An electrochemical sensor has been developed for the selective determination of chlortetracycline ( CTC) using the molecularly imprinted technique. A molecular imprinted polymer ( MIP) on the surface of a glassy carbon electrode ( GCE ) was prepared by electropolymerization of o-aminophenol ( OAP ) in the presence of CTC in the sodium perchlorate ( NaClO4 ) solution using cyclic voltammetry ( CV ) . The electrochemical performance of the sensor was studied by using differential pulse voltammetry ( DPV ) . A linear relationship between the peak current difference and the CTC concentration was found in the range of 2. 0×10-8-6. 1×10-7 mol/L with the detection limit of 1. 5×10-8 mol/L (3σ). After regeneration by washing with the mixture of methanol and sulfuric acid, the sensor showed excellent reproducibility and good stability. The MIP electrode exhibited almost no response to chloramphenicol and penicillin, and very weak responses to tetracycline and oxytetracycline, proving a good selectivity. Recoveries of standard addition measured in the actual samples of milk and chicken meat were between 86 . 4% -96 . 9%. Compared with the reported methods, this sensor showed a low detection limit, simple operation without derivatization, rapid response and low cost.

OBJECTIVE:To detect the contents of chlorogenic acid and rutoside in Saussurea involucrate,and to optimize the decoction and extraction technology of S. involucrate from different producing areas. METHODS:The contents of chlorogenic acid and rutoside in 10 batches of S. involucrate from different producing areas were determined by HPLC. L9(34)orthogonal experiment was used to optimize the water amount,decoction times and decoction time using comprehensive score of extraction transport rate of chlorogenic acid and rutoside as index. The verification test was also conducted. RESULTS:The contents of chlorogenic acid and rutoside in 10 batches of S. involucrate were 0.380%-0.546% and 0.334%-0.617%;the optimal decoction technology was as follows as the amout of crude material of S. involucrate 100 g,soaking for 20 min,decocting for 3 times,12,10 and 10 fold of water,decocting 45,30 and 30 min,respectively. The extraction transfer rates of chlorogenic acid and rutoside were 96.2%(RSD=2.66%,n=3)and 89.3%(RSD=3.31%,n=3)in verification test. CONCLUSIONS:For S. involucrate from different producing areas,the contents of effective components are different;optimized decoction and extraction technology is stable and feasible.

OBJECTIVETo investigate the impact of intravenous nutrition on plasma free amino acid spectrum and immune function for patients with sepsis.

METHODSForty severe sepsis patients were divided into two groups: Group B (amino acids + glucose + fat emulsion) and Group A (glucose + fat emulsion), 20 healthy individuals were enrolled as control group. The concentration of free amino acid and immune globulin were determined after 3 days.

RESULTSIn Group A, the levels of valine, leucine, isoleucine, alanine, serine, glutamic acid, histidine, proline and glycine were decreased; while the levels of threonine, cysteine, the ratio of phenylalanine and tyrosine (Phe/Tyr) were higher than those in control group. Meanwhile, peripheral blood IgM, complement C3 and C4 were decreased. In group B, all amino acid levels were improved, but the level of alanine, serine, glutamic acid, histidine and proline still lower than those in control group. Similarly, the levels of IgM, complement C3 and C4 in group B were increased.

CONCLUSIONIntravenous nutrition can support the basal requirement of amino acid and improve the immune function of patients with sepsis.

Adult ; Aged ; Amino Acids ; blood ; Complement C3 ; metabolism ; Complement C4 ; metabolism ; Female ; Humans ; Immunoglobulin M ; blood ; Male ; Middle Aged ; Parenteral Nutrition, Total ; Sepsis ; blood ; immunology ; therapy ; Time Factors

AIMTo develop a less toxic alternative for sandimmun neoral (Neoral). To study the preparation conditions and to compare its pharmacokinetic characteristics with Neoral.

METHODSPolylactide nanoparticles loaded cyclosporine A was prepared by solvent-nonsolvent method. Polylactide nanoparticles were administered by oral in a dosage of 15 mg.kg-1. The CyA concentration in whole blood sample was determined by HPLC.

RESULTSThe quantities of CyA, PLA and volume of acetone added had significant influence on the NP diameters. Under proper condition, the nanoparticles with diameters of 57.5 nm were obtained. The relative bioavailability in rats was 101.6%, with a smaller absorption rate (P < 0.05) and a smaller elimination rate (P < 0.1).

CONCLUSIONThe nanoparticles (diamater < 100 nm) with relative high bioavailability were prepared using solvent-nonsolvent method. It is suitable for further study.

Administration, Oral ; Animals ; Biological Availability ; Cyclosporine ; administration & dosage ; pharmacokinetics ; Delayed-Action Preparations ; Immunosuppressive Agents ; administration & dosage ; pharmacokinetics ; Male ; Nanotechnology ; Polyesters ; Random Allocation ; Rats ; Rats, Wistar

AIMTo study the preparation of hydroxypropyl methylcellulose phthalate (HPMCP) nanoparticles and compare its pharmacokinetic characteristics with Neoral.

METHODSHPMCP nanoparticles loaded cyclosporine A were prepared by solvent-nonsolvent method. CyA-HP50 nanoparticles, CyA-HP55 nanoparticles and Neoral were orally administered at the dosage of 15 mg x kg(-1) to rats. The CyA concentration in blood were determined by HPLC. Pharmacokinetic parameters were calculated by 3P97 program.

RESULTSThe concentration-time data of the three preparations were best fit by two compartment model. The relative bioavailability of CyA-HP50 and CyA-HP55 nanoparticles calculated by the AUC0-72 were 82.3% and 119.6%, bioequivalent to the reference of Neoral. The relative bioavailability of CyA-HP55 nanoparticles was 145.3% of CyA-HP50 nanoparticles.

CONCLUSIONCyA HPMCP nanoparticles could be prepared easily and reproducibly. It was found that the oral absorption of CyA can be increased by using the HPMCP nanoparticles.

Administration, Oral ; Animals ; Area Under Curve ; Biological Availability ; Cyclosporine ; administration & dosage ; pharmacokinetics ; Immunosuppressive Agents ; administration & dosage ; pharmacokinetics ; Male ; Methylcellulose ; administration & dosage ; analogs & derivatives ; Nanostructures ; Particle Size ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo construct a Mycobacterium tuberculosis DNA vaccine pVAX1/ESAT-6 plasmid and investigate its immunoreactivity.

METHODSThe ESAT-6 gene fragment amplified from Mycobacterium tuberculosis genome was inserted into pVAX1 vector to construct the recombinant plasmid pVAX1/ESAT-6, which was identified by restriction enzyme digestion and sequencing. The recombinant plasmid was transformed into Hela cells using Sofast® Transfection reagent, and the cellular expressions of ESAT-6 mRNA and protein were analyzed by RT-PCR and immunofluorescence assay, respectively. The recombinant plasmid pVAX1/ESAT-6 was also transfected into mouse by electronic pulse method, and the mouse serum IFN-γ level and anti-ESAT-6 IgG antibody level were detected by ELISA, mouse lymphocyte proliferation assessed with flow cytometry, and IFN-γ-secreting lymphocytes counted using ELISPOT.

RESULTSDouble restriction-enzyme digestion and sequencing showed that the inserted fragment in the recombinant plasmid pVAX1/ESAT-6 was identical to ESAT-6 gene with an inframe insertion. RT-PCR yielded the target band as expected on agarose gel, and immunofluorescence assay of the transfected cells showed specific green fluorescence signals. The mice transfected with the recombinant plasmid showed significantly elevated serum level of anti-ESAT-6 IgG antibody and increased serum IFN-γ level, spleen cell proliferation, and number of IFN-γ-secreting lymphocytes.

CONCLUSIONThe Mycobacterium tuberculosis DNA vaccine pVAX1/ESAT-6 plasmid we constructed can induce high levels of cellular and humoral immunoreactivity in mice.

Animals ; Antibodies, Bacterial ; blood ; Antibody Formation ; Antigens, Bacterial ; immunology ; Bacterial Proteins ; immunology ; Female ; Genetic Vectors ; HeLa Cells ; Humans ; Immunity, Cellular ; Immunity, Humoral ; Immunoglobulin G ; blood ; Interferon-gamma ; blood ; Mice ; Mice, Inbred BALB C ; Mycobacterium tuberculosis ; immunology ; Plasmids ; immunology ; Tuberculosis Vaccines ; genetics ; immunology ; Vaccines, DNA ; genetics ; immunology

BACKGROUNDCorticosteroid treatment of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) has been one of the most controversial clinical issues in critical care. Although the administration of high-dose corticosteroids does not benefit patients with early septic shock and ARDS, recent clinical trials have indicated that treatment with relatively low-dose corticosteroids (2 to 3 mg/kg/day of methylprednisolone or equivalent) may improve outcome when used for late ARDS or persistent septic shock. The underlying mechanism was not fully clarified. Whether the administration of corticosteroids can arrest neutrophil-driven organ injury once started remains to be elucidated.

OBJECTIVETo observe the effects of hydrocortisone (HC, 6 mg/kg) on oxygen free radicals (OFR) released by PMN and pulmonary pathological changes in rat ALI model induced by lipopolysaccharide (LPS), to investigate the possible mechanism through which corticosteroids exert protective effect on ALI.

METHODSA rat model of ALI was induced by peritoneal injection of 2 x 10(12) Escherichia coli/kg. Fifty-six rats were randomly divided into three groups: normal control group, LPS group and HC group (6 mg/kg). Samples were collected 2 h, 4 h and 6 h after giving LPS to LPS and HC group (6 h after giving normal saline in normal control group) to measure the level of OFR released by PMN using chemiluminescence method based on lumino, and to compae of pulmonary pathological changes among the three groups.

RESULTSPathological examination with light microscope in LPS group showed thickened pulmonary interstitia, inflammatory cell infiltration, edema and hemorrhage, which were in accordance with the features of ALI. There were significant differences in the release of OFR by PMN among the three groups (P < 0.01). The level of OFR released by PMN in LPS group was significantly higher than that of the control group, and continued to increase during the observation period (2 - 6 h after LPS). The release of OFR by PMN in HC group was significantly suppressed as compared with LPS group, which was peaked at 4 h after LPS injection (to 98.2%); there were also significant differences in the grades of ALI pathologic changes among the three groups (P < 0.01). The grades of ALI pathologic changes in LPS group were significantly increased when compared with the normal control group (P < 0.05) while significantly decreased in HC group as compared with LPS group (P < 0.05).

CONCLUSIONIt was demonstrated in the LPS induced ALI model that OFR might play an important role in onset of ALI. Intervening with HC (6 mg/kg) treatment could ameliorate the lung injury and exert significant and sustained suppression on the release of OFR by PMN, showing that HC has a protective effect on LPS induced ALI and its theraputic effect occurs possibly through suppression on the release of OFR by PMN.

Acute Lung Injury ; etiology ; immunology ; Animals ; Disease Models, Animal ; Free Radicals ; metabolism ; Glucocorticoids ; pharmacology ; Hydrocortisone ; pharmacology ; Lipopolysaccharides ; adverse effects ; Lung ; immunology ; pathology ; Mice ; Neutrophils ; drug effects ; metabolism

AIMTo study the preparation conditions and its oral pharmacokinetic characteristics of cyclosporine A (CyA) pH sensitive nanoparticles.

METHODSThe CyA pH sensitive nanoparticles were prepared by the quasi-emulsion solvent diffusion technique (QESD). Male Sprague-Dawley (SD) rats weighing (250 +/- 20) g were selected and randomly divided into five groups. The bioavailability of CyA from nanoparticles and Neoral microemulsion were assessed at a dose of 15 mg x kg(-1) by gavage. The concentration of CyA in whole blood samples was detected by HPLC to evaluate the relative bioavailability of CyA pH sensitive nanoparticles.

RESULTSThe blood concentration profiles of CyA pH sensitive nanoparticles in rats fitted to two compartment models using 3P87 pharmacokinetic calculation program. Compared with the Neoral microemulsion, the relative bioavailability of CyA was 94.8%, 115.2%, 113.6% and 132.5% for CyA-E100, CyA-L100, CyA-L100-55 and CyA-S100 nanoparticles respectively.

CONCLUSIONCyA-S100 nanoparticles was shown to significantly improve the oral bioavailability of CyA compared with Neoral microemulsion (P < 0.05). While there were no significant differences between Neoral microemulsion and other CyA pH sensitive nanoparticles. With these results, the potential of pH-sensitive nanoparticles for the oral delivery of CyA was confirmed. Furthermore, this formulation approach can be used to improve the oral bioavailability of other poorly soluble and poorly absorbable drugs.

Administration, Oral ; Animals ; Area Under Curve ; Biological Availability ; Cyclosporine ; administration & dosage ; pharmacokinetics ; Hydrogen-Ion Concentration ; Male ; Nanostructures ; Random Allocation ; Rats ; Rats, Sprague-Dawley

Objective: To study retrovirus (RV)-mediated transduction of gastric carcinoma cells with the herpes simplex virus thymidine kinase (HSV-tk) gene and the subsequent treatment with ganciclovir(GCV). Methods: The TK gene was transfected into human gastric carcinoma cell line MKN28 using HSV-TK that packed with PA317 cell, the sensitivity of MKN28TK cells to GCV was examined in vitro. Results: The retroviral-mediated HSV-TK gene can be transfected to MKN28 cells. The growth rate of MKN28 cells transfected with HSV-TK gene did not change. MKN28TK cells became significantly sensitive to GCV and had bystander effect. Conclusion: Transfection of gastric carcinoma with HSV-TK has higher transfection efficiency. MKN28TK cells are significantly sensitive to GCV.

Objective: To study retrovirus (RV)-mediated transduction of gastric carcinoma cells with the herpes simplex virus thymidine kinase (HSV-tk) gene and the subsequent treatment with ganciclovir(GCV). Methods: The TK gene was transfected into human gastric carcinoma cell line MKN28 using HSV-TK that packed with PA317 cell, the sensitivity of MKN28TK cells to GCV was examined in vitro. Results: The retroviral-mediated HSV-TK gene can be transfected to MKN28 cells. The growth rate of MKN28 cells transfected with HSV-TK gene did not change. MKN28TK cells became significantly sensitive to GCV and had bystander effect. Conclusion: Transfection of gastric carcinoma with HSV-TK has higher transfection efficiency. MKN28TK cells are significantly sensitive to GCV.