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Wu T, Patel H, Mukai S, Melino C, Garg R, Ni X, Chang J, Peng C. Activin, inhibin, and follistatin in zebrafish ovary: expression and role in oocyte maturation. Biol Reprod 2000; 62:1585-92. [PMID: 10819759 DOI: 10.1095/biolreprod62.6.1585] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Activins, inhibins, and follistatins are important regulators of mammalian reproduction. However, their roles in lower vertebrates are poorly understood. In this study, we examined the expression of activin A, inhibin A, and follistatins in the zebrafish ovary and determined their role in final oocyte maturation. Using reverse transcription-polymerase chain reaction with primers specific for activin/inhibin beta(A) subunit and for follistatins, we detected DNA fragments of the expected size, which, upon sequencing, conformed to activin/inhibin beta(A) and follistatin. Western blot analysis using an antibody against activin/inhibin beta(A) subunit revealed two bands with sizes similar to those of activin A and inhibin A. The expression of follistatins was also confirmed by Western blot analysis. These results suggest that activin A, an inhibin A-like molecule, and follistatins are expressed in the zebrafish ovary. In cultured zebrafish follicles, activin A and inhibin A both induced final oocyte maturation in a dose-dependent manner. The effects of activin A and inhibin A were blocked by their binding protein, follistatin-288. Interestingly, follistatin-288 also inhibited final oocyte maturation induced by gonadotropin and by maturation-inducing hormone (MIH), suggesting that activin A and/or inhibin A may be local regulators mediating gonadotropin- and MIH-induced final oocyte maturation. Taken together, these findings suggest that activin A and inhibin A are paracrine regulators of ovarian functions in fish.
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Affiliation(s)
- T Wu
- Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3
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152
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Ni X, Guo J, Xia J, Li L. Prenatal determination of a variable number of tandem repeats in intron 40 of the von Willebrand factor gene from maternal peripheral blood using the polymerase chain reaction. Hum Hered 2000; 50:201-4. [PMID: 10686501 DOI: 10.1159/000022915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To determine a fetal variable number of tandem repeats (VNTR) without using fetal tissues, we amplified the whole VNTR region in intron 40 of the von Willebrand factor gene from maternal peripheral blood by the polymerase chain reaction and then separated the amplified fragments by a nonhydratable polyacrylamide gel with an electrolyte gradient. After water elution from the gel, each preliminary product was amplified for the second time and then digested by Alu I restriction endonuclease. Then the VNTR was examined using a hydratable polyacrylamide gel with an electrolyte gradient. We successfully identified the fetal VNTR from 6 cases of 10 maternal peripheral blood samples and 2 cases of 6 maternal blood samples after parturition. This study might offer a theoretical basis for the noninvasive diagnosis of genetic disorders and identification of disputed paternity with common primers.
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Affiliation(s)
- X Ni
- Department of Forensic Serology, Sun Yat-Sen University of Medical Sciences, Guangzhou, People's Republic of China
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153
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Abstract
Activin A has been shown to exert several regulatory functions on human placenta. In the present study, we tested the hypothesis that activin A is an autocrine regulator of trophoblast using a choriocarcinoma cell line, JEG-3, as a model. Messenger RNAs for activin beta(A) subunit, activin binding protein (follistatin), and various activin receptors, including ActR-IA, ActR-IB, ActR-IIA, and ActR-IIB, were detected in JEG-3 cells by reverse transcription-polymerase chain reaction. The expression of activin A in JEG-3 cells was further confirmed by Western blot analysis using an antibody against activin beta(A) subunit. Using Northern blot analysis, Smad-2 and Smad-4 mRNAs were also observed in JEG-3 cells. These data suggest that JEG-3 cells produce activin A and express activin binding proteins and receptors, as well as potential downstream signals. In cultured JEG-3 cells, basal progesterone production was stimulated by activin A but inhibited by follistatin-288. Similarly, in the presence of androstenedione, estradiol production was enhanced by activin A but decreased by follistatin-288. On the other hand, neither activin A nor follistatin affected JEG-3 cell growth. Taken together, these findings strongly suggest that activin A is an autocrine factor that is involved in the regulation of progesterone and estradiol production in JEG-3 cells.
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Affiliation(s)
- X Ni
- Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3. Department of Obstetrics and Gynecology, Gumma University, Maebashi, Japan
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154
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Yan Z, Zhu L, Ni K, Ni X, Qian W. [Partial sympathectomy for treating palmar hyperhidrosis with VATS]. Zhonghua Wai Ke Za Zhi 2000; 38:64-6. [PMID: 11831992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To review the experience with partial sympathectomy for treating palmar hyperhidrosis with VATS. METHODS Between July 1995 and June 1999, 50 patients with palmar hyperhidrosis (26 males and 24 females, mean age 26.7 years) were operated. The major symptom was excessive sweating of hands, feet, and axcillaries, sometimes in drops. Thoracoscopy was performed under general anesthesia with a standard single-lumen endotracheal intubation with the patient in a semi-sitting position and arms stretched at 90 degrees. The approach through two small ports on the chest wall was done using VATS. As the lung was depressed by CO(2) insufflation in a low pressure, an excellent view of the upper mediastinum was obtained. Ganglia T(2) through T(4), sometimes T(5) were resected with a electrocautery probe. Bilateral procedures were completed in the same position. RESULTS All patients after operation became dry immediately after sympathetic denervation with a few minor complications. Occasional side effect was moderate compensatory sweating of the trunk. One case had recurrence but sweating was much less than before operation. CONCLUSIONS Because of excellent view of the upper mediastinum for sympathetic denervation of the hand and axcillaryies, the effect of partial sympathectomy for palmar hyperhidrosis is satisfactory and permanent.
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Affiliation(s)
- Z Yan
- Department of Cardiothoracic Surgery, Zhejiang Provincial People's Hospital, Hangzhou 310014, China
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155
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Garg RR, Bally-Cuif L, Lee SE, Gong Z, Ni X, Hew CL, Peng C. Cloning of zebrafish activin type IIB receptor (ActRIIB) cDNA and mRNA expression of ActRIIB in embryos and adult tissues. Mol Cell Endocrinol 1999; 153:169-81. [PMID: 10459865 DOI: 10.1016/s0303-7207(99)00044-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A full-length cDNA encoding for activin type IIB receptor (ActRIIB) was cloned from zebrafish embryos. It encodes a protein with 509 amino acids consisting of a signal peptide, an extracellular ligand binding domain, a single transmembrane region, and an intracellular kinase domain with predicted serine/threonine specificity. The extracellular domain shows 74-91% sequence identity to human, bovine, mouse, rat, chicken, Xenopus and goldfish activin type IIB receptors, while the transmembrane region and the kinase domain show 67-78% and 82-88% identity to these known activin IIB receptors, respectively. In adult zebrafish, ActRIIB mRNA was detected by RT-PCR in the gonads, as well as in non-reproductive tissues, including the brain, heart and muscle. In situ hybridization on ovarian sections further localized ActRIIB mRNA to cytoplasm of oocytes at different stages of development. Using whole-mount in situ hybridization, ActRIIB mRNA was found to be expressed at all stages of embryogenesis examined, including the sphere, shield, tail bud, and 6-7 somite. These results provide the first evidence that ActRIIB mRNA is widely distributed in fish embryonic and adult tissues. Cloning of zebrafish ActRIIB demonstrates that this receptor is highly conserved during vertebrate evolution and provides a basis for further studies on the role of activin in reproduction and development in lower vertebrates.
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Affiliation(s)
- R R Garg
- Department of Biology, York University, Toronto, ON, Canada
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157
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Myers SI, Badellino M, Bartula L, Seelig AR, Milner R, Ni X, Tuma R. THE EFFECT OF INTESTINALISCHEMIA/REPERFUSION (II/R) ON LEUKOCYTE/ENDOTHELIAL INTERACTION. Shock 1999. [DOI: 10.1097/00024382-199906001-00051] [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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158
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Erbeldinger M, Ni X, Halling PJ. Kinetics of enzymatic solid-to-solid peptide synthesis: intersubstrate compound, substrate ratio, and mixing effects. Biotechnol Bioeng 1999; 63:316-21. [PMID: 10099611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
A systematic study of thermolysin-catalyzed solid-to-solid peptide synthesis using Z-Gln and Leu-NH2 as model substrates was carried out. The aim was to extend the kinetic knowledge of this new reaction system involving highly concentrated substrate mixtures with little water (10% to 20% w/w). Preheating of the substrates, and ultrasonic treatment, as described in the literature, had no significant effect on our system. The formation of a third compound, the salt of the two substrates, was discovered during melting point experiments. This was associated with a very strong dependence of kinetics on the exact substrate ratio (e.g., twofold higher initial rate with 60% Leu-NH2 and 40% Z-Gln than with the equimolar substrate ratio). A model was developed to show how the composition and pH of the liquid phase depends on the substrate ratio, and seemed to explain the experimental rates. In addition, the influences of different mixing and water distribution methods are described. Finally, we can now summarize the major effects of the reaction system as a starting point for further research and scale-up studies.
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Affiliation(s)
- M Erbeldinger
- Department of Bioscience and Biotechnology, University of Strathclyde, Glasgow, UK
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159
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Abstract
It has been well known that immune function is modulated by endogenous opioid peptides: beta-endorphin and enkephalins. However, the effect of dynorphin A on the immune function has not been well documented. In this study, we investigated dynorphin A in the regulation of mitogen-induced proliferation and and interleukin-2 (IL-2) production of rat splenocytes. The results showed that dynorphin A 1-13 as well as dynorphin A 1-17 enhanced concanavalin A-stimulated [(3)H] thymidine uptake 46-112% and IL-2 production in a dose-dependent fashion. These effects were reversed by naloxone and norBNI, a selective kappa-receptor antagonist. Dynorphin A reduced cyclic AMP contents in spenocytes in naloxone and norBNI reversible fashion. The data suggest that dynorphin A enhanced mitogen-stumulated lymphocyte proliferation and IL-2 production via kappa-opioid receptor and cAMP pathway.
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Affiliation(s)
- X Ni
- Department of Neurobiology, Second Military Medical University, Shanghai, 200433, P.R. China.
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Abstract
Methyl chloride transferase, a novel enzyme found in several fungi, marine algae, and halophytic plants, is a biological catalyst responsible for the production of atmospheric methyl chloride. A previous paper reports the purification of this methylase from Batis maritima and the isolation of a cDNA clone of the gene for this enzyme. In this paper, we describe the isolation of a genomic clone of the methylase gene and the expression of recombinant methyl chloride transferase in Escherichia coli and compare the kinetic behavior of the wild-type and recombinant enzyme. The recombinant enzyme is active and promotes the production of methyl chloride by E. coli under in vivo conditions. The kinetic data indicate that the recombinant and wild-type enzymes have similar halide (Cl-, Br-, and I-)-binding capacities. Both the recombinant and wild-type enzymes were found to function well in high NaCl concentrations. This high salt tolerance resembles the activity of halobacterial enzymes rather than halophytic plant enzymes. These findings support the hypothesis that this enzyme functions in the control and regulation of the internal concentration of chloride ions in halophytic plant cells.
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Affiliation(s)
- X Ni
- Department of Biochemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL, 61801, USA
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161
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Ni X, Zhang Y, Mustafa I. Correlation of polymer particle size with droplet size in suspension polymerisation of methylmethacrylate in a batch oscillatory-baffled reactor. Chem Eng Sci 1999. [DOI: 10.1016/s0009-2509(98)00279-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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162
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Weng Q, Ni X, Gopala A, Xu J, Heiden P. Use of low molecular weight oligomers as non-volatile reaction media. POLYMER 1998. [DOI: 10.1016/s0032-3861(98)00147-5] [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: 11/30/2022]
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163
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Abstract
Methyl chloride transferase catalyzes the synthesis of methyl chloride from S-adenosine-L-methionine and chloride ion. This enzyme has been purified 2,700-fold to homogeneity from Batis maritima, a halophytic plant that grows abundantly in salt marshes. The purification of the enzyme was accomplished by a combination of ammonium sulfate fractionation, column chromatography on Sephadex G100 and adenosine-agarose, and TSK-250 size-exclusion HPLC. The purified enzyme exhibits a single band on SDS/PAGE with a molecular mass of approximately 22.5 kDa. The molecular mass of the purified enzyme was 22,474 Da as determined by matrix-associated laser desorption ionization mass spectrometry. The methylase can function in either a monomeric or oligomeric form. A 32-aa sequence of an internal fragment of the methylase was determined (GLVPGCGGGYDVVAMANPER FMVGLDIXENAL, where X represents unknown residue) by Edman degradation, and a full-length cDNA of the enzyme was obtained by rapid amplification of cDNA ends-PCR amplification of cDNA oligonucleotides. The cDNA gene contains an ORF of 690 bp encoding an enzyme of 230 aa residues having a predicted molecular mass of 25,761 Da. The disparity between the observed and calculated molecular mass suggests that the methylase undergoes posttranslational cleavage, possibly during purification. Sequence homologies suggest that the B. maritima methylase defines a new family of plant methyl transferases. A possible function for this novel methylase in halophytic plants is discussed.
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Affiliation(s)
- X Ni
- Department of Biochemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL 61808, USA
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164
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Ni X, Zhang Y, Mustafa I. An investigation of droplet size and size distribution in methylmethacrylate suspensions in a batch oscillatory-baffled reactor. Chem Eng Sci 1998. [DOI: 10.1016/s0009-2509(98)00124-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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165
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Abstract
We have studied a thermolysin-catalyzed solid-to-solid dipeptide synthesis using equimolar amounts of Z-Gln-OH and H-Leu-NH2 as model substrates. The high substrate concentrations make this an effective alternative to enzymatic peptide synthesis in organic solvents. Water content was varied in the range of 0 to 600 mL water per mol substrate and enzyme concentration in the range of 0.5 to 10 g/mol of substrates. High yields around 80% conversion and initial rates from 5 to 20 mmol s-1 kg-1 were achieved. The initial rate increases 10-fold on reducing the water content, to reach a pronounced optimum at 40 mL water per mol substrate. Below this, the rate falls to much lower values in a system with no added water, and to zero in a rigorously dried system. This behavior is discussed in terms of two factors: At higher water contents the system is mass transfer limited (as shown by varying enzyme content), and the diffusion distances required vary. At low water levels, effects reflect the stimulation of the enzymatic activity by water.
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Affiliation(s)
- M Erbeldinger
- Department of Bioscience and Biotechnology, University of Strathclyde, Glasgow G1 1XW, United Kingdom
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166
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Ni X, Brogan G, Struthers A, Bennett D, Wilson S. A Systematic Study of the Effect of Geometrical Parameters on Mixing Time in Oscillatory Baffled Columns. Chem Eng Res Des 1998. [DOI: 10.1205/026387698525162] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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167
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Ni X, Chen L, Guo J. [Simultaneous detecting of C3 phenotypes and C3 cleavage by immunofixation]. Fa Yi Xue Za Zhi 1998; 13:16-7 inside back cover. [PMID: 9644153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The C3 phenotypes and C3 cleavage were simultaneously detected using cellulose acetate electrophoris followed by immunofixation and desitometry. Compared to crossed-immunoelectro-phoresis, this method has some advantages in resolution between different bands and was much more rapid, less expensive and more sensitive.
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Affiliation(s)
- X Ni
- Department of Forensic Serology, Sun Yat-sen University of Medical Sciences
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168
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Wu X, Li J, Cao J, Wu X, Ni X. [Influence of transjugular intrahepatic portosystemic stent shunts on portal and systemic hemodynamics of patients with portal hypertension]. Zhonghua Wai Ke Za Zhi 1998; 36:342-4. [PMID: 11825406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To determine the influence of transjugular intrahepatic portosystemic stent shunts (TIPSS) on portal and systemic hemodynamics of patients with portal hypertension. METHODS Fifteen patients who had undergone TIPSS with 10 mm stents were studied. The parameters of portal, systemic and pulmonary hemodynamics were measured with Doppler sonography, direct portal pressure measurement, blood-gas analysis and Swan-Ganz catheter before and 30 min and 2 weeks after TIPSS. RESULT Portal pressure decreased by 34% and 55.4%, and PO(2), SatO(2) increased by 67.7%, 21.3% and 68%, 20.4% respectively 30 min and 2 weeks after TIPSS. Portal blood velocity increased by 1.4 times 2 weeks after TIPSS. CO, CI, SI increased (P < 0.01) and SVR, PVR decreased (P < 0.01) after TIPSS. Also, RAP, PAP increased (P < 0.05). Renal blood flow increased (P < 0.01) and renal function significantly improved. CONCLUSION TIPSS can not only decrease portal pressure and improve renal function, but also worsen portal and systemic hemodynamics. Cardiac and liver function should be monitored before and after TIPSS.
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Affiliation(s)
- X Wu
- General Hospital of Nanjing Unit, Chinese People's Liberation Army, Nanjing 210002
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169
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Abstract
The methodology for deriving class II force fields has been applied to acetal, hemiacetal, and carbohydrate compounds. A set of eighteen model compounds containing one or more anomeric centers was selected for generating the quantum mechanical energy surface, from which the force field was derived and the functional form assessed. The quality of the fit was tested by comparing the energy surface predicted by the force field with ab initio results. Structural, energetic, and dynamic properties (vibrational frequencies) were analyzed. In addition, alpha and beta anomeric equilibrium structures and energies of 2-methoxytetrahydropyran, 2-deoxyribose, and glucose were computed at the HF/6-31G* and higher ab initio levels. These calculations provide test data from molecules outside the training set used to derive the force field. The quantum calculations were used to assess the ability of the class II force field and two quadratic diagonal (class I) force fields, CVFF, and Homans' extension of the AMBER force field, to account for the anomeric effects on the structural and energetic properties of carbohydrate systems. These class I force fields are unable to account for observed structural and energetic trends, exhibiting deviations as large as 5 kcal/mol in relative energies. The class II force field, on the other hand, is shown to reproduce anomeric structural as well as energetic differences. An energy component analysis of this force field shows that the anomeric differences are dominated by torsional energies, although coupling terms, especially angle/torsion, also make significant contributions (roughly 1 kcal/mol in glucose). In addition, the force field accurately accounts for both anomeric and exo-anomeric energy differences in 2-methoxytetrahydropyran, and anomeric energy differences in 2-deoxyribose and glucose.
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Affiliation(s)
- M J Hwang
- Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan, ROC
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170
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Liu Z, Chen Q, Ni X. [The morphometric study of endometrial spiral arterioles before and after insertion of gamma CuI and TCu 220C intrauterine devices]. Zhonghua Fu Chan Ke Za Zhi 1998; 33:232-4. [PMID: 10682472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
OBJECTIVE To investigate the morphologic changes of endometrial spiral arterioles and its relationship with bleeding pattern after insertion of gamma-shape copper indomethacin-medicated (gamma CuI) and T-shape copper (TCu 220C) intrauterine devices (IUD). METHODS Endometrium specimens of late secretory phase were obtained from fertile age women: 10 from preinsertion, 10 obtained after insertion of TCu 220C IUD, and 9 obtained after insertion of gamma CuI IUD. Samples were sectioned serially and morphometric analysis of endometrial spiral arterioles was performed under light microscope. RESULTS The average cross section area (Area), maximum diameter (Dmax) and minimum diameter (Dmin) of spiral arterioles in both spongeous and dense layers of endometrium increased significantly after insertion of TCu 220C IUD. After insertion of gamma CuI IUD, the Area and Dmax increased in dense layer only, though less obviously than that occurred in TCu 220C group. However, the Dmin increased more obviously in both spongeous and dense layers than after insertion of TCu 220C IUD, implying that the shape of spiral arterioles was more regular in gamma CuI group. CONCLUSION gamma CuI IUD has less effects on the morphological changes of endometrial spiral arterioles, and this may relate to its indomethacin-contained which causes less bleeding.
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Affiliation(s)
- Z Liu
- Sir Run Run Shaw Hospital, Zhejiang Medical University, Hangzhou
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172
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Abstract
Nitric oxide (NO) plays an important role in many cell-cell signaling systems, but its mechanism of action is variable. We have previously reported that NO reduces secretion of the peptide hormone, CRH, from cultured placental cells and the perfused placenta. Because placental CRH production seems linked to human parturition, we wished to explore the mechanism of action of NO in this setting in more detail. We report here that in the placenta, NO specifically inhibited CRH exocytosis, not synthesis, and that endogenous NO affects this process. Cytotrophoblasts were prepared from term human placentas and cultured as monolayers. CRH immunoreactivity in the cell supernatants and cell extracts were measured by RIA. CRH messenger RNA was determined by Northern blot analysis. Sodium nitroprusside (SNP; 1-100 mumol/L) and S-nitroso-N-acetyl-penicillamine (SNAP; 1-100 mumol/L), NO donors, significantly reduced basal CRH concentration in the media, while increasing the concentration of CRH in the cells (P < 0.01), suggesting that exocytosis of CRH was inhibited. These effects could be attenuated by the NO scavenger hemoglobin (20 micrograms/mL). KCl (45 mmol/L), which causes exocytosis by depolarizing the cell membrane, increased CRH release by 2- to 3-fold, and this was inhibited by SNP. Basal release of CRH was augmented by the NO synthase competitive inhibitor N omega-L-arginine methyl ester (1 mmol/L; P < 0.01) and the guanylate cyclase inhibitor, LY83583 (1 mumol/L; P < 0.01). The inhibitory effect of SNP was also blocked by LY83583. CRH messenger RNA content did not change when the placental cells were incubated with SNP, N omega-L-arginine methyl ester, and LY83583 for 6 and 24 h, and this was consistent with studies showing that total CRH immunoreactivity (cells plus media) did not change in the presence of SNP. These studies indicate that exogenous NO inhibits CRH exocytosis, rather than biosynthesis, by human trophoblasts and that endogenous NO has tonic inhibitory effects on CRH release by these cells. The inhibitory effect of NO on basal and stimulated CRH release by placental trophoblasts seems to be a guanylate cyclase-mediated inhibition of exocytosis.
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Affiliation(s)
- X Ni
- Department of Neurobiology, Second Military Medical University, Shanghai, P.R. China
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173
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Ni X, Westpheling J. Direct repeat sequences in the Streptomyces chitinase-63 promoter direct both glucose repression and chitin induction. Proc Natl Acad Sci U S A 1997; 94:13116-21. [PMID: 9371809 PMCID: PMC24272 DOI: 10.1073/pnas.94.24.13116] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The chi63 promoter directs glucose-sensitive, chitin-dependent transcription of a gene involved in the utilization of chitin as carbon source. Analysis of 5' and 3' deletions of the promoter region revealed that a 350-bp segment is sufficient for wild-type levels of expression and regulation. The analysis of single base changes throughout the promoter region, introduced by random and site-directed mutagenesis, identified several sequences to be important for activity and regulation. Single base changes at -10, -12, -32, -33, -35, and -37 upstream of the transcription start site resulted in loss of activity from the promoter, suggesting that bases in these positions are important for RNA polymerase interaction. The sequences centered around -10 (TATTCT) and -35 (TTGACC) in this promoter are, in fact, prototypical of eubacterial promoters. Overlapping the RNA polymerase binding site is a perfect 12-bp direct repeat sequence. Some base changes within this direct repeat resulted in constitutive expression, suggesting that this sequence is an operator for negative regulation. Other base changes resulted in loss of glucose repression while retaining the requirement for chitin induction, suggesting that this sequence is also involved in glucose repression. The fact that cis-acting mutations resulted in glucose resistance but not inducer independence rules out the possibility that glucose repression acts exclusively by inducer exclusion. The fact that mutations that affect glucose repression and chitin induction fall within the same direct repeat sequence module suggests that the direct repeat sequence facilitates both chitin induction and glucose repression.
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Affiliation(s)
- X Ni
- Genetics Department, University of Georgia, Athens 30602, USA
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174
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Ni X, Sun G, Ceolín M, Taylor M, Tröger W, Butz T. Point defects in neutron-irradiated MoO3 studied by 99Mo(β−)99Tc perturbed angular correlation. Chem Phys 1997. [DOI: 10.1016/s0301-0104(97)00212-7] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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175
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Ni X, Borghaei H, Borghaei RC, Thornton RD, Pease E, Laidlaw W, Mochan E. DGLA discoordinately suppresses IL-1 induced metalloproteinase mRNA levels in human synovial fibroblasts. Inflamm Res 1997; 46 Suppl 2:S124-6. [PMID: 9297543 DOI: 10.1007/s000110050137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- X Ni
- Department of Biochemistry/Molecular Biology, Philadelphia College of Osteopathic Medicine, PA 19131, USA
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Borghaei H, Borghaei RC, Ni X, Pease E, Thornton R, Mochan E. Evidence that suppression of IL-1 induced collagenase mRNA expression by dihomo-gamma-linolenic acid (DGLA) involves inhibition of NF kappa B binding. Inflamm Res 1997; 46 Suppl 2:S177-8. [PMID: 9297569 DOI: 10.1007/s000110050168] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- H Borghaei
- Department of Biochemistry/Molecular Biology, Philadelphia College of Osteopathic Medicine, PA 19131, USA
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178
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Ni X, Cai J, Hou L. [Effects of overdose fluoride on metabolism of extracellular matrix collagen and proteoglycan in condylar cartilage]. Zhonghua Kou Qiang Yi Xue Za Zhi 1997; 32:52-4. [PMID: 10677949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The study was conducted to evaluate the effects of chronic fluorosis on the metabolism of extracellular matrix in the development of rabbit condylar cartilage using the technique of pathology, biochemistry and radiographs. The results demonstrated that collagen content of condylar cartilage and the bone under condylar cartilage decreased (P < 0.01), and the proteoglycar contents increased significantly during the process of fluorosis (P < 0.01). The chondroprogenitor was obviously thin, and the cells of maturation zone increased in number. All the results indicated that overdose of fluoride retarded the growth of the condyle and ramus of the mandible.
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Affiliation(s)
- X Ni
- School of Stomatology, Norman Bethune University of Medical Sciences, Changchun
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179
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Ni X, Cheng Y, Cao L, Gardner DG, Humphreys MH. Mechanisms contributing to renal resistance to atrial natriuretic peptide in rats with common bile-duct ligation. J Am Soc Nephrol 1996; 7:2110-8. [PMID: 8915970 DOI: 10.1681/asn.v7102110] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Blunted volume expansion (VE) natriuresis and renal resistance to atrial natriuretic peptide (ANP) characterize states of pathological sodium retention. This study examined rats 1 to 3 wk after common bile-duct ligation (CBDL), at which time they had hyperbilirubinemia and hypoalbuminemia. Sham-operated normal rats (Sham) showed an increased sodium excretion rate (UNaV) from 1.0 +/- 0.1 to 16.3 +/- 3.9 muEq/min in response to acute VE (iv saline, 2 mL/100 g body wt over 5 min), whereas CBDL rats had a blunted response that was apparent after 1 wk and became maximal at 2 and 3 wk (0.3 +/- 0.1 to 3.2 +/- 0.4 muEq/min at 3 wk, P < 0.01 versus Sham response). The peak urinary cGMP excretion rate (UcGMPV) was also blunted (37.9 +/- 3.6 versus 87.5 +/- 8.3 pmol/min, P < 0.01) despite an even greater increase in plasma ANP concentration (Sham, 9.6 +/- 0.4 pg/mL in hydropenia to 22.8 +/- 2.6 pg/mL after VE; CBDL, 15.3 +/- 2.3 to 41.8 +/- 6.8 pg/mL). ANP-dependent cGMP accumulation by isolated inner medullary collecting duct (IMCD) cells from both Sham and CBDL rat kidneys was dose-dependent; however, at higher concentrations of ANP (> 10(-8) M), accumulation by cells from CBDL rats was significantly blunted, indicating resistance to ANP. Binding of 125I-ANP to IMCD cells was not different in CBDL rats compared with Sham control rats. Renal denervation improved but did not completely reverse the blunted natriuresis, and ANP resistance persisted in IMCD cells from denervated kidneys of CBDL rats. Incubation of IMCD cells with the phosphodiesterase inhibitors isomethylbutylxanthine or Zaprinast (each at 10(-3) M) restored ANP responsiveness in both innervated and denervated kidneys from CBDL rats, and intrarenal infusion of Zaprinast (10 micrograms/min) corrected the blunted increase in UNaV and UcGMPV after VE in rats with CBDL. These results suggest that ANP resistance in a model of abnormal sodium metabolism devoid of intrinsic renal disease may be related to increased activity of phosphodiesterase in renal target cells for ANP as well as to heightened renal nerve activity.
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Affiliation(s)
- X Ni
- Division of Nephrology, San Francisco General Hospital, CA, USA
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180
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Ni X, Guo J, Xia J, Li L. [Investigation on VNTR in intron 40 of vWF gene in Chinese Han population]. Yi Chuan Xue Bao 1996; 23:1-10. [PMID: 8695174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The VNTR in the intron 40 of vWF gene was investigated with a method of combination of Amp-FLP and RFLP. Two amplified fragments from a heterozygous person were separated by a non-hydratable polyacrylamide electrolyte gradient electrophoresis. After elution from gel, the preliminary products were amplified again, the amplified fragments were digested with AluI, then the genotype could be directly determined through electrophoresis. For the first time SSCP was used to detect the subtypes of microsatellite DNA. 136 alleles were found from 156 unrelated Hans in Changsha area. There were 153 genotypes in this sample and all of them were heterozygous. The calculated heterozygosity was 0.9884. The distribution of genotypes was in according with the Hardy-Weinberg equilibrium. The polymorphic information content (PIC) was 0.9883. The polymorphism of this VNTR was the highest one in the Amp-FLPs that had been found before. Our data did not show any recombination even in 2 generations of 66 families and 3 generations of 5 families. Aco-dominant segregation was demonstrated.
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Affiliation(s)
- X Ni
- Department of Forensic Serology, Sun Yat-sen University of Medical Sciences, Guangzhou
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181
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Ni X, Lin B, Wang C. [The effect of dynorphin A on intracellular cAMP and cGMP contents in spleen cells of burn rats and its relation to immune function]. Zhonghua Zheng Xing Shao Shang Wai Ke Za Zhi 1995; 11:258-61. [PMID: 8732002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The lymphocyte response to Con A and IL-2 synthesis was clearly suppressed in rats after thermal injury. In burn rats, the cAMP content in lymphocytes was significantly increased, but cGMP level was not changed. The serum of burn rat could inhibit Con A-induced lymphocyte proliferation and IL-2 production. The burn rat serum could also increase intracellular cAMP concentration. Dynorphin A enhanced lymphocyte proliferation and IL-2 synthesis, increased cAMP level in lymphocytes. Naloxone could inhibit the action of dynorphin A. Moreover, ynorphin A could partly reversed suppression effect of burn serum on lymphocyte proliferation and suppressed the increase of intracellular cAMP content induced by burn and rat serum. Our results suggested that dynorphin A augmented immune function of burn rats, and the action of dynorphin A was mediated by cAMP pathway.
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Affiliation(s)
- X Ni
- Department of Neurobiology, Second Military Medical University, Shanghai
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Abstract
The stability of nucleosomes in long chromatin fragments was observed by differential scanning calorimetry over a wide range of solution conditions. The thermal denaturation of chromatin was characterized in general as three major transitions, although the process clearly is more complex. The three major transitions were (1) denaturation of the nucleosome, (2) base unstacking of DNA in the resulting denatured nucleoprotein, and (3) base unstacking of naked DNA. In very low salt concentrations (e.g., 2 mM sodium cacodylate), these three processes were essentially coincident (near 76 degrees C), but in medium salt concentrations (e.g., 100 mM NaCl) the nucleosome denaturation occurred first at about 69 degrees C and then base unstacking occurred at 85 degrees C. As [NaCl] was increased, all three processes were resolved with the observation of increasing amounts of naked DNA being melted, until at 2000 mM NaCl the calorimetric profile showed mainly the melting of DNA. The transition temperature for nucleosome denaturation decreased from 76 to 63 degrees C as the salt concentration increased from 1 to 600 mM. Destabilization of the nucleosome by increasing [NaCl] was also evident above 100 mM as a decrease in enthalpic change attributable to nucleosome denaturation. Similarly, as [NaCl] was increased above 100 mM, less and less denatured nucleoprotein was evident as more and more of the DNA melted as naked DNA. The fatty acid salts, sodium valerate and sodium caproate, destabilized the nucleosome but not the denatured nucleoprotein that resulted from the collapse of the nucleosome. In the series acetate, butyrate, valerate, caproate, it was clear that destabilization of the nucleosome increased as hydrophobicity (chain length) increased.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- X Ni
- Department of Molecular and Cell Biology, University of California, Berkeley 94720
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185
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Xi W, Ni X, Lu T, Zhang J, Xu J, Huang M, Wu C. Early diagnosis of typhoid fever using monoclonal antibody. Chin Med Sci J 1993; 8:123-4. [PMID: 8292799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In our study, a reverse passive hemagglutination assay (RPHA) method was established using monoclonal antibody-IgM to detect the Salmonella typhi O9 antigen. This method has the advantages of sensitivity, specificity, rapidity, and simplicity, and helps make an early diagnosis of typhoid fever using only small amounts of blood.
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Affiliation(s)
- W Xi
- Wu Jin People's Hospital, Jiangsu
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186
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Wang X, Wu Y, Ni X, Xia B, Xu J, Du Q. [Research on sterilization of pathogens by high electrostatic voltage method]. Zhongguo Zhong Yao Za Zhi 1992; 17:604-6, 639. [PMID: 1294177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
An experimental research has been carried out on the sterilization of four kinds of pathogens by high electrostatic method along with an inquiry into the influence of voltage waveform and the treated time on sterilization. It is concluded that pathogens can be killed efficiently by corona discharge field.
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Affiliation(s)
- X Wang
- Institute of Electrostatics, Northeast Normal University, Changchun
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187
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Ni X, Bruch LW. Hartree and Jastrow approximations for monolayer solids of Ne, D2, H2, 4He, and 3He. Phys Rev B Condens Matter 1986; 33:4584-4595. [PMID: 9938921 DOI: 10.1103/physrevb.33.4584] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [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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188
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Cheng C, Ni X. [A preliminary analysis of the internal migration of Indonesia]. Renkou Yanjiu 1983:56-8. [PMID: 12339433] [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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189
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Liang CH, Chen SG, Yang KG, Jia PH, Ma YL, Li TH, Ni X, Wang XY, Deng QP, Yao SP. [Hemoglobin Beijing [alpha 16 (A14) Lys leads to Asn]: a new fast moving hemoglobin variant]. Zhongguo Yi Xue Ke Xue Yuan Xue Bao 1982; 4:197-201. [PMID: 6217905] [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: 01/19/2023]
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