P<0.05 or P<0.01). Conclusions Compared with young rats, abnormal fatty acid metabolism and insulin resistance always exist in aged rats. High-fat feeding results in a significant increase in lipid content in skeletal muscle. Alterations of ACC activity may contribute to fat accumulation in skeletal muscle and insulin resistance.

Objective It is to observe the clinical effect of Wenxinkeli combined with metoprolol on frequent ventricular premature beat (FVEB).Methods234 patients with FVEB were randomly divided into the study group and control group.117 patients in the control group were treated with metoprolol combined with placebo, and 117 patients in the stduy group were treated with Wenxinkeli combined with metoprolol.4 weeks were a course of treatment.After four weeks, the heart rate variability, QT interval dispersion and 24h average heart rate of two groups were observed, and the clinical effect were evaluated.ResultsAfter 4 weeks of treatment, 5 cases in the study group and 7 cases in the control group were excluded.The efficiency of control group and study group were 89.29% and 79.09% (P<0.05), respectively.After treatment, the SDNN、SDANN、RMSSD and PNN50 of two groups were significantly higher than those before treatment(P<0.05), and the increase value of the study group was higher than that of the control group(P<0.05).After treatment, the QTd and QTcd of two groups were decreased than those before treatment(P<0.05), and the decreased value of the study group was higher than that of the control group(P<0.05).There was no significant change in the heart rate of the two groups before and after treatment.ConclusionWenxinkeli combined with metoprolol in the treatment of FVEB can prolong HRV, reduce QTd, improve the treatment effect, has no significant effect on the heart rate.

Objective:To investigate the prognostic value of platelet volume indices (PVIs), neutrophil/lymphocyte ratio (NLR) and the combination of these parameters for the neurological function of acute ischemic stroke (AIS) patients after intravenous thrombolysis.Methods:From January 2016 to January 2019, the data of 147 AIS patients with intravenous thrombolysis in the Emergency Department of Peking University People's Hospital who met the diagnostic criteria of AIS were retrospectively analyzed. The patients were divided into two groups according to modified rank in scale (MRS) score: MRS≤2 and MRS≥3. The general information, past medical history and laboratory examination results of each group were compared. Logistic regression analysis was used to analyze the risk factors of poor prognosis of neurological function in AIS patients with thrombolysis.Results:NLR ( OR=1.045, 95% CI: 1.032-2.350, P=0.032), mean platelet volume (MPV) ( OR=4.212, 95% CI:1.074-16.513, P=0.039), MPV×NLR/PLT ( OR=5.711, 95% CI: 1.342-24.298, P=0.018), platelet distribution width (PDW) ( OR=1.015, 95% CI: 1.001-2.372, P=0.032), and NIHSS score ( OR=1.266, 95% CI: 1.111-1.443, P<0.01) were related with poor prognosis neurological function of AIS patients with intravenous thrombolysis. Conclusions:MPV, NLR, MPV×NLR/PLT PDW and NIHSS scores are the risk factors for poor prognosis of neurological function in AIS patients with thrombolysis. MPV×NLR/PLT can predict the neurological severity of AIS after 3 months.

Objective To investigate the roles of glutamate signaling pathway in melanin transfer.MethodsEpidermal melanocytes and keratinocytes were isolated from human foreskin tissue followed by purification and primary culture.Immunofluorescence microscopy was conducted to observe the intracellular distribution of N-methy-D-aspartate receptor 1 (NMDAR1) and NMDAR2A in melanocytes.Some melanocytes were classified into 4 groups to be pretreated with MK801 (the NMDAR antagonist dizocilpine maleate) at 100μmol/L for 5 minutes followed by treatment with NMDA(an NMDAR agonist) at 100 μmol/L (MK801-pretreated group 1),pretreated with MK801 at 100 μmol/L for 1 hour followed by treatment with NMDA at 100μmol/L (MK801-pretreated group 2),treated with MK801 at 100 μmol/L for 5 minutes (MK801 group),treated with NMDA at 100 μmol/L for 5 minutes (NMDA group),respectively,then,confocal microscopy was performed to measure the intracellular calcium (Ca2+) concentration of the melanocytes.The distribution of β-tubulin was visualized by confocal microscopy in melanocytes treated with MK801 at 100 μmol/L for 24 hours.Some melanocytes and keratinocytes were cocultured with or without MK801 at 100 μmol/L for 24 or 48 hours,then,scaning microscopy was carried out to observe the junction structure between melanocytes and keratinocytes,and alkali method coupled with spectrophotometric analysis to determine melanin content in keratinocytes.Results The intracellular calcium concentration of melanocytes was decreased by MK-801,but increased by NMDA at 100 μmol/L,and the increase was blocked by the pretreatment with MK-801 for 5 minutes or 1 hour.After incubation with MK-801 at 100 μmol/L for 24 hours,a more intense staining for β-tubulin was observed around the nuclei of melanocytes.There was a significant reduction in the number of filopodia on the surface of and between melanocytes and keratinocytes after treatment with MK-801 at 100 μmol/L for 48 hours.Also,the content of melanin(represented as the absorbance value at 375 nm) transferred from melanocytes into keratinocytes was statistically reduced in coculture system treated with MK-801 at 100 μmol/L compared with that without treatment (0.158 ± 0.003 vs.2.203 ± 0.006,t =6.323,P ＜ 0.01 ).Conclusions The glutamate signaling pathway exerts a regulatory effect on intracellular calcium concentration of distribution of β-tubulin in,filopodia formation of melanocytes and melanin transfer between melanocytes and keratinocytes.

Objective To investigate the effects of high-fat diet on fatty acid metabolism in liver and insulin sensitivity in aged rats and to explore the mechanisms of insulin resistance associated with aging. Methods Male Wistar rats aged 22-24 months were randomly divided into old control (OC) group and high-fat diet (HF) group. Male Wistar rats aged 4-5 months were selected as young control (YC) group. The rats in OC and YC were fed with basic diet, and the rats in HF group received high fat diet. Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp technique. Extracted liver triglyceride was measured by an automated biochemistry analyzer. Results (1) Compared with YC group, fasting blood glucose(FBG), fasting insulin(FINS) and free fatty acid were increased in OC group and were increased significantly in HF group. Triglyceride(TG) and total cholesterol(TC) levels were also elevated in HF group. (2) Compared with YC group, glucose infusion rate (GIR) was reduced in OC group and was decreased significantly in HF group. GIR was lower at the end of the 8th week than that at the end of the 4th week in HF group. (3) Compared with YC group, liver triglyceride was increased in OC group and was increased significantly in HF group. Liver triglyceride was negatively correlated with GIR, and positively correlated with FBG. Conclusions Compared with young rats, abnormal fatty acid metabolism and insulin resistance always exist in aged rats. High-fat feeding results in a significant increase in lipid content in liver and more serious insulin resistance in aged rats. Lipid accumulation in liver may contribute to insulin resistance associated with aging and high-fat diet.

Objective To measure serum surfactant protein (SP) A and D levels in patients with interstitial lung disease associated with rheumatoid arthritis (RA).Methods Serum SP-A and SP-D levels of RA,RA-ILD patients and healthy controls were assessed using a sensitive enzyme-linked immunosorbent assay (ELISA).The relationship between SP-A and SP-D and RA-ILD was analyzed.The serum SP-A and SP-Dpositive rate was calculated for the three groups.The correlation between SP-A and SP-D with RF,anti-CCP,antinuclear antibody,antikeratin antibody,anti-perinuclear factor,C-reactive protein,erythrocyte sedimentation rate,were analyzed.Mean value of groups were compared with variance analysis,Spearmam rank correlation test was used for correlation analysis.Results The levels of serum SP-A in RA-ILD patients and RA patients as well as in healthy controls were [ (51.2±9.2),(25.9±2.6),( 15A±0.3 ) μg/L] respectively.The level of serum SP-D of the three groups was [ ( 42.5 ±8.1 ),(20.8 ± 1.5 ),( 16.6±0.8 ) μg/L ] respectively.The levels of serum SP-A and SP-D in patients with RA complicated with ILD were higher than those simple RA patients and healthy controls (P＜0.05).The levels of serum SP-A and SP-D in patients with RA were not significantly higher than those in healthy controls (P＞0.05).The positive rate of serum SP-A and SP-D in RA-ILD patients were significantly higher than those in simple RA patients and healthy controls.The positive rate of serum SP-D of RA-ILD patients was higher than that of SP-A.The levels of serum SP-A and SP-D in patients with RA complicated with ILD were correlated positively with age,C-reactive protein.The level of serum SP-D was correlated positively with RF,anti-CCP,antikeratin antibody.There was no correlation between the level of serum SP-A and SP-D with RA-ILD and antinuclear antibody,antiperinuclear factor,erythrocyte sedimentation rate.Conclusion The levels of serum SP-A and SP-D are correlated with RA-ILD and may be useful markers for ILD in patients with RA.These two paramenters may be helpful to early diagnosis of RA-ILD.The Serum SP-D levels are more sensitive in predicting the development of RA-ILD than other parameters and can help in assessing the severity of lung damage.

ObjectiveTo assess the cause of tadalafil failure and the feasibility of successfully rechallenging nonresponding patients.Methods A total of 80 consecutive erectile dysfunction ( ED ) patients who claimed poor response to tadalafil were enrolled into the study.A self-administered tadalafil-use questionnaire composed of eight questions was applied to assess how they had used tadalafil.Subjects were given thorough instruction based on individual answers and four doses of tadalafil 20mg.After a 2-week follow-up,end point efficacy of rechallenge was evaluated using the sexual encounter profile (SEP),which was recommended by international advisory panel in 2004.ResultsA total of 45 subjects had one or more areas of major suboptimal use of tadalafil:21.2％ did not know that sexual stimulation was necessary for tadalafil to work,87.5％ attempted to use tadalafil less than four times,57.5％ took a maximal dose less than 20 mg,and 84％ felt nervous or anxious.Of the 65 patients undergoing tadalafil rechallenge,30 patients answered “yes” to SEP2 and SEP3.The response rate to rechallenge was 46.2％ ( 30/65 ).ConclusionsInappropriate use of tadalafil was major cause of tadalafil non-pesponse.The efficacy of tadalafil could be improved to a better extent by education of patients.

Objective: To investigate the effect of diabetes on the intensity of sarcoplasmic reticulum Ca2+-ATPase (SERCA2a)-SUMOylation and SERCA2a activity of myocardium in experimental rats.
Methods: The 8 weeks old SD rats were divided into 2 groups, Diabetic group, with diet-induced type 2 diabetic rats and Control group, with normal rats. The systolic and diastolic cardiac functions were evaluated by echocardiography and left ventricular pressure measurement. The intensity of SERCA2a-SUMOylation was examined by co-immunoprecipitation and SUMOylation kit.
Results: Compared with Control group, Diabetic group had decreased systolic and diastolic cardiac functions, especially for diastolic function;decreased SERCA2a protein expression and intensity of SUMOylation;decreased SUMOylation E2 (Ubc9 ) protein expression. The protein levels of SUMO1, SAE1 and SAE2 were similar between 2 groups.
Conclusion: The intensity of SERCA2a-SUMOylation and Ubc9 decreased in diabetic myocardium which implies that SERCA2a-SUMOylation and Ubc9 were closely related to the damage of diabetic myocardium in experimental rats.