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 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.

Objective To observe the relationship between serum lipid concentration profiles and thyroid function after thyroid hormone withdrawal( THW) in patients with differentiated thyroid carcinoma( DTC) .Methods Sixty-five post-operative DTC patients who prepared to receive radioiodine ablation were included in this study.Serum thyroid hormones ( TSH, FT4 , FT3 ) and lipid profile [ total cholesterol ( TC ) , triglycerides ( TG ) , low-density lipoprotein-cholesterol(LDL-C), and high-density lipoprotein-cholesterol(HDL-C)] levels were measured before and 3 weeks after THW.The relationship between serum lipid profile concentrations and thyroid hormone levels were measured.Results Before surgery, HDL-C level showed a significant positive correlation with TSH level(r=0.273, P=0.041), whereas other lipid profile did not show any significant correlation with thyroid hormones levels.Before THW, no correlation was observed between thyroid hormones and lipid profile.After 3 weeks′THW, the TC level was correlated with FT4 and FT3 levels(r were-0.321 and-0.415, respectively, both P<0.01).The LDL-C level was correlated with FT4 level(r=-0.347, P=0.005).The HDL-C level was significantly correlated with TSH, FT3, and FT4 levels (r were 0.342,-0.452, and-0.478, all P<0.01).The serum LDL-C level in patients with TSH above 50 mU/L(n=50) was higher than that in patients with TSH below 50 mU/L(n=15, P=0.001), while serum TC, TG and HDL-C levels were not significantly different between those two groups(P>0.05).Conclusion The serum lipid profile varies with the change of serum thyroid hormones after THW in postoperative DTC patients.

Objective:To evaluate the micro-push-out bond strengths of prefabricated glass fiber posts with poly-dopamine functionalized to root dentin using resin cements, contrasted with silane treatment. Methods:In the study, 30 glass fiber posts were randomly divided into 3 groups ( 10 posts in each group) for different surface treatments. Group 1, treated with poly-dopa; Group 2, treated with silane coupling agent for 60s;Group 3, no surface treatment (Control group). The 30 extracted human, single-rooted teeth were endodontically treated and a 9 mm post space was prepared in each tooth with post drills provided by the manufacturer. Following post cementation, the specimens were stored in distilled water at 37 ℃ for 7 days. The micro-push-out bond strengths were tested using a universal testing machine (0. 5 mm/min), and the failure modes were examined with a stereomicroscope. The data of the three groups were statistically analyzed using the one-way ANOVA test(α= 0. 05). Results:The bond strengths were (7. 909 ± 1. 987) MPa for Group 1, (5. 906 ± 0. 620) MPa for Group 2, and 4. 678 ± 0. 910 MPa for Group 3 . The bond strength of poly-dopamine group was significantly higher than that of the silane group (P<0. 05). Conclusion: Contrasted with silane treatment, surface poly-dopamine functionaliza-tion was confirmed to be a more reliable method for improving the bond strength of resin luting agents to fiber posts.

Objective To assess the toxicity risks of diphenylchlorarsine (DA) to environments, human beings and livestock. Methods Totally 120 mice were randomly divided into 6 groups and given DA by gastric gavage at the doses of 32, 30, 28, 26, 24, 22 mg/kg respectively for LD_(50) of DA in mice. The toxicity of DA in rat skin were evaluated by smearing 50 ?l DA at the concentrations of 140, 70, 35, 17.5, and 8.8 mg/ml to an area of 4 cm2, and that of eyes exposure was carried out by dropping 10 ?l DA of 140.7, 70, 7, 0.7 mg/ml in rat eyes. The counterpart skin area and eyes served as control. Results LD_(50) of DA in mice was 28.07 mg/kg, the estimated doses for no-observed-adverse-effect levels (NOELs) were 8.8 mg/ml (0.44 mg) to the skin and 0.7 mg/ml (0.014 mg) to the eyes respectively. Conclusion DA can induce the injuries on the liver, kidneys, esophagus and stomach. High concentration of DA can cause inflammation of the skin and lens opacification, even blind.

OBJECTIVETo study the effect of hyperthermia on expressions of multidrug resistance (MDR) genes in tongue squamous cell carcinoma cell line Tca8113 and its MDR cell line Tca8113/CBDEA and intracellular ADM concentration.

METHODSCell lines were hyperthermia-treated (42 degrees C for 0.5 h), 4 h and 24 h later real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) detected expressions of MDR relative genes (MDR1, MRPI, GST-pi) and HTS 7000 Plus Bio Assay Reader measured intracellular ADM concentration.

RESULTSExpressions of MDR1, MRPI, GST-'pi genes in Tca8113/CBDEA significantly descended at 4 h and 24 h post-hyperthermia (P < 0.01). Expressions of MDR1, MRP1 genes in Tca8113 significantly descended at 4 h and 24 h post-hyperthermia (P < 0.05), but there was not statistical difference between 4 h and 24 h post-hyperthermia. GST-pi expression had not statistical descent at 4 h, but there was significantly descend at 24 h post-hyperthermia (P < 0.01). Drug tolerance decreased and hyperthermia increased intracellular drug concentration in Tca8113/CBDEA and Tca8113 (P < 0.01).

CONCLUSIONHyperthermia enhance chemotherapy effect and reverse MDR genes expression in tongue squamous cell carcinoma cell line. It is suggested that hyperthermia could be used as a method to overcome MDR, which is worth more investigation.

In order to provide morphological data and theoretical basis for pig-to-human hepatic xenotransplantation, the difference in morphological parameters and vessel wall structural factors between human and porcine hepatic portal vein was studied. From human subjects and pigs of varying ages, hepatic portal veins were collected, paraffin-embedded and cut into sections. The histological structures were stained with HE, and elastin, collagen and smooth muscles were stained with Weigert, Aniline blue and orange G, respectively. Morphological parameters and relative contents of structural components were determined under microscopy and by computer image analysis system, respectively. The results showed that histological structures of human and porcine hepatic portal vein wall were similar. Caliber, wall thickness, lumen and wall area in pigs increased with age, all in linear correlation to months. Morphological parameters of 6- month-old pigs were similar to those of human. In pigs, collagen content increased gradually with months, elastin content remained relatively stable, smooth muscle content reached the peak at the 3rd month, and collagen/elastin (C/E) rose gradually. The contents of collagen and elastin in porcine hepatic portal vein wall were lower, while the content of smooth muscle was higher than in human, and C/E at the 5th and 6th month was similar to that in human. It is concluded that morphological parameters and contents of structural components of porcine hepatic portal vein vary with age. At the 6 month, its caliber, wall thickness, lumen and wall area are similar to those of human. There are differences in contents of structural components between human and pigs. However, in terms of C/E, mechanic properties of pigs at the 5th and 6th month mimic those of human, hence inosculation is viable in xenotransplantation between pigs and human.

Double-stranded oligomeric nucleotide encoding PEP-1 peptides was synthesized, prokaryotic expression pET15b-pep-1-p27mt recombinant constructed, E. coli BL21 (DE3)pLysS transformed and induced with IPTG to highly express fusion protein PEP-1-P27mt. Fusion protein with an N-terminal His-tag could be purified by Ni2+-resin affinity chromatography and identified by SDS-PAGE and Western blotting. Cultured EC9706 cells treated with PEP-1-P27mt revealed that PEP-1-P27mt was transduced into cells after 15 min and reached maximal intracellular concentrations in 2 h. PEP-1-P27mt of 1 μmol/L final concentration could most strongly suppress the growth. It was suggested that PEP-1 can carry P27mt across membrane, which provides a new biological protocol for using cyclin dependent kinase inhibitors p27mt in suppressing the growth of tumor cells.

In this paper we present an easily available method of intracellular dialysis via a microcatheter inserted into glass pipette during patch clamp experiment. An oblique hole through the glass pipette holder (above the lateral hole for cell-seal suction) is drilled, through which a microcatheter (O.D.=0.1 mm) made from the universal pipetter tip by hand-drawing passes and sticks out of the holder mouth in parallel with the Ag-AgCl electrode. With a syringe connected to the microcatheter, substitution of intracellular solution and intracellular dialysis of drugs can be achieved easily. Compared with repatch technique and intracellular solution substitution techniques used abroad, this method operates more easily and can produce more reliable results.
Dialysis ; instrumentation ; methods ; Equipment Design ; Microelectrodes ; Patch-Clamp Techniques ; instrumentation

Objective To investigate the association between serum betatrophin levels and insulin resistance in newly diagnosed type 2 diabetes patients. Methods A total of 31 healthy subjects (control group) and 35 newly-diagnosed type 2 diabetes patients(new T2DM group) were recruited. Serum betatrophin was detected with the methods of ELISA, insulin resistance was assessed with homeostasis model(HOMA-IR). Results The levels of betatrophin, free fatty acids, HOMA-IR, fasting plasma glucose, fasting serum insulin, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol were significantly higher in group B than those in group A (P<0.05). Conclusion Insulin resis-tance leads to elevated serum levels of betatrophin in patients with newly diagnosed type 2 diabetes.