2301
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Xu X, Okumura A, Morimoto A, Kumeda M, Shimizu T. Thermally induced metastable defects in hydrogenated amorphous silicon and silicon-carbon alloy films. Phys Rev B Condens Matter 1988; 38:8371-8376. [PMID: 9945594 DOI: 10.1103/physrevb.38.8371] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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2302
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Abstract
Because of the propensity of nascently formed metabolites towards sequential metabolism within formation organs, theoretical and experimental treatments that achieve mass conservation must recognize the various sources contributing to primary, secondary, and tertiary metabolite formation. A simple one-compartment open model, with first-order conditions and the liver as the only organ of drug disappearance and metabolite formation, was used to illustrate the metabolism of a drug to its primary, secondary, and tertiary metabolites, encompassing the cascading effects of sequential metabolism. The concentration-time profiles of the drug and metabolites were examined for two routes of drug administration, oral and intravenous. Formation of the primary metabolite from drug in the gut lumen, with or without further absorption, and metabolite formation arising from first-pass metabolism of the drug and the primary metabolite during oral absorption were considered. Mass balance equations, incorporating modifications of the various absorption and conversion rate constants, were integrated to provide the explicit solutions. Simulations, with and without consideration of the sources of metabolite formation other than from its immediate precursor, were used to illustrate the expected differences in circulating metabolite concentrations. However, a simple relationship between the area under the curve of any metabolite, M, or [AUC (m)], its clearance [CL(m)], and route of drug administration was found. The drug dose, route, fraction absorbed into the portal circulation, Fabs, fraction available of drug from the liver, F, availabilities of the metabolites F(m) from formation organs, and CL(m) are determinants of the AUC(m)'s. After iv drug dosing, the area of any intermediary metabolites is determined by the iv drug dose divided by the (CL(m)/F(m] of that metabolite. When a terminal metabolite is not metabolized, its area under the curve becomes the iv dose of drug divided by the clearance of the terminal metabolite since the available fraction for this metabolite is unity. Similarly, after oral drug administration, when loss of drug in the gut lumen does not contribute to the appearance of metabolites systematically, the general solution for AUC(m) is the product of Fabs and oral drug dose divided by [CL(m)/F(m)]. A comparison of the area ratios of any metabolite after po and iv drug dosing, therefore, furnishes Fabs. When this fraction is divided into the overall systemic availability or Fsys, the drug availability from the first-pass organs, F, may be found.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- M V St-Pierre
- Faculty of Pharmacy, University of Toronto, Ontario, Canada
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2303
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Wang YZ, Xu YZ, Luo D, Xu X. [Purification and characterization of depressor component of Agkistrodon acutus venom]. Zhongguo Yao Li Xue Bao 1988; 9:334-7. [PMID: 3195344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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2304
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Yin QZ, Ye MJ, Xu X, Liu HC, Liu J, Liu XM. [The use of avidin-biotin peroxidase complex-ELISA for the examination of HBsAg]. Hua Xi Yi Ke Da Xue Xue Bao 1988; 19:174-6. [PMID: 3198100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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2305
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Huang RH, Xu X. [Phosphorimetric method for the determination of dihydroetorphine and its application]. Yao Xue Xue Bao 1988; 23:298-303. [PMID: 3176985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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2306
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Anholt R, Xu X, Stoller C, Molitoris JD, Meyerhof WE, Rude BS, McDonald RJ. Intermediate-velocity atomic collisions: Electron capture and loss in 10-42-MeV C ions. Phys Rev A Gen Phys 1988; 37:1105-1114. [PMID: 9899771 DOI: 10.1103/physreva.37.1105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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2307
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Xu X, Chen S, Tsai W, Huang N. A case study of solving optimization problems using neural networks. Neural Netw 1988. [DOI: 10.1016/0893-6080(88)90190-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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2308
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Kung HF, Guo YZ, Billings J, Xu X, Mach RH, Blau M, Ackerhalt RE. Preparation and biodistribution of [125I]IBZM: a potential CNS D-2 dopamine receptor imaging agent. Int J Rad Appl Instrum B 1988; 15:195-201. [PMID: 2966782 DOI: 10.1016/0883-2897(88)90088-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A new CNS D-2 dopamine receptor imaging agent [125I]IBZM, (S)-3-[125I]-iodo-N-[(1-ethyl-2-pyrrolidinyl)] methyl-2-hydroxy-6-methoxybenzamide, was prepared by either an exchange reaction or by the chloramine-T method. After an i.v. injection, the agent easily passed through the blood-brain barrier and localized in the rat brain. At 2, 15, 30 and 60 min after the injection, the brain uptake was 2.9, 2.3, 1.8 and 0.7% dose/organ, respectively. Regional uptake ratio of striatum/cerebellum (target to nontarget ratio) increased from 1.4 at 30 s to 10.3 at 2 h after the i.v. injection. Digital autoradiography of rat brain sections showed high regional uptake in the caudate putamen and accumbens nucleus, areas known to have a high concentration of the D-2 dopamine receptor. The specific uptake at the D-2 dopamine receptor site was blocked by pretreatment with spiperone, a selective D-2 antagonist. When labeled with 123I (t1/2 = 13 h, 159 keV), [123I]IBZM may be useful for imaging the CNS D-2 dopamine receptor.
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Affiliation(s)
- H F Kung
- Department of Nuclear Medicine, SUNY, Buffalo
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2309
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2310
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Cannizzaro LA, Bollum FJ, Huebner K, Croce CM, Cheung LC, Xu X, Hecht BK, Hecht F, Chang LM. Chromosome sublocalization of a cDNA for human DNA polymerase-beta to 8p11----p12. Cytogenet Cell Genet 1988; 47:121-4. [PMID: 3378450 DOI: 10.1159/000132527] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We have localized a cDNA fragment that codes for human DNA polymerase-beta. Using somatic cell and in situ hybridization techniques, this cDNA was cloned by screening a human KM-3 cell cDNA library in lambda gt 11 for expression of fused beta-galactosidase-human DNA polymerase-beta proteins. We have mapped this human polymerase-beta gene to the short arm of chromosome 8 in the subregion 8p11----p12.
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Affiliation(s)
- L A Cannizzaro
- Genetics and Cancer Center, Southwest Biomedical Research Institute, Scottsdale, AZ 85251
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2311
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Xu X, Pang KS. High-performance liquid chromatographic method for the quantitation of salicylamide and its metabolites in biological fluids. J Chromatogr 1987; 420:313-27. [PMID: 3693503 DOI: 10.1016/0378-4347(87)80187-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A high-performance liquid chromatographic (HPLC) assay is described for the determination of salicylamide (SAM) and its metabolites in biological fluids obtained from an in situ rat liver preparation and rat in vivo. SAM and its six metabolites, salicylamide sulphate, salicylamide glucuronide, gentisamide (GAM), gentisamide 2-sulphate, gentisamide 5-sulphate and gentisamide 5-glucuronide, were separated on a mu Bondapak C18 column with 0.085 M potassium dihydrogenphosphate pH 3.35, as mobile phase and by using a flow gradient. Enriched recovery of SAM and GAM from blood was achieved by extraction followed by a second HPLC procedure with a mobile phase consisting of acetic acid and methanol. Furthermore, the reproducibility and the stability of the samples under assay conditions were investigated.
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Affiliation(s)
- X Xu
- Faculty of Pharmacy, University of Toronto, Ontario, Canada
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2312
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Anholt R, Meyerhof WE, Xu X, Gould H, Feinberg B, McDonald RJ, Wegner HE, Thieberger P. Atomic collisions with relativistic heavy ions. VIII. Charge-state studies of relativistic uranium ions. Phys Rev A Gen Phys 1987; 36:1586-1600. [PMID: 9899039 DOI: 10.1103/physreva.36.1586] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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2313
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Xu X, Guan Y, Tang Y, Wang S. Study of structure–activity relationship for some isomers of cinnamamides. Acta Crystallogr A 1987. [DOI: 10.1107/s0108767387084253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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2314
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Huang RH, Xu X. [Phosphorimetric analysis of amines]. Yao Xue Xue Bao 1987; 22:284-8. [PMID: 3687449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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2315
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Abstract
The messages for two small but abundant apolipoproteins found in lamprey blood plasma were cloned with the aid of oligonucleotide probes based on amino-terminal sequences. In both cases, numerous clones were identified in a lamprey liver cDNA library, consistent with the great abundance of these proteins in lamprey blood. One of the cDNAs (LAL1) has a coding region of 105 amino acids that corresponds to a 21-residue signal peptide, a putative 8-residue propeptide, and the 76-residue mature protein found in blood. The other cDNA (LAL2) codes for a total of 191 residues, the first 23 of which constitute a signal peptide. The two proteins, which occur in the "high-density lipoprotein fraction" of ultracentrifuged plasma, have amino acid compositions similar to those of apolipoproteins found in mammalian blood; computer analysis indicates that the sequences are largely helix-permissive. When the sequences were searched against an amino acid sequence data base, rat apolipoprotein IV was the best matching candidate in both cases. Although a reasonable alignment can be made with that sequence and LAL1, definitive assignment of the two lamprey proteins to typical mammalian classes cannot be made at this point.
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2316
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Spooner DW, Stoller C, Chemin J, Meyerhof WE, Scheurer J, Xu X. Large resonance effect in K-shell ionization probability in elastic proton backscattering on 138Ba. Phys Rev Lett 1987; 58:341-344. [PMID: 10034909 DOI: 10.1103/physrevlett.58.341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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2317
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Hotchkis MA, Reiff JE, Vieira DJ, Blönnigen F, Lang TF, Moltz DM, Xu X, Cerny J. Beta-delayed proton decay of 61Ge. Phys Rev C Nucl Phys 1987; 35:315-319. [PMID: 9953763 DOI: 10.1103/physrevc.35.315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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2318
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Xu X. [A tentative discussion on family planning problems in Xinjiang's minorities]. Renkou Yanjiu 1987:36-40. [PMID: 12341828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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2319
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Gu FL, Xu X, Wu JP. [The problem of tumor cell wound seeding in the open excision and partial cystectomy in bladder cancer]. Zhonghua Wai Ke Za Zhi 1986; 24:533-5, 573. [PMID: 3582039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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2320
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Xu X, L'helgoualc'h A, Morier-teissier E, Rips R. Determination of γ-Aminobutyric Acid in the Mouse Hypothalamus and Hippocampus Using Liquid Chromatography/Electrochemistry. ACTA ACUST UNITED AC 1986. [DOI: 10.1080/01483918608074146] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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2321
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Matsumoto H, Miyazaki T, Xu X, Watanabe H, Kawai N, Suzuki K. Distribution of Gm and Km allotypes among five populations in China. Am J Phys Anthropol 1986; 70:161-5. [PMID: 3740244 DOI: 10.1002/ajpa.1330700203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Serum samples from five populations in China [173 from Huhehote (Naimengu Zhizhiqu), 195 from the Beijing area, 131 from Hefei (Anhui Province), 155 from Hangzhou (Zhejiang Province), and 152 from Guangzhou (Guangdong Province)] were tested for G1m(1, 2, 3, and 17), G2m(23), G3m(5, 10, 11, 13, 14, 15, 16, 21, and 26), and Km(1). The Gm pattern of the Chinese populations are characterized by the presence of four haplotypes, Gm1, 17;..;21, 26, Gm1, 2, 17;..;21, 26, Gm1, 17;..;10, 11, 13, 15, 16, and Gm1, 3;23;5, 10, 11, 13, 14, 26, which are characteristic of Mongoloid populations. Agreement was obtained in all Chinese samples between the observed and expected frequencies on the basis of the Hardy-Weinberg equilibrium of phenotypes. Heterogeneity tests of the haplotypic distributions among the five populations showed no significant differences in the distributions of Gm phenotypes between Huhehote and Beijing nor between Hefei and Hangzhou, whereas highly significant differences were observed among the three districts: northern part (Huhehote and Beijing), central part (Hefei and Hangzhou), and southern part (Guangzhou). The data indicate a south to north genocline, ranging from Huhehote to Guangzhou in which Gm1, 17;..;21, 26 changes from 0.471 to 0.183, Gm1, 17;..;10, 11, 13, 15, 16 from 0.097 to 0.033, and Gm1, 3;23;5, 10, 11, 13, 14, 26 from 0.229 to 0.730. In contrast to the Gm system, no significant regional differences in the frequencies of the Km1 allele were observed among the five populations.
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2322
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Xu X, Zhu YH, Wang YZ, Ma Y, Lu ZX. Studies on the chemical modification of hemorrhagic toxin I from five pace snake (Agkistrodon acutus) venom. Toxicon 1985; 23:283-8. [PMID: 4024138 DOI: 10.1016/0041-0101(85)90151-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The chemical modification of hemorrhagic toxin I (AaHI) from Agkistrodon acutus has been studied. Inactivation was observed upon modification of 3 out of 7 histidine residues with diethyl pyrocarbonate. The His residues are deblocked, accompanied by a return of activity, upon treatment with neutral hydroxylamine. The circular dichroism and fluorescence spectra of diethyl pyrocarbonate inactivated toxin and the native toxin are the same, indicating that modification with diethyl pyrocarbonate does not cause any gross change in the structure of the protein. At least one His residue may thus play an essential role in the enzyme activity. Reaction of the toxin with N-bromosuccimide abolished the enzyme activity, with modification of Trp, Tyr and His residues. The loss of Trp did not parallel the inactivation. Hydrogen peroxide, dioxane and 2-hydroxy-5-nitrobenzyl-bromide treatment damaged the Trp residues, but did not affect the activity. Therefore, the modified tryptophan side chains are not essential for activity. Modification of 2.5-3.0 Tyr residues out of 9 with acetylimidazole did not affect the enzyme activity, nor did nitration of the toxin with tetranitromethane. The reactive tyrosines are apparently not essential.
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2323
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Yeh AG, Xu X. Provincial variation of urbanization and urban primacy in China. Ann Reg Sci 1984; 18:1-20. [PMID: 12279860 DOI: 10.1007/bf01286467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Provincial variations in urbanization and urban primacy in China are analyzed for 1978 using factor analysis and regression techniques. The authors suggest that government policies have not only led to a relatively low level of urbanization but are also responsible for many of the regional differences observed. It is concluded that "low urban primacy in the eastern provinces is mainly the result of the urbanization policy of controlling the development of large cities that favours the development of small and medium cities. The spatial industrial policy of decentralizing industries from the coastal provinces to interior provinces encouraged high urbanization and urban primacy in the western interior provinces of China."
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2324
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Yang SD, Xue Y, Tian XQ, Jin MC, Xu X, Yu YW. [Simultaneous determination of lidocaine, bupivacaine and tetracaine in human plasma by high performance liquid chromatography]. Yao Xue Xue Bao 1984; 19:611-5. [PMID: 6536168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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2325
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Huang RH, Xu X. [A simple phosphorimetric method for the determination of chlorpromazine]. Yao Xue Xue Bao 1984; 19:606-10. [PMID: 6536167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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2326
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Mittag TW, Xu X, Moshoyiannis H, Kornfeld P, Genkins G. Analysis of false negative results in the immunoassay for anti-acetylcholine receptor antibodies in myasthenia gravis. Clin Immunol Immunopathol 1984; 31:191-201. [PMID: 6713740 DOI: 10.1016/0090-1229(84)90239-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Possible causes for the failure of immunoassays to detect anti-acetylcholine receptor activity in serum from confirmed myasthenia gravis (MG) patients were investigated. A more sensitive assay, using Protein A to trap immune complexes (ARIA), was applied to 65 MG sera which were negative in the usual assay and to 42 normal human sera. Normal and negative MG sera had antibody (Ab) activity in the same range (50-70 pM). Titers present in 70% of normal sera appeared to be specific antireceptor antibodies as defined by tests for antigen specificity. Thus, higher sensitivity assays did not improve discrimination of MG from normals. In a second group of 108 MG sera studied, 48 were negative by the usual assay criteria in a rat acetylcholine receptor immunoassay. Further detailed analysis of this negative group showed that 3/48 had IgG3 antibody not detectable in the test, 14/48 had Ab's recognizing human receptor determinants exclusively, 29/48 had toxin blocking Ab's not determined by immunoassays, and 6/48 were negative in all tests. The results indicate that the exclusive occurrence of toxin-blocking antibodies in MG subjects is a major factor contributing to false negatives in the ARIA test. Estimates of the amount of Ab's with this functionality indicated that they are present in very much smaller amounts than other classes of anti-receptor Ab's. Degree of blocking activity in patient serum showed a fair correlation with severity of disease. Thus, blocking antibodies appear capable of causing all degrees of disease severity in the absence of other types of antireceptor Ab's. The development of a sensitive and quantitative in vitro assay for blocking antibodies combined with the usual immunoassay would be a major improvement for a MG diagnostic test, with greater than 94% positivity predicted.
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2327
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Xu X. Trends and changes of the urban system in China. Third World Plann Rev 1984; 6:47-59. [PMID: 12279783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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2328
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Zhang JJ, Chen ZX, He YZ, Xu X. Effect of calcium on proteolytic activity and conformation of hemorrhagic toxin I from five pace snake (Agkistrodon acutus) venom. Toxicon 1984; 22:931-5. [PMID: 6395446 DOI: 10.1016/0041-0101(84)90184-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
AaHI, a proteolytic hemorrhagic toxin from A. acutus venom, contains one g-atom Zn per mole protein and 2 g-atoms Ca per mole protein. AaHI is activated by calcium and slightly inhibited by zinc. When treated with EDTA, AaHI is completely inactivated. When dialyzed against 1,10-O-phenanthroline, 50-80% of the metal content and activities are lost, while 90% of the hemorrhagic and proteolytic activities are retained when dialyzed against 1,10-O-phenanthroline containing 5mM Ca2+. The results suggest that calcium is essential for the hemorrhagic and proteolytic activities. The circular dichroism spectra show that calcium may play an important role in maintaining a proper structure for AaHI. The function of zinc is not clear.
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2329
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Abstract
Trypsin-treated human metaphase chromosomes stained with Giemsa and uranyl acetate showed clear, reproducible band structures under the transmission electron microscope (TEM). The banding pattern observed with TEM corresponded very closely to the G-band pattern visualized by light microscopy. The TEM images were used for karyotype analyses. Trypsin-treated chromosomes stained with uranyl acetate alone also showed clear G-bands under TEM. Shadow casting in addition to uranyl acetate staining revealed more structural detail of the chromosomes. Chromosome fibers, 200 A-300 A in diameter, were observed in the interband regions. Most chromosomes showed the major G-bands under the higher TEM magnification without any trypsin treatment.
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2330
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Huang RH, Xu X. [A phosphorescence method for the determination of 4-amino-4-deoxy-N-10-methyl-P teroylglutamic acid (methotrexate) and folic acid]. Yao Xue Xue Bao 1982; 17:448-51. [PMID: 7148469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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2331
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Chen Z, Qian C, Qin M, Xu X, Xiao Y. Recent advances in anther culture of Hevea brasiliensis (Muell.-Arg.). Theor Appl Genet 1982; 62:103-108. [PMID: 24270556 DOI: 10.1007/bf00293340] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/1981] [Accepted: 11/15/1981] [Indexed: 06/02/2023]
Abstract
The yield of pollen embryoids from cultured Hevea anthers was increased 4 fold by optimizing the proportion of ammonium nitrate to potassium nitrate in the dedifferentiation medium. For optimal differentiation of pollen embryoids, kinetin, 2,4-D and α-naphtalene acetic acid are required. Anther culture for 50 days on the dedifferentiation medium is a prerequisite for the selective development of calli and embryoids from microspores.The determination of chromosome numbers in embryoids, plantlets and regenerated trees reveals that they originate from (poly)haploid pollen grains (n=2x=18). Aneuploid, triploid (3x=27) and tetraploid (4x=36) cells were encountered in increasing frequencies as the embryoids and plants developed. A few haploid cells with 9 chromosomes were consistently observed. Buds from shoots with mixoploid chromosome numbers can be grafted and the change in the chromosome constitution of the developing new shoots followed.
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Affiliation(s)
- Z Chen
- Institute of Genetics, Academia Sinica, Beijing, China
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2332
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Xu X, Wang XS, Xi XT, Liu J, Huang JT, Lu ZX. Purification and partial characterization of hyaluronidase from five pace snake (Agkistrodon acutus) venom. Toxicon 1982; 20:973-81. [PMID: 7164113 DOI: 10.1016/0041-0101(82)90099-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A hyaluronidase (EC 3.2.1. 35) was isolated and purified from Agkistrodon acutus venom. The purification procedure included CM-Sephadex C-50 chromatography, gel-filtration on Sephadex G-75 and CM-Sephadex C-25 chromatography. The purified preparation of the enzyme was homogeneous on polyacrylamide gel electrophoresis at pH 4.3, a 45-fold purification being obtained. The hyaluronidase was a glycoprotein (positive PAS staining) with a molecular weight of 33,000 and a pI of 10.3. No hemorrhagic activity was found. The hyaluronidase had an optimum pH of 3.5-5.0 and an optimum temperature of 37 degrees C. It was heat sensitive, was more stable in the acidic than in the neutral region, and lost its activity in the alkaline region. Fe2+, Cu2+ and heparin inhibited the venom hyaluronidase. The Km value for hyaluronic acid was 6.2 X 10(-3) mg/ml.
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2333
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