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Lo CC, Cheng TC. Racial/ethnic differences in access to substance abuse treatment. J Health Care Poor Underserved 2011; 22:621-37. [PMID: 21551938 DOI: 10.1353/hpu.2011.0054] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A secondary dataset, Collaborative Psychiatric Epidemiology Surveys (CPES), 2001-2003, was employed to examine racial/ethnic differences in access to specialty and non-specialty substance abuse treatment (compared with no access to treatment). The study found that non-Hispanic White Americans were (1) likelier than members of all racial/ethnic minority groups (other than Hispanics) to address substance abuse by accessing care through specialty addiction-treatment facilities, and were (2) also less likely to access substance abuse care through non-specialty facilities. Because non-specialty facilities may have staffs whose professional training does not target treating chronic, bio-psycho-social illness such as substance abuse, our results imply that treatment facilities deemed non-specialty may need to enhance staff training, in order to ensure individuals are properly screened for substance use conditions and are referred for or provided with effective counseling and medications as appropriate.
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Chang CI, Lee CF, Wu CC, Cheng TC, Tsai JM, Lin KJ. A selective and differential medium for Vibrio alginolyticus. JOURNAL OF FISH DISEASES 2011; 34:227-234. [PMID: 21306589 DOI: 10.1111/j.1365-2761.2010.01230.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this paper, we present a selective and differential medium, termed Vibrio alginolyticus (VAL) agar, developed for the isolation and identification of V. alginolyticus. The presence of bile salts, high salinity and high incubation temperature allows the selective growth of moderately halophilic Vibrio species. Differentiation of bacteria is achieved by identifying species capable of sucrose fermentation, made visible by the pH indicator bromocresol purple. In this study, all of the 26 strains of V. alginolyticus and only three of the 99 strains representing 30 species (including 19 Vibrio species) other than V. alginolyticus were able to grow in the VAL medium. The remaining three strains could be further differentiated from V. alginolyticus according to colour or the diameter of colonies produced on VAL agar plates. Colonies isolated from shellfish rearing water and infected shrimp through the use of VAL agar plates were all positively identified as V. alginolyticus by conventional tests and 16S rDNA sequencing. The testing of specificity and differentiation capability of VAL shows the potential of the agar as a medium for the primary isolation of V. alginolyticus from pathological and environmental samples.
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Lin TC, Truong TK, Chen SH, Wang LJ, Cheng TC. Simplified 2-D cubic spline interpolation scheme using direct computation algorithm. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2010; 19:2913-2923. [PMID: 20494853 DOI: 10.1109/tip.2010.2050723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
It has been shown that the 2-D cubic spline interpolation (CSI) proposed by Truong et al. is one of the best algorithms for image resampling or compression. Such a CSI algorithm together with the image coding standard, e.g., JPEG, can be used to obtain a modified image codec while still maintaining a good quality of the reconstructed image for higher compression ratios. In this paper, a fast direct computation algorithm is developed to improve the computational efficiency of the original FFT-based 2-D CSI methods. In fact, this algorithm computes the 2-D CSI directly without explicitly calculating the complex division usually needed in the FFT or Winograd discrete Fourier transform (WDFT) algorithm. In addition, this paper describes a novel way to derivate the 2-D CSI from the 1-D CSI by using the row-column method. This new fast 2-D CSI provides a regular and simple structure based upon linear correlations. Therefore, it can be implemented by the use of a modification of Kung’s pipeline structure and is naturally suitable for VLSI implementations. Experimental results show that the proposed new fast 2-D CSI algorithm can achieve almost the same CSI performance with much fewer arithmetic operations in comparison with existing efficient algorithms.
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Cheng TC, Lo CC. Mental Health Service and Drug Treatment Utilization: Adolescents with Substance Use/Mental Disorders and Dual Diagnosis. JOURNAL OF CHILD & ADOLESCENT SUBSTANCE ABUSE 2010. [DOI: 10.1080/1067828x.2010.515887] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Lo CC, Cheng TC. Onset drinking: how it is related both to mother's drinking and mother-child relationships. Subst Use Misuse 2010; 45:888-900. [PMID: 20397874 DOI: 10.3109/10826080903550513] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Employing the National Longitudinal Survey of Youth (NLSY) as a sample of adolescents and their mothers, the present study connected the onset of adolescents' drinking to certain posited risk and protective factors characterizing their families. Via event history analysis and the discrete-time method, the data analysis involved more than 6,331 pair-interview-year units. The results show that both peer influences and mother's daily alcohol consumption enhance the risk that an adolescent aged between 10 and 14 years will begin drinking. At the same time, the quality of a mother's relationship with her child is an important posited protective factor delaying onset drinking.
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Chen PY, Cheng TC, Tsai JH, Shao YL. Space charge effects in field emission nanodevices. NANOTECHNOLOGY 2009; 20:405202. [PMID: 19738308 DOI: 10.1088/0957-4484/20/40/405202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Electron field emission from a single nanoemitter is a barrier tunneling, quantum mechanical process that can, therefore, be described by the well-known Fowler-Nordheim (FN) equation. At high emission current densities, however, the space charge caused by the cathode may affect the current density-voltage (J-V) characteristics predicted by the FN theory. In this study, we theoretically investigated the effect of space charge on FE nanodevices, including diode and triode structures. The J-V characteristics of FE nanodevices were obtained by analytically (diode structures) or numerically (triode structures) solving the coupled FN equation and Poisson's equation. We discuss the behavior of FE nanodiodes and nanotriodes displaying different geometries, dimensions and work functions of their emitter materials. In the high current density region, space charge plays an important role in FE nanodevices; the threshold current density of space-charge limitation is related to the electric field distributions. Besides, our theoretical results are in good agreement with the experimental results reported previously.
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Chuang FT, Chen PY, Cheng TC, Chien CH, Li BJ. Improved field emission properties of thiolated multi-wall carbon nanotubes on a flexible carbon cloth substrate. NANOTECHNOLOGY 2007; 18:395702. [PMID: 21730427 DOI: 10.1088/0957-4484/18/39/395702] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this paper we report the observation of enhanced field emission properties from thiolated multi-wall carbon nanotubes (MWCNTs) produced by a simple and effective two-step chemical surface modification technique. This technique implements carboxylation and thiolation on the MWCNTs synthesized by microwave plasma chemical vapor deposition (MPCVD) on the flexible carbon cloth substrate. The resulting thiolated MWCNTs were found to have a very low threshold field value of 1.25 V µm(-1) and a rather high field enhancement factor of 1.93 × 10(4), which are crucial for applications in versatile vacuum microelectronics.
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Lo CC, Cheng TC. The impact of childhood maltreatment on young adults' substance abuse. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2007; 33:139-46. [PMID: 17366254 DOI: 10.1080/00952990601091119] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Designed to establish a causal relationship between childhood victimization and young adults' substance abuse, this study also examined depression's role as mediator in that causal relationship. The study employs child-abuse measures that weigh both the type (sexual, physical) and the persistence of abuse. The study took as its substance-abuse measures the DSM-IV criteria for current alcohol abuse, current marijuana abuse, and current drug abuse. Data from the first 5 waves of the National Youth Survey (NYS) was employed, along with data from its 7th wave, to establish the temporal order needed to determine causal relationship. Childhood physical abuse proved a strong predictor of young adults' current substance abuse, although sexual abuse did not. Depression was shown to mediate the relationship of physical abuse to current alcohol abuse and current drug abuse, but not to current marijuana abuse.
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Cheng TC. Impact of work requirements on the psychological well-being of TANF recipients. HEALTH & SOCIAL WORK 2007; 32:41-8. [PMID: 17432740 DOI: 10.1093/hsw/32.1.41] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Psychological distress was investigated in a group of parents who were current and former recipients ofTemporary Assistance for Needy Families (TANF), and a group of parents never enrolled in TANF The study focused on two reported symptoms of distress: depressive and anxiety symptoms. Analysis incorporated cross-sectional data from the Survey of Income and Program Participation, 1996 panel. Results demonstrate that receiving or having received TANF benefits worsened parents' psychological distress. On the other hand, becoming employed reduced parents' psychological distress. Furthermore, participants' physical health state was significantly and negatively related to their psychological distress. Reliance on general assistance (before or after leaving TANF) was associated with psychological distress, although other social support variables (such as availability of child care, Medicaid, food stamps, and so forth) had no significant effect on psychological distress among current or former TANF recipients. Implications of the findings for policy and intervention are discussed.
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Mak CW, Cheng TC, Chuang SS, Wu RH, Chou CK, Chang JM. Malignant mesothelioma of the tunica vaginalis testis. Br J Radiol 2004; 77:780-1. [PMID: 15447967 DOI: 10.1259/bjr/25026914] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Malignant mesothelioma of the tunica vaginalis is rare, and is usually not diagnosed until surgery is undertaken. Reports on the ultrasound features of this tumour are limited. We present an unusual case with ultrasound features mimicking an adenomatoid tumour.
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Chen CH, Tzeng CC, Cheng TC, Chiu AW. Angiomyolipoma of kidney as a part of tuberous sclerosis complex. J Postgrad Med 2003; 49:278-9. [PMID: 14597797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
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Fan EW, Cheng TC, Chiu AW, Lin H. Pyonephrosis and urinary retention secondary to a large Gartner's duct cyst associated with single ectopic ureter in a pregnant woman. BJU Int 2002; 89:136-7. [PMID: 11849179 DOI: 10.1046/j.1464-4096.2001.00935.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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63
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Said JW, Hoyer KK, French SW, Rosenfelt L, Garcia-Lloret M, Koh PJ, Cheng TC, Sulur GG, Pinkus GS, Kuehl WM, Rawlings DJ, Wall R, Teitell MA. TCL1 oncogene expression in B cell subsets from lymphoid hyperplasia and distinct classes of B cell lymphoma. J Transl Med 2001; 81:555-64. [PMID: 11304575 DOI: 10.1038/labinvest.3780264] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Activation of the TCL1 oncogene has been implicated in T cell leukemias/lymphomas and recently was associated with AIDS diffuse large B cell lymphomas (AIDS-DLBCL). Also, in nonmalignant lymphoid tissues, antibody staining has shown that mantle zone B cells expressed abundant Tcl1 protein, whereas germinal center (GC; centrocytes and centroblasts) B cells showed markedly reduced expression. Here, we analyze isolated B cell subsets from hyperplastic tonsil to determine a more precise pattern of Tcl1 expression with development. We also examine multiple B cell lines and B lymphoma patient samples to determine whether different tumor classes retain or alter the developmental pattern of expression. We show that TCL1 expression is not affected by Epstein-Barr virus (EBV) infection and is high in naïve B cells, reduced in GC B cells, and absent in memory B cells and plasma cells. Human herpesvirus-8 infected primary effusion lymphomas (PEL) and multiple myelomas are uniformly TCL1 negative, whereas all other transformed B cell lines tested express moderate to abundant TCL1. This observation supports the hypothesis that PEL, like myeloma, usually arise from post-GC stages of B cell development. Tcl1 protein is also detected in most naïve/GC-derived B lymphoma patient samples (23 of 27 [85%] positive), whereas most post-GC-derived B lymphomas lack expression (10 of 41 [24%] positive). These data indicate that the pattern of Tcl1 expression is distinct between naïve/GC and post-GC-derived B lymphomas (P < 0.001) and that the developmental pattern of expression is largely retained. However, post-GC-derived AIDS-DLBCL express TCL1 at a frequency equivalent to naïve/GC-derived B lymphomas in immune-competent individuals (7 of 9 [78%] positive), suggesting that TCL1 down-regulation is adversely affected by severe immune system dysfunction. These findings demonstrate that TCL1 expression in B cell lymphoma usually reflects the stage of B cell development from which they derive, except in AIDS-related lymphomas.
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MESH Headings
- B-Lymphocyte Subsets/metabolism
- Cell Line, Transformed
- Cell Transformation, Viral
- DNA-Binding Proteins/metabolism
- Down-Regulation
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Neoplastic
- Herpesvirus 4, Human/pathogenicity
- Humans
- Hyperplasia/genetics
- Hyperplasia/metabolism
- Lymphoma, AIDS-Related/genetics
- Lymphoma, AIDS-Related/metabolism
- Lymphoma, B-Cell/classification
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/metabolism
- Lymphoma, Large B-Cell, Diffuse/metabolism
- Multiple Myeloma/genetics
- Multiple Myeloma/metabolism
- Palatine Tonsil/immunology
- Proto-Oncogene Proteins/biosynthesis
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-bcl-6
- RNA, Messenger/biosynthesis
- Transcription Factors/metabolism
- Tumor Cells, Cultured
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Cheng TC, La Peyre JF, Buchanan JT, Tiersch TR, Cooper RK. Cryopreservation of heart cells from the eastern oyster. In Vitro Cell Dev Biol Anim 2001; 37:237-44. [PMID: 11409690 DOI: 10.1007/bf02577536] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Conditions were developed to cryopreserve cells from pronase-dissociated atria and ventricles of eastern oysters (Crassostrea virginica). The effect of three concentrations (5, 10, 15%) of the cryoprotectants (dimethyl sulfoxide, glycerol, and propylene glycol), three thawing temperatures (25, 45, 75 degrees C), and three cooling rates (slow, medium, fast) were compared. Cells were frozen at -80 degrees C and plunged in liquid nitrogen. Thawed cells were seeded in 96-well plates and primary cultures were evaluated after 3 d by measuring the metabolic activity using a tetrazolium compound, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, and by comparing the relative spreading of cells between treatments. The best conditions for freezing and thawing of cells for each cryoprotectant were selected and a final study was performed to compare cryoprotectants. For this final study, we measured the number of cells and their viability 3 d after thawing, in addition to determining cell metabolic activity and cell spreading. Primary cultures of cells fozen without cryoprotectant and of nonfrozen cells were used as controls in all studies. Atrial cells were best cryopreserved with glycerol at a concentration of 10%, a medium cooling rate, and thawing at 45 degrees C. After thawing, atrial cells showed 53+/-5% of the metabolic activity, 84+/-5% of the number, and 92+/-2% of the viability of nonfrozen cells. For ventricular cells, 10% glycerol, a medium cooling rate, and thawing at 25 degrees C yielded the best results. The thawed ventricular cells showed 83+/-5% of the metabolic activity, 91+/-5% of the number, and 96+/-2% of the viability of nonfrozen cells.
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Chang WC, Hsieh YY, Cheng TC, Chang CC, Tsai HD, Lee MS. Effect of methylglyoxal on mouse embryogenesis. CHANG GUNG MEDICAL JOURNAL 2001; 24:251-7. [PMID: 11413883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
BACKGROUND Methylglyoxal (MG), a highly active and mutagenetic compound, has been found widely in a variety of foods and beverages. We investigated the effect of MG on mouse embryo development in-vitro. METHODS Two-cell mouse embryos were divided into six groups according to the MG concentration in the culture medium: Group 1 (control group). 0 mM; Group 2, 10(-4) mM; Group 3, 10(-3) mM; Group 4, 10(-2) mM; Group 5, 10(-1) mM; Group 6, 1 mM. Embryo development and cleavage were compared every day for 5 days. RESULTS The percentages of embryos reaching blastocyst/hatching stages were as follows: Group 1, 66.8%/34.2%; Group 2, 67.9%/38.7%; Group 3, 56.2%/31.5%; Group 4, 39.4%/14.1%; Group 5, 11.4%/10.2%; Group 6, 0%/0%. Higher MG concentrations (> or = 10(-2) mM) were associated with morphological aberrations and blocked development of embryos. CONCLUSION The cutoff value of MG concentration on the mouse embryo development in-vitro is 10(-2) mM. An increased risk of embryotoxicity occurs with MG concentrations > or = 10(-2) mM in vitro. There were no significant effects on the growth rate at MG concentrations of 10(-3) and 10(-4) mM.
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Hill CM, Li WS, Cheng TC, DeFrank JJ, Raushel FM. Stereochemical specificity of organophosphorus acid anhydrolase toward p-nitrophenyl analogs of soman and sarin. Bioorg Chem 2001; 29:27-35. [PMID: 11300693 DOI: 10.1006/bioo.2000.1189] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Organophosphorus acid anhydrolase (OPAA) catalyzes the hydrolysis of p-nitrophenyl analogs of the organophosphonate nerve agents, sarin and soman. The enzyme is stereoselective toward the chiral phosphorus center by displaying a preference for the R(P)-configuration of these analogs. OPAA also exhibits an additional preference for the stereochemical configuration at the chiral carbon center of the soman analog. The preferred configuration of the chiral carbon center is dependent upon the configuration at the phosphorus center. The enzyme displays a two- to four-fold preference for the R(P)-enantiomer of the sarin analog. The k(cat)/K(m) of the R(P)-enantiomer is 250 M(-1) s(-1), while that of the S(P)-enantiomer is 110 M(-1) s(-1). The order of preference for the stereoisomers of the soman analog is R(P)S(C) > R(P)R(C) > S(P)R(C) > S(P)S(C). The k(cat)/K(m) values are 36,300 M(-1)s(-1), 1250 M(-1) s(-1), 80 M(-1) s(-1) and 5 M(-1) s(-1), respectively. The R(P)S(C)-isomer of the soman analog is therefore preferred by a factor of 7000 over the S(P)S(C)-isomer.
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Petrikovics I, Cheng TC, Papahadjopoulos D, Hong K, Yin R, DeFrank JJ, Jaing J, Song ZH, McGuinn WD, Sylvester D, Pei L, Madec J, Tamulinas C, Jaszberenyi JC, Barcza T, Way JL. Long circulating liposomes encapsulating organophosphorus acid anhydrolase in diisopropylfluorophosphate antagonism. Toxicol Sci 2000; 57:16-21. [PMID: 10966507 DOI: 10.1093/toxsci/57.1.16] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
These studies are focused on antagonizing organophosphorous (OP) intoxications by a new conceptual approach using recombinant enzymes encapsulated within sterically stabilized liposomes to enhance diisopropylfluorophosphate (DFP) degradation. The OP hydrolyzing enzyme, organophosphorous acid anhydrolase (OPAA), encapsulated within the liposomes, was employed either alone or in combination with pralidoxime (2-PAM) and/or atropine. The recombinant OPAA enzyme, from the ALTEROMONAS: strain JD6, has high substrate specificity toward a wide range of OP compounds, e.g., DFP, soman, and sarin. The rate of DFP hydrolysis by liposomes containing OPAA (SL)* was measured by determining the changes in fluoride-ion concentration using a fluoride ion-selective electrode. This enzyme carrier system serves as a biodegradable protective environment for the OP-metabolizing enzyme (OPAA), resulting in an enhanced antidotal protection against the lethal effects of DFP. Free OPAA alone showed some antidotal protection; however, the protection with 2-PAM and/or atropine was greatly enhanced when combined with (SL)*.
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Hill CM, Wu F, Cheng TC, DeFrank JJ, Raushel FM. Substrate and stereochemical specificity of the organophosphorus acid anhydrolase from Alteromonas sp. JD6.5 toward p-nitrophenyl phosphotriesters. Bioorg Med Chem Lett 2000; 10:1285-8. [PMID: 10866401 DOI: 10.1016/s0960-894x(00)00213-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The enzyme OPAA hydrolyzes p-nitrophenyl phosphotriesters bearing substituents at the phosphorus center ranging in size from methyl to phenyl. The enzyme exhibits stereoselectivity toward the hydrolysis of chiral substrates with a preference for the Sp enantiomer.
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Petrikovics I, McGuinn WD, Sylvester D, Yuzapavik P, Jiang J, Way JL, Papahadjopoulos D, Hong K, Yin R, Cheng TC, DeFrank JJ. In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism. Drug Deliv 2000; 7:83-9. [PMID: 10892408 DOI: 10.1080/107175400266641] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.
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Cheng TC, Ramakrishnan V, Chan SI. Purification and characterization of a cobalt-activated carboxypeptidase from the hyperthermophilic archaeon Pyrococcus furiosus. Protein Sci 1999; 8:2474-86. [PMID: 10595552 PMCID: PMC2144183 DOI: 10.1110/ps.8.11.2474] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A novel metallocarboxypeptidase (PfuCP) has been purified to homogeneity from the hyperthermophilic archaeon, Pyrococcus furiosus, with its intended use in C-terminal ladder sequencing of proteins and peptides at elevated temperatures. PfuCP was purified in its inactive state by the addition of ethylenediaminetetraacetic acid (EDTA) and dithiothreitol (DTT) to purification buffers, and the activity was restored by the addition of divalent cobalt (K, = 24 +/- 4 microM at 80 degrees C). The serine protease inhibitor phenylmethylsulfonyl fluoride (PMSF) had no effect on the activity. The molecular mass of monomeric PfuCP is 59 kDa as determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 58 kDa by SDS-PAGE analysis. In solution, PfuCP exists as a homodimer of approximately 128 kDa as determined by gel filtration chromatography. The activity of PfuCP exhibits a temperature optimum exceeding 90 degrees C under ambient pressure, and a narrow pH optimum of 6.2-6.6. Addition of Co2+ to the apoPfuCP at room temperature does not alter its far-UV circular dichroism (CD) or its intrinsic fluorescence spectrum. Even when the CoPfuCP is heated to 80 degrees C, its far-UV CD shows a minimal change in the global conformation and the intrinsic fluorescence of aromatic residues shows only a partial quenching. Changes in the intrinsic fluorescence appear essentially reversible with temperature. Finally, the far-UV CD and intrinsic fluorescence data suggest that the overall structure of the holoenzyme is extremely thermostable. However, the activities of both the apo and holo enzyme exhibit a similar second-order decay over time, with 50% activity remaining after approximately 40 min at 80 degrees C. The N-blocked synthetic dipeptide, N-carbobenzoxy-Ala-Arg (ZAR), was used in the purification assay. The kinetic parameters at 80 degrees C with 0.4 mM CoCl2 were: Km, 0.9 +/- 0.1 mM; Vmax, 2,300 +/- 70 U mg(-1); and turn over number, 600 +/- 20 s(-1). Activity against other ZAX substrates (X = V, L, I, M, W, Y, F, N, A, S, H, K) revealed a broad specificity for neutral, aromatic, polar, and basic C-terminal residues. This broad specificity was confirmed by the C-terminal ladder sequencing of several synthetic and natural peptides, including porcine N-acetyl-renin substrate, for which we have observed (by MALDI-TOF MS) stepwise hydrolysis by PfuCP of up to seven residues from the C-terminus: Ac-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser.
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Huang CC, Cheng TC, Chang HH, Chang CC, Chen CI, Liu J, Lee MS. Birth after the injection of sperm and the cytoplasm of tripronucleate zygotes into metaphase II oocytes in patients with repeated implantation failure after assisted fertilization procedures. Fertil Steril 1999; 72:702-6. [PMID: 10521114 DOI: 10.1016/s0015-0282(99)00309-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To assess the technique of injecting a single sperm and cytoplasm obtained from tripronucleate zygotes into metaphase II oocytes for the treatment of patients with repeated implantation failure after intracytoplasmic sperm injection or IVF. DESIGN Clinical study. SETTING Private infertility clinic. PATIENT(S) Patients with repeated implantation failure after intracytoplasmic sperm injection or IVF. INTERVENTION(S) The metaphase II oocytes of recipients were injected with their husbands' spermatozoa and cytoplasm aspirated from the tripronucleate zygotes of donors. MAIN OUTCOME MEASURE(S) Fertilization after cytoplasm and sperm injection, embryo development, and successful pregnancy. RESULT(S) In total, 62 metaphase II oocytes from nine recipients were injected. Of the 62 injected oocytes, 3 (5%) degenerated and 43 (69%) had two pronuclei 18 hours after injection. Thirty-nine oocytes with two pronuclei cleaved to the two-cell to six-cell stage after another 24 hours of culture. All cleaved embryos were transferred into the uteruses of recipients. Four clinical pregnancies occurred in four recipients. No abnormal chromosomes were observed after amniocentesis and karyotyping in all pregnancies. Five healthy infants were born. CONCLUSION(S) Injection of the cytoplasm of tripronucleate zygotes may enhance the clinical pregnancy rate in patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.
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Cheng TC, DeFrank JJ, Rastogi VK. Alteromonas prolidase for organophosphorus G-agent decontamination. Chem Biol Interact 1999; 119-120:455-62. [PMID: 10421483 DOI: 10.1016/s0009-2797(99)00058-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enzymes catalyzing the hydrolysis of highly toxic organophosphorus compounds (OPs) are classified as organophosphorus acid anhydrolases (OPAA; EC 3.1.8.2). Recently, the genes encoding OPAA from two species of Alteromonas were cloned and sequenced. Sequence and biochemical analyses of the cloned genes and enzymes have established Alteromonas OPAAs to be prolidases (E.C. 3.4.13.9), a type of dipeptidase hydrolyzing dipeptides with a prolyl residue in the carboxyl-terminal position (X-Pro). Alteromonas prolidases hydrolyze a broad range of G-type chemical warfare (CW) nerve agents. Efforts to over-produce a prolidase from A. sp.JD6.5 with the goal of developing strategies for long-term storage and decontamination have been successfully achieved. Large-scale production of this G-agent degrading enzyme is now feasible with the availability of an over-producing recombinant cell line. Use of this enzyme for development of a safe and non-corrosive decontamination system is discussed.
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Cheng TC, Rastogi VK, DeFrank JJ, Sawiris GP. G-type nerve agent decontamination by Alteromonas prolidase. Ann N Y Acad Sci 1998; 864:253-8. [PMID: 9928098 DOI: 10.1111/j.1749-6632.1998.tb10316.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rastogi VK, DeFrank JJ, Cheng TC, Wild JR. Enzymatic hydrolysis of Russian-VX by organophosphorus hydrolase. Biochem Biophys Res Commun 1997; 241:294-6. [PMID: 9425265 DOI: 10.1006/bbrc.1997.7569] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Russian-VX (R-VX) is the principle V-type nerve agent in the chemical warfare (CW) arsenal of the Former Soviet Union. We here report the enzymatic hydrolysis of the P-S bond of Russian-VX by organophosphorus hydrolase (OPH) from Pseudomonas diminuta. While the Michaelis constant, K(m) for R-VX (474 microM), was similar to that for VX (434 microM), the Vmax for R-VX (2.1 mumoles/mg/min) was about four-fold higher compared to that for VX (0.56 mumoles/mg/min). A 50% inhibition in the rate of the enzymatic hydrolysis of R-VX was observed in the presence of 0.5% ethanol, isoamyl-alcohol, or isopropanol. The presence of acetonitrile, diethylene glycol, or methanol had marginal effects. These results comprise the first demonstration of enzymatic detoxification of R-VX.
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