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Gao D, Wagner AH, Fankhaenel S, Stojanovic T, Schweyer S, Panzner S, Hecker M. CD40 antisense oligonucleotide inhibition of trinitrobenzene sulphonic acid induced rat colitis. Gut 2005; 54:70-7. [PMID: 15591506 PMCID: PMC1774378 DOI: 10.1136/gut.2003.029587] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 05/17/2004] [Accepted: 06/03/2004] [Indexed: 01/23/2023]
Abstract
BACKGROUND CD154/CD40 interactions play a pivotal role both in humoral and cellular immune responses. Their involvement in the pathogenesis of chronic inflammatory bowel disease (IBD) has been revealed by increased expression of CD40 and CD154 in the inflamed mucosa of patients and the therapeutic effects of anti-CD154 antibodies in experimental colitis. Because of adverse side effects however, the use of such antibodies in patients with IBD may be limited. AIMS An alternative approach to blocking CD154/CD40 interactions by employing a CD40 antisense oligonucleotide (ODN) was explored. RESULTS After sequencing of the rat CD40 gene, five antisense ODNs were designed, of which one (rAS3) effectively downregulated CD40 expression in rat vascular smooth muscle cells as well as the subsequent changes in gene expression in response to CD40 stimulation. The therapeutic potency of rAS3 was evaluated in the 2,4,6-trinitrobenzene sulphonic acid (TNBS) induced colitis model of the rat. Single intracolonic injection of a liposomal formulation of rAS3 either prior to or post colitis induction markedly suppressed the inflammatory reaction in these animals monitored both macroscopically and microscopically over one week, while application of a scrambled control ODN had no such effects. Moreover, reverse transcription-polymerase chain reaction analyses revealed reduced expression of vascular cell adhesion molecule 1, interleukin 12 p40, and monocyte chemoatractive protein 1 in the inflamed mucosa, which in turn may have contributed to the decrease in leucocyte infiltration judged by immunohistochemistry. CONCLUSIONS These results suggest that CD40 antisense ODNs effectively interfere with CD154/CD40 interactions in vivo and, therefore, may provide a novel approach to the treatment of patients with chronic IBD.
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MESH Headings
- Animals
- CD40 Antigens/genetics
- CD40 Antigens/metabolism
- CD40 Ligand/metabolism
- Cells, Cultured
- Colitis/chemically induced
- Colitis/immunology
- Colitis/prevention & control
- Crohn Disease/chemically induced
- Crohn Disease/immunology
- Crohn Disease/prevention & control
- Drug Design
- Gene Expression Regulation/immunology
- Immunity, Mucosal
- Intestinal Mucosa/immunology
- Liposomes
- Male
- Muscle, Smooth, Vascular/immunology
- Muscle, Smooth, Vascular/metabolism
- Oligonucleotides, Antisense/administration & dosage
- Oligonucleotides, Antisense/genetics
- Oligonucleotides, Antisense/therapeutic use
- Rats
- Rats, Wistar
- Transfection
- Trinitrobenzenesulfonic Acid
- Vascular Cell Adhesion Molecule-1/metabolism
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177
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Morley N, Smolentsev S, Munipalli R, Ni MJ, Gao D, Abdou M. Progress on the modeling of liquid metal, free surface, MHD flows for fusion liquid walls. FUSION ENGINEERING AND DESIGN 2004. [DOI: 10.1016/j.fusengdes.2004.07.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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178
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Zhao X, Kinouchi Y, Yasuno E, Gao D, Iritani T, Morimoto T, Takeuchi M. A new method for noninvasive measurement of multilayer tissue conductivity and structure using divided electrodes. IEEE Trans Biomed Eng 2004; 51:362-70. [PMID: 14765709 DOI: 10.1109/tbme.2003.820403] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper outlines a new method for measuring multilayer tissue conductivity and structure by using divided electrodes, in which current electrodes are divided into several parts. Our purpose is to estimate the multilayer tissue structure and the conductivity distribution in a cross section of the local tissue by using bioresistance data measured noninvasively. The effect of the new method is assessed by computer simulations using a typical two-dimensional (2-D) model. In this paper, the conductivity distribution in the model is analyzed based on a finite difference method (FDM) and a steepest descent method (SDM). Simulation results show that the conductivity values of skin, fat, and muscle layers can be estimated with an error of less than 0.1%. When random noise at various levels is added to the measured resistance values, estimates of the conductivity values for skin, fat, and muscle layers are still reasonably precise: their root mean square errors are about 1.06%, 1.39%, and 1.61% for 10% noise. In a 2-D model, increasing the number of divided electrodes permits simultaneous estimates of tissue structure and conductivity distribution. Optimal configuration for divided electrodes is examined in terms of dividing pattern.
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179
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Zheng GD, Chen TB, Gao D, Luo W. Dynamic of lead speciation in sewage sludge composting. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2004; 50:75-82. [PMID: 15580997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A large-scale sewage sludge composting experiment was conducted to develop an understanding of changes that occur to Pb chemical speciation, distribution and bio-availability during the course of composting. The four-stage Tessier sequential extraction method was employed to investigate the dynamics of heavy metal Pb speciation (exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter and sulphides, residual) during the course of sewage sludge composting. The concentrations of the total Pb and the five Pb fractions concentrations were increased during the whole stage of compost. However, the percentages of Pb distribution with respect to total Pb were changed in the following manner: exchangeable, bound to Fe-Mn oxides and bound to carbonates Pb with respect to total Pb were increased, while the percentages of bound to organic matter and sulphides, and residual Pb with respect to total Pb were decreased during composting. The data showed that the quantity of Pb in the less toxic portion, such as consisting of organic matter and sulphides bound and residual Pb, was increased, and that the contamination and bio-availability of heavy metal Pb in sewage sludge was reduced during the composting process.
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180
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Proctor MH, Moore LL, Gao D, Cupples LA, Bradlee ML, Hood MY, Ellison RC. Television viewing and change in body fat from preschool to early adolescence: The Framingham Children's Study. Int J Obes (Lond) 2003; 27:827-33. [PMID: 12821969 DOI: 10.1038/sj.ijo.0802294] [Citation(s) in RCA: 261] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To prospectively examine the relation between television watching and body fat change in children from preschool to early adolescence. METHODS In a longitudinal study, 106 children were enrolled during preschool years (mean age 4.0 y) and followed into early adolescence (mean age 11.1 y). Parents completed an annual questionnaire on the child's television and video habits. Body mass index (BMI), triceps skinfolds, and sum of five skinfolds were recorded yearly at annual clinic visits. Longitudinal statistical analyses were carried out using mixed modeling procedures to control for potential confounding by a number of factors. RESULTS Television watching was an independent predictor of the change in the child's BMI, triceps, and sum of five skinfolds throughout childhood. Its effect was only slightly attenuated by controlling for the baseline body fat, level of physical activity (as measured repeatedly by Caltrac accelerometer), percent of calories from fat, total calorie intake, or the parents' BMI or education. By age 11, children who watched 3.0 h or more of television per day had a mean sum of skinfolds of 106.2 mm, compared with a mean sum of skinfolds of 76.5 mm for those who watched less than 1.75 h per day (P=0.007). Furthermore, the adverse effect of television viewing was worse for those children who were also sedentary or had a higher-fat diet. CONCLUSIONS Children who watched the most television during childhood had the greatest increase in body fat over time. Healthy lifestyle education designed to prevent obesity and its consequences should target television-watching habits of children.
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181
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Mayo SC, Miller PR, Wilkins SW, Davis TJ, Gao D, Gureyev TE, Paganin D, Parry DJ, Pogany A, Stevenson AW. Applications of phase-contrast X-ray microscopy in an SEM. ACTA ACUST UNITED AC 2003. [DOI: 10.1051/jp4:20030140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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182
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Gao D, Morley N, Dhir V. Numerical study of liquid metal film flows in a varying spanwise magnetic field. FUSION ENGINEERING AND DESIGN 2002. [DOI: 10.1016/s0920-3796(02)00266-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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183
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Stevenson AW, Gao D, Gureyev TE, Davis TJ, Wilkins SW. Hard X-ray tomography with a microfocus source and including phase contrast. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302087135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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184
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Wilkins SW, Mayo SC, Miller PR, Davis TJ, Gureyev TE, Paganin D, Pogany A, Stevenson AW, Gao D, Parry DJ. Quantitative X-ray projection ultramicroscopy using a scanning electron microscope. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302095338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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185
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Mayo SC, Miller PR, Wilkins SW, Davis TJ, Gao D, Gureyev TE, Paganin D, Parry DJ, Pogany A, Stevenson AW. Quantitative X-ray projection microscopy: phase-contrast and multi-spectral imaging. J Microsc 2002; 207:79-96. [PMID: 12180954 DOI: 10.1046/j.1365-2818.2002.01046.x] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We outline a new approach to X-ray projection microscopy in a scanning electron microscope (SEM), which exploits phase contrast to boost the quality and information content of images. These developments have been made possible by the combination of a high-brightness field-emission gun (FEG)-based SEM, direct detection CCD technology and new phase retrieval algorithms. Using this approach we have been able to obtain spatial resolution of < 0.2 micro m and have demonstrated novel features such as: (i) phase-contrast enhanced visibility of high spatial frequency image features (e.g. edges and boundaries) over a wide energy range; (ii) energy-resolved imaging to simultaneously produce multiple quasi-monochromatic images using broad-band polychromatic illumination; (iii) easy implementation of microtomography; (iv) rapid and robust phase/amplitude-retrieval algorithms to enable new real-time and quantitative modes of microscopic imaging. These algorithms can also be applied successfully to recover object-plane information from intermediate-field images, unlocking the potentially greater contrast and resolution of the intermediate-field regime. Widespread applications are envisaged for fields such as materials science, biological and biomedical research and microelectronics device inspection. Some illustrative examples are presented. The quantitative methods described here are also very relevant to projection microscopy using other sources of radiation, such as visible light and electrons.
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186
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Gao D, Lu Y, Lu Y, Wang Y, Zhang B, Wu B. Significance of HER-2/neu expression in ovarian epithelial tumours. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 2002; 31:268-70. [PMID: 12475446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To investigate expression of Her-2/neu (c-erbB-2) and its significance in ovarian epithelial tumors. METHODS 106 specimens and clinical history of ovarian epithelial tumors were collected including 54 cases of malignant, 33 cases of borderline and 19 benign cases. There were 19 cases of stages I and II and 35 cases of stages III and IV in ovarian carcinoma and all borderline malignant cases were stage I according to FIGO's standard. Immunohistochemical staining for Her-2/neu was performed by LSAB method. RESULTS The positives rates of Her-2/neu of benign, borderline and malignant tumors were 47.4% (9/19), 84.8% (28/33,), and 85.2% (46/54), respectively. Both borderline and malignant cases were found to have higher expression of Her-2/neu than those of benign cases (P < 0.02 and P < 0.01) respectively. Overexpression of Her-2/neu showed in 14/54 (25.9%) of malignant cases, 3/33 (9.1%) of borderline, and none of benign cases. Overexpression of Her-2/neu in malignant tumors cases with metastasis was higher than those without metastasis (P < 0.001). CONCLUSION Overexpression of Her-2/neu is associated with biological aggressiveness of ovarian cancer.
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187
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Takeshita S, Inoue N, Gao D, Rikitake Y, Kawashima S, Tawa R, Sakurai H, Yokoyama M. Lysophosphatidylcholine enhances superoxide anions production via endothelial NADH/NADPH oxidase. J Atheroscler Thromb 2002; 7:238-46. [PMID: 11521688 DOI: 10.5551/jat1994.7.238] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Reactive oxygen species (ROS) including superoxide anions (O2(-)) play a key role in atherogenesis, and endothelial cells have the ability to generate ROS. To investigate the enzymatic sources of ROS and the effects of lysophosphatidylcholine (LPC), an atherogenic lipid, we measured ROS production in cultured bovine aortic endothelial cells (BAECs) by the lucigenin-enhanced chemiluminescence (CL) method and electron spin resonance (ESR). BAEC homogenates had the enzymatic activity of NADH/NADPH oxidase. BAECs cultured on microcarrier beads generated O2(-) under basal conditions. The inhibition of NADH/ NADPH oxidase by diphenylene iodonium (DPI) significantly attenuated O2(-) production, whereas no inhibitors of other oxidases suppressed it. Although LPC enhanced O2(-) production approximately 3.1-fold, its action was suppressed by DPI. Tyrosine kinase inhibitors significantly attenuated LPC-induced O2(-) production. ESR with DMPO demonstrated that LPC increased the formation of the DMPO-hydroxyl adduct in dose- and time-dependent manners. These data suggest that the basal production of O2(-) in endothelial cells is mainly mediated by the NADH/NADPH oxidase system and that LPC activates this oxidase to enhance O2(-) production through a tyrosine kinase-dependent pathway. The enhancement of ROS production by LPC is probably involved in its atherogenic property.
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188
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Mathias RS, Mathews CH, Machule C, Gao D, Li W, Denbesten PK. Identification of the calcium-sensing receptor in the developing tooth organ. J Bone Miner Res 2001; 16:2238-44. [PMID: 11760837 DOI: 10.1359/jbmr.2001.16.12.2238] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Calcium (Ca2+) is a critical component of tooth enamel, dentin, and the surrounding extracellular matrix. Ca2+ also may regulate tooth formation, although the mechanisms for such action are poorly understood. The Ca2+-sensing receptor (CaR) that is expressed in the parathyroid gland, kidney, bone, and cartilage has provided a mechanism by which extracellular Ca2+ can regulate cell function. Because these tissues play an important role in maintaining mineral homeostasis and because Ca2+ is hypothesized to play a crucial role in tooth formation, we determined whether the CaR was present in teeth. In this study, using immunohistochemistry, CaR protein was detected in developing porcine molars localized in the predentin (pD), early secretory-stage ameloblasts, maturation-stage smooth-ended ameloblasts (SA), and certain cells in the stratum intermedium. CaR protein and messenger RNA (mRNA) were detected also in an immortalized ameloblast-like cell line (PABSo-E) using immunofluorescence, reverse-transcription polymerase chain reaction (RT-PCR), and Northern analysis. Based on the observation that the CaR is expressed in cultured ameloblasts, we determined whether increments in medium Ca2+ concentration could activate the intracellular Ca2+ signal transduction pathway. In PABSo-E cells, increasing extracellular Ca2+ in the medium from 0 (baseline) to 2.5mM or 5.0 mM resulted in an increase in intracellular Ca2+ above baseline to 534 +/- 69 nM and 838 +/- 86 nM, respectively. Taken together, these results suggest that the CaR is expressed in developing teeth and may provide a mechanism by which these cells can respond to alterations in extracellular Ca2+ to regulate cell function and, ultimately, tooth formation.
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189
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Yuan J, Xu X, Gao D, Shi G. [Weak signal detection in every heart cycle]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 2001; 18:515-9. [PMID: 11791295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
In this article, a new approach is introduced to lowering the myo-electronic noise in weak ECG signals. We use artificial neural network to make the noise be white, and then we adopt an adaptive filter of which the reference signal is achieved by extracting from other ECG cycle. The outcome is the reduction of both white noise and non-white noise in ECG signal. Satisfactory results have been achieved by using this method in the experiment of late potential detection.
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190
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Gardner SC, Grunwald GK, Rumsfeld JS, Mackenzie T, Gao D, Perlin JB, McDonald G, Shroyer AL. Risk factors for intermediate-term survival after coronary artery bypass grafting. Ann Thorac Surg 2001; 72:2033-7. [PMID: 11789789 DOI: 10.1016/s0003-4975(01)03217-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Risk factors for short-term mortality after coronary artery bypass grafting are well established, but little is known about risk factors for intermediate-term mortality. METHODS We analyzed the outcomes of 11,815 patients undergoing coronary artery bypass grafting in one of the 43 cardiac surgery programs of the Department of Veteran Affairs. Risk factors for intermediate- and short-term mortality were determined using Cox proportional hazards regression models. Effects of risk factors during these two periods were explicitly compared. RESULTS We found important differences in mortality risk-factor sets between the intermediate- and short-term periods after coronary artery bypass grafting. The majority of predictors of intermediate-term mortality were noncardiac-related variables, whereas the majority of predictors of short-term mortality were cardiac-related variables. Impaired functional status, chronic obstructive pulmonary disease, and renal dysfunction had greater effects in the intermediate-term period. Previous heart operation, angina class III or IV, previous myocardial infarction, and preoperative use of an intraaortic balloon pump had greater effects in the short-term period. CONCLUSIONS The risk factors for intermediate-term mortality identified in this study can augment preoperative risk assessment and counseling of patients. Clinicians should be aware of the importance of noncardiac-related variables as predictors of mortality in the intermediate-term period after coronary artery bypass grafting.
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191
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Basye J, Trent JO, Gao D, Ebbinghaus SW. Triplex formation by morpholino oligodeoxyribonucleotides in the HER-2/neu promoter requires the pyrimidine motif. Nucleic Acids Res 2001; 29:4873-80. [PMID: 11726697 PMCID: PMC96684 DOI: 10.1093/nar/29.23.4873] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Triplex-forming oligonucleotides (TFOs) are good candidates to be used as site-specific DNA-binding agents. Two obstacles encountered with TFOs are susceptibility to nuclease activity and a requirement for magnesium for triplex formation. Morpholino oligonucleotides were shown in one study to form triplexes in the absence of magnesium. In the current study, we have compared phosphodiester and morpholino oligonucleotides targeting a homopurine-homopyrimidine region in the human HER2/neu promoter. Using gel mobility shift analysis, our data demonstrate that triplex formation by phosphodiester oligonucleotides at the HER-2/neu promoter target is possible with pyrimidine-parallel, purine-antiparallel and mixed sequence (GT)-antiparallel motifs. Only the pyrimidine-parallel motif morpholino TFO was capable of efficient triple helix formation, which required low pH. Triplex formation with the morpholino TFO was efficient in low or no magnesium. The pyrimidine motif TFOs with either a phosphodiester or morpholino backbone were able to form triple helices in the presence of potassium ions, but required low pH. We have rationalized the experimental observations with detailed molecular modeling studies. These data demonstrate the potential for the development of TFOs based on the morpholino backbone modification and demonstrate that the pyrimidine motif is the preferred motif for triple helix formation by morpholino oligonucleotides.
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192
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Berrocal MJ, Badr IH, Gao D, Bachas LG. Reducing the thrombogenicity of ion-selective electrode membranes through the use of a silicone-modified segmented polyurethane. Anal Chem 2001; 73:5328-33. [PMID: 11721937 DOI: 10.1021/ac010375i] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The susceptibility of segmented polyurethanes (SPUs) to in vivo oxidative cleavage and hydrolysis constitutes a drawback in the use of these materials in the fabrication of implantable devices. The introduction of poly(dimethylsiloxane) (PDMS) groups into the polymer main chain has been previously reported to enhance the stability of SPUs. Herein, we evaluated the use of BioSpan-S, a silicone-modified SPU, in the design of membranes for cation-selective electrodes. The resulting electrodes exhibited good potentiometric response with all of the tested ionophores (valinomycin, sodium ionophore X, and nonactin). The obtained selectivity coefficients meet the selectivity requirements for the determination of sodium and potassium in blood. Moreover, as reflected by SEM studies, membranes prepared with BioSpan-S showed less adhesion of platelets than membranes prepared with conventional poly(vinyl chloride) (PVC). These results lead to the conclusion that BioSpan-S would be an appropriate candidate for the fabrication of implantable ion-selective electrodes.
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193
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Zhao W, Liu Y, Gao D. [Effects of aspiration of airway dead space on blood gases and respiratory mechanics in acute hypercapnia model dogs]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 2001; 24:643-6. [PMID: 16136899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
OBJECTIVE To establish the method of aspiration of airway dead space (ASPIDS) and evaluate the effects of ASPIDS on elimination of CO2 and improvement of ventilation efficiency. METHODS Using self-designed ASPIDS device, physiological parameters such as PaCO2, P(peak), P(pause), end expiratory carbon dioxide pressure (PaCO2), lung statistic compliance (Cst), respiratory resistance (Re) and hemodynamics in two animal groups of conventional mechanical ventilation (CMV) and hypercapnia (HC) were observed by applying tracheal gas insufflation (TGI 4.0 L/min) and ASPIDS (4.0 L/min). RESULTS ASPIDS significantly decreased PaCO2 level, enhanced CO2 elimination and maintained PaCO in normal range while decreased VT by 30%, the elimination of CO2 of ASPIDS was superior to that of TGI. ASPIDS significantly decreased airway pressure in both animal groups . P(et)CO2 and Re levels significantly decreased after ASPIDS. ASPIDS showed no influence on Cst, hemodynamics and oxygenation. CONCLUSIONS The ASPIDS device is a simple and practical adjunct method to mechanical ventilation, it can more effectively decrease PaCO2 than TGI, and maintain lower airway pressure.
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194
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Xu J, Stevenson AW, Gao D, Tykocinski M, Lawrence D, Wilkins SW, Clark GM, Saunders E, Cowan RS. The role of radiographic phase-contrast imaging in the development of intracochlear electrode arrays. Otol Neurotol 2001; 22:862-8. [PMID: 11698810 DOI: 10.1097/00129492-200111000-00026] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study describes the application of a new radiographic imaging modality, phase-contrast radiography, to in vitro human temporal bone imaging and investigates its use in the development of new electrode arrays for cochlear implants. BACKGROUND The development of perimodiolar electrode arrays for cochlear implants requires detailed information from postoperative radiologic assessment on the position of the array in relation to the cochlear structures. Current standard radiographic techniques provide only limited details. MATERIALS AND METHODS Nucleus standard electrode arrays and perimodiolar Contour electrode arrays were implanted into the scala tympani of 11 human temporal bones. Both conventional and phase-contrast radiographs were taken of each temporal bone for comparative purposes. RESULTS Phase-contrast imaging provides better visualization of anatomic details of the inner ear and of the structure of the intracochlear electrode array, and better definition of electrode location in relation to cochlear walls. CONCLUSION Phase-contrast radiography offers significant improvement over conventional radiography in images of in vitro human temporal bones. It seems to be a valuable tool in the development of intracochlear electrode arrays and cochlear implant research. However, this new radiographic technique still requires certain computational and physics challenges to be addressed before its clinical use can be established.
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195
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Gao D, Okuda R, Lopez-Avila V. Supercritical fluid extraction of halogenated monoterpenes from the red alga Plocamium cartilagineum. J AOAC Int 2001; 84:1313-31. [PMID: 11601448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Supercritical fluid extraction (SFE) of the marine red alga Plocamium cartilagineum, which is known to contain complex mixtures of halogenated monoterpenes, was investigated. P. cartilagineum samples were extracted by SFE with carbon dioxide and modified carbon dioxide containing up to 10% methanol at different pressure and temperature conditions to establish the optimum conditions for extraction. These conditions were then used in the extraction of halogenated monoterpenes from 2 different samples of P. cartilagineum: one from Davenport, CA, and the other from Casa Beach (San Diego, CA). Several halogenated monoterpenes isolated by conventional solvent extraction with methanol and purified by column chromatography were used as the reference compounds for the determination of the extraction efficiency in the SFE experients. Plocamium cartilagineum belongs to the red alga family--Plocamiaceae, and has been found to contain a large number of halogenated monoterpenes, whose structures typically contain 1-6 bromine and/or chlorine atoms. P. cartilagineum grows along the Pacific coast from Washington to Chile, the British Isles, Australia, and Spain. Interestingly, P. cartilagineum collected from different geographical areas in the world are all reported to produce halogenated monoterpenes, but of different structural types and halogen substitution patterns. Most of these halogenated monoterpenes have been found to exhibit varied biological activities, including antifungal, antimicrobial, and molluscicidal activity.
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196
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Seno T, Inoue N, Gao D, Okuda M, Sumi Y, Matsui K, Yamada S, Hirata KI, Kawashima S, Tawa R, Imajoh-Ohmi S, Sakurai H, Yokoyama M. Involvement of NADH/NADPH oxidase in human platelet ROS production. Thromb Res 2001; 103:399-409. [PMID: 11553372 DOI: 10.1016/s0049-3848(01)00341-3] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Platelets play an important role in atherosclerotic and thromboembolic vascular diseases. It has been reported that reactive oxygen species (ROS) could modify platelet function, and platelets themselves have the ability to produce ROS. However, the enzymatic sources of ROS in platelets have not been fully determined. The NADH/NADPH oxidase system was originally identified as the major source of ROS in phagocytes. Recently, it has become evident that this oxidase is functionally expressed not only in phagocytes but also in various cell types. The present study was undertaken to test the hypothesis that NADH/NADPH oxidase might be expressed in human platelets. Lucigenin-enhanced chemiluminescence (L-CL) and electron spin resonance (ESR) method demonstrated that human platelets obtained from healthy volunteers released ROS, and the released ROS were increased by stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA) or calcium ionophore. Homogenates of human platelets, as well as MEG01 cells, megakaryocytic cell line, had the enzymatic activity to produce superoxide in NADH/NADPH-dependent manners. This enzymatic activity was suppressed by diphenylene iodonium (DPI), an inhibitor of NADH/NADPH oxidase. Western blot analysis demonstrated that platelets and MEG01 cells expressed p22(phox) and p67(phox) proteins, components of NADH/NADPH oxidase. Thus, human platelets have the enzymatic activity of p22(phox)-based NADH/NADPH oxidase, and this oxidase is likely one of the important sources of ROS in platelets.
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Dai L, Ji C, Gao D, Wang J, Jiang T, Bi A, Sheng X, Mao Y. Modeling and analysis of the structure of the thermostable catechol 2,3-dioxygenase from Bacillus Stearothermophilus. J Biomol Struct Dyn 2001; 19:75-83. [PMID: 11565853 DOI: 10.1080/07391102.2001.10506721] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The three-dimensional structure of thermostable catechol 2,3-dioxygenase(TC230) from Bacillus Stearothermophilus has been modeled basing on the known x-ray structure of catechol 2,3-dioxygenase(metapyrocatechase) from Pseudomonas putida mt-2, using computer graphics energy minimization techniques. The rationality of the resulting model was validated by Ramachandran plot and Profile-3D. The structure-functionally important residues, such as M++ binding residues and the substrate binding residues, were identified from the model. These residues are candidates for further site-directed mutagenesis experiments. The reason that the thermostability of TC230 is greater than metapyrocatechase(MPC) has been found, which may be due to the specific structure of the TC230 in the C-end mainly.
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Ni Z, Gao D, Bouali-Benazzouz R, Benabid AL, Benazzouz A. Effect of microiontophoretic application of dopamine on subthalamic nucleus neuronal activity in normal rats and in rats with unilateral lesion of the nigrostriatal pathway. Eur J Neurosci 2001; 14:373-81. [PMID: 11553287 DOI: 10.1046/j.0953-816x.2001.01644.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The subthalamic nucleus (STN) receives dopamine inputs from the substantia nigra but their implication in the pathophysiology of parkinsonism is still debated. Extracellular microrecordings were used to study the effect of microiontophoretic injection of dopamine and the D1 receptor agonist SKF 38393 on the activity of STN neurons in normal and 6-hydroxydopamine-lesioned rats under urethane anaesthesia. Dopamine and SKF induced an increase in the firing rate of the majority of STN neurons in both normal and 6-OHDA rats. In rats with 6-OHDA lesions, the percentage of firing rate increase did not differ from that of controls. When GABA, glutamate and dopamine were all applied to the same individual STN neurons, GABA induced an inhibitory effect and glutamate and dopamine caused an excitatory effect in both groups. This excitatory response was suppressed by the application of GABA. Systemic administration of apomorphine provoked a decrease in the firing rate of STN neurons in rats with 6-OHDA lesions. These results show that dopamine exerts an excitatory influence on STN neurons, suggesting that the inhibitory effect induced by the systemic injection of apomorphine is due to the GABAergic inputs from the globus pallidus as predicted by the current model of basal ganglia organization. In addition, we show that dopamine, GABA and glutamate can act on the same STN neuron and that GABA can reverse the excitatory effect of dopamine and glutamate, suggesting the predominant influence of GABAergic inputs to the subthalamic nucleus.
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Wang L, Tang Z, Xue Q, Sun H, Chen J, Gao D, Zhao Y, Chen J, Sun R, Liu Y, Ye S. [Effects of interferon-alpha on recurrence and metastasis of hepatocellular carcinoma after curative resection in nude mice]. ZHONGHUA GAN ZANG BING ZA ZHI = ZHONGHUA GANZANGBING ZAZHI = CHINESE JOURNAL OF HEPATOLOGY 2001; 9:154-6. [PMID: 11412390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
OBJECTIVE To study the effect of interferon-alpha (IFN-alpha) on the recurrence and metastasis of hepatocellular carcinoma (HCC) in nude mice, and to clarify if there is synergistic effect treated by combination of IFN-alpha and all-trans retinoic acid (ATRA). METHODS The effect of IFN-alpha and/or ATRA on the proliferation of HCC cell lines was measured in vitro. The metastatic model of human HCC in nude mice LCI-D20 was used in present study. Curative resection was performed at 10th day after implantation in 44 nude mice. Drugs were given at the next day after resection. IFN-alpha was administered subcutaneously at doses of 3+/-10(5) U/day, 6+/-10(5) U/day, respectively. ATRA was administered p.o. at a dose of 20 mg/kg/day, and IFN-alpha 6+/-10(5)U/day combined with ATRA 20 mg/kg/day. The mice were sacrificed 35 days after treatment. The recurrent tumor size was measured and the presence of intrahepatic dissemination and lung metastases were recorded. RESULTS The effect of IFN-alpha and/or ATRA on the proliferation of HCC cells SMMC7721, BEL-7402, BEL-7405, and MHCC97 was not obvious. The combination of IFN-alpha and ATRA had no synergistic effect in vitro. The lung metastatic rate, the liver recurrent rate, the size of main recurrent lesions, the number of intrahepatic disseminating nodules and the largest disseminating nodule of the controlled group was 100%(12/12), 100%(12/12), (1346.3+/-4.2 ) mm(3), 8.2+/-4.4, 864 mm(3), respectively; whereas it was 0, 87.5%(7/8), (8.7+/-2.9) mm(3), 2.3+/-0.6, and 7.8mm(3), respectively in the IFN-alpha 3+/-10(5) U/day treated group(P<0.05); 0, 12.5%(1/8), 0.5mm(3), 2, 0.5 mm(3) in the IFN-alpha 6+/-10(5)U/day treated group(P<0.05); 0, 12.5%(1/8), 1 mm(3), 2.5+/-0.7, 8 mm(3) in the IFN-alpha 3+/-10(5) U/day and ATRA treated group(P<0.05); 87.5%, 100%, (1472.6+/-5.6) mm(3), 7.3+/-3.8, 768.5 mm(3) in the ATRA treated group (P>0.05). CONCLUSIONS IFN-alpha has an inhibitory effect on intrahepatic recurrence and lung metastasis of human HCC after curative resection in nude mice, and the effect is enhanced with increasing dose. IFN-alpha and ATRA have no synergistic effect according to in vivo and in vitro test. ATRA has no effect on recurrence and metastasis of HCC.
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Abstract
Biological metabolism in living cells dramatically diminishes at low temperatures, a fact that permits the long-term preservation of living cells and tissues for either scientific research or many medical and industrial applications (e.g., blood transfusion, bone marrow transplantation, artificial insemination, in vitro fertilization, food storage). However, there is an apparent contradiction between the concept of preservation and experimental findings that living cells can be damaged by the cryopreservation process itself. The challenge to cells during freezing is not their ability to endure storage at very low temperatures (less than -180 degrees C); rather, it is the lethality of an intermediate zone of temperature (-15 to -60 degrees C) that a cell must traverse twice--once during cooling and once during warming. Cryobiological research studies the underlying physical and biological factors affecting survival of cells at low temperatures (during the cooling and warming processes). These factors and mechanisms (or hypotheses) of cryoinjury and its prevention are reviewed and discussed, including the most famous two-factor hypothesis theory of Peter Mazur, concepts of cold shock, vitrification, cryoprotective agens (CPAs), lethal intracellular ice formation, osmotic injury during the addition/removal of CPAs and during the cooling/warming process, as well as modeling/methods in the cryobiological research.
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