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Manieri W, Franchini L, Raeber L, Dai S, Stritt-Etter AL, Schürmann P. N-terminal truncation of the variable subunit stabilizes spinach ferredoxin:thioredoxin reductase. FEBS Lett 2003; 549:167-70. [PMID: 12914945 DOI: 10.1016/s0014-5793(03)00811-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The variable subunit of spinach ferredoxin:thioredoxin reductase (FTR) has an extended N-terminus compared to FTRs from other sources and this was proposed to contribute to the instability of the protein. We constructed two N-terminal truncation mutants of recombinant FTR by removing 16 or 24 residues from the variable subunit. The mutant proteins are readily expressed and show half-saturation values (S(0.5)) for ferredoxin and thioredoxin f comparable to WT. However, truncation increases significantly their stability. Using the stabilized FTR an exposed Cys on its thioredoxin contact surface could be substituted without altering its properties, whereas the replacement of an active site Cys by Ser completely destabilized the protein.
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127
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Dai S, Sio ST, Tam KC, Jenkins RD. Rheology and Aggregation Behavior of Hydrophobically Modified Urethane Ethoxylate in Ethylene Glycol−Water Mixtures. Macromolecules 2003. [DOI: 10.1021/ma025728+] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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128
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Song T, Dai S, Tam K, Lee S, Goh S. Aggregation behavior of two-arm fullerene-containing poly(ethylene oxide). POLYMER 2003. [DOI: 10.1016/s0032-3861(03)00107-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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129
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Dai S, Tam KC, Jenkins RD. Dynamic Light Scattering of Semi-Dilute Hydrophobically Modified Alkali-Soluble Emulsion Solutions with Varying Length of Hydrophobic Alkyl Chains. MACROMOL CHEM PHYS 2002. [DOI: 10.1002/macp.200290004] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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130
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Zhang ZT, Konduru M, Dai S, Overbury SH. Uniform formation of uranium oxide nanocrystals inside ordered mesoporous hosts and their potential applications as oxidative catalysts. Chem Commun (Camb) 2002:2406-7. [PMID: 12430463 DOI: 10.1039/b204987b] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Highly dispersed uranium oxide nanocrystals supported on ordered mesoporous silica matrixes with large surface areas and porosities have been synthesized via a co-assembly methodology; the preliminary catalysis tests showed that these materials have a high catalytic activity for the thermal oxidation of volatile organic compounds (VOCs).
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131
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Xu W, Dai S, Toth LM, Del Cul GD, Peterson JR. Green Upconversion Emission from Er3+ Ion Doped into Sol-Gel Silica Glasses under Red Light (647.1 nm) Excitation. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100013a013] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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132
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Dai S, Toth LM, Del Cul GD, Metcalf DH. Visible and near-IR spectroscopic studies of uranium(IV) oxychloride in a MgCl2-KCl melt. Inorg Chem 2002. [DOI: 10.1021/ic00105a066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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133
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Pan Q, Petit-Frére C, Dai S, Huang P, Morton HC, Brandtzaeg P, Hammarström L. Regulation of switching and production of IgA in human B cells in donors with duplicated alpha1 genes. Eur J Immunol 2001; 31:3622-30. [PMID: 11745382 DOI: 10.1002/1521-4141(200112)31:12<3622::aid-immu3622>3.0.co;2-h] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
IgA is the predominant immunoglobulin class synthesized in humans and can be subdivided into two subclasses, IgA1 and IgA2, each encoded by a separate gene and differentially expressed depending on age and anatomical localization of the producing cells. Duplication of the alpha1 gene is frequently observed in selected populations. As this duplication may serve to enhance IgA-mediated immunity, we determined its effect on switching and production of IgA in human B cells. We developed a nested PCR strategy, involving sequencing the switch (S) alpha2 region, the only human S region not sequenced to date, to assess the proportion of cells switching to IgA1 and IgA2 in vivo. Our results show that there is no difference in the serum and salivary levels of IgA1 and IgA or rate of switching to IgA1 and IgA between normal donors and individuals carrying alpha1 gene duplications, suggesting involvement of a regulatory step in the production of IgA.
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134
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Mueller WH, Dai S, Labarthe DR. Tracking body fat distribution during growth: using measurements at two occasions vs one. Int J Obes (Lond) 2001; 25:1850-5. [PMID: 11781767 DOI: 10.1038/sj.ijo.0801832] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2001] [Revised: 05/15/2001] [Accepted: 06/13/2001] [Indexed: 01/05/2023]
Abstract
OBJECTIVE To investigate whether within-individual variation is a factor in the generally reported poor tracking of central body fat distribution (CBFD) during development and whether two measurements of CBFD during each measurement occasion would improve the estimate of tracking over time. METHODS A longitudinal study compared the results of two measurements of body fat (BF) and CBFD during each measurement occasion to the results of one measurement of BF and CBFD during each occasion every 4 months over 1-3 y. A total of 345 boys and 333 girls in three age cohorts of 8, 11 and 14 y at baseline were examined. BF variables were: body mass index (BMI); fat mass and percentage body fat from bioelectrical impedance; two skinfold sums; and abdominal circumference. CBFD variables were: waist/hip and waist/thigh ratios; conicity; and log upper-lower skinfold ratio. RESULTS Three-year tracking of BF varied from 0.79 to 0.90 for one- and from 0.81 to 0.93 for two-occasion measurements showing no apparent sex- or cohort-effects. Three-year tracking of CBFD was lower than that of BF (0.68-0.75), but improved significantly with two-occasion measurements (0.75-0.82). CONCLUSIONS Within-individual variation is a significant factor in reported low tracking of CBFD in childhood. Estimates of tracking currently in the literature may underestimate the predictive value of CBFD, possibly because this research has used one-occasion measurement. The increased use of two-occasion measurement should significantly improve the tracking of CBFD during development and provide a more realistic understanding of its predictive value.
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135
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Burleigh M, Dai S, Barnes C, Xue Z. ENHANCED IONIC RECOGNITION BY A FUNCTIONALIZED MESOPOROUS SOL-GEL: SYNTHESIS AND METAL ION SELECTIVITY OF DIAMINOETHANE DERIVATIVE. SEP SCI TECHNOL 2001. [DOI: 10.1081/ss-100107910] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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136
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Wang Q, Wang K, Dai S, Yang Y, Chen Y, Mo Z. [Regulation on the immunological effect of mogrosides in mice]. ZHONG YAO CAI = ZHONGYAOCAI = JOURNAL OF CHINESE MEDICINAL MATERIALS 2001; 24:811-2. [PMID: 15575165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
OBJECTIVE To investigate the cellular immunological effect of mogrosides in mice. METHODS Mogrosides was administered to normal or CTX-induced immunosuppressive mice, and their macrophage function and T lymphocyte proliferation were detected. RESULTS Mogrosides could promote phagocytosis and T lymphocyte proliferation significantly in the CTX-induced immunosuppressive mice, but not in the normal mice. CONCLUSION The results suggested that mogrosides had certain up-regulation on cellular immunity in the CTX-induced immunosuppressive mice.
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137
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Dai S, Tam KC. Isothermal Titration Calorimetry Studies of Binding Interactions between Polyethylene Glycol and Ionic Surfactants. J Phys Chem B 2001. [DOI: 10.1021/jp0110354] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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138
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Dai S, Tam KC, Jenkins RD. Binding Characteristics of Hydrophobic Ethoxylated Urethane (HEUR) and an Anionic Surfactant: Microcalorimetry and Laser Light Scattering Studies. J Phys Chem B 2001. [DOI: 10.1021/jp010672r] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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139
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Zhang Z, Dai S. Preparation and characterization of novel inorganic-organic mesoscopic ordered composites with bridges formed by coordination compounds. J Am Chem Soc 2001; 123:9204-5. [PMID: 11552846 DOI: 10.1021/ja0158556] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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140
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Zhang Q, Xiong Y, Li D, Dai S. [A simple and rapid procedure for detection of DNA damage caused by Aldicarb]. HUAN JING KE XUE= HUANJING KEXUE 2001; 22:126-8. [PMID: 11769219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
A simple and rapid procedure for detection of low levels DNA damage caused by Aldicarb was developed and compared with some other methods. In the original position the gel was set in high-pH buffer to run electrophoresis after the diluent of bacteria or fragmentized organ was added into hole of agarose gel directly and cells were treated with detergent and high alkaline condition. The impact of Aldicarb to biological individual or ecosystem was assessed according to the quantity of DNA and the extent of DNA migration.
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141
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Wu L, Zhang H, Zhu H, Zhang Z, Zhuang Y, Dai S. [Sulfa-drug wastewater treatment with anaerobic/aerobic process]. HUAN JING KE XUE= HUANJING KEXUE 2001; 22:87-90. [PMID: 11769237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Sulfa drug wastewater was treated with anaerobic/aerobic process. The removal ratios of TOC reached about 50% in anaerobic phase and about 70% in aerobic phase respectively, while volume loading rate of TOC was about 1.2 kg/(m3.d) in anaerobic phase and about 0.6 kg/(m3.d) in aerobic phase. Removal of TOC in anaerobic phase was attributed to the reduction of sulfate.
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142
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Koffman MD, Dai S. Cholesterol screening. BUSINESS AND HEALTH 2001; 19:42. [PMID: 11569315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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143
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Dai S, Tam KC, Li L. Isothermal Titration Calorimetric Studies on Interactions of Ionic Surfactant and Poly(oxypropylene)−Poly(oxyethylene)− Poly(oxypropylene) Triblock Copolymers in Aqueous Solutions. Macromolecules 2001. [DOI: 10.1021/ma010329k] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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144
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Dai S, Best S, St John M. Bartonella henselae neuroretinitis in cat scratch disease. THE NEW ZEALAND MEDICAL JOURNAL 2001; 114:360-1. [PMID: 11587306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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145
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Wang P, Dai S, Waezsada SD, Tsao AY, Davison BH. Enzyme stabilization by covalent binding in nanoporous sol-gel glass for nonaqueous biocatalysis. Biotechnol Bioeng 2001; 74:249-55. [PMID: 11400098 DOI: 10.1002/bit.1114] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A unique nanoporous sol-gel glass possessing a highly ordered porous structure (with a pore size of 153 A in diameter) was examined for use as a support material for enzyme immobilization. A model enzyme, alpha-chymotrypsin, was efficiently bound onto the glass via a bifunctional ligand, trimethoxysilylpropanal, with an active enzyme loading of 0.54 wt%. The glass-bound chymotrypsin exhibited greatly enhanced stability both in aqueous solution and organic solvents. The half-life of the glass-bound alpha-chymotrypsin was >1000-fold higher than that of the native enzyme, as measured either in aqueous buffer or anhydrous methanol. The enhanced stability in methanol, which excludes the possibility of enzyme autolysis, particularly reflected that the covalent binding provides effective protection against enzyme inactivation caused by structural denaturation. In addition, the activity of the immobilized alpha-chymotrypsin was also much higher than that of the native enzyme in various organic solvents. From these results, it appears that the glass-enzyme complex developed in the present work can be used as a high-performance biocatalyst for various chemical processing applications, particularly in organic media. Published by John Wiley & Sons
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146
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Petruccelli S, Dai S, Carcamo R, Yin Y, Chen S, Beachy RN. Transcription factor RF2a alters expression of the rice tungro bacilliform virus promoter in transgenic tobacco plants. Proc Natl Acad Sci U S A 2001; 98:7635-40. [PMID: 11390974 PMCID: PMC34720 DOI: 10.1073/pnas.121186398] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/16/2001] [Indexed: 11/18/2022] Open
Abstract
The promoter from rice tungro bacilliform badnavirus (RTBV) is expressed only in phloem tissues in transgenic rice plants. RF2a, a b-Zip protein from rice, is known to bind to the Box II cis element near the TATA box of the promoter. Here, we report that the full-length RTBV promoter and a truncated fragment E of the promoter, comprising nucleotides -164 to +45, result in phloem-specific expression of beta-glucuronidase (GUS) reporter genes in transgenic tobacco plants. When a fusion gene comprising the cauliflower mosaic virus 35S promoter and RF2a cDNA was coexpressed with the GUS reporter genes, GUS activity was increased by 2-20-fold. The increase in GUS activity was positively correlated with the amount of RF2a, and the expression pattern of the RTBV promoter was altered from phloem-specific to constitutive. Constitutive expression of RF2a did not induce morphological changes in the transgenic plants. In contrast, constitutive overexpression of the b-ZIP domain of RF2a had a strong effect on the development of transgenic plants. These studies suggest that expression of the b-Zip domain can interfere with the function of homologues of RF2a that regulate development of tobacco plants.
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147
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Dai S, Liu G, Qian Y, Cheng X. The sorption behavior of complex pollution system composed of aldicarb and surfactant--SDBS. WATER RESEARCH 2001; 35:2286-2290. [PMID: 11358309 DOI: 10.1016/s0043-1354(00)00491-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The behavior of complex pollution system in soil composed of aldicarb, a carbamate pesticide, and sodium dodecylbenzenesulfonate (SDBS), an anionic surfactant, was studied by the experiment of shaking sorption balance. The range of concentration of aldicarb and SDBS was 0.4-5.0 and 1-1000 mg/kg of dried soil, respectively. Linear sorption isotherm was well fitted for these two chemicals. SDBS can decrease the sorption of aldicarb in soil remarkably. While the concentration of SDBS increased from 0 to 1000 mg/kg, the linear sorption coefficient can be decreased by 50%. But aldicarb showed no effect on the sorption of SDBS in experiment. In addition the mechanism of the effect of SDBS on sorption of aldicarb was discussed.
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148
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Zhang X, Chen J, Peng Q, Wang D, Ma W, Dai S, Chen D. [Analysis of the lineshape of laser frequency modulation]. GUANG PU XUE YU GUANG PU FEN XI = GUANG PU 2001; 21:257-262. [PMID: 12947640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this paper, we analyze the dependence of the output signal spectral lineshape and intensity on the modulation, waveform and modulation index in first- and second-harmonic detection of triangle modulation, square demodulation and saw modulation square demodulation. The signal lineshape in the case of saw modulation, square demodulation is quite different from, whereas the signal lineshape in the case of triangle modulation, square demodulation is similar to that in traditional sine modulation, sine demodulation. Experiments of tunable IR laser frequency modulation absorption spectrum of methane are also done to verify the theoretical analysis. Then we reach a conclusion; the lineshape and intensity of frequency modulation spectrum can be influenced by modulation waveform, demodulation waveform and modulation index. Calculation results can be used to choose better experimental parameters and optimize experimental designs.
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149
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Dai S, Tam KC, Jenkins RD. Microstructure of Dilute Telechelic Associative Polymer in Sodium Dodecyl Sulfate Solutions. Macromolecules 2001. [DOI: 10.1021/ma0100807] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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150
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Nie Y, Li Y, Sha W, Dai S, She Q, Wu H. [Effect of octreotide on intragastric pH in patients with duodenal ulcer bleeding]. ZHONGHUA YI XUE ZA ZHI 2001; 81:520-2. [PMID: 11809113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To evaluate the effect of octreotide on the intragastric pH of patients with duodenal ulcer bleeding during the period of 24 hours and to observe if it can advance the effect of hemostasis by endoscopic injection of epinephrine. METHODS Twenty-four patients with duodenal ulcer bleeding were randomly divided into three groups, eight in each. Patients in group 1 received an intravenous injection of 0.1 mg of octreotide followed by continuous intravenous drip of octreotide at a constant speed of 25 microg/h for 24 hours. The patients in group 2 received an intravenous injection of 0.1 mg of octreotide followed by continuous intravenous drip of octreotide at a constant speed of 42 microg/h for 24 hours. The patients in group 3 received an intravenous injection of 40 mg of omeprazole followed by continuous intravenous drip of omeprazole at a constant speed of 8 mg/h for 24 hours. Intragastric pH was continuously recorded with a pH meter. The patients with active ulcer bleeding was treated with injection of epinephrine via endoscope and then received intravenous drip of octreotide (with the same dosage as in group 1, n = 42) or omeprazole (with the same dosage as in group 3, n = 54) for 72 hours and were given omeprazole (20 mg Bid). RESULTS The mean and median intragastric pH values among the patients in group 2 treated by a larger dosage of octreotide (6.7 +/- 0.5 and 6.9 +/- 0.4) were similar to those in the group 3 treated by omeprazole (6.8 +/- 0.4 and 7.0 +/- 0.4). There was no statistically significant difference between these two groups in percentage of intragastric pH above 4, 6, and 7 The mean and median of intragastric pH among the patients in group 1 treated by a smaller dosage of octreotide were statistically significantly smaller (5.2 +/- 0.5 and 5.4 +/- 0.4) than those in the omeprazole group. There was no statistically significant difference between octreotide treatment and omeprazole treatment in terms of volume of blood transfusion (0.7 +/- 0.5 vs. 0.6 +/- 0.4 L), rebleeding rate (11.6% vs. 12.9%), emergency operation rate (7.1% vs. 3.7%), and mortality (2.3% vs. 3.7%). CONCLUSION Octreotide effectively inhibits the secretion of gastric acid. However, the dosage in common use clinically fails to increase the intragastric pH to the best situation needed for effective hemostasis. Only a large dosage (1.10 mg/d) works.
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