[Determination of the carboxyl content of oxidized starch by fourier transform infrared (FTIR) spectroscopy].

In the present study, the carboxyl content of oxidized starch was determined by FTIR spectroscopy. Standard curve was drawn in which the ordinate was carboxyl content determined by national standard method with the ratio of carbonyl absorbance to the key of C-H absorbance in FTIR spectroscopy as the abscissa. The ratio of absorbance of unknown oxidized starch tested by FTIR spectroscopy was obtained, The carboxyl content was calculated by standard curve, and then compared with the carboxyl content determined by national standard method, and the deviation is between 2% and 4%. In order to improve the accuracy of the experiment, standard sample was selected to draw standard curve to better ensure that the carboxyl content of the unknown oxidized starch is in the range of standard curve calculation limit, and deviates from the limit of standard curve. Compared with the carboxyl content determined by national standard method, testing with FTIR spectroscopy is simple, easy to operate, and of high efficiency and better accuracy. So, it is significant to forecast the carboxyl content of oxidized starch by FTIR spectroscopy.

Engineering single crystalline Mn3O4 nano-octahedra with exposed highly active {011} facets for high performance lithium ion batteries.

Well shaped single crystalline Mn3O4 nano-octahedra with exposed highly active {011} facets at different particle sizes have been synthesized and used as anode materials for lithium ion batteries. The electrochemical results show that the smallest sized Mn3O4 nano-octahedra show the best cycling performance with a high initial charge capacity of 907 mA h g(-1) and a 50th charge capacity of 500 mA h g(-1) at a current density of 50 mA g(-1) and the best rate capability with a charge capacity of 350 mA h g(-1) when cycled at 500 mA g(-1). In particular, the nano-octahedra samples demonstrate a much better electrochemical performance in comparison with irregular shaped Mn3O4 nanoparticles. The best electrochemical properties of the smallest Mn3O4 nano-octahedra are ascribed to the lower charge transfer resistance due to the exposed highly active {011} facets, which can facilitate the conversion reaction of Mn3O4 and Li owing to the alternating Mn and O atom layers, resulting in easy formation and decomposition of the amorphous Li2O and the multi-electron reaction. On the other hand, the best electrochemical properties of the smallest Mn3O4 nano-octahedra can also be attributed to the smallest size resulting in the highest specific surface area, which provides maximum contact with the electrolyte and facilitates the rapid Li-ion diffusion at the electrode/electrolyte interface and fast lithium-ion transportation within the particles. The synergy of the exposed {011} facets and the smallest size (and/or the highest surface area) led to the best performance for the Mn3O4 nano-octahedra. Furthermore, HRTEM observations verify the oxidation of MnO to Mn3O4 during the charging process and confirm that the Mn3O4 octahedral structure can still be partly maintained after 50 discharge-charge cycles. The high Li-ion storage capacity and excellent cycling performance suggest that Mn3O4 nano-octahedra with exposed highly active {011} facets could be excellent anode materials for high-performance lithium-ion batteries.

[Diagnosis of obscure gastrointestinal bleeding among different age groups by double balloon enteroscope].

OBJECTIVE: To investigate the diagnostic value of double balloon enteroscope (DBE) on obscure gastrointestinal bleeding(OGIB) and to analyze etiological characteristics among different age groups. METHODS: The clinical data of patients undergoing DBE due to OGIB in the Department of Gastroenterology in Renmin Hospital of Wuhan University from January 2007 to January 2012 were retrospectively analyzed and compared among different age groups. Patients were divided into the young group(age≤40, n=86), the middle age group(aged 41-59, n=81), and the elderly group (age≥60, n=49). The detection of bleeding origin by DBE was compared between different age groups. RESULTS: Diagnosis rates in young, middle age, elderly group were 83.7%(72/86), 87.7%(71/81), 81.6%(40/49) without statistical differences(P>0.05). Complication rates in the young, middle age, and elderly group were 1.2%(1/86), 2.5%(2/81), 2.0%(1/49) without statistic difference(P>0.05). The most common cause in young group was diverticulum/replica malformation while the most common location was ileum. The most common cause in both middle age and elderly group was tumor. CONCLUSIONS: DBE is an effective and safe method for diagnosis of OGIB among different age groups. Each age group has its etiological characteristics. Diagnosis and therapeutic strategy based on age-related characteristics is worthy of further investigation.

A new development of FG-CC' siRNA blocking interaction of Tim-1 and Tim-4 can enhance DC vaccine against gastric cancer .

BACKGROUND/AIMS: Dendritic cells (DCs) are professional antigen-presenting cells responsible for initiating of immune response. However, because of immune tolerance, it is difficult to induce long-term tumor-specific immune response in humans. This is probably because DCs, which combine with Th2 in the Tim-1/Tim-4 pathway, will induce Th2 to proliferation. METHODOLOGY: We have transfected siRNA of FG-CC' gene into DCs stimulated by gastric cancer lysate (lysate-FG-CC-siRNA group), FG-CC-siRNA will block FG-CC' loop,which plays an important role in interaction between Tim-1 and Tim-4. Their potential effect on gastric cancer immunotherapy is assessed by an experimental model. RESULTS: It was observed that lysate-FG-CC-siRNA had the strongest ability of adjusting balance on the Thl/Th2, as a result, these DCs can inhibit gastric cancer growth. In order to test the ability of FG-CC-siR-NA DCs to inhibit tumor growth, we immunized mice subcutaneously with DCs transfected with FG-CC-siR-NA plus tumor antigen. Compared with the control group, a significant inhibition of tumor growth was obvious for the group of lysate-FG-CC-siRNA DC. CONCLUSIONS: We have shown that FG-CC-siRNA blocks FG-CC'loop and significantly enhances the anti-tumor immunity in vitro and in vivo.

Combination DLL4 with Jagged1-siRNA can enhance inhibition of the proliferation and invasiveness activity of human gastric carcinoma by Notch1/VEGF pathway.

BACKGROUND/AIMS: To evaluate the effects of adenovirus- mediated gene transfer of DLL4 and Jagged1 siRNA on proliferation and invasion of SGC7901 cells by Notch/ VEGFR pathway. METHODOLOGY: Plasmid of DLL4 and Jagged1 siRNA were constructed and transfected into SGC7901 cells. siRNA and endostatin (VEGF inhibitor) were designed as the control group. The mRNA and protein expressions of DLL4 and Jagged1 were respectively detected with RT-PCR and western blotting. In order to find out the changes of proliferation and invasion power of SGC7901 cell lines, we analyzed the data by MTT, Boyden chamber and evaluated apoptosis of cell with flow cytometry. We treated BALB/C nude mice with DLL4 and Jagged1-siRNA, and tumor control rate (%) in nude mice was calculated. RESULTS: DLL4 and Jagged1 siRNA transfections specifically down-regulated the corresponding mRNA and protein levels in SGC7901 cells. The experiment of permeated artificial basal membrane showed that the invasion power of SGC7901 cell lines were on the decline after treatment of Ad-DLL4- Jagged1-siRNA (12.23±3.12 vs. 78.38±17.38, p<0.05). The values of 490nm wavelength light absorption were different in the five groups. The number of alive cells in the group of DLL4-Jagged1-siRNA was lower than others in the 6th d (0.77±0.01 vs. 3.00±0.11 p<0.05). The apoptosis rate of transfected DLL4 and Jagged1 group with FACS were 18.07%±0.98±1.78 and there were significant differences between treated and control groups (18.07%±0.98 vs. 1.08%±0.23, p<0.01). The tumor transplantation experiment in BALB/C nude mice showed that intratumoral injection of DLL4 and Jagged1 siRNA could inhibit tumor growth. CONCLUSIONS: DLL4 and Jagged1 siRNA gene therapy mediated by adenovirus may be useful for inhibiting growth and invasion of SGC7901 through a Notch/VEGFR pathway. These results provided a novel therapeutic target in preventing gastric cancer cell invasion and metastasis.

RhoA and RhoC -siRNA inhibit the proliferation and invasiveness activity of human gastric carcinoma by Rho/PI3K/Akt pathway.

AIM: To evaluate the effects of adenovirus-mediated gene transfer of RhoA siRNA and RhoC siRNA on proliferation and invasion of SGC7901 cells by Rho/PI3K/Akt pathway. METHODS: Plasmid of RhoA siRNA and RhoC siRNA were constructed and transfected into SGC7901 cells. siRNA and LY294002 (PI3K inhibitor) were designed as the control group. The mRNA and protein expressions of RhoA and RhoC were respectively detected with RT-PCR and western blotting. In order to find out the changes of proliferation and invasion power of SGC7901 cell lines, we analyzed the data by MTT, Boyden chamber and evaluated apoptosis of cell with flow cytometry. We treated BALB/C nude mice with RhoA and RhoC-siRNA, and tumor control rate (%) in nude mice was calculated. RESULTS: RhoA and RhoC siRNA transfections specifically down-regulated the corresponding mRNA and protein levels in SGC7901 Cells. The experiment of permeated artificial basal membrane showed that the invasion power of SGC7901 cell lines are on the decline after treatment of Ad-RhoA and RhoC-siRNA (12.64 +/-3.27 vs 87.38 +/- 17.38, P < 0.05). The values of 490 nm wavelength light absorption were different in the five groups. The number of alive cells in the group of RhoA and RhoC-siRNA was lower than others in the 6(th) d (0.71 +/- 0.01 vs 3.82 +/- 0,11 P < 0.05). The apoptosis rate of transfected RhoA and RhoC-siRNA group with FACS were 19.07% +/- 1.78 and there were significant differences between treated and control groups (19.07 +/- 1.78% vs 1.23 +/- 0.11%, P < 0.01). The tumor transplantation experiment in BALB/C nude mice showed intratumoral injection of RhoA or RhoC siRNA can inhibit tumor growth. CONCLUSION: RhoA and RhoC siRNA gene therapy mediated by adenovirus may be useful for inhibiting growth and invasion of SGC7901 through a PI3K/Akt pathway. These results provide a novel therapeutic target in preventing gastric cancer cell invasion and metastasis.

Disilver(I) rectangular-shaped metallacycles: X-ray crystal structure and dynamic behavior in solution.

Reaction of the ditopic semirigid ligand 1,2-bis(imidazolylmethyl)benzene (1,2-bImb) or the flexible ligand 1,4-bis(2-benzimidazolyl)butane (C4BIm) with AgX (X = ClO4-, BF4-, CF3CO2-) afforded five new complexes, namely, [Ag2(1,2-bImb)2](ClO4)2 (1), [Ag2(1,2-bImb)2](BF4)2 (2), [Ag2(1,2-bImb)2](CF3CO2)2.2CH3OH (3.2CH3OH), [Ag2(C4BIm)2](ClO4)2.2DMF (4.2DMF), and [Ag2(C4BIm)2](CF3CO2)2.2H2O (5.2H2O), all of which contain a centrosymmetric, rectangular-shaped cationic disilver(I) metallacycle [Ag2(L)2]2+. In 1-3, a pair of 1,2-bImb ligands takes on the syn conformation to connect two Ag(I) ions to give a compressed rectangle with a transannular Ag...Ag separation of 3.27-3.36 angstroms, whereas in 4 and 5, the pair of planar C4BIm ligands acts in the cis conformation to connect two Ag(I) ions to yield a normal rectangle with a transannular Ag...Ag separation of 7.67-7.91 angstroms. The anions form Ag...O or Ag...F weak interactions in 1-3 and O-H...O or N-H...O hydrogen bonds in 4 and 5 in crystal packing but exhibit no significant influence on the formation of the disilver(I) macrocycles. The solution structure and dynamic behavior of the complexes studied by electrospray ionization mass spectrometry, 1H NMR, and variable-temperature NMR indicated that the dynamic equilibrium between the [Ag2(L)2]2+ cation and the open-ring oligomers or other potential species occurs via solvent-assisted dissociative exchange. The metal-ligand exchange barrier was estimated to be 54.5 kJ mol(-1).

Expression of a novel apoptosis inhibitor-survivin in colorectal carcinoma.

AIM: To investigate the role of survivin expression in the pathogenesis of colorectal carcinoma. METHODS: Immunohistochemistry S-P method and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) were used to detect the expression of survivin and apoptotic cell in situ in colorectal cancerous tissues, para-cancerous tissues and normal tissues of 48 cases of colorectal carcinoma. RESULTS: The survivin positive unit (PU) was higher in cancerous tissues (38.76+/-5.14) than in para-cancerous (25.17+/-7.26) or normal tissues (0.57+/-0.03) (P<0.05). The apoptosis index (AI) of para-cancerous tissues was (7.51+/-2.63%) higher than cancerous tissues (4.65+/-1.76%). The expression of survivin was associated with pathological grade, lymph node metastasis and Dukes stage of colorectal carcinoma. CONCLUSION: Survivin expression may play an important role in carcinogenesis of colorectal carcinoma and may be associated with malignant biological behaviors of colorectal carcinoma.

Expression and purification of recombinant bone morphogenetic protein-2 in E.coli.

OBJECTIVE: To explore the method for producing human bone morphogenetic protein-2 (hBMP-2) by gene engineering techniques. METHODS: E.coli BL21 was transformed with recombinant plasmid pYR (pBV220-hBMP-2) under different conditions, and SDS-PAGE analysis was conducted to observe the effects of the activation status and induction time of the bacterium on the target protein expression. The inclusion bodies obtained from E.coli were purified by anion exchange chromatography DEAE and molecular sieve S-300, and the recombinant protein was renatured by dialyse. RESULTS: SDS-PAGE analysis showed a conspicuous band after induction signifying a new foreign protein with relative molecular mass of approximately 13 000. After activation of the bacteria when D600 was about 0.45, most efficient expression of rhBMP-2 was achieved which reached the peak 4 h after induction with heat. Implantation of the purified recombinant hBMP-2 resulted in proliferation of mesenchymal cells and new cartilage and bone formation, as shown by histological analysis 4 weeks after implantation. CONCLUSION: hBMP-2 produced by gene engineering techniques possesses the biological capacity of ectopic bone formation.